Enblend

This manual is for Enblend (version 4.1.4, 28 September 2015), a tool for compositing images in such a way that the seam between the images is invisible, or at least very difficult to see.

1 Overview

Enblend overlays multiple images using the BURT-ADELSON multiresolution spline algorithm.1 This technique tries to make the seams between the input images invisible. The basic idea is that image features should be blended across a transition zone proportional in size to the spatial frequency of the features. For example, objects like trees and windowpanes have rapid changes in color. By blending these features in a narrow zone, you will not be able to see the seam because the eye already expects to see color changes at the edge of these features. Clouds and sky are the opposite. These features have to be blended across a wide transition zone because any sudden change in color will be immediately noticeable.

Enblend expects each input file to have an alpha channel. The alpha channel should indicate the region of the file that has valid image data. Enblend compares the alpha regions in the input files to find the areas where images overlap. Alpha channels can be used to indicate to Enblend that certain portions of an input image should not contribute to the final image.

Enblend does not align images. Use a tool such as hugin or PanoTools to do this. The TIFF files produced by these programs are exactly what Enblend is designed to work with. Sometimes these GUIs allow you to select feathering for the edges of your images. This treatment is detrimental to Enblend. Turn off feathering by deselecting it or setting the feather width to zero.

Enblend blends the images in the order they are specified on the command line. You should order your images according to the way that they overlap, for example from left-to-right across the panorama. If you are making a multi-row panorama, we recommend blending each horizontal row individually, and then running Enblend a last time to blend all of the rows together vertically.

Enblend reads all layers of multi-layer images, like, for example, multi-directory TIFF images2. The input images are processed in the order they appear on the command line. Multi-layer images are processed from the first layer to the last before Enblend considers the next image on the command line.

Find out more about Enblend on its SourceForge web page.

2 Workflow

Enblend is a part of a chain of tools to assemble images. It combines a series of pictures taken at the same location but in different directions.

2.1 Standard Workflow

Figure 2.1 shows where Enblend and Enfuse sit in the tool chain of the standard workflow.

Take Images

Take multiple images to form a panorama, an exposure series, a focus stack, etc.

There is one exception with Enfuse when a single raw image is converted multiple times to get several – typically differently “exposed” – images.

Exemplary Benefits

• Many pictures taken from the same vantage point but showing different viewing directions. – Panorama
• Pictures of the same subject exposed with different shutter speeds. – Exposure series
• Images of the same subject focussed at differing distances. – Focus stack

Remaining Problem: The “overlayed” images may not fit together, that is the overlay regions may not match exactly.

Convert Images

Convert the raw data exploiting the full dynamic range of the camera and capitalize on a high-quality conversion.

Align Images

Align the images so as to make them match as well as possible.

Again there is one exception and this is when images naturally align. For example, a series of images taken from a rock solid tripod with a cable release without touching the camera, or images taken with a shift lens, can align without further user intervention.

This step submits the images to affine transformations. If necessary, it rectifies the lens’ distortions (e.g. barrel or pincushion), too. Sometimes even luminance or color differences between pairs of overlaying images are corrected (“photometric alignment”).

Benefit: The overlay areas of images match as closely as possible given the quality if the input images and the lens model used in the transformation.

Remaining Problem: The images may still not align perfectly, for example, because of parallax errors, or blur produced by camera shake.

Combine Images

Enblend and Enfuse combine the aligned images into one.

Benefit: The overlay areas become imperceptible for all but the most mal-aligned images.

Remaining Problem: Enblend and Enfuse write images with an alpha channel. (For more information on alpha channels see Understanding Masks.) Furthermore, the final image rarely is rectangular.

Postprocess

Postprocess the combined image with your favorite tool. Often the user will want to crop the image and simultaneously throw away the alpha channel.

View

Print

Enjoy

In the usual workflow Enblend and Enfuse generate the blending and fusing masks according to the command-line options and the input images and then they immediately use these masks for blending or fusing the output image.

Sometimes more control over the masks is needed or wanted. To this end, both applications provide the option pair --load-masks and --save-masks. See Invocation, for detailed explanations of both options. With the help of these options the processing can be broken up into two steps:

Generate masks and save them into image files.

Avoid option --output unless the blended or fused image at this point is necessary.

In between these two steps the user may apply whatever transformation to the mask files, as long as their geometries and offsets remain the same. Thus the “Combine Images” box of Figure 2.1 becomes three activities as is depicted in Figure 2.2.

To further optimize this kind of workflow, both Enblend and Enfuse stop after mask generation if option --save-masks is given, but no output file is specified with the --output option. This way the time for pyramid generation, blending, fusing, and writing the final image to disk is saved, as well as no output image gets generated.

3 Invocation

enblend [OPTIONS] [--output=IMAGE] INPUT...

Assemble the sequence of images INPUT… into a single IMAGE.

Input images are either specified literally or via so-called response files (see below). The latter are an alternative to specifying image filenames on the command line.

3.1 Image Requirements

All input images must comply with the following requirements.

• Parts of the images overlap.
• Each image has an alpha channel also called “mask”.
• The images agree on their number of channels:
• – one plus alpha or
• – three plus alpha.

This is, either all images are black-and-white (one channel and alpha channel) or all are RGB-color images (three channels and alpha channel).

• The images agree on their number of bits-per-channel, this is, their “depth”:
• UINT8,
• UINT16,
• FLOAT,
• – etc.

See option --depth below for an explanation of different (output) depths.

• Enblend understands the images’ filename extensions as well as their file formats.

You can check the supported extensions and formats by calling Enblend with the option pair --version --verbose and scan the output for ‘Supported image formats’ or ‘Supported file extensions’.

Moreover, there are some “good practices”, which are not enforced by the application, but almost certainly deliver superior results.

• Either all files lack an ICC profile, or all images are supplied with the same ICC profile.
• If the images’ meta-data contains resolution information (“DPI”), it is the same for all pictures.

3.2 Response Files

A response file contains names of images or other response filenames. Introduce response file names with an at-character (‘@’).

Enblend and Enfuse process the list INPUT strictly from left to right, expanding response files in depth-first order. (Multi-layer files are processed from first layer to the last.) The following examples only show Enblend, but Enfuse works exactly the same.

Solely image filenames.

Example:

enblend image-1.tif image-2.tif image-3.tif


The ultimate order in which the images are processed is: image-1.tif, image-2.tif, image-3.tif.

Single response file.

Example:

enblend @list


where file list contains

img1.exr
img2.exr
img3.exr
img4.exr


Ultimate order: img1.exr, img2.exr, img3.exr, img4.exr.

Mixed literal names and response files.

Example:

enblend @master.list image-09.png image-10.png


where file master.list comprises of

image-01.png
@first.list
image-04.png
@second.list
image-08.png


first.list is

image-02.png
image-03.png


and second.list contains

image-05.png
image-06.png
image-07.png


Ultimate order: image-01.png, image-02.png, image-03.png, image-04.png, image-05.png, image-06.png, image-07.png, image-08.png, image-09.png, image-10.png,

3.2.1 Response File Format

 response-file ::= line* line ::= (comment | file-spec) [‘\r’] ‘\n’ comment ::= space* ‘#’ text file-spec ::= space* ‘@’ filename space* space ::= ‘ ’ | ‘\t’

where text is an arbitrary string and filename is any filename.

Table 3.1: EBNF definition of the grammar of response files.

In a response file relative filenames are used relative the response file itself, not relative to the current-working directory of the application.

The above grammar might unpleasantly surprise the user in the some ways.

Whitespace trimmed at both line ends

For convenience, whitespace at the beginning and at the end of each line is ignored. However, this implies that response files cannot represent filenames that start or end with whitespace, as there is no quoting syntax. Filenames with embedded whitespace cause no problems, though.

Comments in response files always occupy a complete line. There are no “line-ending comments”. Thus, in

# exposure series
img-0.33ev.tif # "middle" EV
img-1.33ev.tif
img+0.67ev.tif


only the first line contains a comment, whereas the second line includes none. Rather, it refers to a file called ‘img-0.33ev.tif # "middle" EV.

An at-sign invariably introduces a response file, even if the filename’s extension hints towards an image.

If Enblend or Enfuse do not recognize a response file, they will skip the file and issue a warning. To force a file being recognized as a response file add one of the following syntactic comments to the first line of the file.

response-file: true
enblend-response-file: true
enfuse-response-file: true


Finally, here is an example of a valid response file.

# 4\pi panorama!

# These pictures were taken with the panorama head.
@round-shots.list

# Freehand sky shot.
zenith.tif

# "Legs, will you go away?" images.


Comments that follow the format described in Table 3.2 are treated as instructions how to interpret the rest of the response file. A syntactic comment is effective immediately and its effect persists to the end of the response file, unless another syntactic comment undoes it.

 syntactic-comment ::= space* ‘#’ space* key space* ‘:’ space* value key ::= (‘A’ .. ‘Z’ | ‘a’ .. ‘z’ | ‘-’)+

where value is an arbitrary string.

Table 3.2: EBNF definition of the grammar of syntactic comments in response files.

Unknown syntactic comments are silently ignored.

3.2.3 Globbing Algorithms

The three equivalent syntactic keys

control the algorithm that Enblend or Enfuse use to glob filenames in response files.

All versions of Enblend and Enfuse support at least two algorithms: literal, which is the default, and wildcard. See Table 3.3 for a list of all possible globbing algorithms. To find out about the algorithms in your version of Enblend or Enfuse team up the options --version and --verbose.

Example:

# Horizontal panorama
# 15 images

# filename-globbing: wildcard

image_000[0-9].tif
image_001[0-4].tif


3.2.4 Default Layer Selection

This syntactic comment affects the layer selection of all images listed after it including those in included response files until another layer-selector overrides it.

3.3 Common Options

Common options control some overall features of Enblend.

Enblend accepts arguments to any option in uppercase as well as in lowercase letters. For example, ‘deflate’, ‘Deflate’ and ‘DEFLATE’ as arguments to the --compression option described below, all instruct Enblend to use the DEFLATE compression scheme. This manual denotes all arguments in lowercase for consistency.

-a

Pre-assemble non-overlapping images before each blending iteration.

This overrides the default behavior which is to blend the images sequentially in the order given on the command line. Enblend will use fewer blending iterations, but it will do more work in each iteration.

--compression=COMPRESSION

Write a compressed output file.

Depending on the output file format, Enblend accepts different values for COMPRESSION.

JPEG format.

The compression either is a literal integer or a keyword-option combination.

LEVEL

Set JPEG quality LEVEL, where LEVEL is an integer that ranges from 0–100.

jpeg[:LEVEL]

Same as above; without the optional argument just switch on (standard) JPEG compression.

jpeg-arith[:LEVEL]

Switch on arithmetic JPEG compression. With optional argument set the arithmetic compression LEVEL, where LEVEL is an integer that ranges from 0–100.

TIF format.

Here, COMPRESSION is one of the keywords:

none

Do not compress. This is the default.

deflate

Use the DEFLATE compression scheme also called ZIP-in-TIFF. DEFLATE is a lossless data compression algorithm that uses a combination of the LZ77 algorithm and HUFFMAN coding.

jpeg[:LEVEL]

Use JPEG compression. With optional argument set the compression LEVEL, where LEVEL is an integer that ranges from 0–100.

lzw

Use LEMPEL-ZIV-WELCH (LZW) adaptive compression scheme. LZW compression is lossless.

packbits

Use PACKBITS compression scheme. PACKBITS is a particular variant of run-length compression; it is lossless.

Any other format.

Other formats do not accept a COMPRESSION setting.

However, VIGRA automatically compresses png-files with the DEFLATE method.

--layer-selector=ALGORITHM

Override the standard layer selector algorithm, which is ‘all-layers’.

This version of Enblend offers the following algorithms:

all-layers

Select all layers in all images.

first-layer

Select only first layer in each multi-layer image. For single-layer images this is the same as ‘all-layers’.

largest-layer

Select largest layer in each multi-layer image, where the “largeness”, this is the size is defined by the product of the layer width and its height. The channel width of the layer is ignored. For single-layer images this is the same as ‘all-layers’.

no-layer

Do not select any layer in any image.

This algorithm is useful to temporarily exclude some images in response files.

-h
--help

Print information on the available options and exit.

-l LEVELS
--levels=LEVELS

Use at most this many LEVELS for pyramid 3 blending if LEVELS is positive, or reduce the maximum number of levels used by -LEVELS if LEVELS is negative; ‘auto’ or ‘automatic’ restore the default, which is to use the maximum possible number of levels for each overlapping region.

The number of levels used in a pyramid controls the balance between local and global image features (contrast, saturation, …) in the blended region. Fewer levels emphasize local features and suppress global ones. The more levels a pyramid has, the more global features will be taken into account.

As a guideline, remember that each new level works on a linear scale twice as large as the previous one. So, the zeroth layer, the original image, obviously defines the image at single-pixel scale, the first level works at two-pixel scale, and generally, the n-th level contains image data at 2^n-pixel scale. This is the reason why an image of widthxheightpixels cannot be deconstructed into a pyramid of more than $⌊{log}_{2}\left(min\left(\mathit{width},\mathit{height}\right)\right)⌋$ levels.

If too few levels are used, “halos” around regions of strong local feature variation can show up. On the other hand, if too many levels are used, the image might contain too much global features. Usually, the latter is not a problem, but is highly desired. This is the reason, why the default is to use as many levels as is possible given the size of the overlap regions. Enblend may still use a smaller number of levels if the geometry of the overlap region demands.

Positive values of LEVELS limit the maximum number of pyramid levels. Depending on the size and geometry of the overlap regions this may or may not influence any pyramid. Negative values of LEVELS reduce the number of pyramid levels below the maximum no matter what the actual maximum is and thus always influence all pyramids. Use ‘auto’ or ‘automatic’ as LEVELS to restore the automatic calculation of the maximum number of levels.

The valid range of the absolute value of LEVELS is 1 to 29.

-o
--output=FILE

Place output in FILE.

If --output is not specified, the default is to put the resulting image in a.tif.

--parameter=KEY[=VALUE]:…

Set a KEY-VALUE pair, where VALUE is optional. This option is cumulative. Separate multiple pairs with the usual numeric delimiters.

Parameters allow the developers to change the internal workings of Enblend without the need to recompile.

-v
--verbose[=LEVEL]

Without an argument, increase the verbosity of progress reporting. Giving more --verbose options will make Enblend more verbose. Directly set a verbosity level with a non-negative integral LEVEL.

Each level includes all messages of the lower levels.

Level

Messages

0

only warnings and errors

1

2

3

reading of response files, color conversions

4

image sizes, bounding boxes and intersection sizes

5

detailed information on the optimizer runs (Enblend only)

6

estimations of required memory in selected processing steps

The default verbosity level of Enblend is 1.

-V
--version

Output information on the Enblend version.

Team this option with --verbose to show configuration details, like the extra features that have been compiled in.

-w
--wrap=MODE

Blend around the boundaries of the panorama.

As this option significantly increases memory usage and computation time only use it, if the panorama will be

Otherwise, always avoid this option!

MODE takes the following values:

none
open

This is a “no-op”; it has the same effect as not giving --wrap at all. The set of input images is considered open at its boundaries.

horizontal

Wrap around horizontally:

${S}_{P}\left(x,y\right)=\left\{P\left(x+mw,y\right):m\text{\hspace{0.28em}in\hspace{0.28em}}Z\right\}\text{.}$

This is useful for 360° horizontal panoramas as it eliminates the left and right borders.

vertical

Wrap around vertically:

${S}_{P}\left(x,y\right)=\left\{P\left(x,y+nh\right):n\text{\hspace{0.28em}in\hspace{0.28em}}Z\right\}\text{.}$ This is useful for 360° vertical panoramas as it eliminates the top and bottom borders.
both
horizontal+vertical
vertical+horizontal

Wrap around both horizontally and vertically:

${S}_{P}\left(x,y\right)=\left\{P\left(x+mw,y+nh\right):m,n\text{\hspace{0.28em}in\hspace{0.28em}}Z\right\}\text{.}$

In this mode, both left and right borders, as well as top and bottom borders, are eliminated.

Specifying --wrap without MODE selects horizontal wrapping.

-x

Checkpoint partial results to the output file after each blending step.

3.4 Extended Options

Extended options control the image cache, the color model, and the cropping of the output image.

-b BLOCKSIZE

Set the BLOCKSIZE in kilobytes (KB) of Enblend’s image cache.

Note that Enblend must have been compiled with the image-cache feature for this option to be effective. Find out about extra features with enblend --version --verbose.

--blend-colorspace=COLORSPACE

Force blending in selected COLORSPACE. For well matched images this option should not change the output image much. However, if Enblend must blend vastly different colors (as e.g. anti-colors) the result image heavily depends on the COLORSPACE.

Usually, Enblend chooses defaults depending on the input images:

Enblend supports two blend colorspaces:

IDENTITY’, ‘ID’, ‘UNIT

Naively compute blended colors in the luminance interval (grayscale images) or RGB-cube (RGB images) spanned by the input ICC profile or sRGB if no profiles are present. Consider option --fallback-profile to force a different profile than sRGB on all input images.

CIECAM’, ‘CIECAM02’, ‘JCH

Blend pixels in the CIECAM02 colorspace.

Please keep in mind that by using different blend colorspaces, blending may not only change the colors in the output image, but Enblend may choose different seam line routes as some seam-line optimizers are guided by image differences, which may be different when viewed in different colorspaces.

-c
--ciecam

Use ‘--blend-colorspace=CIECAM’ instead. To mimic the negated option --no-ciecam use ‘--blend-colorspace=IDENTITY’.

-d
--depth=DEPTH

Force the number of bits per channel and the numeric format of the output image.

Enblend always uses a smart way to change the channel depth to assure highest image quality (at the expense of memory), whether requantization is implicit because of the output format or explicit with option --depth.

• If the output-channel width is larger than the input-channel width of the input images, the input images’ channels are widened to the output channel width immediately after loading, that is, as soon as possible. Enblend then performs all blending operations at the output-channel width, thereby preserving minute color details which can appear in the blending areas.
• If the output-channel width is smaller than the input-channel width of the input images, the output image’s channels are narrowed only right before it is written to disk, that is, as late as possible. Thus the data benefits from the wider input channels for the longest time.

All DEPTH specifications are valid in lowercase as well as uppercase letters. For integer format, use

8, uint8

Unsigned 8bit; range: 0..255

int16

Signed 16bit; range: -32768..32767

16, uint16

Unsigned 16bit; range: 0..65535

int32

Signed 32bit; range: -2147483648..2147483647

32, uint32

Unsigned 32bit; range: 0..4294967295

For floating-point format, use

r32, real32, float

IEEE754 single precision floating-point, 32bit wide, 24bit significant

• Minimum normalized value: 1.2e-38
• Epsilon: 1.2e-7
• Maximum finite value: 3.4e38
r64, real64, double

IEEE754 double precision floating-point, 64bit wide, 53bit significant

• Minimum normalized value: 2.2e-308
• Epsilon: 2.2e-16
• Maximum finite value: 1.8e308

If the requested DEPTH is not supported by the output file format, Enblend warns and chooses the DEPTH that matches best.

The OpenEXR data format is treated as IEEE754 float internally. Externally, on disk, OpenEXR data is represented by “half” precision floating-point numbers.

OpenEXR half precision floating-point, 16bit wide, 10bit significant

• Minimum normalized value: 9.3e-10
• Epsilon: 2.0e-3
• Maximum finite value: 4.3e9
-f WIDTHxHEIGHT
-f WIDTHxHEIGHT+xXOFFSET+yYOFFSET

Ensure that the minimum “canvas” size of the output image is at least WIDTHxHEIGHT. Optionally specify the XOFFSET and YOFFSET, too.

Note that option -f neither rescales the output image, nor shrinks the canvas size below the minimum size occupied by the union of all input images.

--fallback-profile=PROFILE-FILENAME

This option only is effective if the input images come without color profiles and blending is performed in CIECAM02 color appearance model.

-g

Save alpha channel as “associated”. See the TIFF documentation for an explanation.

Gimp (before version 2.0) and CinePaint (see Helpful Programs) exhibit unusual behavior when loading images with unassociated alpha channels. Use option -g to work around this problem. With this flag Enblend will create the output image with the associated alpha tag set, even though the image is really unassociated alpha.

--gpu

Use the graphics card – in fact the graphics processing unit (GPU) – to accelerate some computations.

This is an experimental feature that may not work on all systems. In this version of Enblend, 4.1.4, only mask optimization by Simulated Annealing benefits from this option.

Note that GPU-support must have been compiled into Enblend for this option to be available. Find out about this feature with enblend --version --verbose.

-m CACHESIZE

Set the CACHESIZE in megabytes (MB) of Enblend’s image cache.

Note that Enblend must have been compiled with the image-cache feature for this option to be effective. Find out about extra features with enblend --version --verbose.

--no-ciecam

These options control the generation and the usage of masks.

--anneal=TAU[:DELTA-E-MAX[:DELTA-E-MIN[:K-MAX]]]
TAU

TAU is the temperature reduction factor in the Simulated Annealing; it also can be thought of as “cooling factor”. The closer TAU is to one, the more accurate the annealing run will be, and the longer it will take.

Append a percent sign (‘%’) to specify TAU as a percentage.

Valid range: 0 < TAU < 1.

The default is 0.75; values around 0.95 are reasonable. Usually, slower cooling results in more converged points.

DELTA-E-MAX
DELTA-E-MIN

DELTA-E-MAX and DELTA-E-MIN are the maximum and minimum cost change possible by any single annealing move.

Valid range: 0 < DELTA-E-MIN < DELTA-E-MAX.

In particular they determine the initial and final annealing temperatures according to:

$\begin{array}{c}{\mathit{T}}_{\mathrm{initial}}=\frac{\mathit{DELTA-E-MAX}}{log\left(\mathit{K-MAX}/\left(\mathit{K-MAX}-2\right)\right)}\\ {\mathit{T}}_{\mathrm{final}}=\frac{\mathit{DELTA-E-MIN}}{log\left({\mathit{K-MAX}}^{2}-\mathit{K-MAX}-1\right)}\end{array}$

The defaults are: DELTA-E-MAX: 7000.0 and DELTA-E-MIN: 5.0.

K-MAX

K-MAX is the maximum number of “moves” the optimizer will make for each line segment. Higher values more accurately sample the state space, at the expense of a higher computation cost.

Valid range: K-MAX ≥ 3.

The default is 32. Values around 100 seem reasonable.

--coarse-mask[=FACTOR]

Use a scaled-down version of the input images to create the seam line. This option reduces the number of computations necessary to compute the seam line and the amount of memory necessary to do so. It is the default.

If omitted FACTOR defaults to 8, this means, option --coarse-mask shrinks the overlapping areas by a factor of 8x8. With FACTOR = 8 the total memory allocated during a run of Enblend shrinks approximately by 80% and the maximum amount of memory in use at a time is decreased to 60% (Enblend compiled with image cache) or 40% (Enblend compiled without image cache).

Valid range: FACTOR = 1, 2, 3,….

--dijkstra=RADIUS

A small value prefers straight line segments and thus shorter seam lines. Larger values instruct the optimizer to let the seam line take more detours when searching for the best seam line.

Default: 25pixels.

--fine-mask

Instruct Enblend to employ the full-size images to create the seam line, which can be slow. Use this option, for example, if you have very narrow overlap regions.

--image-difference=ALGORITHM[:LUMINANCE-WEIGHT[:CHROMINANCE-WEIGHT]]

Enblend calculates the difference of a pair of overlapping color images when it generates the primary seam with a Graph-Cut or before it optimizes a seam. It employs a user-selectable ALGORITHM that itself is controlled by the weights for luminance differences LUMINANCE-WEIGHT, ${w}_{\text{luminance}}$ and color differences CHROMINANCE-WEIGHT, ${w}_{\text{chrominance}}\text{.}$

For black-and-white images the difference is simple the absolute difference of each pair of pixels.

maximum-hue-luminance
maximum-hue-lum
max-hue-luminance
max-hue-lum
max

Calculate the difference d as the maximum of the differences of the luminances l and hues h of each pair of pixels ${P}_{1}$ and ${P}_{2}\text{:}$

$d=max\left({w}_{\text{luminance}}×|l\left({P}_{1}\right)-l\left({P}_{2}\right)|,{w}_{\text{chrominance}}×|h\left({P}_{1}\right)-h\left({P}_{2}\right)|\right)$

This algorithm was the default for Enblend up to version 4.0.

delta-e
de

Calulate the difference d as the EUCLIDEAN distance of the pixels in L*a*b* space:

$d={\left({w}_{\text{luminance}}×{\left(L\left({P}_{1}\right)-L\left({P}_{2}\right)\right)}^{2}+{w}_{\text{chrominance}}×{\left(a\left({P}_{1}\right)-a\left({P}_{2}\right)\right)}^{2}+{w}_{\text{chrominance}}×{\left(b\left({P}_{1}\right)-b\left({P}_{2}\right)\right)}^{2}\right)}^{1/2}$

This is the default in Enblend version 4.1 and later.

Note that the “delta-E” mentioned here has nothing to do with DELTA-E-MAX and DELTA-E-MIN of option --anneal.

Both LUMINANCE-WEIGHT and CHROMINANCE-WEIGHT must be non-negative, their sum must be positive. Enblend automatically normalizes the sum of LUMINANCE-WEIGHT and CHROMINANCE-WEIGHT to one. Thus ‘--image-difference=delta-e:2:1’ and ‘--image-difference=delta-e:0.6667:0.3333’ define the same weighting function.

The default LUMINANCE-WEIGHT is 1.0 and the default CHROMINANCE-WEIGHT is 1.0.

At higher verbosity levels Enblend computes the true size of the overlap area in pixels and it calculates the average and standard deviation of the difference per pixel in the normalized luminance interval [0…1]. These statistical measures are based on ALGORITHM, therefore they should only be compared for identical ALGORITHMs. The average difference is a rough measure of quality with lower values meaning better matches.

--load-masks[=IMAGE-TEMPLATE]

--mask-vectorize=DISTANCE

Set the mask vectorization DISTANCE Enblend uses to partition each seam. Thus, break down the seam to segments of length DISTANCE each.

If Enblend uses a coarse mask (--coarse-mask) or Enblend optimizes (--optimize) a mask it vectorizes the initial seam line before performing further operations. See Table 3.4 for the precise conditions. DISTANCE tells Enblend how long to make each of the line segments called vectors here.

The unit of DISTANCE is pixels unless it is a percentage as explained in the next paragraph. In fine masks one mask pixel corresponds to one pixel in the input image, whereas in coarse masks one pixel represents for example 8pixels in the input image.

Append a percentage sign (‘%’) to DISTANCE to specify the segment length as a fraction of the diagonal of the rectangle including the overlap region. Relative measures do not depend on coarse or fine masks, they are recomputed for each mask. Values around 5%–10% are a good starting point.

This option massively influences the mask generation process! Large DISTANCE values lead to shorter, straighter, less wiggly, less baroque seams that are on the other hand less optimal, because they run through regions of larger image mismatch instead of avoiding them. Small DISTANCE values give the optimizers more possibilities to run the seam around high mismatch areas.

What should never happen though, are loops in the seam line. Counter loops with higher weights of DISTANCE-WEIGHT (in option --optimizer-weights), larger vectorization DISTANCEs, TAUs (in option --anneal) that are closer to one, and blurring of the difference image with option --smooth-difference. Use option --visualize to check the results.

Valid range: DISTANCE ≥ 4.

Enblend limits DISTANCE so that it never gets below 4 even if it has been given as a percentage. The user will be warned in such cases.

--no-optimize

Also see Table 3.4.

--optimize

Use a multi-strategy approach to route the seam line around mismatches in the overlap region. This is the default. Table 3.5 explains these strategies; also see Table 3.4.

Simulated Annealing

Tune with option --anneal = TAU : DELTA-E-MAX : DELTA-E-MIN : K-MAX.

DIJKSTRA Shortest Path

Tune with option --dijkstra = RADIUS.

DIJKSTRA algorithm

Table 3.5: Enblend’s strategies to optimize the seam lines between images.

--optimizer-weights=DISTANCE-WEIGHT[:MISMATCH-WEIGHT]

Set the weights of the seam-line optimizer. If omitted, MISMATCH-WEIGHT defaults to 1.

The seam-line optimizer considers two qualities of the seam line:

• The distance of the seam line from its initial position, which has been determined by NFT (see option --no-optimize).
• The total “mismatch” accumulated along it.

The optimizer weights DISTANCE-WEIGHT and MISMATCH-WEIGHT define how to weight these two criteria. Enblend up to version 3.2 used 1:1. This version of Enblend (4.1.4) uses 8.0:1.0.

A large DISTANCE-WEIGHT pulls the optimized seam line closer to the initial postion. A large MISMATCH-WEIGHT makes the seam line go on detours to find a path along which the mismatch between the images is small. If the optimized seam line shows cusps or loops (see option --visualize), reduce MISMATCH-WEIGHT or increase DISTANCE-WEIGHT.

Both weights must be non-negative. They cannot be both zero at the same time. Otherwise, their absolute values are not important as Enblend normalizes their sum.

--primary-seam-generator=ALGORITHM

Select the algorithm responsible for generating the general seam route.

This is the ALGORITHM that produces an initial seam line, which is the basis for later, optional optimizations (see --optimize). Nearest Feature Transform (NFT) is the only algorithm up to and including Enblend version 4.0. Version 4.1 adds a Graph-Cut (GC) algorithm. In this version of Enblend NFT is the default.

Valid ALGORITHM names are:

nearest-feature-transform
nft

Nearest Feature Transform

graph-cut
gc

Graph-Cut

See Primary Seam Generators for details.

--save-masks
--save-masks=IMAGE-TEMPLATE

Save the generated masks to IMAGE-TEMPLATE. The default is mask-%n.tif. Enblend saves masks as 8bit grayscale (single channel) images. For accuracy we recommend to choose a lossless format.

Use this option if you wish to edit the location of the seam line by hand. This will give you images of the right sizes that you can edit to make your changes. Later, use option --load-masks to blend the project with your custom seam lines.

Enblend will stop after saving all masks unless option --output is given, too. With both options given, this is, --save-masks and --output, Enblend saves all masks and then proceeds to blend the output image.

A fancy mask filename template could look like this:

%D/mask-%02n-%f.tif


It puts the mask files into the same directory as the output file (‘%D’), generates a two-digit index (‘%02n’) to keep the mask files nicely sorted, and decorates the mask filename with the name of the associated input file (‘%f’) for easy recognition.

--smooth-difference=RADIUS

This option has been deprecated.

Smooth the difference image prior to seam-line optimization to get a shorter and – on the length scale of RADIUS – also a straighter seam-line. The default is not to smooth.

If RADIUS is larger than zero Enblend blurs the difference images of the overlap regions with a GAUSSIAN filter having a radius of RADIUSpixels. Values of 0.5 to 1.5pixels for RADIUS are good starting points; use option --visualize to directly judge the effect.

When using this option in conjunction with option --coarse-mask=FACTOR, keep in mind that the smoothing occurs after the overlap regions have been shrunken. Thus, blurring affects a FACTORxFACTOR times larger area in the original images.

--visualize[=VISUALIZE-TEMPLATE]

Create an image according to VISUALIZE-TEMPLATE that visualizes the unoptimized mask and the applied optimizations (if any). The default is vis-%n.tif.

VISUALIZE-TEMPLATE defines a template that is expanded for each input file. In a template, a percent sign (‘%’) introduces a variable part; all other characters are copied literally. Lowercase letters refer to the name of the respective input file, whereas uppercase ones refer to the name of the output file (see Common Options). Table 3.7 lists all variables.

Visualization Image. The visualization image shows the symmetric difference of the pixels in the rectangular region where two images overlap. The larger the difference the lighter shade of gray it appears in the visualization image. Enblend paints the non-overlapping parts of the image pair – these are the regions where no blending occurs – in dark red. Table 3.6 shows the meanings of all the colors that are used in seam-line visualization images.

Figure 3.1 shows an example of a seam-line visualization. It was produced with an Enblend run at all defaults, but --fine-mask and --visualize enabled.

The large dark red border is “off-limits” for Enblend, for the images do not overlap there. The dark wedge inside the dark red frame is where the images share a common region.

The initial seam-line (dark yellow) is almost straight with the exception of a single bend on the left side of the image and the final seam-line (bright yellow) meanders around it.

4 Primary Seam Generators

This version (4.1.4) of Enblend supports two main algorithms to generate seam lines. Use option --primary-seam-generator to select one of the generators.

Nearest Feature Transform (NFT)

The NFT, also known as Distance Transform, is a fast and efficient technique to produce a seam line route given the geometries of multiple overlapping images.

NFT as implemented in this version of Enblend only takes into account the shape of the overlap area. It completely ignore the images’ contents.

Graph-Cut (GC)

GC is a region-oriented way of segmenting images.

The generator is based on the idea of finding a minimum cost “cut” of a graph created from a given image pair. A “cut” is where the seam line appears. GC determines the cost from the overlapping images’ contents.

The most significant difference between the two algorithms is the output mask gradation. NFT produces a coarse approximation of the seam, running as far away from the overlap-region borders as possible. The resulting mask could then be blended as-is, however, Enblend by default runs image-content dependent optimizers to increase the mask gradation and for example omits the regions where the images differ. The result is a finer seam line, which only loosely follows the shape of NFT’s primary seam.

Graph-Cut, on the other hand, is capable of producing the final mask in one pass without the need of further optimizers. It looks for a seam line that is globally optimal, taking into account

• feature frequency, as well as
• image dissimilarity.

This means, the seam is less likely to cross lines like for example fences, lampposts, or road markings, where they would be visible.

The optimizers which run after NFT can also be run after GC. Nevertheless, GC works best just with a fine mask (option --fine-mask); optimizers are then automatically turned off to take full advantage of the detailed seam GC produces.

GC requires more memory and computation time to complete than NFT. Thus, it is best to prefer NFT where the images used are large and execution time is crucial. If quality is the priority, using GC and fine mask usually produces visually more pleasing results.

GC is currently limited to seams that begin and end on the images’ borders. This means that the algorithm cannot run in cases where, for example, one image is contained in another, resulting in a loop-like seam. In such cases, though, Enblend automatically falls back to a NFT-generated seam, making its application transparent to the user.

5 Color Profiles

Enblend and Enfuse expect that either

1. no input image has a color profile or
2. all come with the same ICC profile.

In case 1 the applications blend or fuse in the RGB-cube, whereas in case 2 the images first are transformed to CIECAM02 color space – respecting the input color profile – then they are blended or fused, and finally the data transformed back to RGB color space. Moreover, in case 2, Enblend and Enfuse assign the input color profile to the output image.

Mixing different ICC profiles or alternating between images with profiles and without them generates warnings as it generally leads to unpredictable results.

The options --ciecam (see Extended Options) and its opposite --no-ciecam (see Extended Options) overrule the default profile selection procedure described above. Use option --ciecam on a set of input images without color profiles to assign a profile to them and perform the blending or fusing process in CIECAM02 color space.

The default profile is sRGB. Override this setting with option --fallback-profile (see Extended Options).

On the other hand, suppress the utilization of CIECAM02 blending or fusing of a set of input images with color profiles with option --no-ciecam. The only reason for the latter is to shorten the blending- or fusing-time, because transforming to and back from the CIECAM02 color space are computationally expensive operations.

Option --ciecam as well as --fallback-profile have no effect on images with attached color profiles, just as option --no-ciecam has no effect on images without profiles.

The impact of blending in CIECAM02 color space as opposed to the RGB cube vary with the contents of the input images. Generally colors lying close together in RGB space experience less change when switching the blending spaces. However, colors close the border of any color space can see marked changes.

For color geeks: The transformations to CIECAM02 color space and back use

A binary mask indicates for every pixel of an image if this pixel must be considered in further processing, or ignored. For a weight mask, the value of the mask determines how much the pixel contributes, zero again meaning “no contribution”.

Masks arise in two places: as part of the input files and as separate files, showing the actual pixel weights prior to image blendung or fusion. We shall explore both occurrences in the next sections.

Each of the input files for Enfuse and Enblend can contain its own mask. Both applications interpret them as binary masks no matter how many bits per image pixel they contain.

Use ImageMagick’s identify or, for TIFF files, tiffinfo to inquire quickly whether a file contains a mask. Helpful Programs shows where to find these programs on the web.

$identify -format "%f %m %wx%h %r %q-bit" remapped-0000.tif remapped-0000.tif TIFF 800x533 DirectClassRGBMatte 8-bit ^^^^^ mask  $ tiffinfo remapped-0000.tif
TIFF Directory at offset 0x1a398a (1718666)
Subfile Type: (0 = 0x0)
Image Width: 800 Image Length: 533
Resolution: 150, 150 pixels/inch
Position: 0, 0
Bits/Sample: 8
Sample Format: unsigned integer
Compression Scheme: PackBits
Photometric Interpretation: RGB color
Orientation: row 0 top, col 0 lhs
Samples/Pixel: 4                           <<<<< R, G, B, and mask
Rows/Strip: 327
Planar Configuration: single image plane


The “Matte” part of the image class and the “Extra Samples” line tell us that the file features a mask. Also, many interactive image manipulation programs show the mask as a separate channel, sometimes called “Alpha”. There, the white (high mask value) parts of the mask enable pixels and black (low mask value) parts suppress them.

The multitude of terms all describing the concept of a mask is confusing.

A mask defines a selection of pixels. A value of zero represents an unselected pixel. The maximum value (“white”) represents a selected pixel and the values between zero and the maximum are partially selected pixels. See Gimp-Savy.

Alpha Channel

The alpha channel stores the transpacency value for each pixel, typically in the range from zero to one. A value of zero means the pixel is completely transparent, thus does not contribute to the image. A value of one on the other hand means the pixel is completely opaque.

Matte

The notion “matte” as used by ImageMagick refers to an inverted alpha channel, more precisely: 1 - alpha. See ImageMagick for further explanations.

Enblend and Enfuse only consider pixels that have an associated mask value other than zero. If an input image does not have an alpha channel, Enblend warns and assumes a mask of all non-zero values, that is, it will use every pixel of the input image for fusion.

Stitchers like nona add a mask to their output images.

Sometimes it is helpful to manually modify a mask before fusion. For example to suppress unwanted objects (insects and cars come into mind) that moved across the scene during the exposures. If the masks of all input images are black at a certain position, the output image will have a hole in that position.

...

7 Tuning Memory Usage

The default configuration of Enblend and Enfuse assumes a system with 3–4GB of RAM.

If Enblend and Enfuse have been compiled with the “image-cache” feature, they do not rely on the operating system’s memory management, but use their own image cache in the file system. To find out whether your version uses the image cache say

enblend --verbose --version


or

enfuse --verbose --version


Enblend and Enfuse put the file that holds the image cache either in the directory pointed to by the environment variable TMPDIR, or, if the variable is not set, in directory /tmp. It is prudent to ensure write permissions and enough of free space on the volume with the cache file.

The size of the image cache is user configurable with the option ‘-m CACHE-SIZE’ (see Extended Options). Furthermore, option ‘-b BUFFER-SIZE’ (see Extended Options) allows for fine-tuning the size of a single buffer inside the image cache. Note that CACHE-SIZE is given in megabytes, whereas the unit of BUFFER-SIZE is kilobytes.

Usually the user lets the operating system take care of the memory management of all processes. However, users of Enblend or Enfuse might want to control the balance between the operating systems’ Virtual Memory system and the image cache for several reasons.

• Paging in or out parts of a process’ image runs at kernel level and thus can make user processes appear unresponsive or “jumpy”. The caching mechanism of Enblend and Enfuse of course runs as a user process, which is why it has less detrimental effects on the system’s overall responsiveness.
• The image cache has been optimized for accesses to image data. All algorithms in Enblend and Enfuse have been carefully arranged to play nice with the image cache. An operating system’s cache has no knowledge of these particular memory access patterns.
• The disk access of the operating system to the swap device has been highly optimized. Enblend and Enfuse on the other hand use the standard IO-layer, which is a much slower interface.
• Limiting the amount of image cache prevents Enblend and Enfuse from eating up most or all RAM, thereby forcing all user applications into the swap.

The CACHE-SIZE should be set in such a way as to reconcile all of the above aspects even for the biggest data sets, that is, projects with many large images.

Table 7.1 suggests some cache- and buffer-sizes for different amounts of available RAM.

RAMCACHE-SIZEBUFFER-SIZEComment
MBMBKB
409610242048default
2048512–10241024
1024256–512256–512

Table 7.1: Suggested cache-size settings

On systems with considerably more than 4GB of RAM it is recommended to run Enblend or Enfuse versions without image cache.

Several programs and libraries have proven helpful when working with Enfuse and Enblend.

Raw Image Conversion
• DCRaw is a universal raw-converter written by DAVID COFFIN.
• UFRaw, a raw converter written by UDI FUCHS and based on DCRaw, adds a GUI (ufraw), versatile batch processing (ufraw-batch), and some additional features such as cropping, noise reduction with wavelets, and automatic lens error correction.
Image Alignment and Rendering
Image Manipulation
• CinePaint is a branch of an early Gimp forked off at version 1.0.4. It sports much less features than the current Gimp, but offers 8bit, 16bit and 32bit color channels, HDR (for example floating-point TIFF, and OpenEXR), and a tightly integrated color management system.
• The Gimp is a general purpose image manipulation program. At the time of this writing it is still limited to images with only 8bits per channel.
• ImageMagick and its clone GraphicsMagick are general purpose command-line driven image manipulation programs, for example, convert, display, identify, and montage.
High Dynamic Range
• OpenEXR offers libraries and some programs to work with the EXR HDR format.
• PFSTools create, modify, and tonemap high-dynamic range images.
Libraries
Meta-Data Handling
• EXIFTool reads and writes EXIF meta data. In particular it copies meta data from one image to another.
• LittleCMS is the color management library used by Hugin, DCRaw, UFRaw, Enblend, and Enfuse. It supplies some binaries, too. tifficc, an ICC color profile applier, is of particular interest.

Appendix A Bug Reports

Most of this appendix was taken from the
Octave documentation.


Bug reports play an important role in making Enblend and Enfuse reliable and enjoyable.

When you encounter a problem, the first thing to do is to see if it is already known. To this end visit the package’s LaunchPad bug database. Search it for your particular problem. If it is not known, please report it.

In order for a bug report to serve its purpose, you must include the information that makes it possible to fix the bug.

A.1 Have You Really Found a Bug?

If you are not sure whether you have found a bug, here are some guidelines:

• If Enblend or Enfuse get a fatal signal, for any options or input images, that is a bug.
• If Enblend or Enfuse produce incorrect results, for any input whatever, that is a bug.
• If Enblend or Enfuse produce an error message for valid input, that is a bug.
• If Enblend or Enfuse do not produce an error message for invalid input, that is a bug.

A.2 How to Report Bugs

The fundamental principle of reporting bugs usefully is this: report all the facts. If you are not sure whether to state a fact or leave it out, state it. Often people omit facts because they think they know what causes the problem and they conclude that some details do not matter. Play it safe and give a specific, complete example.

Keep in mind that the purpose of a bug report is to enable someone to fix the bug if it is not known. Always write your bug reports on the assumption that the bug is not known.

Try to make your bug report self-contained. If we have to ask you for more information, it is best if you include all the previous information in your response, as well as the information that was missing.

To enable someone to investigate the bug, you should include all these things:

• The exact version and configuration of Enblend or Enfuse. You can get this by running it with the options --version and --verbose.
• A complete set of input images that will reproduce the bug. Strive for a minimal set of small7 images.
• The type of machine you are using, and the operating system name and its version number.
• A complete list of any modifications you have made to the source. Be precise about these changes. Show a diff for them.
• Details of any other deviations from the standard procedure for installing Enblend and Enfuse.
• The exact command line you use to call Enblend or Enfuse, which then triggers the bug.

Examples:

~/local/bin/enblend -v \
image-1.png image-2.png


or:

/local/bin/enfuse \
--verbose \
--exposure-weight=0 --saturation-weight=0 --entropy-weight=1 \
--gray-projector=l-star \
--entropy-cutoff=1.667% \
layer-01.ppm layer-02.ppm layer-03.ppm


If you call Enblend or Enfuse from within a GUI like, for example, Hugin or KImageFuser by HARRY VAN DER WOLF, copy&paste or write down the command line that launches Enblend or Enfuse.

• A description of what behavior you observe that you believe is incorrect. For example, “The application gets a fatal signal,” or, “The output image contains black holes.”

Of course, if the bug is that the application gets a fatal signal, then one cannot miss it. But if the bug is incorrect output, we might not notice unless it is glaringly wrong.

A.3 Sending Patches for Enblend or Enfuse

If you would like to write bug fixes or improvements for Enblend or Enfuse, that is very helpful. When you send your changes, please follow these guidelines to avoid causing extra work for us in studying the patches. If you do not follow these guidelines, your information might still be useful, but using it will take extra work.

• Send an explanation with your changes of what problem they fix or what improvement they bring about. For a bug fix, just include a copy of the bug report, and explain why the change fixes the bug.
• Always include a proper bug report for the problem you think you have fixed. We need to convince ourselves that the change is right before installing it. Even if it is right, we might have trouble judging it if we do not have a way to reproduce the problem.
• Include all the comments that are appropriate to help people reading the source in the future understand why this change was needed.
• Do not mix together changes made for different reasons. Send them individually.

If you make two changes for separate reasons, then we might not want to install them both. We might want to install just one.

• Use the version control system to make your diffs. Prefer the unified diff format: hg diff --unified 4.
• You can increase the probability that your patch gets applied by basing it on a recent revision of the sources.

Appendix B Authors

ANDREW MIHAL (acmihal@users.sourceforge.net) has written Enblend and Enfuse.

Contributors

Thanks to SIMON ANDRIOT and PABLO JOUBERT for suggesting the MERTENS-KAUTZ-VAN REETH technique and the name “Enfuse”.

Appendix C GNU Free Documentation License

Version 1.2, November 2002

Copyright © 2000, 2001, 2002 Free Software Foundation, Inc.
51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA

Everyone is permitted to copy and distribute verbatim copies
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This License is a kind of “copyleft”, which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software.

We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.

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6. COMBINING DOCUMENTS

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In the combination, you must combine any sections Entitled “History” in the various original documents, forming one section Entitled “History”; likewise combine any sections Entitled “Acknowledgements”, and any sections Entitled “Dedications”. You must delete all sections Entitled “Endorsements.”

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You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.

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9. TRANSLATION

Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail.

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11. FUTURE REVISIONS OF THIS LICENSE

The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See http://www.gnu.org/copyleft/.

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Program Index

Jump to: A   C   D   E   F   G   H   I   M   N   P   T   U
Index Entry Section ale: Helpful Programs align_image_stack (Hugin): Helpful Programs cinepaint: Extended Options cinepaint: Helpful Programs convert (ImageMagick): Helpful Programs dcraw: Standard Workflow dcraw: Helpful Programs display (ImageMagick): Helpful Programs exiftool: Helpful Programs exrdisplay (OpenEXR): Helpful Programs fulla (Hugin): Helpful Programs gimp: Standard Workflow gimp: Extended Options gimp: Helpful Programs gm (GraphicsMagick): Helpful Programs hugin: Overview hugin: Standard Workflow hugin: Extended Options hugin: Helpful Programs identify (ImageMagick): Understanding Masks identify (ImageMagick): Helpful Programs montage (ImageMagick): Helpful Programs nona (Hugin): Extended Options nona (Hugin): Helpful Programs PanoTools: Overview PanoTools: Standard Workflow pfshdrcalibrate (PFScalibration): Helpful Programs pfsin (PFSTools): Helpful Programs pfsout (PFSTools): Helpful Programs pfstmo_* (PFStmo): Helpful Programs pfsview (PFSTools): Helpful Programs PTmender (PanoTools): Helpful Programs PTOptimizer (PanoTools): Helpful Programs tifficc (LittleCMS): Helpful Programs tiffinfo (libtiff): Understanding Masks tiffinfo (libtiff): Helpful Programs ufraw: Standard Workflow ufraw: Helpful Programs ufraw-batch: Helpful Programs
Jump to: A   C   D   E   F   G   H   I   M   N   P   T   U

Syntactic-Comment Index

Index Entry Section enblend-response-file: Response Files enfuse-response-file: Response Files filename-globbing: Response Files glob: Response Files globbing: Response Files layer-selector: Response Files response-file: Response Files

Option Index

Index Entry Section --anneal: Mask Generation Options --blend-colorspace: Extended Options --ciecam: Extended Options --coarse-mask: Mask Generation Options --compression: Common Options --depth: Extended Options --dijkstra: Mask Generation Options --fallback-profile: Extended Options --fine-mask: Mask Generation Options --gpu: Extended Options --help: Common Options --image-difference: Mask Generation Options --layer-selector: Common Options --levels: Common Options --load-masks: Mask Generation Options --mask-vectorize: Mask Generation Options --no-ciecam: Extended Options --no-optimize: Mask Generation Options --no-parameter: Common Options --optimize: Mask Generation Options --optimizer-weights: Mask Generation Options --output: Common Options --parameter: Common Options --primary-seam-generator: Mask Generation Options --save-masks: Mask Generation Options --smooth-difference: Mask Generation Options --verbose: Common Options --version: Common Options --visualize: Mask Generation Options --wrap: Common Options -a: Common Options -b: Extended Options -b: Tuning Memory Usage -b: Tuning Memory Usage -c: Extended Options -d: Extended Options -f: Extended Options -g: Extended Options -h: Common Options -l: Common Options -m: Extended Options -m: Tuning Memory Usage -m: Tuning Memory Usage -o: Common Options -v: Common Options -V: Common Options -w: Common Options -x: Common Options

General Index

Jump to: #   3   @   A   B   C   D   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W
Index Entry Section ‘#’ (response file comment): Response Files 360° panoramas: Common Options ‘@’ (response file prefix): Response Files a.tif: Common Options affine transformation: Standard Workflow algorithms, globbing: Response Files algorithms, globbing: Response Files alpha channel: Overview alpha channel: Standard Workflow alpha channel, associated: Extended Options anneal parameters: Mask Generation Options arithmetic JPEG compression: Common Options authors, list of: Authors binary mask: Understanding Masks bits per channel: Extended Options blend colorspace: Extended Options blur difference image: Mask Generation Options bug database, LaunchPad: Bug Reports bug reports: Bug Reports bug reports: Bug Reports Burt-Adelson multiresolution spline: Overview canvas size: Extended Options channel width: Extended Options channel, alpha: Overview checkpoint results: Common Options chrominance weight: Mask Generation Options CIECAM02: Extended Options CIECAM02: Extended Options CIECAM02: Extended Options CIECAM02: Color Profiles CIECAM02 colorspace: Extended Options coarse mask: Mask Generation Options color appearance model: Extended Options color appearance model: Extended Options color appearance model: Extended Options color appearance model: Color Profiles color cube, RGB: Color Profiles color profile: Color Profiles color profile: Color Profiles color space, sRGB: Color Profiles colors, visualization image: Mask Generation Options colorspace, blend: Extended Options compression: Common Options compression, arithmetic JPEG: Common Options compression, deflate: Common Options compression, JPEG: Common Options compression, JPEG: Common Options compression, LZW: Common Options compression, packbits: Common Options conversion, raw: Standard Workflow D50 white point: Color Profiles default layer selection: Response Files default output filename: Common Options deflate compression: Common Options delta-E: Mask Generation Options difference image: Mask Generation Options DIJKSTRA radius: Mask Generation Options DIJKSTRA radius: Mask Generation Options double precision float, IEEE754: Extended Options fallback profile: Extended Options feathering, detrimental effect of: Overview filename, literal: Invocation fine mask: Mask Generation Options format of response file: Response Files free documentation license (FDL): FDL frozen seam-line endpoint: Mask Generation Options general index: General Index generator, seam: Mask Generation Options glob(7): Response Files globbing algorithm ‘literal’: Response Files globbing algorithm ‘literal’: Response Files globbing algorithm ‘none’: Response Files globbing algorithm ‘sh’: Response Files globbing algorithm ‘shell’: Response Files globbing algorithm ‘wildcard’: Response Files globbing algorithm ‘wildcard’: Response Files globbing algorithms: Response Files globbing algorithms: Response Files GNU free documentation license: FDL GPU (Graphics Processing Unit): Extended Options grammar, response file: Response Files grammar, syntactic comment: Response Files graph-cut (GC): Mask Generation Options graphcut (GC): Primary Seam Generators graphcut, details: Primary Seam Generators graphcut, limitations: Primary Seam Generators graphics processing unit: Extended Options half precision float, OpenEXR: Extended Options helpful programs: Helpful Programs hue-luminance maximum: Mask Generation Options Hugin: Bug Reports ICC profile: Extended Options ICC profile: Color Profiles ICC profile: Color Profiles IEEE754 double precision float: Extended Options IEEE754 single precision float: Extended Options image cache: Tuning Memory Usage image cache, block size: Extended Options image cache, cache size: Extended Options image cache, location: Tuning Memory Usage image colors, visualization: Mask Generation Options image difference: Mask Generation Options image, multi-layer: Overview image, visualization: Mask Generation Options index, general: General Index index, option: Option Index index, program: Program Index index, syntactic-comment: Syntactic-Comment Index input image requirements: Image Requirements input mask: Understanding Masks invocation: Invocation JPEG compression: Common Options KImageFuser: Bug Reports LaunchPad: Bug Reports LaunchPad, bug database: Bug Reports layer selection: Common Options layer selection: Common Options layer selection, all layers: Common Options layer selection, default: Response Files layer selection, first layer: Common Options layer selection, largest-layer: Common Options layer selection, no layer: Common Options lens distortion, correction of: Standard Workflow levels, pyramid: Common Options LibJPEG: Helpful Programs LibPNG: Helpful Programs LibTiff: Helpful Programs literal filename: Invocation load mask: Mask Generation Options loops in seam line: Mask Generation Options luminance weight: Mask Generation Options luminance-hue maximum: Mask Generation Options LZW compression: Common Options mask template character, ‘%’: Mask Generation Options mask template character, ‘b’: Mask Generation Options mask template character, ‘B’: Mask Generation Options mask template character, ‘d’: Mask Generation Options mask template character, ‘D’: Mask Generation Options mask template character, ‘e’: Mask Generation Options mask template character, ‘E’: Mask Generation Options mask template character, ‘f’: Mask Generation Options mask template character, ‘F’: Mask Generation Options mask template character, ‘i’: Mask Generation Options mask template character, ‘n’: Mask Generation Options mask template character, ‘p’: Mask Generation Options mask template character, ‘P’: Mask Generation Options mask template characters, table of: Mask Generation Options mask, binary: Understanding Masks mask, coarse: Mask Generation Options mask, fine: Mask Generation Options mask, generation: Mask Generation Options mask, input files: Understanding Masks mask, load: Mask Generation Options mask, optimization visualization: Mask Generation Options mask, save: Mask Generation Options mask, vectorization distance: Mask Generation Options mask, weight: Understanding Masks mask, weight: Understanding Masks masks, understanding: Understanding Masks match quality: Mask Generation Options maximum hue-luminance: Mask Generation Options memory, tuning usage of: Tuning Memory Usage multi-directory TIFF: Overview multi-layer image: Overview nearest feature transform (NFT): Mask Generation Options nearest feature transform (NFT): Primary Seam Generators nearest-feature transform (NFT): Mask Generation Options nearest-feature transform (NFT): Mask Generation Options nearest-feature transform (NFT), Graph-Cut (GC): Mask Generation Options Octave: Bug Reports only save mask: Mask Generation Options OpenEXR, data format: Extended Options OpenEXR, half precision float: Extended Options optimize seam: Mask Generation Options optimize seam: Mask Generation Options optimize strategy: Mask Generation Options optimize, anneal parameters: Mask Generation Options optimizer weights: Mask Generation Options optimizer, simulated annealing: Extended Options optimizer, simulated annealing: Mask Generation Options option index: Option Index options, common: Common Options options, extended: Extended Options options, mask generation: Mask Generation Options order, of processing: Response Files output file compression: Common Options output filename, default: Common Options output image, set size of: Extended Options overview: Overview packbits compression: Common Options parallax error: Standard Workflow perceptual rendering intent: Color Profiles photometric alignment: Standard Workflow primary seam generator: Mask Generation Options primary seam generator: Primary Seam Generators problem reports: Bug Reports processing order: Response Files profile, fallback: Extended Options profile, ICC: Extended Options profile, ICC: Color Profiles profile, ICC: Color Profiles program index: Program Index programs, helpful additional: Helpful Programs pyramid levels: Common Options quality, match: Mask Generation Options radius, DIJKSTRA: Mask Generation Options radius, DIJKSTRA: Mask Generation Options raw conversion: Standard Workflow rendering intent, perceptual: Color Profiles response file: Invocation response file: Response Files response file, comment (‘#’): Response Files response file, force recognition of: Response Files response file, format: Response Files response file, grammar: Response Files response file, syntactic comment: Response Files results, checkpoint: Common Options RGB color cube: Color Profiles RGB-cube: Extended Options save mask: Mask Generation Options save mask, only: Mask Generation Options seam generation: Primary Seam Generators seam generation, details: Primary Seam Generators seam line, loops: Mask Generation Options seam optimization: Mask Generation Options seam optimization: Mask Generation Options seam optimization: Mask Generation Options seam, primary generator: Mask Generation Options seam-line endpoint, frozen: Mask Generation Options seam-line visualization example: Mask Generation Options simulated annealing optimizer: Extended Options simulated annealing optimizer: Mask Generation Options single precision float, IEEE754: Extended Options size, canvas: Extended Options smooth difference image: Mask Generation Options SourceForge: Overview sRGB: Extended Options sRGB color space: Color Profiles syntactic comment, grammar: Response Files syntactic comment, response file: Response Files syntactic-comment index: Syntactic-Comment Index TIFF, multi-directory: Overview tiffcopy: Overview tiffsplit: Overview TMPDIR: Tuning Memory Usage transformation, affine: Standard Workflow understanding masks: Understanding Masks virtual reality: Common Options visualization example: Mask Generation Options visualization image: Mask Generation Options visualization image colors: Mask Generation Options visualization of mask: Mask Generation Options weight mask: Understanding Masks weight mask: Understanding Masks weight, chrominance: Mask Generation Options weight, luminance: Mask Generation Options weights, optimizer: Mask Generation Options white point, D50: Color Profiles workflow: Workflow workflow with Enblend: Standard Workflow workflow with Enfuse: Standard Workflow workflow, external mask manipulation: External Mask Manipulation workflow, external masks: External Mask Manipulation workflow, standard: Standard Workflow wrap around: Common Options
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(1)

PETER J. BURT and EDWARD H. ADELSON, “A Multiresolution Spline With Application to Image Mosaics”, ACM Transactions on Graphics, Vol. 2, No. 4, October 1983, pages 217–236.

(2)

Use utilities like, e.g., tiffcopy and tiffsplit of LibTIFF to manipulate multi-directory TIFF images. See Helpful Programs.

(3)

As Dr. Daniel Jackson correctly noted, actually, it is not a pyramid: “Ziggaurat, it’s a Ziggaurat.”

(4)

Solid-state physicists will be reminded of the BORN-VON KÁRMÁN boundary condition.

(5)

The stitcher nona is part of Hugin. See Helpful Programs.

(6)

MUHAMMAD H. ALSUWAIYEL and MARINA GAVRILOVA, “On the Distance Transform of Binary Images”, Proceedings of the International Conference on Imaging Science, Systems, and Technology, June 2000, Vols. I and II, pages 83–86.

(7)

Images of a size less than 1500x1000 pixels qualify as small.