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Combining Multiple Images with Enblend 4.1.4

Table of Contents


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.

[Image "photographic-workflow" is not displayed, because of lacking SVG and PNG support.]

Figure 2.1: Photographic workflow with Enblend and Enfuse.

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




2.2 External Mask Manipulation

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:

Save masks with --save-masks.

Generate masks and save them into image files.

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

Load masks with --load-masks.

Load masks from files and then blend or fuse the final image with the help of the loaded masks.

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.

[Image "external-mask-workflow" is not displayed, because of lacking SVG and PNG support.]

Figure 2.2: Workflow for externally modified masks.

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.

Note that options --save-masks and --load-masks cannot be used simultaneously.

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.

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

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.


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.


enblend @list

where file list contains


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

Mixed literal names and response files.


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

where file master.list comprises of


first.list is


and second.list contains


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 files contain one filename per line. Blank lines or lines beginning with a sharp sign (‘#’) are ignored; the latter can serve as comments. Filenames that begin with an at-character (‘@’) denote other response files. Table 3.1 states a formal grammar of response files in EBNF.

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.

Only whole-line comments

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

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.

Image filenames cannot start with ‘@

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.

# Freehand sky shot.

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

3.2.2 Syntactic Comments

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.


Do not glob. Interpret all filenames in response files as literals. This is the default.

Please keep in mind that whitespace at both ends of a line in a response file always gets discarded.


Glob using the wildcard characters ‘?’, ‘*’, ‘[’, and ‘]’.

The W*N32 implementation only globs the filename part of a path, whereas all other implementations perform wildcard expansion in all path components. Also see glob(7).


Alias for literal.


The shell globbing algorithm works as literal does. In addition, it interprets the wildcard characters ‘{’, ‘}’, and ‘~’. This makes the expansion process behave more like common UN*X shells.


Alias for shell.

Table 3.3: Globbing algorithms for the use in response files


# Horizontal panorama
# 15 images

# filename-globbing: wildcard


3.2.4 Default Layer Selection

The key layer-selector provides the same functionality as does the command-line option --layer-selector, but on a per response-file basis. See Common Options.

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.


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.


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.


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


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


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:


Do not compress. This is the default.


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.


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


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


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.


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

This version of Enblend offers the following algorithms:


Select all layers in all images.


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


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’.


Do not select any layer in any image.

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


Print information on the available options and exit.


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 log2(minwidthheight) 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.


Place output in FILE.

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


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

This option has the negated form --no-parameter, which takes one or more KEYs and removes them from the list of defined parameters. The special key ‘*’ deletes all parameters at once.

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


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.




only warnings and errors


reading and writing of images


mask generation, pyramid, and blending


reading of response files, color conversions


image sizes, bounding boxes and intersection sizes


detailed information on the optimizer runs (Enblend only)


estimations of required memory in selected processing steps

The default verbosity level of Enblend is 1.


Output information on the Enblend version.

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


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!

With this option Enblend treats the panorama of width w and height h as an infinite data structure, where each pixel P(x, y) of the input images represents the set of pixels SPxy 4.

MODE takes the following values:


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.


Wrap around horizontally:

SPxy={Px+mwy:m   in   Z}.

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


Wrap around vertically:

SPxy={Pxy+nh:n   in   Z}. This is useful for 360° vertical panoramas as it eliminates the top and bottom borders.

Wrap around both horizontally and vertically:

SPxy={Px+mwy+nh:m,n   in   Z}.

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

Specifying --wrap without MODE selects horizontal wrapping.


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.


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

This is the amount of data that Enblend will move to and from the disk at one time. The default is 2048KB, which should be ok for most systems. See Tuning Memory Usage for details.

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.


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:


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.


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.


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


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


Signed 16bit; range: -32768..32767

16, uint16

Unsigned 16bit; range: 0..65535


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

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

This option only is useful when the input images are cropped TIFF files, such as those produced by nona5.

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.


Use the ICC profile in PROFILE-FILENAME instead of the default sRGB. See option --blend-colorspace and Color Profiles.

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


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.


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.


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

This is the amount of memory Enblend will use for storing image data before swapping to disk. The default is 1024MB, which is good for systems with 3–4gigabytes (GB) of RAM. See Tuning Memory Usage for details.

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.


Use ‘--blend-colorspace=IDENTITY’ instead.

See option --blend-colorspace for details. Also see Color Profiles.

3.5 Mask Generation Options

These options control the generation and the usage of masks.


Set the parameters of the Simulated Annealing optimizer (see Table 3.5).


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 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:


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


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.


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,….

Also see Table 3.4.


Set the search RADIUS of the DIJKSTRA Shortest Path algorithm used in DIJKSTRA Optimization (see Table 3.5).

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.

Valid range: RADIUS ≥ 1.

Default: 25pixels.


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.

Also see Table 3.4.


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, wluminance and color differences CHROMINANCE-WEIGHT, wchrominance.

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


Calculate the difference d as the maximum of the differences of the luminances l and hues h of each pair of pixels P1 and P2:


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


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


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.


Instead of generating masks, use those in IMAGE-TEMPLATE. The default is mask-%n.tif. The mask images have to be a 8-bit grayscale images.

See --save-masks below for details.


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.

Default: 4pixels for coarse masks and 20pixels for fine masks.


Turn off seam line optimization. Combined with option --fine-mask this will produce the same type of mask as Enblend version 2.5, namely the result of a Nearest-Feature Transform (NFT).6

Also see Table 3.4.


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.


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.


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



See Primary Seam Generators for details.


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.

IMAGE-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.

A fancy mask filename template could look like this:


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.


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.

Valid range: RADIUS ≥ 0.0.


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

The image shows Enblend’s view of the overlap region and how it decided to route the seam line. If you are experiencing artifacts or unexpected output, it may be useful to include this visualization image in your bug report. See Bug Reports.

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.


Produces a literal ‘%’-sign.


Expands to the index of the mask file starting at zero.

%i’ supports setting a pad character or a width specification:


PAD is either ‘0’ or any punctuation character; the default pad character is ‘0’. WIDTH is an integer specifying the minimum width of the number. The default is the smallest width given the number of input images, this is 1 for 2–9 images, 2 for 10–99 images, 3 for 100–999 images, and so on.

Examples: ‘%i’, ‘%02i’, or ‘%_4i’.


Expands to the number of the mask file starting at one. Otherwise it behaves identically to ‘%i’, including pad character and width specification.


This is the full name (path, filename, and extension) of the input file associated with the mask.

Example: If the input file is called /home/luser/snap/img.jpg, ‘%p’ expands to /home/luser/snap/img.jpg, or shorter: ‘%p’ ⇒ /home/luser/snap/img.jpg.


This is the full name of the output file.


Is replaced with the directory part of the associated input file. See Info file, node “dirname invocation”.

Example (cont.): ‘%d’ ⇒ /home/luser/snap.


Is replaced with the directory part of the output file.


Is replaced with the non-directory part (often called “basename”) of the associated input file. See Info file, node “basename invocation”.

Example (cont.): ‘%b’ ⇒ img.jpg.


Is replaced with the non-directory part of the output file.


Is replaced with the filename without path and extension of the associated input file.

Example (cont.): ‘%f’ ⇒ img.


Is replaced with the filename without path and extension of the output file.


Is replaced with the extension (including the leading dot) of the associated input file.

Example (cont.): ‘%e’ ⇒ .jpg.


Is replaced with the extension of the output file.

Table 3.7: Special characters to control the generation of mask filenames.

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

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

6 Understanding Masks

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.

6.1 Masks in Input Files

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
  Extra Samples: 1<unassoc-alpha>            <<<<< mask
  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.


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.

6.2 Weight Mask Files


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


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.

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.


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.

8 Helpful Additional Programs

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.
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:

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:

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.

Appendix B Authors

ANDREW MIHAL ( has written Enblend and Enfuse.


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

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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

Jump to:   E   F   G   L   R  
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

Jump to:   E   F   G   L   R  

Option Index

Jump to:   -
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

Jump to:   -

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

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  



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.


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


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


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


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


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.


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