enblend(1)enblend(1)NAMEenblend - combine images using a multiresolution spline
SYNOPSISenblend [OPTIONS] -o output-file input-files...
DESCRIPTION
Enblend overlays multiple TIFF images using the Burt & Adelson mul‐
tiresolution spline. 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 TIFF 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 for you. Use a tool like Hugin or Pan‐
oTools to do this. The TIFFs 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 set‐
ting the feather width to zero.
Enblend blends the images in the order you specify 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, I recommend blending each horizontal row individ‐
ually, and then running Enblend a final time to blend all of the rows
together vertically.
COMMON OPTIONS-a Pre-assemble non-overlapping images before each blending itera‐
tion. This overrides the default behavior which is to blend the
images sequentially in the order given on the command line.
Enblend will do fewer blending iterations, but it will do more
work in each iteration.
-h Print information on the available options.
-l num Use exactly this many levels for pyramid blending. This trades
off quality of results for faster execution time and lower mem‐
ory usage. The default is to use as many levels as possible
given the size of the overlap region. Enblend may still use a
smaller number of levels if the geometry of the images demands
it.
-o output-file
Required. Specify the name of the output file.
-v Verbose output.
-w Blend around the -180/+180 boundary. Useful for full-360 panora‐
mas. Enblend currently does not blend the zenith or the nadir,
so you may still see some seams in these areas.
--compression=COMP
Select the type of compression used for the output image. For
TIFF files, the valid settings are NONE, PACKBITS, LZW, and
DEFLATE. The default is NONE. For JPEG files, the valid setting
is an integer between 0 and 100.
-z Use LZW compression for the output image.
-x Checkpoint partial results to the output file after each blend‐
ing step.
input-files
Two or more TIFF files.
EXTENDED OPTIONS-b kilobytes
Set the block size for Enblend's image cache. This is the amount
of data that Enblend will move to and from the disk in one go.
The default is 2 MiB which should be good for most systems.
-c Use the CIECAM02 color appearance model for blending colors.
Your input TIFF files should have embedded ICC profiles. If no
ICC profile is present, Enblend will assume that image uses the
sRGB color space. The difference between using this option and
Enblend's default color blending algorithm is very slight, and
will be most noticeable when you need to blend areas of differ‐
ent primary colors together.
-g Gimp (ver. < 2) and Cinepaint exhibit unusual behaviors when
loading images with unassociated alpha channels. Use the -g flag
to work around this. With this flag Enblend will create the out‐
put image with the associated alpha tag set, even though the
image is really unassociated alpha.
--gpu Use the graphics card to accelerate some computations. This is
an experimental feature and it may not work on all systems.
Currently, only mask optimization strategy 1 benefits from this
option.
-f WIDTHxHEIGHT
Set the size of the output image manually. This is useful when
the input images are cropped TIFF files, such as those produced
by Nona.
-m megabytes
Set the size 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 1 GiB.
--visualize=FILE
Create an output image that visualizes the mask optimization
process. This 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.
MASK GENERATION OPTIONS--coarse-mask
Use a scaled-down version of the input images to create the seam
line. This is the default.
--fine-mask
Use the full-size images to create the seam line. This can be
slow. Use this option if you have very narrow overlap regions.
--optimize
Use a two-strategy approach to route the seam line around mis‐
matches in the overlap region. This is the default.
--no-optimize
Turn off seam line optimization. Combined with --fine-mask, this
will produce the same type of mask as Enblend 2.5.
--save-mask=FILE
Save the generated mask to an image file. Use this option if
you wish to edit the location of the seam line by hand. This
will give you a template of the right size that you can edit to
make your changes. Then, use the --load-mask option to blend
the project with your custom seam line.
--load-mask=FILE
Instead of generating a mask, use the one in the given file.
ADDITIONAL INFORMATION
Please see the Enblend web page at:
http://enblend.sourceforge.net/
AUTHOR
Andrew Mihal <acmihal@users.sourceforge.net>
September 8, 2008 enblend(1)