This manual was last updated March 20, 2009 for version 1.0.0 of cvtool.
Copyright © 2005, 2006, 2007, 2008, 2009, 2010 Martin Lambers
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled “GNU Free Documentation License”.
Cvtool is a filter that manipulates one or more images (called frames): it reads frames from standard input and writes the manipulated frames to standard output. It can read and write streams of NetPBM (pbm, pgm, ppm, pnm, pam) and PFS frames.
Cvtool integrates all its functionality into a single binary, and makes
it available through commands such as
The following command scales a NetPBM frame by a factor of 3:
$ cvtool scale --factor 3.0 < input.ppm > output.ppm
This is how one would select a rectangle from an PFS frame stream:
$ cvtool cut --left 10 --top 10 --width 100 --height 100 \ < input.pfs > output.pfs
cvtool help prints a list of available commands, and
cvtool help cmd prints help for the command
Due to the use of OpenGL textures to store frame data, some limitations apply:
All NetPBM image formats (pbm, pgm, ppm, pnm, pam) are supported, except for their old "plain" variants. Multiple images in one file are supported. They may differ in size and type.
If the input images use more than 8 bit per channel, they are treated as floating point images.
Cvtool supports the PFS format used by pfstools.
Currently, cvtool ignores channel tags. This will be fixed in a future version.
Cvtool normally prints messages to
stderr. It prepends messages with its
name, the level of information, and the name of the command.
The level of information is
DBG for debugging messages,
WRN for warnings,
ERR for error
REQ for requested information. Normally, cvtool prints only
messages of level
INF or higher, but this can be changed with
--quiet and --verbose; see below.
Some commands, for example info, print special information messages
that the user explicitly requests. Such special messages have the level
REQ, and can usually be redirected using the --output option.
In this case, no additional information will be prepended to the messages.
The special filename
- means standard output (
Redirecting messages to
stdout is only allowed when no frames are
WRNand higher will be printed.
DBG. This will include progress information in many cases, but much of the output is really only useful for debugging purposes.
Some commands need arrays of integer or floating point values as parameters. Matrices are treated as two-dimensional arrays. Higher dimensions are also possible.
All of these array types are treated the same: the first part of the argument determines the number of dimensions of the array and its size in each dimension. The second part lists all values, separated by commas.
If the command requests an array or matrix of fixed dimension and size (or of dimension 1 and arbitrary size), then the first part can be omitted: only the value list is necessary in this case.
Colors can be given in one of three forms:
0xrrggbb. For example,
0xffffffis white, and
g255is green (the red and blue components default to zero),
r255g255b255is white, and
0 on success and
1 on error.
Print general or command specific help.
Print version information.
info [-s|--statistics] [-S|--single] [-o|--output=file
Print information about frames in the input stream.
If ‘--single’ is used, the command exits after the first frame has been processed. If ‘--statistics’ is used, additional statistics about the frame contents are printed. The output can be redirected to a file or to standard output (-) using the ‘--output’ option.
The following information will be printed: STREAM (pfs or pnm), CHANNELS (0-4), FORMAT (luminance or color), TYPE (uint8 or float), WIDTH, HEIGHT.
Statistics are computed for each available channel c: CHc_MIN, CHc_MAX, CHc_MEAN, CHc_MEDIAN, CHc_STDDEVIATION.
$ cvtool info < file.pnm cvtool: [REQ] info: STREAM=pnm CHANNELS=3 FORMAT=color TYPE=uint8 WIDTH=394 HEIGHT=454 $ eval `cvtool info -o - < file.pnm` $ echo $WIDTH 394
Combine the given files by placing the frames side by side (‘leftright’) or one below the other (‘topbottom’).
The default is ‘leftright’. If the frames have different sizes, then the smaller ones have to be aligned with the biggest one. The default is to center them. The remaining space will be filled with the given color; the default is black.
$ cvtool combine left.pnm right.pnm > lr.pnm $ cvtool combine -m tb \ <(cvtool combine a.pnm b.pnm) \ <(cvtool combine c.pnm d.pnm) \ > 2x2.pnm
convert [-t|--type=uint8|float] [-f|--format=lum|color|data]
Converts the input frames to another type and format. The default is to keep the input type and format. The output will be PNM for type uint8 and PFS for type float. If the format is set to ‘data’, no color space conversion will take place.
$ cvtool convert -t float < in.pnm > out.pfs
create [-t|--type=uint8|float] [-f|--format=lum|color] [-n|--n=n
Create n (default 1) frames with the given format (default color) and the given type (default uint8). The frames will have the given width and height, and they will be filled with the given color (default black). The resulting stream type will be PNM if the type is uint8, and PFS otherwise.
$ cvtool create -t uint8 -f lum -w 720 -h 576 > out.pgm $ cvtool create -t float -f color -w 10 -h 10 -c green > green.pfs
Execute the given command for every frame.
The command is expected to read n frames from standard input (default is
n=1), and write an arbitrary number (including zero) of frames to
standard output. The original frame(s) that were given to the command are
replaced by the output of the command. The frames that the command produces are
converted to the format of the original frames. The foreach command replaces
the following special strings in the command cmd before executing the
%N (replaced with frame number),
%W (replaced with frame
%H (replaced with frame height). If n is greater than
1, these values refer to the first frame that is piped to the command. The
command cmd is executed by passing it to the system shell. The default
is ‘/bin/sh -c’ on most systems. This can be overridden with the
--shell option. It expects a string with zero or one spaces: The first
part of the string is the shell, the second part (if any) is the first option
to the shell. The next option will then be the command to execute.
# Rotate a video. Resize after rotation to keep the original dimensions. $ cvtool foreach 'cvtool rotate -a %N | cvtool resize -w 352 -h 240' \ < video.pnm > rotating-video.pnm
merge [-s|--shuffle] [-o|--output=file
Merges files into one stream, in the given order.
--shuffle is used, the order will be randomized. The file names will
be printed to stderr in the order they are merged. If
--output is used,
the file names will be written to the given file instead.
$ ls frame000.pnm frame001.pnm frame002.pnm $ cvtool merge frame*.pnm > video.pnm
Reverses the order of the frames in the stream.
This requires a temporary file that is big enough to hold the complete input stream.
$ cvtool reverse < video.pnm > oediv.pnm
select [-d|--drop] [-f|--fps=fps
Selects frames from a stream.
By default, frames in the given ranges are kept and all others dropped. With
--drop, frames in the given ranges are dropped and all others kept.
A range must be of the following form: l-h (from l to
h), -h (from beginning to h), l- (from l to end),
l (only l), or - (everything). Each start and end point can be a
frame number (counting from 0) or a time in the format
[hours:]minutes:seconds[.fraction]. In short: if it contains a colon, it's a
time. Time ranges can only be used if the ‘--fps’ option is used to specify
the number of frames per second.
IMPORTANT: If you use frame number ranges, the high frame number is inclusive: the frame with this number will be dropped/kept. If you use time ranges, the high time is exclusive and marks the first frame that will not be dropped/kept.
# Drop the frames 0 to 124 from the stream (with a framerate of 25 fps, # these are the first five seconds). $ cvtool select --drop 0-124 < in.pnm > out.pnm # Drop the first 5 seconds of the stream (with a framerate of 25 fps, # these are the frames 0 to 124. The frame at 0:05, with the frame # number 125, will be the first that is kept!) $ cvtool select --fps 25 --drop 0:00-0:05 < in.pnm > out.pnm # Keep the second 5-minutes-block and drop all the rest. Both # commands are equivalent. $ cvtool select --fps 25 5:00-10:00 < in.pnm > out.pnm $ cvtool select --fps 25 --drop -5:00 10:00- < in.pnm > out.pnm
Split the input stream into multiple files.
Each new files contains n frames (default is n=1). The filename
will be generated from the template: the template must contain exactly one
appearance of the character
%. This character must be followed by one of
9. The digit must be followed by the
N. This special string
%xN will be replaced
by the number of the first frame of the stream contained in this file. The
number will be left-padded with zeros until its width is at least
characters. The default template is ‘frame-%6N’.
A start number i for the first frame can be given, and the frames can be counted backwards. If the frames are counted backwards, a start number is required, because negative frame numbers are not accepted.
$ cvtool split -t frame%3N.pnm < ../video.pnm $ ls frame000.pnm frame001.pnm frame002.pnm $ cvtool split -s 99 -b -t img%2N.pnm < ../video.pnm $ ls img99.pnm img98.pnm img97.pnm
Resize the frames to the given new width and height.
Place the original frame contents at the position (x,y) relative to the new frame (these offsets may be negative). If no or an incomplete position is given, compute the missing part(s) so that the old contents are centered on the new frame. Fill holes that might result with the given color (default is black).
# Add a green border of 10 pixels to a 352x240 frame $ cvtool resize -w 372 -h 260 -c green < img.pnm > img2.pnm
Only let the given rectangle through; cut the rest of each frame.
$ cvtool cut -l 0 -t 0 -w 10 -h 10 < in.pnm > out.pnm
Most geometric transformation commands support the option ‘--interpolation’ to choose one of the following interpolation types:
none: No interpolation / Nearest Neighbor.
bilinear: Bilinear interpolation.
biquadratic: Biquadratic interpolation.
bicubic: Default bicubic interpolation (Mitchell-Netravali).
bicubic-b-spline: Bicubic B-Spline interpolation.
bicubic-cr-spline: Bicubic Catmull-Rom Spline interpolation.
Apply the affine tranformation defined by the given matrix (4 floating point values separated by commas) to the frames. The frame dimensions will be adapted so that the resulting frame will fit. Possible holes will be filled with the given color; the default is black.
$ cvtool affine -m 2.0,0.1,0.75,1.0 < in.pnm > out.pnm
Flip frames (left/right).
$ cvtool flip < in.pnm > out.pnm
Flop frames (top/bottom).
$ cvtool flop < in.pnm > out.pnm
Rotate frames with the given angle (in degrees), counterclockwise.
The dimensions of the rotated frame will be big enough to hold all informations from the source. "Holes" will be filled with the given color; the default is black.
$ cvtool rotate -a -45 < in.pnm > out.pnm
Scale frames to new size.
First form: Give new width and/or height. If one value is missing, it is computed from the other so that the aspect ratio remains the same.
Second form: Give scale factors for width and height.
Third form: Give one scale factor for both width and height.
# The following three commands do the same for a 400x200 frame: $ cvtool scale -w 100 -h 50 < in.pnm > out.pnm $ cvtool scale -x 0.25 -y 0.25 < in.pnm > out.pnm $ cvtool scale -f 0.25 < in.pnm > out.pnm
Shear frames in horizontal and/or vertical direction.
The frames are sheared with the given angle(s) from (-90,90). Negative angles shear clockwise. "Holes" will be filled with the given color; the default is black.
$ cvtool shear -x 20 -y 10 < in.pnm > out.pnm
Blends the source into the frame stream, using an alpha map.
With no alpha map, the source is simply copied into the frames. x and y specify the position that the source should be copied to. The default is (0,0). Positions outside of the frames are possible: parts of the source that do not fit into the frames will be ignored. When --single is used, only the first frame of the source will be used; this frame will be copied into all frames of the stream.
$ cvtool blend --single -s logo.pnm -a logo-alpha.pgm -x 700 -y 0 \ < video.pnm > video-with-logo.pnm
layer -m|--mode=min|max|median|or|and|xor|diff|add|xadd|sub|xsub|mul|div file...
Layers the frames from the given files on top of each other, using the given mode.
Layering will be done for each channel separately. The input frames may differ in size. In this case, they will be implicitly scaled to a common size. Graylevel frames have
The modes are as follows:
min: Use minimum value.
max: Use maximum value.
median: Use median value.
or: Bitwise or.
and: Bitwise and.
xor: Bitwise xor.
diff: Use difference between maximum and minimum value.
add: Use sum of values.
xadd: Use sum of values. The ranges are transformed so that the results fit in [0,1]. Example for two layers: X = (A/2) + (B/2).
sub: Subtract values from the first value.
xsub: Subtract values from the first value. The ranges are transformed so that the results fit in [0,1]. Example for two layers: X = (A/2) - (B/2) + 1/2.
mul: Multiply values.
div: Divide values.
$ cvtool layer --mode=or red.pnm green.pnm blue.pnm \ > allchannels.pnm
Mixes the given sources into a single stream using the given weights.
The default is to produce a single step, i.e. one output frame for each set of input frames. If more steps are requested, the weights are interpolated between the set of first weights and the set of last weights. By default, this interpolation is done linearly, which corresponds to a bias setting of 0.5. Smaller bias values will give more attention to the first weights, larger values more to the last weigths. The bias must be from (0,1).
The input frames may differ in size. In this case, they will be implicitly scaled to a common size.
$ cvtool mix --weight=1,1 black.pgm white.pgm > gray.pgm $ cvtool mix -w 1,0 -W 0,1 -s 10 black.pgm white.pgm \ > from-black-to-white.pgm
Extract the given channel from the input. If ‘channel’ is 0, 1, 2, or 3, then the data is copied unmodified. If the ‘channel’ is r, g, b, or lum, then the input is first converted to the red, gree, blue, or luminance form.
$ cvtool channelextract -c r < color.ppm > red.pgm
channelcombine file0 [file1 [file2 [file3]]]
Extract the first channel from the given files and combine them into multichannel output data.
$ cvtool channelcombine red.pgm green.pgm blue.pgm > rgb.ppm
Hue, saturation, lightness, and constrast are manipulated in the HSL (Hue, Saturation, Lightness) color space. h is an additive constant to the hue angle, in degrees. s, l, c measure the relative change in saturation, lightness, contrast: -1 means the result will be zero, 0 means the result will be the same as the original, and +1 means that the result will be two times as high as the original. Values greater than +1 are possible. For example, s = -1 will convert the input frames to graylevels. See the Wikipedia entry for HSL color space for more information.
$ cvtool color -h 120 < red.pnm > green.pnm $ cvtool color -h 120 < green.pnm > blue.pnm $ cvtool color -h 120 < blue.pnm > red.pnm $ cvtool color -s -1 < colored.pnm > gray.pnm $ cvtool color -l +1 < dark.pnm > light.pnm
$ cvtool gamma -g 2.2 < dark.pnm > bright.pnm
Invert input frames.
$ cvtool invert < in.pnm > out.pnm
Draw simple geometric forms, lines and curves, and/or text.
The style for the object lines and the filling can be specified separately; it is either ‘none’ (line/filling is not drawn), ‘color’ (solid color), ‘pattern’ (a pattern read from a file), ‘multipattern’ (a different pattern for each input frame, all read from a file), ‘linear-gradient’ (a linear gradient), or ‘radial-gradient’ (a radial gradient). The default is the solid color black for lines and no filling.
A linear gradient specification
x0,y0,color0,x1,y1,color1 defines a
gradient along the line from start point
x0,y0 (with color
to end point
x1,y1 (with color
color1). Any number of additional
color stops can be added by appending an offset value and its associated color
to the gradient specification. The offsets must be between 0.0 and 1.0 and
describe the position on the gradient line, where 0.0 is the start point and
1.0 is the end point.
A radial gradient specification
a gradient from the start cirlce
x0,y0,r0 with color
the end circle
x1,y1,r1 with color
color1. Additional stops can
be added in the same way as for linear gradients.
The style of lines can be further adjusted with the --width, --dash, --line-cap, and --line-join options. The --width option selects the line width; it is 2.0 by default. The --dash takes a list of values that specify alternating lengths for "line on" and "line off" segments of a line. If only one value is given, these lengths are equal. The --line-cap option selects the style of line and curve ends. The --line-join options selects the style of the meeting point of two line or curve segments.
Antialiasing can be turned on (default) and off with --antialias.
If --unit is given, then all coordinates and sizes on the command line refer to a frame of size 1x1. All values are then scaled so that they match the real frame dimensions. For example, the point (0.5,0.5) will always be in the middle of a frame, regardless of the frame dimensions.
Text is drawn relative to the current drawing position (previously set with
move_to, for example). By default, the current drawing position sets the
bottom left point of the first character of the text. This can be changed with
the --justify-x and --justify-y options.
The font family, slant, weight, and size can be chosen. Note that you may not
get an error message if --font-family fails to set the given font,
because the underlying library may not report this error. If you use two
values for the font size, then the first applies to the horizontal direction
and the second to the vertical direction, so that you can scale the font
A drawing command consists of a command name and parameter sets that define one or more instances of the command.
Simple geometric forms:
Lines and curves:
Open lines and curves will automatically be closed when drawing geometric forms or text.
The draw command is only a simple interface to the excellent CAIRO graphics library. Much of the CAIRO documentation is useful for this command, too, especially the FAQ.
# Draw two green circles with a line width of 5. $ cvtool draw -w 5 -c green circle 50,50,40 50,50,20 \ < blank.pnm > circle.pnm # The same, but filled with linear gradient from red to yellow to blue. $ cvtool draw -w 5 -S linear-gradient \ -G 10,50,red,90,50,blue,0.5,yellow circle 50,50,40 50,50,20 \ < blank.pnm > circle.pnm # Display one video inside another video in the form of a circle. $ cvtool draw -s none -S multipattern -P video2.pnm circle 50,50,40 \ < video1.onm > out.pnm # Print a string exactly centered in the middle of blank.pnm. $ cvtool draw -u -f "Serif" -F 0.1,0.1 -j center -J center \ move_to 0.5,0.5 text "Hello world" \ < blank.pnm > text.pnm
filter gauss [-3|--3d] -k|--k=k
filter gauss [-3|--3d] -s|--sigma=s
filter gauss [-3|--3d] -x|--k-x=kx
filter gauss [-3|--3d] [-k|--k=k
Filter framess with a Gauss filter, in 2D or 3D (with the third dimension being the time). The kernel size can be given for each dimension, or once for all. It will be (2kx+1)x(2ky+1)[x(2kt+1)]. Different values for each direction lead to asymmetric filtering. The gauss filter can be specified by the sigma value(s): the mask size will be computed so that roughly 95% of the mass lies within the resulting mask. It is also possible to specify both sigma and k.
$ cvtool gauss --3d -k 3 < video.pnm > smoothed-video.pnm
filter mean [-3|--3d] -k|--k=k
filter mean [-3|--3d] -x|--k-x=kx
Filter frames with a Mean filter, in 2D or 3D (with the third dimension being the time). The kernel size can be given for each dimension, or once for all. It will be (2kx+1)x(2ky+1)[x(2kt+1)]. Different values for each direction lead to asymmetric filtering.
$ cvtool mean -k 2 < in.pnm > out.pnm
filter median [-a|--approximated] [-3|--3d] -k|--k=k
filter median [-a|--approximated] [-3|--3d] -x|--k-x=kx
Filter frames with a Median filter, in 2D or 3D (with the third dimension being the time). The kernel size can be given for each dimension, or once for all. It will be (2kx+1)x(2ky+1)[x(2kt+1)]. Different values for each direction lead to asymmetric filtering.
If the –approxmated option is given, then the median will be approximated. This helps to allow larger mask sizes.
$ cvtool median -a -k 2 < in.pnm > out.pnm
filter min [-3|--3d] -k|--k=k
filter min [-3|--3d] -x|--k-x=kx
Filter frames with a Minimum filter, in 2D or 3D (with the third dimension being the time). The kernel size can be given for each dimension, or once for all. It will be (2kx+1)x(2ky+1)[x(2kt+1)]. Different values for each direction lead to asymmetric filtering.
$ cvtool min -k 2 < in.pnm > out.pnm
filter max [-3|--3d] -k|--k=k
filter max [-3|--3d] -x|--k-x=kx
Filter frames with a Maximum filter, in 2D or 3D (with the third dimension being the time). The kernel size can be given for each dimension, or once for all. It will be (2kx+1)x(2ky+1)[x(2kt+1)]. Different values for each direction lead to asymmetric filtering.
$ cvtool max -k 2 < in.pnm > out.pnm
Convolve frames with the given convolution kernel.
Both 2D and 3D kernels are accepted (the third dimension is the time). If the kernel is separable, the vectors that generate it can be given instead, to reduce computation costs. All kernel elements must be integers. The size of the kernel must be an odd number in each dimension.
# Both commands are equivalent to 2D smoothing with the # mean filter with k=1: $ cvtool convolve -K 3x3:1,1,1,1,1,1,1,1,1 < in.pnm > out.pnm $ cvtool convolve -X 3:1,1,1 -Y 3:1,1,1 < in.pnm > out.pnm
Sharpens the input frames using the Laplace operator.
The sharpness factor c must be greater than or equal to zero. Larger values increase the effect. The default is 0.5.
$ cvtool laplace -c 0.7 < smooth.pnm > sharp.pnm
Sharpens the input frames using unsharp masking.
The unsharp version of the input frames must be given using the ‘--unsharp’ option. It can be produced using e.g. a 3x3 Gauss filter. The sharpness parameter c must be from (0.5, 1.0). The default is 0.7.
$ cvtool unsharpmask -u smoothsmooth.pnm -c 0.7 < smooth.pnm > sharp.pnm
wavelets -t|--task=dwt -D|--daubechies=D
wavelets -t|--task=idwt -D|--daubechies=D
wavelets -t|--task=hard-thresholding -l|--level=l
wavelets -t|--task=soft-thresholding -l|--level=l
Perform Discrete Wavelet Transform (DWT), Inverse Discrete Wavelet transform (IDWT), or manipulations on transformed data.
The parameter D chooses the Daubechies wavelet (D2, ..., D20; only even numbers). The level l must be at least 1. The threshold parameter for soft thresholding is applied to all input channels. The output of this command is always of type float; it has to be manually converted if necessary.
$ cvtool wavelets -t dwt -D 2 -l 1 < in.pfs > dwt.pfs $ cvtool wavelets -t soft-thresholding -l 1 -T 0.5 < dwt.pfs > st.pfs $ cvtool wavelets -t idwt -D 2 -l 1 < st.pfs > out.pfs
edge canny -s|--sigma=sigma
Sobel will generate graylevel frames: the brighter a point, the stronger the edge.
Canny will generate binary frames. The sigma parameter is for Gauss smoothing. l and h are used for Hysterese thresholding; both must be from [0,1].
If the input is PFS, then the output will be PFS too and will contain both a channel containing the edge strengths and a channel containing the edge directions. If the input is PNM, then the output will be graylevel frames containing only the strength information.
$ cvtool edge sobel < in.pgm > gray-edges.pgm $ cvtool edge canny -s 1.2 -l 4 -h 8 < in.pgm > bw-edges.pgm
diff [-s|--statistics] [-o|--output=file
] file-1 file-2
Shows the differences between the two sources.
The sources must have the same pixel type, width, and height. This command produces frames of the same dimensions and of the same pixel type. Each pixel will be the absolute value of the difference of the corresponding pixels in the two sources. For RGB frames, the values will be computed for each channel separately.
If --statistics is used, the command will also compute the minimum,
maximum, mean, and median error, and the standard deviation. For RGB frames,
these values will be computed for each channel separately. For YUV frames, only
the Y channel is considered. The output will be printed to
stderr, unless it
is redirected with the --output option. If the output is redirected to
stdout (-), then only the statistics and no frames will be written to
$ cvtool create -w 10 -h 10 -c r255g0b0 > red.pnm $ cvtool create -w 10 -h 10 -c r0g255b0 > green.pnm $ cvtool diff -s -o - red.pnm green.pnm frame pair 0: minimum error = 1.0000 1.0000 0.0000 frame pair 0: maximum error = 1.0000 1.0000 0.0000 frame pair 0: median error = 1.0000 1.0000 0.0000 frame pair 0: mean error = 1.0000 1.0000 0.0000 frame pair 0: standard deviation = 0.0000 0.0000 0.0000
tonemap -m|--method=schlick94 [--brightness=b
tonemap -m|--method=tumblin99 [-l|--max-absolute-luminance=l
tonemap -m|--method=drago03 [-l|--max-absolute-luminance=l
tonemap -m|--method=reinhard05 [--intensity=i
tonemap -m|--method=ashikhmin02 [-l|--max-absolute-luminance=l
tonemap -m|--method=durand02 [-l|--max-absolute-luminance=l
tonemap -m|--method=reinhard02 [--key-value=a
Tone map frames.
High dynamic range (HDR) frames are read from standard input, and low dynamic range (LDR) frames are written to standard output. See the original papers for a description of the parameters. For some methods, the results should be gamma corrected.
The default for the maximum absolute luminance is to get it from the file (if specified), or else 150.0.
The default for schlick94 is b=100.0.
The defaults for tumblin99 are d=100.0, c=70.0.
The defaults for drago03 are d=200.0, b=0.85.
The defaults for reinhard05 are i=0.0, l=0.5, c=0.5.
The default for ashikhmin02 is c=0.5.
The defaults for durand02 are ss=0.3, sc=0.4, bc=2.0.
The defaults for reinhard02 are a=0.1, w=1.0, s=10.0, e=0.5.
Sort frame contents. The channel k is used as the sorting key. If k is -1, then all channels are sorted independently.
$ cvtool sort < in.pnm > out.pnm
visualize scalar [-p|--pseudo-color] [-m|--min=m
visualize vector2 -m|--mode=color
visualize vector2 -m|--mode=needle [-x|--sample-x=x
visualize scalar: Visualizes scalar values by transforming values from
[m,M] to [0,1] and writing the result as graylevel frames. M
and m are automatically determined from the input if they are not given.
By default, the transformation is linear. If ‘--log’ is given, then the
transformation will use the logarithm with the given base. If
‘--pseudo-color’ is given, then pseudo colors are used instead of gray
visualize vector2: Reads vector fields and visualizes them.
Visualization as colors: Each of the x,y,z components, which range from -1 to
1, are transformed to R,G,B values that range from 0 to 1. Visualization as
needle diagrams: Every x-th vector in horizontal direction and every
y-th vector in vertical direction will be represented by a needle. The
needles will have a distance of dx pixels in horizontal and dy
pixels in vertical direction. The needle length is the length of the vector
after it was scaled with the factor f. The default values are
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A patent license is “discriminatory” if it does not include within the scope of its coverage, prohibits the exercise of, or is conditioned on the non-exercise of one or more of the rights that are specifically granted under this License. You may not convey a covered work if you are a party to an arrangement with a third party that is in the business of distributing software, under which you make payment to the third party based on the extent of your activity of conveying the work, and under which the third party grants, to any of the parties who would receive the covered work from you, a discriminatory patent license (a) in connection with copies of the covered work conveyed by you (or copies made from those copies), or (b) primarily for and in connection with specific products or compilations that contain the covered work, unless you entered into that arrangement, or that patent license was granted, prior to 28 March 2007.
Nothing in this License shall be construed as excluding or limiting any implied license or other defenses to infringement that may otherwise be available to you under applicable patent law.
If conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot convey a covered work so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not convey it at all. For example, if you agree to terms that obligate you to collect a royalty for further conveying from those to whom you convey the Program, the only way you could satisfy both those terms and this License would be to refrain entirely from conveying the Program.
Notwithstanding any other provision of this License, you have permission to link or combine any covered work with a work licensed under version 3 of the GNU Affero General Public License into a single combined work, and to convey the resulting work. The terms of this License will continue to apply to the part which is the covered work, but the special requirements of the GNU Affero General Public License, section 13, concerning interaction through a network will apply to the combination as such.
The Free Software Foundation may publish revised and/or new versions of the GNU General Public 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.
Each version is given a distinguishing version number. If the Program specifies that a certain numbered version of the GNU General Public License “or any later version” applies to it, you have the option of following the terms and conditions either of that numbered version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of the GNU General Public License, you may choose any version ever published by the Free Software Foundation.
If the Program specifies that a proxy can decide which future versions of the GNU General Public License can be used, that proxy's public statement of acceptance of a version permanently authorizes you to choose that version for the Program.
Later license versions may give you additional or different permissions. However, no additional obligations are imposed on any author or copyright holder as a result of your choosing to follow a later version.
THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
If the disclaimer of warranty and limitation of liability provided above cannot be given local legal effect according to their terms, reviewing courts shall apply local law that most closely approximates an absolute waiver of all civil liability in connection with the Program, unless a warranty or assumption of liability accompanies a copy of the Program in return for a fee.
If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms.
To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively state the exclusion of warranty; and each file should have at least the “copyright” line and a pointer to where the full notice is found.
one line to give the program's name and a brief idea of what it does. Copyright (C) year name of author This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.
Also add information on how to contact you by electronic and paper mail.
If the program does terminal interaction, make it output a short notice like this when it starts in an interactive mode:
program Copyright (C) year name of author This program comes with ABSOLUTELY NO WARRANTY; for details type ‘show w’. This is free software, and you are welcome to redistribute it under certain conditions; type ‘show c’ for details.
The hypothetical commands ‘show w’ and ‘show c’ should show the appropriate parts of the General Public License. Of course, your program's commands might be different; for a GUI interface, you would use an “about box”.
You should also get your employer (if you work as a programmer) or school, if any, to sign a “copyright disclaimer” for the program, if necessary. For more information on this, and how to apply and follow the GNU GPL, see http://www.gnu.org/licenses/.
The GNU General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Lesser General Public License instead of this License. But first, please read http://www.gnu.org/philosophy/why-not-lgpl.html.