NAME

       idiff - compare two images

SYNOPSIS

       idiff [options] image1 image2

DESCRIPTION

       The idiff utility is invoked as follows:

       idiff [options] image1 image2

       Where input1 and input2 are the names of two image files that should be compared. They may
       be of any format recognized by OpenImageIO (i.e.,  for  which  image-reading  plugins  are
       available).

       If  the  two  input images are not the same resolutions, or do not have the same number of
       channels, the comparison will return FAILURE immediately and will not attempt  to  compare
       the  pixels  of  the  two  images.  If they are the same dimensions, the pixels of the two
       images will be compared, and a report will be  printed  including  the  mean  and  maximum
       error,  how  many  pixels  were  above the warning and failure thresholds, and whether the
       result is PASS, WARNING, or FAILURE. For example:

       $ idiff a.jpg b.jpg
       Comparing "a.jpg" and "b.jpg"
         Mean error = 0.00450079
         RMS error = 0.00764215
         Peak SNR = 42.3357
         Max error = 0.254902 @ (700, 222, B)
         574062 pixels (82.1%) over 1e-06
         574062 pixels (82.1%) over 1e-06
       FAILURE

       The "mean error" is the average difference (per channel, per pixel). The  "max  error"  is
       the largest difference in any pixel channel, and will point out on which pixel and channel
       it was found. It will also give a count of how many pixels  were  above  the  warning  and
       failure thresholds.

       The  metadata  of  the  two  images  (e.g., the comments) are not currently compared; only
       differences in pixel values are taken into consideration.

       For a complete description, see /usr/share/doc/openimageio-doc/openimageio.pdf.gz.

OPTIONS

       --help Print help message

       -v     Verbose status messages

       -a     Compare all subimages/miplevels

   Thresholding and comparison options
       -fail %g
              Failure threshold difference (0.000001)

       -failpercent %g
              Allow this percentage of failures (0)

       -hardfail %g
              Fail if any one pixel exceeds this error (infinity)

       -warn %g
              Warning threshold difference (0.00001)

       -warnpercent %g
              Allow this percentage of warnings (0)

       -hardwarn %g
              Warn if any one pixel exceeds this error (infinity)

       -p     Perform perceptual (rather than numeric) comparison

   Difference image options
       -o %s  Output difference image

       -od    Output image only if nonzero difference

       -abs   Output image of absolute value, not signed difference

       -scale %g
              Scale the output image by this factor

SEE ALSO

       iconvert(1), igrep(1), iinfo(1), iv(1), maketx(1), oiiotool(1).

AUTHOR

       OpenImageIO was written by Larry Gritz and the other authors and contributors.

       This manual page was written by IRIE Shinsuke <irieshinsuke@yahoo.co.jp>, for  the  Debian
       project (and may be used by others).

                                           Dec 11, 2012                                  IDIFF(1)