| IDIFF(1) | General Commands Manual | IDIFF(1) |
idiff - compare two images
idiff [options] image1 image2
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.
iconvert(1), igrep(1), iinfo(1), iv(1), maketx(1), oiiotool(1).
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).
| December 11, 2012 |