compare(1)		    General Commands Manual		    compare(1)



NAME
       compare	-  mathematically and visually annotate the difference between
       an image and its reconstruction.

SYNOPSIS
       compare input-file input-file [options] output-file

OVERVIEW
       The compare program is a member of the ImageMagick(1) suite  of	tools.
       Use  it	to mathematically and visually annotate the difference between
       an image and its reconstruction.

       For more information about the compare command, point your  browser  to
       file:///usr/share/doc/ImageMagick-6/www/compare.html@EXTRA_DOC_DIR@  or
       http://imagemagick.org/script/compare.php.

DESCRIPTION
       Image Settings:
	 -alpha option	      on, activate, off, deactivate, set, opaque, copy
			       transparent, extract, background, or shape
	 -authenticate value  decrypt image with this password
	 -background color    background color
	 -channel type	      apply option to select image channels
	 -colorspace type     alternate image colorspace
	 -compose operator    set image composite operator
	 -compress type	      type of pixel compression when writing the image
	 -decipher filename   convert cipher pixels to plain pixels
	 -define format:option
			      define one or more image format options
	 -density geometry    horizontal and vertical density of the image
	 -depth value	      image depth
	 -dissimilarity-threshold value
			       maximum distortion for (sub)image match
	 -encipher filename   convert plain pixels to cipher pixels
	 -extract geometry    extract area from image
	 -format "string"     output formatted image characteristics
	 -fuzz distance	      colors within this distance are considered equal
	 -gravity type	      horizontal and vertical text placement
	 -identify	      identify the format and characteristics  of  the
       image
	 -interlace type      type of image interlacing scheme
	 -highlight-color color
			      emphasize pixel differences with this color
	 -limit type value    pixel cache resource limit
	 -lowlight-color color
			      de-emphasize pixel differences with this color
	 -mask filename	      associate a mask with the image
	 -metric  type		measure	 differences  between images with this
       metric
	 -monitor	      monitor progress
	 -passphrase filename get the passphrase from this file
	 -profile filename    add, delete, or apply an image profile
	 -quality value	      JPEG/MIFF/PNG compression level
	 -quiet		      suppress all warning messages
	 -quantize colorspace reduce colors in this colorspace
	 -regard-warnings     pay attention to warning messages
	 -repage geometry     size and location of an image canvas
	 -respect-parentheses settings	remain	in  effect  until  parenthesis
       boundary
	 -sampling-factor geometry
			      horizontal and vertical sampling factor
	 -seed value	      seed a new sequence of pseudo-random numbers
	 -set attribute value set an image attribute
	 -similarity-threshold value
			       minimum distortion for (sub)image match
	 -size geometry	      width and height of image
	 -subimage-search     search for subimage
	 -synchronize	      synchronize image to storage device
	 -taint		      declare the image as modified
	 -transparent-color color
			      transparent color
	 -type type	      image type
	 -verbose	      print detailed information about the image
	 -virtual-pixel method
			      virtual pixel access method

       Image Operators:
	 -brightness-contrast geometry
			      improve brightness / contrast of the image
	 -distort method args
			       distort	images	according  to given method and
       args
	 -level value	      adjust the level of image contrast
	 -resize geometry     resize the image
	 -rotate degrees      apply Paeth rotation to the image
	 -separate	      separate an image channel into a grayscale image
	 -trim		      trim image edges
	 -write filename      write images to this file

       Image Sequence Operators:
	 -crop geometry	      cut out a rectangular region of the image

       Image Stack Operators:
	 -delete indexes      delete the image from the image sequence

       Miscellaneous Options:
	 -debug events	      display copious debugging information
	 -help		      print program options
	 -log format	      format of debugging information
	 -list type	      print a list of supported option arguments
	 -version	      print version information

       By default, the image format of `file' is determined by its magic  num-
       ber.   To  specify a particular image format, precede the filename with
       an image format name and a colon (i.e. ps:image) or specify  the	 image
       type as the filename suffix (i.e. image.ps).  Specify 'file' as '-' for
       standard input or output.

       Two images are considered similar if their difference according to  the
       specified metric and fuzz value is 0, with the exception of the normal-
       ized cross correlation metric (NCC), where two  images  are  considered
       similar	when their normalized cross correlation is 1. The default met-
       ric is NCC.

       The compare program returns 2 on error, 0 if the images are similar, or
       a value between 0 and 1 if they are not similar.

SEE ALSO
       ImageMagick(1)


COPYRIGHT
       Copyright  (C)  1999-2020 ImageMagick Studio LLC. Additional copyrights
       and	licenses      apply	 to	 this	   software,	   see
       file:///usr/share/doc/ImageMagick-6/www/license.html@EXTRA_DOC_DIR@  or
       http://imagemagick.org/script/license.php



ImageMagick		   Date: 2009/01/10 01:00:00		    compare(1)