Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help
Point::Point(3)	      User Contributed Perl Documentation      Point::Point(3)

       IPA::Point - single pixel transformations and image arithmetic

       Single-pixel processing is a simple method of image enhancement.	 This
       technique determines a pixel value in the enhanced image	dependent only
       on the value of the corresponding pixel in the input image.  The
       process can be described	with the mapping function

	  s = M(r)

       where "r" and "s" are the pixel values in the input and output images,

       combine [ images, conversionType	= conversionScale, combineType =
       combineSum, rawOutput = 0]
	   Combines set	of images of same dimension and	bit depth into one and
	   returns the resulting image.

	   Supported types: Byte, Short, Long.


	   images ARRAY
	       Array of	image objects.

	   conversionType INTEGER
	       An integer constant, one	of the following, that indicates how
	       the resulting image would be adjusted in	accord to the minimal
	       and maximal values of the result. "Trunc" constants cut off the
	       output values to	the bit	maximum, for example, a	result vector
	       in 8-bit	image [-5,0,100,300] would be transformed to
	       [0,0,100,255]. "Scale" constants	scale the whole	image without
	       the cutoff; the previous	example	vector would be	transformed
	       into [0,4,88,255]. The "Abs" suffix shows whether the range
	       calculation would use the whole domain, including the negative
	       values, or the absolute values only.


	       Default is "conversionScale".

	   combineType INTEGER
	       An integer constant, indicates the type of action performed
	       between pixels of same [x,y] coordinates.

		  combineMaxAbs		 - store the maximal absolute pixel value
		  combineSignedMaxAbs	 - compute the maximal absolute	value, but store its original (	before abs()) value
		  combineSumAbs		 - store the sum of absolute pixel values
		  combineSum		 - store the sum of pixel values
		  combineSqrt		 - store the square root of the	sum of the squares of the pixel	values

	       Default is "combineSum".

	   rawOutput BOOLEAN
	       Discards	"conversionType" parameter and performs	no conversion.
	       If set to true value, the conversion step is omitted.

	       Default is 0.

       threshold IMAGE [ minvalue, maxvalue = 255]
	   Performs the	binary thresholding, governed by "minvalue" and
	   "maxvalue".	The pixels, that are below "minvalue" and above
	   "maxvalue", are mapped to value 0; the other	values mapped to 255.

	   Supported types: Byte

       gamma IMAGE [ origGamma = 1, destGamma =	1]
	   Performs gamma correction of	IMAGE by a product of "origGamma" and

	   Supported types: Byte

       remap IMAGE [ lookup ]
	   Performs image mapping by a passed "lookup" array of	256 integer
	   values. Example:

	      IPA::Point::remap( $i, lookup => [ (0) x 128, (255) x 127]);

	   is an equivalent of

	      IPA::Point::threshold( $i, minvalue => 128);

	   Supported types: 8-bit

       subtract	IMAGE1,	IMAGE2,	[ conversionType = conversionScale, rawOutput
       = 0]
	   Subtracts IMAGE2 from IMAGE1. The images must be of same dimension.
	   For description of "conversionType" and "rawOutput" see combine.

	   Supported types: Byte

       mask IMAGE [ test, match, mismatch ]
	   Test	every pixel of IMAGE whether it	equals to "test", and assigns
	   the resulting pixel with either "match" or "mismatch" value.	 All
	   "test", "match", and	"mismatch" scalars can be either integers ( in
	   which case "mask" operator is similar to threshold ), or image
	   objects. If the image objects passed, they must be of the same
	   dimensions and bit depth as IMAGE.

	   Supported types: Byte, Short, Long.

       average LIST
	   Combines images of same dimensions and bit depths, passed as	an
	   anonymous array in LIST and returns the average image.

	   Supported types: Byte, Short, Long, 64-bit integer.

       equalize	IMAGE
	   Returns a histogram-equalized image.

	   Supported types: Byte

       ab IMAGE, a, b
	   Returns "IMAGE*a+b".

       exp IMAGE
	   Retuns "exp(IMAGE)"

       log IMAGE
	   Retuns "log(IMAGE)"

perl v5.24.1			  2011-05-08		       Point::Point(3)


Want to link to this manual page? Use this URL:

home | help