Name

iscale — Image scaler

Synopsis

iscale -v +scale -contrast p=outpath infile

Description

The iscale command loads any number of input files, reduces their sizes by a given scale factor in both x and y directions, and writes the results to a common output folder.

The scale factor may be specified on the command line following a plus sign. The default is 8.

An integer contrast may be specified to increase the image contrast. This works in a slightly unusual way: If <x> is the average intensity of the image, then a pixel with intensity x is mapped to 128 + c * (x - <x>).

Normally, each output pixel is the average of a block of scale x scale input pixels. If, however, one or more -v arguments are given, the output is instead the | x - <x> | noise in each block.

If an input file is /path/to/file.ext and the scale factor is n, then the output file is /path/to/Snfile.ext.

Exception: if “p=outpath” is specified on the command line, the output file is outpath/Snfile.ext.

iscale is primarily intended for grayscale images. It will run on RGB images as well, but contrast adjustment and variance measurement are not supported.

Authors

iscale was written by Tom Wetzel. This page was written by Daniel Wagenaar.