pfsstat1

Usage

Overview

This command will show a short text statistic on each image in the pfs stream. In the statistics you can find:

File - name of the input file

Width, Height - image dimensions

Minimum - minimum luminance of an image(*), given in linear

units (relative luminance in cd/m^2) and logarithmic units

Maximum - maximum luminance of an image(*)

Average - average luminance of an image(*)

Mean - mean luminance of an image(*)

(*) Before min, max, average, median and dynamic range is computed, the following processing is performed on an image: 1) negative and zero values are replaced with the smallest positive value (to compute logarithms); 2) the image is low-pass filtered. The low-pass filtering removes few very dark or very bright pixels that can significantly influence estimation of the dynamic range. The percentile, instead of a low-pass filter, is sometimes used for the same purpose. However, a low-pass filter is preferred to the percentile in pfstools since, taking into account the processing that is happening in the human visual system, low-frequency band filter is more plausible.

Note: This command requires GNU Octave.

Examples

pfsin memorial.hdr | pfsstat

Show statistics for the memorial image.