The PFM which is an acronym for Portable Float-Map is a simple structured raster image format. It is actually part of Netpbm converters, an open-source package of graphics programs used in Unix operating systems. To be specific, PFM is a floating-point image format that can be used for 32-bits-per-channel HDR files.
Because of its simple and general design, it's easy to develop programs to convert, manipulate and create the image. The file contents could be either ASCII or binary defined in its simple always ASCII header information.
The PFM header contains an ASCII identifier line. It could be the characters "PF" or "Pf". PF means it's a color PFM and Pf means it's a grayscale one. Each pixel consists of 3 or 1 sample based on this structure.
|High Dynamic Range image storage and processing. Easily exchange binary images between platforms back in the '80s.