Convert PFM to G3

The Portable Floatmap (PFM) file format, also known as Portable FloatMap, is an image file format designed to store High Dynamic Range (HDR) images using floating-point values. Developed in the spirit of the Portable Pixmap format, PFM files contain image data with resolutions and byte order specified in the header. This format is particularly useful for applications requiring precise image data, such as computer graphics and image processing. PFM has been widely adopted in the IT industry for its ability to handle a wide range of pixel values beyond the standard 0-255 range, making it ideal for HDR imaging and other advanced visualizations.

The G3 file extension refers to the CCITT Group 3 Fax Image, a standardized format developed by the Consultative Committee for International Telegraphy and Telephony (CCITT), now known as ITU-T. This format was created to efficiently compress black-and-white fax documents for transmission over telephone lines. It employs a method called Modified Huffman Coding for data compression, enabling reduced transmission time and bandwidth usage. G3 was widely adopted in the 1980s and 1990s as the primary standard for fax transmissions, ensuring compatibility across different fax machines and systems.