Convert PHM to VIPS

The PHM file extension stands for Portable Float-map Image (16-bit half), a format used for storing High Dynamic Range (HDR) images with 16-bit half-precision floating-point values. This format is particularly useful in applications requiring precise color representation and extensive dynamic range, such as computer graphics, image processing, and scientific visualization. Originating from the Portable FloatMap (PFM) format, PHM was developed to provide a more efficient storage solution by utilizing half-precision floats, thereby reducing file size while maintaining significant detail and accuracy.

The VIPS (Virtual Image Processing System) file format, developed by the libvips library, is designed for high-performance image processing with low memory usage. It supports arbitrary metadata and is optimized for command-line operations. Although not widely supported by other programs, it serves as an efficient intermediate format for tasks like image inversion and gamma correction. The format includes a 64-byte header with basic fields such as image width and a set of band-interleaved scanlines for the image data.