Besides matlab, what else is like processing software?

Basically, all tools that can be used for mathematical calculation can be used as image processing software. In addition to matlab, there are python (GIMP-commonly known as free photoshop, which uses Python code to realize its dazzling ps function), Octave (commonly known as free MATLAB usually cooperates with R language to deal with medical and biological java) and opencv (all languages have interfaces and can be written in Python or C language) for machine learning. Processing an image is actually processing a matrix of color values. Matlab has its own image toolkit, which can easily process images, such as radon transform, graying, singular value processing and so on. But these are not the patents of matlab, and opencv also provides quite efficient image processing tools (free of charge).