Related principles

First of all I have to say that artoolkit is a particularly excellent augmented reality tool. Not long ago I tried to use artoolkit and unity to complete an AR chess project, but I couldn't solve the problem of identifying multiple identical chess pieces at the same time. Later, I chose to use the current artoolkitx to try to solve this problem, because I noticed that you have an option for 2Dmarker‘s number in ARXController, but this function was not available after I tried it. I would like to ask if you have left the corresponding function in the code? In addition, I am very interested in artoolkitx, but there are few relevant learning materials. I would like to ask if you can provide me with some information so that I can understand how artoolkitx performs feature extraction and template matching.