Hello everyone

I've been working on the improvement of the DMD based maskless lithography. I read somewhere else that in the UV/DUV lithography industry, in order to measure the aerial image intensity distribution of the litho tool, ASML, Nikon, Canon all develop their methods and devices. What kind of device and method should I use in order to measure the aerial image intensity distribution of the DMD based maskless lithography？ I‘ve done a lot of search and digging, but nothing is quite helpful.