How to quantify the similarity of spatial patterns?

I am not a GISer, but I do believe a GIS (more specifically, spatial statistics) algorithm could help with the task I am carrying on. If posting a question that has already been posted (by me) on stackoverflow here does break the rule, I would delete this question.

I have several 10000*10000 grids (raster data) denoting the same tissue in mice, each representing the expression pattern of a specific type of gene (each grid-point has a value between 0 and 100). The task I am working on now is to quantify the similarity between each spatial expression patterns of genes. Since I want to take spatial information into account, I am thinking about either applying image similarity comparison algorithms from image processing (or computer vision), or spatial similarity comparison algorithms from GIS (spatial statistics). Among the two I believe spatial statistics might be more appropriate.

Sample images:

Please refer to my original question on stackoverflow for more details:
https://stackoverflow.com/questions/65912256/how-do-i-quantify-the-similarity-of-spatial-patterns