Steps 3 and 4 seem like a largely solved problem using blob detection in computer vision libraries. The last step is in plated via detection. If no microvias

Steps 3 and 4 seem like a largely solved problem using blob detection in computer vision libraries. The last step is in plated via detection. If no microvias are present this seems pretty easy: just look for circles. If microvias are present then you need to check for plating at each layer for each hole below a certain size. That seems difficult if the sanding process does not result in very clean features.