I am using ArcGIS for a geology mapping project. I've mapped 500+ features as polygons using a basemap of a planet's surface. I want to get information regarding the "darkness," that is, the greyscale values (0-255) of the pixels contained within the polygons. Ideally I want the descriptive statistics of all the pixels (mean, mode, variance, etc.) contained within the bounds of the polygon.
Does such a tool exist in ArcToolbox, or has anyone ever heard of a plug-in for such a thing?