what's he building over there

pixels come in many different colours even though they describe the same shapes. a red circle is only different from a blue circle because of the colours. as a preprocessing step prior to neural analysis images must be converted into a map of change gradients or else the network fails as a classifier. changes are evaluated across the plane and reconstituted with thresholds for each magnitude of change. mustaches present their own special challenge. I haven't solved that one yet.