Using multiple separate emitters and detectors it should be possible to determine how every point reflects light (i.e. sample its BRDF for a limited angular ran

Using multiple separate emitters and detectors it should be possible to determine how every point reflects light (i.e. sample its BRDF for a limited angular range and set of wavelengths), which should allow to distinguish at least between a limited set of materials such as snow, solid ice, liquid water and asphalt. Cameras alone seems unsuitable, since it doesn't seem possible to make a camera-based system that works correctly all the time, ideally provably so, as required for a life-critical system.