System for optical determination of coefficient of friction for a surface

An image processing system for determining a coefficient of friction for a surface comprising:

• an active imaging sensor including:
• at least one emitter configured to emit active light toward the surface as predetermined flux densities of emitted light throughout a field of illumination that includes at least a portion of the surface;
• at least one photodetector configured to receive light for a field of view that includes the portion of the surface, wherein the at least one photodetector is configured to produce an intensity value in response to a number of incident photons of light;
• control circuitry operably coupled to the at least one emitter and the at least one photodetector and configured to store an image of data as image pixels in at least one frame buffer, wherein a frame buffer intensity value of each image pixel is based at least in part on the intensity value of the at least one photodetector;
• and
• a processing system operably coupled to the at least one frame buffer, wherein the processing system is configured to:
• determine a flux density of incident light for a given image pixel based on the predetermined flux densities of emitted light;
• and
• utilize the frame buffer intensity value of the given image pixel to convert the frame buffer intensity value to a radiance value;
• compute a reflectivity value for a given image pixel based on dividing the radiance value by the flux density for the given image pixel;
• determine a set of image pixels that represent the surface and for each of such surface pixels compute a set of characteristic values, including:
• a normal angle to the surface, and
• an entrance angle value defined as an angle between a surface normal angle and an angle at which a reflected signal contacts the surface;
• and
• compute a coefficient of friction for the surface based on the reflectivity values and the entrance angle values for the set of surface pixels.