Abstract: A Two-Dimensional Optical encoder (“2-D Encoder”), including a light emitter and a light detector array. The light detector array includes at least one band of light detectors arranged on at least one diagonal of an X-Y grid having an X-axis and a Y-axis, wherein the X-axis and Y-axis are approximately orthogonal. A process for making a 2-D Encoder; and a method for encoding two-dimensional motion.

Abstract: The color of a surface is determined by tracking the position of the surface using grayscale image sensing and then using captured grayscale image information, position information, and grayscale-to-color conversion information to determine color. In one embodiment, the technique requires establishing grayscale-to-color conversion information and a relationship between position and the grayscale-to-color conversion information. A calibration pattern is printed on a piece of paper and the surface of the paper is illuminated. Grayscale image information and position information related to the surface is generated in response to the illumination. Color-specific portions of the grayscale-to-color conversion information that are to be used in color determination are selected based on the position information.