Real time precise position measurement based on low-cost CMOS image sensor: DSP implementation and sub-pixel measurement precision verification

Construction of an embedded position measurement sensor based on the real-time image processing and a low-cost CMOS image sensor is presented in this work. Position measurement task is simplified with the use of assisted videometry concept - the target object is equipped with an additional marker (active or passive). An effective implementation of algorithm for the marker position estimation for Digital Signal Processor Blackfin^® is presented. Having realized a set of measurements in the real-world conditions it has been shown that achievable linearity of the position measurement in the short-range of ±7 pixels is about 1/52 of pixel with pixel-size dependent period of linearity error. Position measurement resolution is better than 1/200 of pixel.