Precise and stable centroid estimation is crucial for many tasks that require locating a light spot.We present an algorithm for fitting a deformed sigmoid function (two-dimensional sigmoid function) to the edge shape and profiled intensity of a light spot. The information of the spot (such as the center position,the size, and the tilt,) can be obtained by this fitting.
The robustness of our proposal against noise, contrast,aspect ratio, and tilt is assessed compared with the adaptive circle–ellipse fitting and the centroid weighted Kalman filter algorithm, and the performance is validated experimentally.
We show that our proposed algorithm provides better results than these algorithms, especially with regards to noise immunity. It is an effective and precise algorithm for estimating the centroid location of a light spot and can be used in a wide variety of optical sensing applications.