Charge-coupled devices combined with centroid algorithm for laser beam deviation measurements compared to a position-sensitive device

A position sensitive device (PSD) is frequently used in laser beam deviation measurement. However, it lacks the capability to retrieve the power distribution information of a laser beam. A charge-coupled device (CCD) gives much more information of a laser beam than a PSD. The requirement of a multifunctional sensor makes the replacement of a PSD with a CCD in measuring laser beam deviation to be a reasonable topic. In this paper a performance comparison between a PSD and a CCD combined with a centroid algorithm are discussed with special attention paid to the CCD-based system. According to the operating principle of the CCD-based system, several experiments were carried out to evaluate five factors of the CCD-based system: image window size, number of processed images, threshold, binning, and saturation. By applying the optimized parameters, several experiments were made to compare the CCD-based system with the state-of-the-art PSD-based system in terms of two performance indicators, namely resolution and speed. It is shown that, by applying the optimized parameters, the performance of a CCD-based system is comparable to that of a PSD-based system in measuring laser beam deviation.