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An improved sub-pixel algorithm for laser spot center determination based on Zernike moments

The laser spot determination is the critical technique in laser detecting systems. Due to atmospheric turbulence and other factors, the laser spot intensity distributes unevenly in the long-distance measurement. In order to improve the location precision of the laser spot detection, an improved sub-pixel algorithm based on Zernike moments is presented in this paper with theoretical analysis. The experimental results of the proposed algorithm with CCD image test are also given and compared with that of four conventional algorithms including gravity model, Hough transform, circle fitting, and spatial moment operators. The comparative results demonstrate that the improved algorithm based on Zernike moments has the virtue of higher measuring precision. The stability and interference suppression ability are also improved. The proposed algorithm has already been applied into the processing of our laser detecting system, which can also play an important role in automatic recognition, etc.