Algorithm of selecting the optimal focusing region

Since it will be taken so much time to compute the focusing evaluation function for high resolution images, the real-time character of focusing system is sharply influenced. This can be improved by selecting the sub-image with the most detail to focus. Adaptive genetic algorithm (AGA) which can search this region rapidly is presented. It uses weighing entropy as the fitness function and changes the probabilities of crossover and mutation self-adapting to search the global convergence. The experiment proves that this algorithm is efficient and stable. At the same time, the focus characteristic curve of the selected region is fine.