Autofocus using image phase congruency

The key issue in passive autofocus is to choose robust focus measures to judge optical blur in defocused images. Existing focus measures are sensitive to image contrast (illumination) as they use image intensity. In this report we demonstrate a focus measure using phase congruency. The proposed focus measure is robust for noisy imaging sensors in varying illumination conditions, and has great balance of defocus sensitivity and effective range. Its advantages are shown with a number of synthetic image sequences.