Patent ID: 8295581

Claim:
A method for detecting defects in an optical component to be tested, such as a lens, comprising the steps of: providing a structured pattern; recording the reflected or transmitted image of the pattern on the optical component to be tested; phase shifting the pattern and recording again similarly the reflected or transmitted image; calculating the local phase and amplitude images of the optical component to be tested; calculating a model image of a defect free optical component and determining corresponding phase and amplitude images of the defect free model optical component; comparing phase and amplitude images of both optical component to be tested and defect free model optical component; determining suspect zones in the optical component to be tested; and applying a metrics to separate dust and noise from other defects; wherein the metrics compare the values of A 1 =M z −μ v and A 2 =μ v −m z with threshold values so as to separate dust from other defects, M z being the maximum value, m z the minimum value and μ v the mean of the values of the phase or amplitude over a suspect zone.