An image processing method capable of detecting noise includes adjusting a lighting unit to acquire an over-exposure image, comparing each pixel of the over-exposure image with at least one threshold value, labeling a pixel of the over-exposure image as the noise while bright intensity of the pixel is lower than the threshold value, calculating a simulating value according to bright intensity of pixels around the noise and except the noise, and utilizing the simulating value and bright intensity of other pixels except the noise to execute a displacement detecting calculation.