Patent ID: 8189942

Claim:
A focus-quality judging method for discriminating focus quality of a test image pickup device, said focus-quality judging method comprising steps of: providing a comparing object including a target area; providing a reference image pickup device to shoot said comparing object to obtain a standard image including a standard target area image; using a computer to count a pixel number P 1 contained in said standard target area image; shooting said comparing object by said test image pickup device to obtain a test image including a test target area image, wherein said test image has the same resolution as said standard image; using the computer to count a pixel number P 2 contained in said test target area image; and using the computer to compare said pixel number P 1 contained in said standard target area image with said pixel number P 2 contained in said test target area image, wherein if P 2 is more than or equal to P 1 , said test image pickup device is deemed to perform an accurate focusing operation, or if P 2 is less than P 1 , said test image pickup device is deemed to perform an erroneous focusing operation.