Patent ID: 8437577

Claim:
A method for aligning a test image and a reference image, said method comprising: a) determining a first reduction factor associated with a first direction; b) determining a second reduction factor associated with a second direction; c) scaling the reference image according to the first reduction factor and the second reduction factor; d) scaling the test image according to the first reduction factor and the second reduction factor; e) determining a first alignment measurement between the test image and the reference image using the scaled test image and the scaled reference image; f) adjusting the test image according to the first alignment measurement; and g) determining a second alignment measurement between the test image and the reference image using the adjusted test image and the reference image; wherein: a) the first reduction factor is based on a first search range in the first direction; and b) the second reduction factor is based on a second search range in the second direction; and wherein: a) the first reduction factor is calculated according to ⌊ ( 3 2 ⁢ FirstSearchRange ) 2 5 ⌋ , where FirstSearchRange denotes the first search range; and b) the second reduction factor is calculated according to ⌊ ( 3 2 ⁢ SecondSearchRange ) 2 5 ⌋ , where SecondSearchRange denotes the second search range.