Patent ID: 7480420

Claim:
A method comprising: selecting two adjacent image line, using a processor, each line representing a plurality of pixels, the image lines having respective level values P i and P i−1 , the values P i and P i−1 each representing the brightness level of the pixels represented by a corresponding one of the image lines; calculating an absolute value of a difference between said values P i and P 1−1 ; comparing said absolute value of the difference between said values P i and P i−1 to a value X, wherein if said absolute value of the difference between said values P i and P i−1 is smaller than said value X, said two adjacent image lines are determined as normal, and wherein if said absolute value of the difference between said values P i and P i−1 is larger than said value X, said two adjacent image lines are determined as abnormal; if said absolute value of the difference between said values P i and P i−1 is larger than said value X, selecting an image line having a level value P i+1 adjacent to said image line having the level value P i and further selecting an image line having a level value P i−2 adjacent to said image line having the level value P i−1 , each of the newly selected image lines representing a plurality of pixels, the values P i+1 and P i−2 of the newly selected image lines each representing the brightness level of the pixels represented by a corresponding one of the newly selected image lines; calculating an absolute value of a difference between said values P i+1 and P i−2 ; and comparing said absolute value of the difference between said values P i+1 and P i−2 to said value X.