Patent ID: 7417774

Claim:
A method of identifying intended response marks in an optically scanned image of a response sheet having key marks and response targets printed in the same color, comprising the steps of: (a) providing a digital imaging scanner capable of capturing an image of a response sheet with RGB values assigned to each pixel corresponding to the color of that pixel, (b) providing a response sheet having key marks and response targets printed in the same color, (c) capturing with the scanner a digital image of the sheet with each pixel having RGB values assigned thereto, (d) locating key marks in the captured image by processing pixels having RGB values that correspond to the color of the key marks, (e) calculating from the location of the key marks in the image an expected location of response targets in the image, (f) processing pixels having RGB values corresponding to any color other than the color of the target to determine whether an intended response mark was made at a response target.