Patent ID: 7570394

Claim:
A method of determining a size of an image associated with a set of digital image data, the image data comprising a plurality of scanlines, each scanline comprising a plurality of pixels, each pixel having a luminance associated therewith, the method comprising: scanning an original image on a sheet, thereby obtaining a set of image data comprising a plurality of scanlines, each scanline comprising a plurality of pixels; for each pixel of a plurality of pixels in a scanline, incrementing a pixel difference counter if a luminance difference of the pixel relative to a second pixel in the scanline exceeds a predetermined luminance difference threshold; for each pixel of a plurality of pixels in a scanline, incrementing a line difference counter if a luminance difference of the pixel relative to a corresponding pixel in a corresponding position in a second scanline exceeds a predetermined luminance difference threshold; for each scanline, updating a scanline number register if the pixel difference counter is within a predetermined pixel difference counter range or the line difference counter is within a predetermined line difference counter range; determining a dimension of the original image based on a value of the scanline number register; and printing an image derived from the original image, using a determined dimension of the original image.