Abstract: In an array of pixels, a method for segmenting a selected pixel of the array between at least two layers including identifying an N-by-N window centered upon the selected pixel, evaluating at least one pixel in the N-by-N window to determine whether the selected pixel is a potential text element, identifying an M-by-M window centered upon the selected pixel when the evaluation determines that the selected pixel is a potential text element, wherein the M-by-M window is smaller than the N-by-N window, and determining whether the potential text element includes text by comparing at least two pixels within the M-by-M window.

Abstract: One method for determining a gray background value of a scanned document having left, right, top and bottom edges includes obtaining a scanned image of a horizontal strip which includes at least one portion of the document and which includes at least one non-document area, and includes creating a histogram of pixel values, of the horizontal strip, inside the document edges while excluding from the histogram pixel values, of the horizontal strip, located outside the document edges. Another method for determining a gray background value includes obtaining a scanned image of a vertical strip. One method for determining skew of a scanned document includes obtaining a scanned image, which includes a leading document edge, using vertically-displaced successive horizontal scan lines, includes determining points of the leading edge, and includes fitting a line to the points. Another method for determining a skew uses horizontally-displaced successive vertical scan lines.

Abstract: Method for shading one of a first plurality of sensing elements of an optical sensor. High-reflectivity and low-reflectivity reference values of the output signal of each of a second plurality of sensing elements of the sensor are obtained. An average or nominal high-reflectivity value of the high-reflectivity reference values for each sensing element of the second plurality is calculated. An average or nominal low-reflectivity value of the low-reflectivity reference values for each sensing element of the second plurality is calculated. An offset value for one of the sensing elements of the first plurality is calculated using at least the average or nominal high-reflectivity values and the average or nominal low-reflectivity values. The one sensing element of the first plurality is calibrated using at least the calculated offset value. In one example, the first plurality and the second plurality are identical.