Determining a gray background value and/or skew of a scanned document

摘要

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.