Run length encoded data derived from a raster scanner at an arbitrary angle to the horizontal direction of a rectilinear symbol such as a two-dimensional PDF code is examined to detect the skew angle between the horizontal direction of the symbol and the horizontal direction of the raster. Using the...http://www.google.com.au/patents/US6490376?utm_source=gb-gplus-sharePatent US6490376 - Skew processing of raster scan images
