1. Field of the Invention
The present invention relates to image processing devices, image processing methods and image processing programs. More particularly, the present invention relates to image processing devices, image processing methods and image processing programs capable of detecting and correcting the inclinations of images.
2. Description of the Related Art
In the field of image creating devices as typified by MFPs (Multi Function Peripherals) and laser beam printers, there have been developed “document electronic watermarking” techniques for embedding data as tint-block patterns on the backgrounds of document images.
In order to scan a printed-out object having data embedded therein as tint-block patterns and detect the data, there has been a need for addressing the inclination of the document during the scanning.
Japanese Laid-Open Patent Publication No. 2004-128845 discloses a method of detecting the inclinations of documents on the basis of the relationship among three types of dots embedded therein as electronic watermarks, as a technique relating to countermeasure to the inclinations of documents.
Further, Japanese Laid-Open Patent Publication No. 03-144863 discloses a document-image inclination detecting and correcting method which calculates integral values of a document image in a plurality of directions and detects a peak value of the integral values as the direction of inclination, wherein during the detection the testing angle is changed in two steps (the testing angle is smaller at first and then widened) to enable rapid detection of the inclination.