This invention relates to an image processing method and an image processing apparatus, and more particularly, to an image processing method and image processing apparatus for detecting a rectangular image.
Various algorithms have been proposed so far for the sake of detecting and carving out a rectangular area from an original image. For instance, Japanese Patent Laid-Open No. 8-237537 has a technology described wherein an outline is extracted first and the rectangular area detected by looking for a portion of the outline constituting a straight line.
According to the conventional algorithms for carving out a rectangle, however, it was difficult, in an environment of plenty of noise, to detect a straight line portion of a rectangular outline and to further detect one rectangle by associating four straight lines. Therefore, it was difficult to accurately carve it out so that precision of the results of carving it out was not sufficient.