Patent attributes
After an original image, including half-tone dot meshed characters are inputted and a prescribed process is applied to the original image, black pixel connection patterns are extracted from a target process area. If the density of the extracted pattern exceeds prescribed density, it is judged that the pattern is half-tone dot meshed and both the respective average values and standard deviations of the vertical/horizontal sizes of the connection pattern are calculated. Then, respective threshold values are calculated based on both the respective average values and standard deviations, and half-tone dot patterns are eliminated. Furthermore, a pattern, the outline of which is long compared with an included black pixel, of all the remaining connection patterns is eliminated as an unnecessary pattern. Lastly, projections attached to a character are deleted and character extraction is terminated.
