Patent ID: 6369916
Filing Date: 2002-04-09
Classification: H04N

Abstract:
A dot area judging apparatus, comprising:data retaining means for retaining image data indicative of densities of individual pixels in a plurality of lines in a document original image; dot candidate pixel detecting means for detecting a dot candidate pixel on the basis of the image data retained in the data retaining means; detection result retaining means for retaining detection results obtained for a plurality of lines by the dot candidate pixel detecting means; extension means for extensively applying a dot candidate pixel detection result obtained for an object line by the dot candidate pixel detecting means to lines adjacent to the object line by modifying the detection results retained in the detection result retaining means; and dot area judging means for judging, on the basis of a distribution of dot candidate pixels within a predetermined judgment base area which distribution is obtained after the extension operation performed by the extension means, that a judgment area having a predetermined positional relationship with the judgment base area is a dot area, the dot area judging means including: means for defining a second object pixel and a plurality of judgment pixels having a predetermined positional relationship with the second object pixel as constituent pixels of the judgment base area, the constituent pixels of the judgment base area not being adjacent to the second object pixel; judging means for judging whether a number of the dot candidate pixels out of the constituent pixels in the judgment base area is not smaller than a predetermined number; and determining means for determining, if it is judged by the judging means that the number of dot candidate pixels out of the constituent pixels is not smaller than the predetermined number, that the judgment area which is a predetermined area on the object line including the second object pixel is a dot area.