Image processing apparatus and control method therefor

Abstract

An image processing apparatus according to the present invention comprises: an acquisition unit that acquires a statistical value of pixel values for each divided region; a determination unit that compares for each divided region the statistical value of the divided region acquired by the acquisition unit with a first threshold and determines whether the divided region is as color region or a monochrome region; and a re-determination unit that compares a statistical value of an adjacent divided region with a second threshold, by which a divided region is more likely determined as a color region than by the first threshold, for each adjacent divided region, and re-determines whether the adjacent divided region is a color region or a monochrome region.

What is claimed is: 
     
         1 . An image processing apparatus that divides an input image into a color region and a monochrome region,
 the apparatus comprising:   an acquisition unit that acquires a statistical value of pixel values for each divided region obtained by dividing the input image;   a division unit that divides the input image into a color region and a monochrome region on the basis of the statistical value for each divided region acquired by the acquisition unit; and   a movement unit that moves a boundary between the color region and the monochrome region, which are divided by the division unit, so that the boundary passes inside a boundary proximity region, which is a region separated from the boundary by a predetermined distance toward a monochrome region, when a brightness value of the boundary proximity region is lower than a predetermined value.   
     
     
         2 . The image processing apparatus according to  claim 1 , wherein the boundary proximity region is a region in a divided region adjacent to the boundary. 
     
     
         3 . The image processing apparatus according to  claim 1 , wherein the boundary proximity region is a small divided region separated by the predetermined distance from the boundary toward a monochrome region, from among a plurality of small divided regions obtained by dividing the input image to a degree smaller than that of the divided regions. 
     
     
         4 . The image processing apparatus according to  claim 3 , wherein
 the small divided region is a region obtained by dividing the divided region into two columns and two rows, which are four regions; and   the boundary proximity region is a small divided region that is not adjacent to the boundary, from among small divided regions in a divided region adjacent to the boundary.   
     
     
         5 . The image processing apparatus according to  claim 1 , wherein when a plurality of boundaries between color regions and monochrome regions divided by the division unit are present, the movement unit performs boundary moving processing for each boundary. 
     
     
         6 . A control method for an image processing apparatus that divides an input image into a color region and a monochrome region,
 the control method comprising:   an acquisition step of acquiring a statistical value of pixel values for each divided region obtained by dividing the input image;   a division step of dividing the input image into a color region and a monochrome region on the basis of the statistical value for each divided region acquired in the acquisition step; and   a movement step of moving a boundary between the color region and the monochrome region, which are divided in the division step, so that the boundary passes inside a boundary proximity region, which is a region separated from the boundary by a predetermined distance toward a monochrome region, when a brightness value of the boundary proximity region is lower than a predetermined value.