Image processing apparatus and image processing method

Abstract

To detect an image region to be an object of thinning processing appropriately and through the use of simple processing. An image processing apparatus detects a line region being a region sandwiched by white pixel regions and consisting only of a non-white pixel region, and detects a thinning candidate region being a region sandwiched by black pixel regions in the line region. A thinning region is detected from the inside of the thinning candidate region.

1 . An image processing apparatus detecting an image region from an input image, comprising:
 a unit configured to detect a white pixel region being a line having only white dots and extending in a main scanning direction;   a unit configured to detect a non-white pixel region being a line having at least one black dot and extending in the main scanning direction;   a unit configured to detect a black pixel region being a line having only black dots and extending in the main scanning direction;   a unit configured to detect a line region sandwiched by the white pixel regions and including only the non-white pixel region;   a unit configured to detect a thinning candidate region being a region sandwiched between the black pixel regions in the line region; and   a unit configured to detect a region located at a predetermined distance from the black pixel region located at the front end in a sub scanning direction to rearward of the sub scanning direction in the thinning candidate region and having a predetermined width in the sub scanning direction, as a thinning region.   
     
     
         2 . The image processing apparatus according to  claim 1 , wherein the input image is binary image data. 
     
     
         3 . The image processing apparatus according to  claim 1 , wherein the input image is multi-value image data. 
     
     
         4 . The image processing apparatus according to  claim 1 , wherein the input image is an image read optically. 
     
     
         5 . The image processing apparatus according to  claim 1 , wherein the input image is an image received from an external device. 
     
     
         6 . The image processing apparatus according to  claim 1 , comprising a unit configured to perform thinning processing on the detected thinning region. 
     
     
         7 . The image processing apparatus according to  claim 1 , wherein the detected thinning region is a region adjacent to the rearward of the black pixel region, in the sub scanning direction, located at the front end in the sub scanning direction in the thinning candidate region. 
     
     
         8 . The image processing apparatus according to  claim 1 , wherein the unit configured to detect the line region has a line width counter starting counting at the moment when the non-white pixel region adjacent to the white pixel region in the sub scanning direction is detected, and counting up every time the continuous non-white pixel regions are detected; and
 wherein the line region is detected by using the line width counter.   
     
     
         9 . The image processing apparatus according to  claim 1 ,
 wherein the unit configured to detect the thinning candidate region comprising:
 a thinning region flag switched ON when detecting the black pixel region appearing first in the sub scanning direction in the line region; 
 a thinning region width counter counting up every time the non-white pixel region is detected continuously in the sub scanning direction while the thinning region flag is ON; and 
 a gray width counter being cleared when the black pixel region is detected, and counting up every time a region of neither the black pixel region nor the white pixel region is detected continuously in the sub scanning direction, in the line region, and 
   wherein the thinning candidate region is detected through the use of a value obtained by subtracting the value of the gray width counter from the value of the thinning region width counter when the white pixel region is detected.   
     
     
         10 . An image processing method executed in an image processing apparatus detecting an image region from an input image, comprising:
 a step of detecting a white pixel region being a line having only white dots and extending in a main scanning direction;   a step of detecting a non-white pixel region being a line having at least one black dot and extending in the main scanning direction;   a step of detecting a black pixel region being a line having only black dots and extending in the main scanning direction;   a step of detecting a line region sandwiched by the white pixel regions and including only the non-white pixel region;   a step of detecting a thinning candidate region being a region sandwiched between the black pixel regions in the line region; and   a step of detecting a region located at a predetermined distance from the black pixel region located at the front end in a sub scanning direction to rearward of the sub scanning direction in the thinning candidate region and having a predetermined width in the sub scanning direction, as a thinning region.   
     
     
         11 . A program on a computer-readable recording medium, having computer-executable instructions for performing a method, the method comprising:
 a step of detecting a white pixel region being a line having only white dots and extending in a main scanning direction;   a step of detecting a non-white pixel region being a line having at least one black dot and extending in the main scanning direction;   a step of detecting a black pixel region being a line having only black dots and extending in the main scanning direction;   a step of detecting a line region sandwiched by the white pixel regions and including only the non-white pixel region;   a step of detecting a thinning candidate region being a region sandwiched between the black pixel regions in the line region; and   a step of detecting a region located at a predetermined distance from the black pixel region located at the front end in a sub scanning direction to rearward of the sub scanning direction in the thinning candidate region and having a predetermined width in the sub scanning direction, as a thinning region.   
     
     
         12 . An image processing apparatus comprising:
 a unit for detecting, in a region consisting of N dots in a main scanning direction and M dots in a sub scanning direction included in binary image data (N and M are counting number), a region as a line edge region which includes at least one black dot and consists of N dots in a main scanning direction and one dot in a sub scanning direction, the line edge region being adjacent to a region whose every dot is a white dot and which consists of N dots in a main scanning direction and one dot in a sub scanning direction;   a unit for detecting a region as a black pixel region which is sandwiched by a plurality of the detected line edge region and consists of N dots in a main scanning direction and one dot in a sub scanning direction and whose every dot is a black dot; and   a unit for processing to change a part of black dots in a thinning candidate region into white dots, the thinning candidate region being a region sandwiched by a plurality of the detected black pixel region.   
     
     
         13 . An image processing apparatus comprising:
 a unit for detecting, in a region consisting of N dots in a main scanning direction and M dots in a sub scanning direction included in multi-value image data (N and M are counting number), a region as a line edge region whose not all of dots are white dots and which consists of N dots in a main scanning direction and one dot in a sub scanning direction, the line edge region being adjacent to a region whose every dot is a white dot and which consists of N dots in a main scanning direction and one dot in a sub scanning direction;   a unit for detecting a region as a black pixel region which is sandwiched by a plurality of the detected line edge region and consists of N dots in a main scanning direction and one dot in a sub scanning direction and whose every dot is a black dot; and   a unit for processing to change a part of black dots in a thinning candidate region into white dots, the thinning candidate region being a region sandwiched by a plurality of the detected black pixel region.   
     
     
         14 . An image processing method comprising:
 a step of detecting, in a region consisting of N dots in a main scanning direction and M dots in a sub scanning direction included in binary image data (N and M are counting number), a region as a line edge region which includes at least one black dot and consists of N dots in a main scanning direction and one dot in a sub scanning direction, the line edge region being adjacent to a region whose every dot is a white dot and which consists of N dots in a main scanning direction and one dot in a sub scanning direction;   a step of detecting a region as a black pixel region which is sandwiched by a plurality of the detected line edge region and consists of N dots in a main scanning direction and one dot in a sub scanning direction and whose every dot is a black dot; and   a step of processing to change a part of black dots in a thinning candidate region into white dots, the thinning candidate region being a region sandwiched by a plurality of the detected black pixel region.   
     
     
         15 . An image processing method comprising:
 a step of detecting, in a region consisting of N dots in a main scanning direction and M dots in a sub scanning direction included in multi-value image data (N and M are counting number), a region as a line edge region whose not all of dots are white dots and which consists of N dots in a main scanning direction and one dot in a sub scanning direction, the line edge region being adjacent to a region whose every dot is a white dot and which consists of N dots in a main scanning direction and one dot in a sub scanning direction;   a step of detecting a region as a black pixel region which is sandwiched by a plurality of the detected line edge region and consists of N dots in a main scanning direction and one dot in a sub scanning direction and whose every dot is a black dot; and   a step of processing to change a part of black dots in a thinning candidate region into white dots, the thinning candidate region being a region sandwiched by a plurality of the detected black pixel region.   
     
     
         16 . A program on a computer-readable recording medium, having computer-executable instructions for performing a method, the method comprising:
 a step of detecting, in a region consisting of N dots in a main scanning direction and M dots in a sub scanning direction included in binary image data (N and M are counting number), a region as a line edge region which includes at least one black dot and consists of N dots in a main scanning direction and one dot in a sub scanning direction, the line edge region being adjacent to a region whose every dot is a white dot and which consists of N dots in a main scanning direction and one dot in a sub scanning direction;   a step of detecting a region as a black pixel region which is sandwiched by a plurality of the detected line edge region and consists of N dots in a main scanning direction and one dot in a sub scanning direction and whose every dot is a black dot; and   a step of processing to change a part of black dots in a thinning candidate region into white dots, the thinning candidate region being a region sandwiched by a plurality of the detected black pixel region.   
     
     
         17 . A program on a computer-readable recording medium, having computer-executable instructions for performing a method, the method comprising:
 a step of detecting, in a region consisting of N dots in a main scanning direction and M dots in a sub scanning direction included in multi-value image data (N and M are counting number), a region as a line edge region whose not all of dots are white dots and which consists of N dots in a main scanning direction and one dot in a sub scanning direction, the line edge region being adjacent to a region whose every dot is a white dot and which consists of N dots in a main scanning direction and one dot in a sub scanning direction;   a step of detecting a region as a black pixel region which is sandwiched by a plurality of the detected line edge region and consists of N dots in a main scanning direction and one dot in a sub scanning direction and whose every dot is a black dot; and   a step of processing to change a part of black dots in a thinning candidate region into white dots, the thinning candidate region being a region sandwiched by a plurality of the detected black pixel region.