Image processing apparatus, image processing method and program

Abstract

There is provided an image processing apparatus which can generate a vector image with a high image quality at a high speed in a small memory capacity. The present invention generates an image with low resolution by performing resolution conversion to a compressed image with high resolution and obtains information of a character object with low resolution by performing object division to the image with the low resolution. The compressed image with the high resolution is decompressed and an image showing a character contour with high resolution is generated by using the information of the character object with the low resolution obtained by the object dividing and the decompressed image with the high resolution. At the time of performing the decompression, the compressed image with the high resolution may be partially decompressed based upon the information of the character object.

1 . An image processing apparatus comprising:
 a resolution converting unit configured to generate an image with low resolution by performing resolution conversion to a compressed image with high resolution;   an object dividing unit configured to obtain information of a character object with low resolution by performing object division to the image with the low resolution;   a decompressing unit configured to decompress the compressed image with the high resolution; and   a character contour generating unit configured to generate an image showing a character contour with high resolution by using the information of the character object with the low resolution obtained by the object dividing unit and the image with the high resolution decompressed by the decompressing unit.   
   
   
       2 . An image processing apparatus according to  claim 1 , wherein:
 the information of the character object with the low resolution obtained by the object dividing unit is a binary image with low resolution where pixels of a character and pixels of a background contained in a character region determined as containing a character image are shown in a binary value; and   the character contour generating unit specifies pixels in which the pixels of the character may exist using the binary image with the low resolution and generates the image showing the character contour with the high resolution using the each specified pixel and the decompressed image with the high resolution.   
   
   
       3 . An image processing apparatus according to  claim 2 , wherein:
 the character contour generating unit determines a threshold value in the adjacence of the each specified pixel using the each specified pixel and the decompressed image with the high resolution to generate the image showing the character contour with the high resolution by binarizing a portion of the decompressed image with the high resolution corresponding to the each specified pixel by using the determined threshold value.   
   
   
       4 . An image processing apparatus according to  claim 1 , further comprising:
 a function approximate unit configured to function-approximate the character contour based upon the image showing the character contour with the high resolution generated by the character contour generating unit; and   a formatting unit configured to format the function-approximated result.   
   
   
       5 . An image processing apparatus according to  claim 1 , further comprising:
 a compressing unit configured to compress an inputted image with high resolution to generate the compressed image with the high resolution; and   a spooling unit configured to spool the compressed image with the high resolution, wherein:   the decompressing unit decompress the compressed image with the high resolution spooled by the spooling unit.   
   
   
       6 . An image processing apparatus according to  claim 1 , wherein:
 the character contour generating unit converts the image with the high resolution decompressed by the decompressing unit into a luminance image with high resolution in a case where the image with the high resolution is a color image, and generates the image showing the character contour with the high resolution by using the information of the character object with the low resolution obtained by the object dividing unit and the luminance image with the high resolution.   
   
   
       7 . An image processing apparatus according to  claim 1 , wherein:
 the decompressing unit partially decompress the compressed image with the high resolution based upon the information of the character object.   
   
   
       8 . An image processing apparatus according to  claim 7 , wherein:
 the decompressing unit decompress a portion in the compressed image with the high resolution corresponding to the character object region containing plural characters.   
   
   
       9 . An image processing apparatus according to  claim 7 , wherein:
 the decompressing unit decompress a portion in the compressed image with the high resolution corresponding to one character.   
   
   
       10 . An image processing apparatus according to  claim 7 , wherein:
 the decompressing unit determines whether or not a memory capacity necessary for processing the character object region is smaller than a memory capacity set preliminarily, based upon the information of the character object;   the decompressing unit decompress a portion in the compressed image with the high resolution corresponding to the character object region in a case where it is determined that the memory capacity necessary for processing the character object region is smaller than the memory capacity set preliminarily; and   the decompressing unit decompress a portion in the compressed image with the high resolution corresponding to one character in a case where it is determined that the memory capacity necessary for processing the character object region is not smaller than the memory capacity set preliminarily.   
   
   
       11 . An image processing apparatus according to  claim 7 , wherein:
 the decompressing unit determines whether or not a memory capacity necessary for processing the character object region is smaller than a memory capacity set preliminarily, based upon the information of the character object;   the decompressing unit decompress a portion in the compressed image with the high resolution corresponding to the character object region in a case where it is determined that the memory capacity necessary for processing the character object region is smaller than the memory capacity set preliminarily; and the decompressing unit divides the character object region into regions each having a process-possible size and decompress a portion in the compressed image with the high resolution corresponding to the divided region in a case where it is determined that the memory capacity necessary for processing the character object region is not smaller than the memory capacity set preliminarily.   
   
   
       12 . An image processing method, the method comprising the steps of:
 generating an image with low resolution by performing resolution conversion to a compressed image with high resolution by a resolution converting unit;   obtaining information of a character object with low resolution by performing object division to the image with the low resolution by an object dividing unit;   decompressing the compressed image with the high resolution by a decompressing unit; and   generating an image showing a character contour with high resolution by using the information of the character object with the low resolution obtained by the object dividing step and the image with the high resolution decompressed by the decompressing step by a character contour generating unit.   
   
   
       13 . A program on a computer readable medium for making a computer perform:
 a resolution converting step of generating an image with low resolution by performing resolution conversion to a compressed image with high resolution;   an object dividing step of obtaining information of a character object with low resolution by performing object division to the image with the low resolution;   a decompressing step of decompressing the compressed image with the high resolution; and   a character contour generating step of generating an image showing a character contour with high resolution by using the information of the character object with the low resolution obtained by the object dividing step and the image with the high resolution decompressed by the decompressing step.