Apparatus and method for image processing
AssigneeCanon Kabushiki Kaisha
InventorKunihiro Yamamoto
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Abstract
This disclosure relates to an image processing apparatus or an image processing method, and takes as its technical problem the fact that conventionally it is difficult to perform a process of carving out a rectangle with high precision in a noisy environment. Therefore, as to an image made by binarizing an original image, histograms of the numbers of horizontal and vertical black pixels thereof are created and trapezoidal approximation is performed on the histograms so as to detect vertex coordinates indicating an extent of a rectangular area in the binary image. An inclination direction of the rectangular area in the extent is detected so that the rectangular area can be detected from the binary image with high precision.
Claims58
An image processing method for detecting a rectangular area from an image, comprising:
- a histogram creation step of creating histograms of the numbers of horizontal and vertical black pixels of a binary image made by binarizing an original image;
- a rectangle extent detection step of performing trapezoidal approximation to the histograms so as to detect an extent of the rectangular area in said binary image;
- and
- an inclination direction detection step of detecting an inclination direction of said rectangular area in said extent.
An image processing apparatus for detecting a rectangular area from an image, comprising:
- a histogram creation component for creating histograms of the numbers of horizontal and vertical black pixels in a binary image made by binarizing an original image;
- a rectangle extent detection component for performing trapezoidal approximation to the histograms so as to detect an extent of the rectangular area in said binary image;
- and
- an inclination direction detection component for detecting an inclination direction of said rectangular area in said extent.
An image processing program for detecting a rectangular area from an image, comprising:
- a code of a histogram creation step creating histograms of the numbers of horizontal and vertical black pixels in a binary image made by binarizing an original image;
- a code of a rectangle extent detection step of performing trapezoidal approximation to the histograms so as to detect an extent of the rectangular area in said binary image;
- and
- a code of an inclination direction detection step of detecting an inclination direction of said rectangular area in said extent.
An image processing method for labeling an object in a binary image, comprising:
- a black block detection step of, in said binary image, detecting as a black block a block of a predetermined size having a number of black pixels therein equal to or higher than a predetermined ratio;
- and
- a label replacement step of replacing the black pixels inside and connected to the detected black block with a predetermined label value.
An image processing apparatus for labeling an object in a binary image, comprising:
- a black block detection component for, in said binary image, detecting as a black block a block of a predetermined size having a number of black pixels therein equal to or higher than a predetermined ratio;
- and
- a label replacement component for replacing the black pixels inside and connected to the detected black block with a predetermined label value.
An image processing method for trimming an end of a rectangular image, comprising:
- a histogram generation step of generating a histogram of the number of white pixels in a binary rectangular image;
- a mixed area determination step of determining a white pixel mixed area at an end of said rectangular image based on said histogram;
- and
- an elimination step of eliminating said white pixel mixed area from the end of said rectangular image.
An image processing apparatus for trimming an end of a rectangular image, comprising:
- a histogram generation component for generating a histogram of the number of white pixels in a binary rectangular image;
- a mixed area determination component for determining a white pixel mixed area at an end of said rectangular image based on said histogram;
- and
- an elimination component for eliminating said white pixel mixed area from the end of said rectangular image.
An image processing program for trimming an end of a rectangular image, comprising:
- a code of a histogram generation step of generating a histogram of the number of white pixels in a binary rectangular image;
- a code of a mixed area determination step of determining a white pixel mixed area at an end of said rectangular image based on said histogram;
- and
- a code of an elimination step of eliminating said white pixel mixed area from the end of said rectangular image.
Dependencies are inferred from the claim text.