Background noise removing apparatus and method applicable to color image processing apparatus
AssigneeRicoh Company, Ltd.
InventorsHisao Shirasawa, Kaoru Imao
Life of this patent
Estimating the term…
Abstract
A density converting unit converts densities concerning respective color components in color-image data for each pixel so as to change the densities concerning respective color components for the pixel into lower densities when the densities concerning respective color components for the pixel are determined to be white or approximately white. The density converting unit converts the densities concerning color components in the color-image data for each pixel so as to change the densities concerning respective color components for the pixel into densities corresponding to white ones when all of the densities concerning respective color components for the pixel are lower than a predetermined threshold density value.
Claims33
A background noise removing apparatus for removing background noise from color image data represented as pixels, each pixel having a plurality of color components, and each color component having a respective density, the apparatus comprising a density converting means including:
- means for determining whether or not the density of each color component of a pixel corresponds to a white or approximately white area in an input image, the determining means determining the density of each color component based on a single, collective piece of information concerning the densities of all the respective color components of the pixel;
- and
- means for converting the density of each color component of said pixel to a lower density only when the determining means determines that the densities for all color components of said pixel correspond to a white or approximately white area in the input image.
A background noise removing method for removing background noise from color image data represented as pixels, each pixel having a plurality of color components, and each color component having a respective density, the method comprising:
- (a) determining whether or not each one of the densities of a pixel's color components corresponds to a white or approximately white area in an image, the determining relating to each one of the densities being based on information concerning all densities of all the respective color components of the pixel;
- (b) converting the density of each color component so that all the densities for the pixel are changed together into lower densities when it is determined in the determining step that the densities correspond to a white or approximately white area of the image;
- and
- (c) determining, for each pixel, whether or not the color image data constitutes data corresponding to a white or approximately-white image portion, based on:
- 1) the minimum reflectance from among the red component reflectance, the green component reflectance and the blue component reflectance of the color image data for the pixel;
- and
- 2) the maximum difference in density between the red density, the green density and the blue density of the color image data for the pixel.
A background noise removing apparatus for removing background noise from color image data represented as pixels, each pixel having a plurality of color components, and each color component having a respective density, the apparatus comprising:
- means for determining whether or not each one of the densities of a pixel's color components corresponds to a white or approximately white area in an image, the determining relating to each one of the densities being based on information concerning all densities of all the respective color components of the pixel;
- density converting means for converting the density of each color component so that all the densities for the pixel are changed together into lower densities when the determining means determines that the densities correspond to a white or approximately white area in the image;
- maximum-density-component detecting means for detecting for each pixel which color component thereof has the maximum density from among a red component, a green component and a blue component of the color image
- data, said determining means determining, for each pixel, whether or not the color image data constitutes data having densities approximately corresponding to white color, the determination being executed based on the maximum-density component of the color image data for each pixel, the maximum-density color component having been detected by said maximum-density component detecting means;
- wherein said density converting means includes means for converting densities for each pixel in the color image data in manners determined by using the maximum density of the color component of the color image data for the pixel, the color component having been detected for the pixel by said maximum-density component detecting means.
A background noise removing apparatus for removing background noise from color image data represented as pixels, each pixel having a plurality of color components, and each color component having a respective density, the apparatus comprising:
- means for determining whether or not each one of the densities of a pixel's color components corresponds to a white or approximately white area in an image, the determining relating to each one of the densities being based on information concerning all densities of all the respective color components of the pixel;
- density converting means for converting the density of each color component so that all the densities for the pixel are changed together into lower densities when the determining means determines that the densities correspond to a white or approximately white area in the image,
- said determining means determining, for each pixel, whether or not the color image data thereof constitutes data of a white or approximately-white image portion, the color image data including data of a white or approximately-white image portion being data to be converted by said density converting means, the determination being executed based on:
- 1) the maximum density from among the red density, the green density and the blue color density of the color image data for the pixel;
- and
- 2) the maximum difference in density between densities of the red density, the green density and the blue color density of the color image data for the pixel.
A background noise removing apparatus for removing background noise from color image data represented as pixels, each pixel having a plurality of color components, and each color component having a respective density, the apparatus comprising:
- means for determining whether or not each one of the densities of a pixel's color components corresponds to a white or approximately white area in an image, the determining relating to each one of the densities being based on information concerning all densities of all the respective color components of the pixel;
- density converting means for converting the density of each color component so that all the densities for the pixel are changed together into lower densities when the determining means determines that the densities correspond to a white or approximately white area in the image,
- said determining means determining, for each pixel, whether or not the color image data thereof constitutes data of a white or approximately-white image portion, the determination for each pixel being executed based on the minimum reflectance among the red component reflectance, the green component reflectance and the blue component reflectance of the color image data for the pixel.
A background noise removing apparatus for removing background noise from color image data represented as pixels, each pixel having a plurality of color components, and each color component having a respective density, the apparatus comprising:
- means for determining whether or not each one of the densities of a pixel's color components corresponds to a white or approximately white area in an image, the determining relating to each one of the densities being based on information concerning all densities of all the respective color components of the pixel;
- and
- density converting means for converting the density of each color component so that all the densities for the pixel are changed together into lower densities when the determining means determines that the densities correspond to a white or approximately white area in the image,
- said determining means determining, for each pixel, whether or not the color image data constitutes data thereof constitutes data of a white or approximately-white image portion, the determination for each pixel being executed based on:
- 1) the minimum reflectance from among the red component reflectance, the green component reflectance and the blue component reflectance of the color image data for the pixel;
- and
- 2) the maximum difference in density between densities among the red density, the green density and the blue color density of the image data for the pixel.
A background noise removing method for removing background noise from color image data represented as pixels, each pixel having a plurality of color components, and each color component having a respective density, the method comprising the steps of:
- determining whether or not the density of each color component of a pixel corresponds to a white or approximately white area in an image, the determining being performed for the density of each color component based on a single piece of collective information concerning the densities of all the respective color components of the pixel;
- and
- converting the density of each color component of said pixel to a lower density only when it is determined in the determining step that the densities for all color components of said pixel correspond to a white or approximately white area of the image.
A background noise removing method for removing background noise from color image data represented as pixels, each pixel having a plurality of color components, and each color component having a respective density, the method comprising:
- (a) determining whether or not each one of the densities of a pixel's color components corresponds to a white or approximately white area in an image, the determining relating to each one of the densities being based on information concerning all densities of all the respective color components of the pixel;
- (b) converting the density of each color component so that all the densities for the pixel are changed together into lower densities when it is determined in the determining step that the densities correspond to a white or approximately white area of the image;
- (c) detecting, for each pixel, a color component having the maximum density from among a red component, a green component and a blue component of the color image data;
- and
- (d) determining, for each pixel, whether or not the color image data constitutes data corresponding to approximately white color densities, the determination being executed based on the maximum density color component of the color image data for the pixel, the maximum density color component having been detected for the pixel in said maximum-density-component detecting step (c);
- wherein said density converting step (b) includes converting densities for each pixel in the color image data in manners determined by using the maximum density color component of the color image data for each pixel, the maximum density color component having been detected for the pixel in said maximum-density-component detecting step (c).
A background noise removing method for removing background noise from color image data represented as pixels, each pixel having a plurality of color components, and each color component having a respective density, the method comprising:
- (a) determining whether or not each one of the densities of a pixel's color components corresponds to a white or approximately white area in an image, the determining relating to each one of the densities being based on information concerning all densities of all the respective color components of the pixel;
- (b) converting the density of each color component so that all the densities for the pixel are changed together into lower densities when it is determined in the determining step that the densities correspond to a white or approximately white area of the image;
- and
- (c) determining, for each pixel, whether or not the color image data constitutes data of a white or approximately-white image portion, the color image data including data of a white or approximately-white image portion being data to be converted by said density converting step (b), the determination being executed based on:
- 1) the maximum density from among the red density, the green density and the blue color density of the color image data for each pixel;
- and
- 2) the maximum difference in density between densities of the red density, the green density and the blue density of the color image data for the pixel.
A background noise removing method for removing background noise from color image data represented as pixels, each pixel having a plurality of color components, and each color component having a respective density, the method comprising:
- (a) determining whether or not each one of the densities of a pixel's color components corresponds to a white or approximately white area in an image, the determining relating to each one of the densities being based on information concerning all densities of all the respective color components of the pixel;
- (b) converting the density of each color component so that all the densities for the pixel are changed together into lower densities when it is determined in the determining step that the densities correspond to a white or approximately white area of the image;
- and
- (c) determining, for each pixel, whether or not the color image data constitutes data corresponding to a white or approximately-white image portion, the determination for each pixel being executed based on the minimum reflectance among the red component reflectance, the green component reflectance and the blue component reflectance of the color image data for the pixel.
Dependencies are inferred from the claim text.