Back to results
US 6,978,045 B1Granted
Image-processing apparatus
AssigneeMinolta Co., Ltd.
InventorsKeisuke Hashimoto, Yoshihiko Hirota
Life of this patent
Estimating the term…
Abstract
In an image processor on multi-level image data, an edge direction of a target pixel is discriminated from differences in density level between the target pixel and adjacent pixels thereof. A pixel is divided into a plurality of sub-pixels, and the image is formed in the unit of sub-pixels. The density level is set for each of the sub-pixels in the target pixel in accordance with the discrimination on the edge direction of the target pixel so that the center of gravity in density is changed in the target level. Then a character edge portion is reproduced more smoothly.
Claims19
An image processor which processes grayscale image data on density levels of pixels, comprising:
- an edge judgment circuit which discriminates an edge direction of a target pixel from differences in density level between the target pixel and adjacent pixels thereof based upon the grayscale image data;
- and
- a density level determining circuit which determines grayscale density levels in a plurality of sub-pixels in the target pixel, where the target pixel is divided into the sub-pixels, in accordance with the density level of the target pixel and the edge direction of the target pixel discriminated by the edge judgment circuit, wherein the density level determining circuit comprises:
- a density controller circuit which sets density-level setting parameters for each of the sub-pixels in the target pixel in accordance with the edge direction of the target pixel discriminated by said edge judgment circuit;
- and
- a density-level setter circuit which sets the density level of each of the plurality of sub-pixels in the target pixel based upon the density level of the target pixel by using the parameters set by said density controller circuit;
- wherein the density level of the sub-pixels are determined by using a calculation for input gradation data with the parameters, the parameter for each pixel being determined based on the determined edge direction.
4 more elements
An image processor which processes grayscale image data on density levels of pixels, comprising:
- an edge judgment circuit which discriminates an edge direction of a target pixel from differences in density level between the target pixel and adjacent pixels thereof based upon the grayscale image data;
- a density level determining circuit which determines grayscale density levels in a plurality of sub-pixels in the target pixel, where the target pixel is divided into the sub-pixels, in accordance with the density level of the target pixel and the edge direction of the target pixel discriminated by the edge judgment circuit;
- a line width judgment circuit which determines a width of a line including the target pixel;
- and
- a smoothing circuit which performs smoothing on the image data of the target pixel and the adjacent pixels thereof in accordance to the line width determined by said line width judgment circuit and outputs the image data of the target pixel which have been smoothed;
- wherein the density level determining circuit determines the density levels in the plurality of sub-pixels in accordance with the density level of the target pixel subjected to smoothing by said smoothing circuit and the edge direction of the target pixel discriminated by the edge judgment circuit.
3 more elements
An image processor which processes grayscale image data on density levels of pixels, comprising:
- an edge judgment circuit which discriminates an edge direction of a target pixel from differences in density level between the target pixel and adjacent pixels thereof based upon the grayscale image data;
- and
- a density level determining circuit which determines grayscale density levels in a plurality of sub-pixels in the target pixel, where the target pixel is divided into the sub-pixels, in accordance with the density level of the target pixel and the edge direction of the target pixel discriminated by the edge judgment circuit;
- the image processor further comprising a smoothing circuit which performs smoothing on image data of the pixel, on which said edge judgment circuit discriminates an edge, by using an asymmetric filter having the target pixel at a center thereof, wherein said density level determining circuit determines density level of each of the sub-pixels in the target pixel based on the density level of the image data of the target pixel smoothed by said smoothing circuit and on the edge direction of the target pixel discriminated by said edge judgment circuit.
1 more element
A method for processing processes grayscale image data on density levels of pixels, where a pixel is divided into a plurality of sub-pixels, comprising the steps of:
- discriminating an edge direction of a target pixel from differences in density level between the target pixel and adjacent pixels thereof based upon the grayscale image data;
- determining grayscale density levels in a plurality of sub-pixels in the target pixel in accordance with the density level of the target pixel and the discriminated edge direction of the target pixel;
- setting density level setting parameters for each of the sub-pixels in the target pixel in accordance with the discriminated edge direction of the target pixel;
- and
- setting the density level of each of the plurality of sub-pixels in the target pixel based upon the density level of the target pixel by using the set parameters;
- smoothing the image data of the pixel whose edge is discriminated, by using an asymmetric filter having a target pixel at a center thereof, and determining density level of each of the sub-pixels in the target pixel based on the density level of the image data of the target pixel smoothed and on the edge direction of the target pixel discriminated;
- wherein the density level of the sub-pixels are determined by using a calculation for input gradation data with the parameters, the parameter for each pixel being determined based on the determined edge direction.
4 more elements
A method for processing processes grayscale image data on density levels of pixels, where a pixel is divided into a plurality of sub-pixels, comprising the steps of:
- discriminating an edge direction of a target pixel from differences in density level between the target pixel and adjacent pixels thereof based upon the grayscale image data;
- and
- determining grayscale density levels in a plurality of sub-pixels in the target pixel in accordance with the density level of the target pixel and the discriminated edge direction of the target pixel;
- determining a width of a line including the target pixel;
- and
- performing smoothing on the image data of the target pixel and the adjacent pixels thereof in accordance to the determined line width and outputting the image data of the target pixel which have been smoothed;
- wherein an aid step of determining density levels ef determines the density levels in the plurality of sub-pixels in accordance with the density level of the target pixel subjected to smoothing and the discriminated edge direction of the target pixel.
4 more elements
An image processor which processes grayscale image data on density levels of pixels, comprising:
- an edge judgment circuit which discriminates an edge direction of a target pixel from differences in density level between the target pixel and adjacent pixels thereof based upon the grayscale image data;
- and
- a density level determining circuit which determines density levels in a plurality of sub-pixels in the target pixel, where the target pixel is divided into the sub-pixels, in accordance with the density level of the target pixel and the edge direction of the target pixel discriminated by the edge judgment circuit;
- wherein the density level determining circuit comprises:
- a density controller circuit which sets density-level setting parameters for each of the sub-pixels in the target pixel in accordance with the edge direction of the target pixel discriminated by said edge judgment circuit;
- and
- a density-level setter circuit which sets the density level of each of the plurality of sub-pixels in the target pixel based upon the density level of the target pixel by using the parameters set by said density controller circuits
- a smoothing circuit which performs smoothing on image data of the pixel, on which said edge judgment circuit discriminates an edge, by using an asymmetric filter having the target pixel at a center thereof, wherein said density level determining circuit determines density level of each of the sub-pixels in the target pixel based on the density level of the image data of the target pixel smoothed by said smoothing circuit and on the edge direction of the target pixel discriminated by said edge judgment circuit;
- wherein the density level of the sub-pixels are determined by using a calculation for input gradation data with the parameters, the parameter for each pixel being determined based on the determined edge direction.
6 more elements
An image processor which processes grayscale image data on density levels of pixels, comprising:
- an edge judgment circuit which discriminates an edge direction of a target pixel from differences in density level between the target pixel and adjacent pixels thereof based upon the grayscale image data;
- and
- a density level determining circuit which determines density levels in a plurality of sub-pixels in the target pixel, where the target pixel is divided into the sub-pixels, in accordance with the density level of the target pixel and the edge direction of the target pixel discriminated by the edge judgment circuit;
- wherein the density level determining circuit comprises:
- a density controller circuit which sets density-level setting parameters for each of the sub-pixels in the target pixel in accordance with the edge direction of the target pixel discriminated by said edge judgment circuit;
- and
- a density-level setter circuit which sets the density level of each of the plurality of sub-pixels in the target pixel based upon the density level of the target pixel by using the parameters set by the density controller circuit;
- a smoothing circuit which performs smoothing on image data of the pixel, on which said edge judgment circuit discriminates an edge, by using an asymmetric filter having the target pixel at a center thereof, wherein said density level determining circuit determines density level of each of the sub-pixels in the target pixel based on the density level of the image data of the target pixel smoothed by said smoothing circuit and on the edge direction of the target pixel discriminated by said edge judgment circuit;
- wherein the density level of the sub-pixels are determined by using a calculation for input gradation data with the parameters, the parameter for each pixel being determined based on the determined edge direction;
- and
- wherein said edge judgment circuit cancels the discriminated edge direction when the density level of a pixel adjacent to the target pixel in the edge direction is larger than a threshold value.
8 more elements
Dependencies are inferred from the claim text.