Image processing apparatus, image forming apparatus, image processing method, and computer readable recording medium
First Claim
1. An image processing apparatus comprising:
- a segmentation process section, which performs classification processing for an object pixel based on a pixel surrounding the object pixel, for classifying whether each of pixels forming inputted image data belongs to at least an edge area or a non-edge area; and
a tone reproduction process section for converting the inputted image data into an image data with a predetermined gray level and outputting the converted image data,the tone reproduction process section including;
an error diffusion process section for performing conversion of gray level using an error diffusion method;
a blue noise mask process section for performing conversion of the gray level using a blue noise mask method; and
an output selection section for outputting a gray level value converted by the error diffusion process section in the case in which the object pixel belongs to the edge area, and outputting a gray level value converted by the blue noise mask process section in the case in which the pixel belongs to the non-edge area.
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Abstract
An error diffusion process section performs an error diffusion process on a pixel value of each of processing object pixels and outputs the processed pixel value to an output selection section. A blue noise mask process performs a blue noise mask process on a pixel value of each of processing object pixels and outputs the processed pixel value to the output selection section. The output selection section selects and outputs the pixel value outputted from the error diffusion process section when a segmentation class signal indicates a character (text) area or a halftone dot area, namely an edge area, and selects and outputs the pixel value outputted from the blue noise mask process section when a segmentation class signal indicates an area other than the character area or the halftone dot area, namely non-edge area.
11 Citations
20 Claims
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1. An image processing apparatus comprising:
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a segmentation process section, which performs classification processing for an object pixel based on a pixel surrounding the object pixel, for classifying whether each of pixels forming inputted image data belongs to at least an edge area or a non-edge area; and a tone reproduction process section for converting the inputted image data into an image data with a predetermined gray level and outputting the converted image data, the tone reproduction process section including; an error diffusion process section for performing conversion of gray level using an error diffusion method; a blue noise mask process section for performing conversion of the gray level using a blue noise mask method; and an output selection section for outputting a gray level value converted by the error diffusion process section in the case in which the object pixel belongs to the edge area, and outputting a gray level value converted by the blue noise mask process section in the case in which the pixel belongs to the non-edge area. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An image processing apparatus comprising:
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a segmentation process section, which performs classification processing for an object pixel based on a pixel surrounding the object pixel, for classifying whether each of pixels forming inputted image data belongs to at least an edge area or a non-edge area; and a tone reproduction process section for converting the inputted image data into an image data with a predetermined gray level and outputting the converted image data, wherein the tone reproduction section performs the conversion of the gray level using an error diffusion method, and selects a fixed threshold value in the case in which the object pixel belongs to the edge area, and selects a threshold value corresponding to a position of the object pixel from a threshold mask to quantize a gray level value by a threshold process using the selected threshold value. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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17. An image processing method comprising:
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a segmentation process step of performing classification processing for an object pixel based on a pixel surrounding the object pixel, and classifying whether each of pixels forming inputted image data belongs to at least an edge area or a non-edge area; and a tone reproduction process step of converting the inputted image data into an image data with a predetermined gray-scale and outputting the converted image data, wherein in the tone reproduction process step, the conversion of the gray-scale is performed by the error diffusion method in the case in which the processing object pixel belongs to the edge area, and the conversion of the gray-scale is performed by the blue noise mask method in the case in which the pixel belongs to the non-edge area. - View Dependent Claims (18)
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19. An image processing method comprising:
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a segmentation process step of performing classification processing for an object pixel based on a pixel surrounding the object pixel, and classifying whether each of pixels forming inputted image data belongs to at least an edge area or a non-edge area; and a tone reproduction process step of converting the inputted image data into an image data with a predetermined gray-scale and outputting the converted image data, the tone reproduction process step including; a selection step of selecting a fixed threshold value in the case in which a processing the object pixel belongs to the edge area, and selecting a threshold value corresponding to a position of the processing object pixel from a threshold mask; a quantization step of quantizing the gray-scale value by a threshold process using the selected threshold value; and an error diffusion step of performing the error diffusion using the error diffusing method. - View Dependent Claims (20)
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Specification