Image forming apparatus and image forming method
First Claim
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1. An image forming apparatus which reads a color image on an original and subjects a signal of the read color image to image processing, thus forming a color image, the apparatus comprising:
- an image reading section which reads a color image on an original;
a first memory section which stores basic filter coefficients and decimal-point reference position information for subjecting a color image signal of the color image read by the image reading section to image processing;
a second memory section which has a predetermined bit width and stores filter coefficients;
a calculation section which re-calculates, when a degree of sharpness has been adjusted in the image processing, the basic filter coefficients stored in the first memory section in accordance with a value of the adjustment;
a computing section which calculates a bit number between a lowest bit and a highest bit, which are obtained by expressing in binary form a coefficient with a maximum absolute value of the filter coefficients calculated by the calculation section;
a first processing section which effects a bit shift of the filter coefficients calculated by the calculation section and stores the bit-shifted filter coefficients in the second memory section, on the basis of the bit number calculated by the computing section and the bit width of the second memory section;
an altering section which alters the decimal-point reference position information on the basis of the decimal-point reference position information stored in the first memory section and the bit width of the second memory section;
an arithmetic section which subjects the filter coefficients stored in the second memory section and the color image signal of the color image read by the image reading section to a matrix arithmetic operation in the processing of the first processing section; and
a second processing section which effects a bit shift of the image signal produced by the arithmetic section, on the basis of the decimal-point reference position information altered by the altering section.
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Abstract
A main CPU re-calculates, when the degree of sharpness has been adjusted, a coefficient in accordance with the value of adjustment. The main CPU finds a maximum bit number from the calculated filter coefficients, effects a bit shift of the filter coefficients in accordance with the size (bit width) of a filter coefficient register, and stores the bit-shifted filter coefficients in the filter coefficients register, thus carrying out a filtering process.
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Citations
9 Claims
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1. An image forming apparatus which reads a color image on an original and subjects a signal of the read color image to image processing, thus forming a color image, the apparatus comprising:
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an image reading section which reads a color image on an original;
a first memory section which stores basic filter coefficients and decimal-point reference position information for subjecting a color image signal of the color image read by the image reading section to image processing;
a second memory section which has a predetermined bit width and stores filter coefficients;
a calculation section which re-calculates, when a degree of sharpness has been adjusted in the image processing, the basic filter coefficients stored in the first memory section in accordance with a value of the adjustment;
a computing section which calculates a bit number between a lowest bit and a highest bit, which are obtained by expressing in binary form a coefficient with a maximum absolute value of the filter coefficients calculated by the calculation section;
a first processing section which effects a bit shift of the filter coefficients calculated by the calculation section and stores the bit-shifted filter coefficients in the second memory section, on the basis of the bit number calculated by the computing section and the bit width of the second memory section;
an altering section which alters the decimal-point reference position information on the basis of the decimal-point reference position information stored in the first memory section and the bit width of the second memory section;
an arithmetic section which subjects the filter coefficients stored in the second memory section and the color image signal of the color image read by the image reading section to a matrix arithmetic operation in the processing of the first processing section; and
a second processing section which effects a bit shift of the image signal produced by the arithmetic section, on the basis of the decimal-point reference position information altered by the altering section. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An image forming method for forming a color image by reading a color image on an original and subjecting a signal of the read color image to image processing, the method comprising:
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reading a color image on an original;
storing basic filter coefficients and decimal-point reference position information for subjecting a color image signal of the read color image to image processing;
re-calculating, when a degree of sharpness has been adjusted in the image processing, the stored basic filter coefficients in accordance with a value of the adjustment;
calculating a bit number between a lowest bit and a highest bit, which are obtained by expressing in binary form a coefficient with a maximum absolute value of the calculated filter coefficients;
performing a process for effecting a bit shift of the calculated filter coefficients and storing the bit-shifted filter coefficient, on the basis of the calculated bit number and a bit width of a memory section that stores the calculated filter coefficients;
altering the decimal-point reference position information on the basis of the stored decimal-point reference position information and the bit width of the memory section;
subjecting the filter coefficients stored in the memory section and the color image signal of the read color image to a matrix arithmetic operation in said process; and
effecting a bit shift of the image signal produced by the matrix arithmetic operation, on the basis of the altered decimal-point reference position information.
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Specification