Image-signal processing apparatus, image-signal processing method and image-signal processing program
First Claim
Patent Images
1. An image-signal processing apparatus, comprising:
- a band pass filter configured to increase the bit count of an input digital image signal in a bit decompression process and pass on an image signal of a high frequency band, wherein said band pass filter extracts horizontal-direction frequency signal components from said input digital image signal and passes on said horizontal-direction frequency signal components;
an amplitude limiting section configured to limit the amplitude of said image signal passed on by said band pass filter to a level determined in advance;
a subtractor configured to subtract an image signal output by said amplitude limiting section from said input digital image signal;
a vertical-direction frequency-component band pass filter configured to extract vertical-direction frequency signal components from said input digital image signal and pass on said vertical-direction frequency signal components;
an overlapping-frequency-component band pass filter configured to extract an image signal component overlapping any one of said horizontal-direction frequency signal components passed on by said band pass filter from said vertical-direction frequency signal components passed on by said vertical-direction frequency-component band pass filter and pass on said extracted overlapping signal component; and
an adder configured to subtract said overlapping signal passed on by said overlapping-frequency-component band pass filter from said vertical-direction frequency signal components passed on by said vertical-direction frequency-component band pass filter.
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Abstract
Disclosed herein is an image-signal processing apparatus, including: a band pass filter configured to increase the bit count of an input digital image signal in a bit decompression process and pass on an image signal of a high frequency band; an amplitude limiting section configured to limit the amplitude of the image signal passed on by the band pass filter to a level determined in advance; and a subtractor configured to subtract an image signal output by the amplitude limiting section from the input digital image signal.
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Citations
13 Claims
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1. An image-signal processing apparatus, comprising:
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a band pass filter configured to increase the bit count of an input digital image signal in a bit decompression process and pass on an image signal of a high frequency band, wherein said band pass filter extracts horizontal-direction frequency signal components from said input digital image signal and passes on said horizontal-direction frequency signal components; an amplitude limiting section configured to limit the amplitude of said image signal passed on by said band pass filter to a level determined in advance; a subtractor configured to subtract an image signal output by said amplitude limiting section from said input digital image signal; a vertical-direction frequency-component band pass filter configured to extract vertical-direction frequency signal components from said input digital image signal and pass on said vertical-direction frequency signal components; an overlapping-frequency-component band pass filter configured to extract an image signal component overlapping any one of said horizontal-direction frequency signal components passed on by said band pass filter from said vertical-direction frequency signal components passed on by said vertical-direction frequency-component band pass filter and pass on said extracted overlapping signal component; and an adder configured to subtract said overlapping signal passed on by said overlapping-frequency-component band pass filter from said vertical-direction frequency signal components passed on by said vertical-direction frequency-component band pass filter.
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2. An image-signal processing apparatus, comprising
a band pass filter configured to increase the bit count of an input digital image signal in a bit decompression process and pass on an image signal of a high frequency band; -
an amplitude limiting section configured to limit the amplitude of said image signal passed on by said band pass filter to a level determined in advance; a gain adjustment section configured to adjust the gain of an image signal output by said amplitude limiting section as a signal having the amplitude limited by said amplitude limiting section; a subtractor configured to subtract an image signal output by said amplitude limiting section from said input digital image signal; and a pseudo-contour existence determination section configured to produce a result of determination as to whether or not an image represented by said input digital image signal is an image with a striking pseudo contour on the basis of a rate of gradation changes in an area composed of an observed pixel selected among pixels composing said image and neighbor pixels located in the vicinity of said observed pixel, wherein said gain adjustment section changes the gain from one value to another in accordance with said result of said determination. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification