US6753910B1
Expired / Lapsed
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Image processing apparatus and image processing method
Assignee: Sony Corp
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Filing: 1999-11-17
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Granted: 2004-06-22
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Expires: 2019-11-17
Abstract
Abstract The invention provides an image processing apparatus and an image processing method and can be applied to an image information apparatus such as, for example, a television receiver, a video tape recorder, a television camera and a printer so that the gradation can be corrected while effectively preventing a finally obtained image from partial deterioration of the contrast. An area to which each of image data belongs is discriminated with reference to, for example, a low frequency component of a pixel value, and a correction coefficient is produced for the area. Such correction coefficients are smoothed between successive frames, and the pixel values of the image data are corrected with the smoothed correction coefficients.
Inventors
- 👤 Masami Ogata
- 👤 Takashi Tsuchiya
- 👤 Kazuhiko Ueda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 21:18
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/14; H04N5/20; H04N5/205
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
116 words
An image processing apparatus capable of correcting the gradation of image data, comprising: area discrimination means for discriminating areas to which the image data belong and outputting discrimination results; coefficient calculation means for outputting correction coefficients to be used for correction of pixel values of the image data based on the discrimination results; smoothing means for smoothing corresponding ones of the correction coefficients between corresponding ones of the image data of successive frames, said smoothing means including a filter for recursively processing input data with a predetermined time constant and switches the time constant in response to the image data; and correction means for correcting the pixel values of the image data with the correction coefficients.
Claim 2
Dependent Claim
116 words
An image processing apparatus capable of correcting the gradation of image data, comprising: area discrimination means for discriminating areas to which the image data belong and outputting discrimination results; coefficient calculation means for outputting correction coefficients to be used for correction of pixel values of the image data based on the discrimination results; smoothing means for smoothing corresponding ones of the correction coefficients between corresponding ones of the image data of successive frames, said smoothing means including a filter for recursively processing input data with a predetermined time constant and switches the time constant in response to the image data; and correction means for correcting the pixel values of the image data with the correction coefficients.
Claim 3
Dependent Claim
62 words
An image processing apparatus according to claim 1 , wherein said area discrimination means detects a characteristic amount indicative of a characteristic of a predetermined range neighboring to each of the image data and outputting the characteristic amount as the discrimination result, and said coefficient calculation means outputs the correction coefficients based on the characteristic amounts received from said area discrimination means.
Claim 4
Dependent Claim
51 words
An image processing apparatus according to claim 1 , wherein said area discrimination means includes a low-pass filter for extracting a low frequency component of each of the image,e data, and said coefficient calculation means produces the correction coefficients in response to the low frequency components received from said low-pass filter.
Claim 5
Dependent Claim
64 words
An image processing apparatus according to claim 1 , wherein said area discrimination means includes quantization means for quantizing the image data, and a low-pass filter for extracting a low frequency component from each of the image data quantized by said quantization means, and said coefficient calculation means produces the correction coefficients in response to the low frequency components received from said low-pass filter.
Claim 6
Dependent Claim
72 words
An image processing apparatus according to claim 1 , wherein said area discrimination means includes a plurality of low-pass filters for individually extracting low frequency components of each of the image data, and signal composition means for producing single composite signals based on the low frequency components outputted from said low-pass filters, and said coefficient calculation means produces the correction coefficients based on the composite signals received from said signal composition means.
Claim 7
Dependent Claim
30 words
An image processing apparatus according to claim 5 , wherein said signal composition means weighted averages the low frequency components outputted from said low-pass filters to produce the composite signals.
Claim 8
Dependent Claim
36 words
An image processing apparatus according to claim 5 , wherein said signal composition me;ms weighted adds the low frequency components outputted from said low-pass filters with weighting coefficients set in advance to produce the composite signals.
Claim 9
Dependent Claim
72 words
An image processing apparatus according to claim 1 , wherein said area discrimination means includes a plurality of low-pass filters for individually extracting low frequency components of each of the image data, and said coefficient calculation means includes partial coefficient calculation means for producing coefficients for correction from the low frequency components outputted from said low-pass filters, and coefficient composition means for producing the correction coefficients based on the coefficients for correction.
Claim 10
Dependent Claim
25 words
An image processing apparatus according to claim 8 , wherein said coefficient composition means weighted adds the coefficients for correction to produce the correction coefficients.
Claim 11
Dependent Claim
31 words
An image processing apparatus according to claim 8 , wherein said coefficient composition means weighted adds the coefficients for correction with weighting coefficients set in advance to produce the correction coefficients.
Claim 12
Dependent Claim
34 words
An image processing apparatus according to claim 1 , wherein said correction means multiplies the pixel values of the image data by the correction coefficients to correct the pixel values of the image data.
Claim 13
Dependent Claim
22 words
An image processing apparatus according to claim 1 , wherein said smoothing means smoothes the processing results from said area discrimination means.
Claim 14
Dependent Claim
28 words
An image processing apparatus according to claim 1 , wherein said smoothing means includes a filter for recursively processing input data with a time constant set in advance.
Claim 15
Dependent Claim
27 words
An image processing apparatus according to claim 1 , wherein said smoothing means switches the time constant based on a difference value between input pixel values thereto.
Claim 16
Dependent Claim
40 words
An image processing apparatus according to claim 1 , wherein the number of bits of the image data outputted from said correction means is smaller than the number of bits of the image data inputted to said image processing apparatus.
Claim 17
Dependent Claim
37 words
An image processing apparatus according to claim 1 , wherein the image data are data obtained by sampling a signal, wherein an amplitude modulated color signal is sequentially superposed on a luminance signal, with a predetermined frequency.
Claim 18
Dependent Claim
25 words
An image processing apparatus according to claim 1 , wherein the image data are data obtained by sampling a color signal with a predetermined frequency.
Claim 19
Dependent Claim
30 words
An image processing apparatus according to claim 1 , wherein the image data are data obtained by sampling a luminance signal and a color difference signal with a predetermined frequency.
Claim 20
Dependent Claim
120 words
An image processing method for correcting the gradation of image data, comprising: an area discrimination step of discriminating areas to which the image data belong and outputting discrimination results; a coefficient calculation step of outputting correction coefficients to be used for correction of pixel values of the image data based on the discrimination results; a smoothing step of smoothing corresponding ones of the correction coefficients between corresponding ones of the image data of successive frames, said smoothing including recursively filtering input data with a predetermined time constant to smooth the correction coefficients and switching the time constant in response to the image data; and a correction step of correcting the pixel values of the image data with the correction coefficients.
Claim 21
Dependent Claim
120 words
An image processing method for correcting the gradation of image data, comprising: an area discrimination step of discriminating areas to which the image data belong and outputting discrimination results; a coefficient calculation step of outputting correction coefficients to be used for correction of pixel values of the image data based on the discrimination results; a smoothing step of smoothing corresponding ones of the correction coefficients between corresponding ones of the image data of successive frames, said smoothing including recursively filtering input data with a predetermined time constant to smooth the correction coefficients and switching the time constant in response to the image data; and a correction step of correcting the pixel values of the image data with the correction coefficients.
Claim 22
Dependent Claim
56 words
An image processing method according to claim 19 , wherein the area discrimination step detects a characteristic amount indicative of a characteristic of a predetermined range neighboring to each of the image data and outputting the characteristic amount as the discrimination result, and the coefficient calculation step outputs the correction coefficients based on the characteristic amounts.
Claim 23
Dependent Claim
41 words
An image processing method according to claim 19 , wherein the area discrimination step extracts a low frequency component of each of the image data, and the coefficient calculation step produces the correction coefficients in response to the low frequency components.
Claim 24
Dependent Claim
59 words
An image processing method according to claim 19 , wherein the area discrimination step includes a quantization step of quantizing the image data, and a step of extracting a low frequency component from each of the image data quantized by the quantization step, and the coefficient calculation step produces the correction coefficients in response to the low frequency components.
Claim 25
Dependent Claim
63 words
An image processing method according to claim 19 , wherein the area discrimination step includes an extraction step of extracting low frequency components of each of the image data with different frequency bands, and a signal composition step of producing single composite signals based on the low frequency components, and the coefficient calculation step produces the correction coefficients based on the composite signals.
Claim 26
Dependent Claim
25 words
An image processing method according to claim 23 , wherein the signal composition step weighted averages the low frequency components to produce the composite signals.
Claim 27
Dependent Claim
31 words
An image processing method according to claim 23 , wherein the signal composition step weighted adds the low frequency components with weighting coefficients set in advance to produce the composite signals.
Claim 28
Dependent Claim
68 words
An image processing method according to claim 19 , wherein the area discrimination step extracts a plurality of low frequency components of each of the image data with different frequency bands, and the coefficient calculation step includes a partial coefficient calculation step of producing coefficients for correction from the low frequency components, and a coefficient composition step of producing the correction coefficients based on the coefficients for correction.
Claim 29
Dependent Claim
25 words
An image processing method according to claim 26 , wherein the coefficient composition step weighted adds the coefficients for correction to produce the correction coefficients.
Claim 30
Dependent Claim
31 words
An image processing method according to claim 26 , wherein the coefficient composition step weighted adds the coefficients for correction with weighting coefficients set in advance to produce the correction coefficients.
Claim 31
Dependent Claim
34 words
An image processing method according to claim 19 , wherein the correction step multiplies the pixel values of the image data by the correction coefficients to correct the pixel values of the image data.
Claim 32
Dependent Claim
22 words
An image processing method according to claim 19 , wherein the smoothing step smoothes the processing results of the area discrimination step.
Claim 33
Dependent Claim
29 words
An image processing method according to claim 19 , wherein the smoothing step recursively filters input data with a time constant set in advance to smooth the correction coefficients.
Claim 34
Dependent Claim
27 words
An image processing method according to claim 19 , wherein the smoothing step switches the time constant based on a difference value between input pixel values thereto.
Claim 35
Dependent Claim
35 words
An image processing method according to claim 19 , wherein the number of bits of the images data outputted from the correction step is smaller than the number of bits of the image data inputted.
Claim 36
Dependent Claim
37 words
An image processing method according to claim 19 , wherein the image data are data obtained by sampling a signal, wherein an amplitude modulated color signal is sequentially superposed on a luminance signal, with a predetermined frequency.
Claim 37
Dependent Claim
25 words
An image processing method according to claim 19 , wherein the image data are data obtained by sampling a color signal with a predetermined frequency.
Claim 38
Dependent Claim
30 words
An image processing method according to claim 19 , wherein the image data are data obtained by sampling a luminance signal and a color difference signal with a predetermined frequency.
References Cited (Backward Citations)
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