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US5907370A
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Apparatus and method for reducing qauntization error in digital image signals
Assignee: Sony Corp
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Filing: 1996-02-27
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Granted: 1999-05-25
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Expires: 2016-02-27
Abstract
Abstract In an image signal processing apparatus and processing method, intermediate gradation is produced by way of a bit expansion to reduce a quantizing noise. The image signal processing apparatus is comprised of: bit expanding means for bit-expanding an n-bit quantized input image signal into an m-bit (symbols "n" and "m" are integers, and own a relationship of n<m); control signal output means for outputting a control signal based upon the input image signal; and a converting unit for adaptively converting the signal from the bit expanding means into an m-bit signal in response to the control signal from the control signal output means. Also, the image signal processing method comprises the steps of: bit-expanding an n-bit quantized input image signal to an m-bit (symbol "n" and "m" are integers and own a relationship of n>m); and adaptively producing lower order (m-n) bits in accordance with an image nature of the input image signal to thereby be converted into an m-bit signal.
Inventors
- 👤 Teruhiko Suzuki
- 👤 Yoichi Yagasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:31
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/14; H04N5/20; H04N5/205; H04N5/208; H04N19/00; H04N19/10; H04N19/102; H04N19/12; H04N19/122; H04N19/134; H04N19/157; H04N19/16; H04N19/169; H04N19/184; H04N19/46; H04N19/60; H04N19/61; H04N19/85; H04N19/86; H04N5/21; H04N5/213
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
197 words
An apparatus for processing digital image signals to reduce the effect of quantizing noise in the images represented by the digital image signals, comprising: means for converting an n-bit image signal into an m-bit image signal, wherein m and n are integers and m is greater than n; means for filtering said m-bit image signal to generate a low frequency m-bit image signal; means for estimating the high frequency content of said m-bit signal; and means for generating a reduced quantizing noise m-bit image signal by extracting at least one least significant bit from said low frequency m-bit image signal and adding said at least one least significant bit to said m-bit image signal when said estimate of the high frequency content of said m-bit image signal is below a predetermined threshold; such that when said estimate of the high frequency content of said m-bit image signal is below said predetermined threshold and the magnitude of said low frequency m-bit image signal is less than the magnitude of said m-bit image signal, a predetermined amount is subtracted from said m-bit image signal prior to adding said at least one least significant bit to said m-bit image signal.
Claim 2
Independent Claim
197 words
An apparatus for processing digital image signals to reduce the effect of quantizing noise in the images represented by the digital image signals, comprising: means for converting an n-bit image signal into an m-bit image signal, wherein m and n are integers and m is greater than n; means for filtering said m-bit image signal to generate a low frequency m-bit image signal; means for estimating the high frequency content of said m-bit signal; and means for generating a reduced quantizing noise m-bit image signal by extracting at least one least significant bit from said low frequency m-bit image signal and adding said at least one least significant bit to said m-bit image signal when said estimate of the high frequency content of said m-bit image signal is below a predetermined threshold; such that when said estimate of the high frequency content of said m-bit image signal is below said predetermined threshold and the magnitude of said low frequency m-bit image signal is less than the magnitude of said m-bit image signal, a predetermined amount is subtracted from said m-bit image signal prior to adding said at least one least significant bit to said m-bit image signal.
Claim 3
Dependent Claim
37 words
The apparatus as set forth in claim 1, wherein said means for estimating the high frequency content of said m-bit signal comprises means for determining a difference between said m-bit signal and said low frequency m-bit signal.
Claim 4
Dependent Claim
44 words
The apparatus as set forth in claim 1, wherein said means for generating is operable to set the reduced quantizing noise m-bit image signal to the m-bit image signal for portions of said m-bit signal having a high frequency content above said predetermined threshold.
Claim 5
Dependent Claim
28 words
The apparatus as set forth in claim 1, further comprising means for eliminating noise from said n-bit signal prior to converting said n-bit signal into said m-bit signal.
Claim 6
Dependent Claim
52 words
The apparatus as set forth in claim 1, wherein said means for estimating is operable to estimate the high frequency content of each portion of said m-bit signal according to at least one of: a dispersion of said portion, a dynamic range of said portion and a luminance level of said portion.
Claim 7
Independent Claim
193 words
A method for processing digital image signals to reduce the effect of quantizing noise in the images represented by the digital image signals, comprising the steps of: converting an n-bit image signal into an m-bit image signal, wherein m and n are integers and m is greater than n; filtering said m-bit image signal to generate a low frequency m-bit image signal; estimating the high frequency content of said m-bit image signal; and generating a reduced quantizing noise m-bit image signal by extracting at least one least significant bit from said low frequency m-bit image signal and adding said at least one least significant bit to said m-bit image signal when said estimate of the high frequency content of said m-bit image signal is below a predetermined threshold; such that when said estimate of the high frequency content of said m-bit image signal is below said predetermined threshold and the magnitude of said low frequency m-bit image signal is less than the magnitude of said m-bit image signal, a predetermined amount is subtracted from said m-bit image signal prior to adding said at least one least significant bit to said m-bit image signal.
Claim 8
Independent Claim
193 words
A method for processing digital image signals to reduce the effect of quantizing noise in the images represented by the digital image signals, comprising the steps of: converting an n-bit image signal into an m-bit image signal, wherein m and n are integers and m is greater than n; filtering said m-bit image signal to generate a low frequency m-bit image signal; estimating the high frequency content of said m-bit image signal; and generating a reduced quantizing noise m-bit image signal by extracting at least one least significant bit from said low frequency m-bit image signal and adding said at least one least significant bit to said m-bit image signal when said estimate of the high frequency content of said m-bit image signal is below a predetermined threshold; such that when said estimate of the high frequency content of said m-bit image signal is below said predetermined threshold and the magnitude of said low frequency m-bit image signal is less than the magnitude of said m-bit image signal, a predetermined amount is subtracted from said m-bit image signal prior to adding said at least one least significant bit to said m-bit image signal.
Claim 9
Dependent Claim
38 words
The method as set forth in claim 6, wherein the step of estimating the high frequency content of said m-bit signal comprises the step of determining a difference between said m-bit signal and said low frequency m-bit signal.
Claim 10
Dependent Claim
51 words
The method as set forth in claim 6, wherein the step of generating a reduced quantizing noise m-bit image signal comprises setting said reduced quantizing noise m-bit image signal equal to the m-bit image signal for portions of said m-bit image signal having a high frequency content above said predetermined threshold.
Claim 11
Dependent Claim
29 words
The method as set forth in claim 6, further comprising the step of eliminating noise from said n-bit signal prior to converting said n-bit signal into said m-bit signal.
Claim 12
Dependent Claim
46 words
The method as set forth in claim 6, wherein the high frequency content of each portion of said m-bit signal is estimated according to at least one of: a dispersion of said portion, a dynamic range of said portion and a luminance level of said portion.
Claim 13
Independent Claim
228 words
An apparatus for decoding encoded digital image signals while reducing the effect of quantizing noise in the images represented by the encoded digital image signals, comprising: means for decoding an encoded digital image signal into an n-bit image signal; means for converting said n-bit image signal into an m-bit image signal, wherein m and n are integers and m is greater than n; means for filtering said m-bit image signal to generate a low frequency m-bit image signal; means for estimating the high frequency content of said m-bit image signal; means for generating a reduced quantizing noise m-bit image signal by extracting at least one least significant bit from said low frequency m-bit image signal and adding said at least one least significant bit to said m-bit image signal when said estimate of the high frequency content of said m-bit image signal is below a predetermined threshold; such that when said estimate of the high frequency content of said m-bit image signal is below said predetermined threshold and the magnitude of said low frequency m-bit image signal is less than the magnitude of said m-bit image signal a predetermined amount is subtracted from said m-bit image signal prior to adding said at least one least significant bit to said m-bit image signal; and means for converting said reduced quantizing noise m-bit image signal into an output video signal.
Claim 14
Independent Claim
228 words
An apparatus for decoding encoded digital image signals while reducing the effect of quantizing noise in the images represented by the encoded digital image signals, comprising: means for decoding an encoded digital image signal into an n-bit image signal; means for converting said n-bit image signal into an m-bit image signal, wherein m and n are integers and m is greater than n; means for filtering said m-bit image signal to generate a low frequency m-bit image signal; means for estimating the high frequency content of said m-bit image signal; means for generating a reduced quantizing noise m-bit image signal by extracting at least one least significant bit from said low frequency m-bit image signal and adding said at least one least significant bit to said m-bit image signal when said estimate of the high frequency content of said m-bit image signal is below a predetermined threshold; such that when said estimate of the high frequency content of said m-bit image signal is below said predetermined threshold and the magnitude of said low frequency m-bit image signal is less than the magnitude of said m-bit image signal a predetermined amount is subtracted from said m-bit image signal prior to adding said at least one least significant bit to said m-bit image signal; and means for converting said reduced quantizing noise m-bit image signal into an output video signal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2002-05-24 | 2002-11-23 | 2003-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-05-24 | 2006-11-23 | 2007-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-05-24 | 2010-11-23 | 2011-05-25 | $7700.00 | Window Closed / Lapsed |