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US5657085A
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Wavelet transform coding method
Assignee: NEC Corp
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Filing: 1996-02-14
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Granted: 1997-08-12
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Expires: 2016-02-14
Abstract
Abstract An improved coding performance for wavelet transform coding. The method comprises: two-dimensional wavelet transforming an input picture signal to output transform coefficients; two-dimensionally arranging the transform coefficients; quantizing the arranged transform coefficients; choosing a scanning pattern for the quantized transform coefficients based on the correlation between these coefficients; generating a one-dimensional signal series by scanning the transform coefficients after they are quantized according to a scanning pattern decided in the above step; coding the one-dimensional signal series; and, finally, terminating the coding of the signal series using a symbol indicating the end of scanning.
Inventors
- 👤 Jiro Katto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 12:25
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/60; H04N19/61; H04N19/10; H04N19/102; H04N19/129; H04N19/63; H04N19/64; H04N19/647; H04N19/13
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
161 words
A wavelet transform coding method comprising: two-dimensional wavelet transforming of an input picture signal, said transformation resulting in an output of a plurality of transform coefficients within a number of frequency subbands expressing a spatial area; two-dimensionally arranging said transform coefficients; quantizing said two-dimensionally arranged transform coefficients; adaptively choosing a scanning pattern for each respective subband in accordance with the correlation between the respective transform coefficients found therein; generating a one-dimensional signal series by scanning said transform coefficients after said transform coefficients are quantized according to said scanning pattern; coding said one-dimensional signal series; terminating said coding of said one-dimensional signal series by using a symbol indicating an end of said scanning when a zero order value continues to be scanned; and wherein said step of choosing said scanning pattern further comprises adaptively choosing a scanning start point when scanning said quantized transform coefficients in said each of said frequency subbands in accordance with a locality of said input picture signal.
Claim 2
Dependent Claim
161 words
A wavelet transform coding method comprising: two-dimensional wavelet transforming of an input picture signal, said transformation resulting in an output of a plurality of transform coefficients within a number of frequency subbands expressing a spatial area; two-dimensionally arranging said transform coefficients; quantizing said two-dimensionally arranged transform coefficients; adaptively choosing a scanning pattern for each respective subband in accordance with the correlation between the respective transform coefficients found therein; generating a one-dimensional signal series by scanning said transform coefficients after said transform coefficients are quantized according to said scanning pattern; coding said one-dimensional signal series; terminating said coding of said one-dimensional signal series by using a symbol indicating an end of said scanning when a zero order value continues to be scanned; and wherein said step of choosing said scanning pattern further comprises adaptively choosing a scanning start point when scanning said quantized transform coefficients in said each of said frequency subbands in accordance with a locality of said input picture signal.
Claim 3
Dependent Claim
79 words
The wavelet transform coding method of claim 1, wherein said step of choosing said scanning pattern further comprises: a) horizontally scanning for said transform coefficients in a frequency band of which a horizontal portion belongs to a low-frequency band and a vertical portion belongs to a high-frequency band; and b) vertically scanning for said transform coefficients in a frequency band of which a horizontal portion belongs to a high-frequency band and a vertical portion belongs to a low-frequency band.
Claim 4
Dependent Claim
47 words
The wavelet transform coding method of claim 1, wherein said step of adaptively choosing said scanning start point further comprises: scanning said transform coefficients in a predetermined frequency subband and deciding, based on this scanning result, a scanning start point in a number of following frequency subband.
Claim 5
Dependent Claim
71 words
The wavelet transform coding method of claim 1, wherein said step of adaptively choosing said scanning start point in said each of said frequency subbands in accordance with said locality of said input picture signal comprises: choosing said scanning start point in each of said frequency subbands based on a significant transform coefficient distribution derived from said transform coefficients after these coefficients have been quantized in each of said frequency subbands.
Claim 6
Dependent Claim
72 words
The wavelet transform coding method of claim 4, wherein said step of adaptively choosing said scanning start point further comprises: calculating a number of significant transform coefficients on each scanning line in each of said frequency subbands; and detecting a largest number from among said number of significant transform coefficients and choosing said scanning start point so that said scanning may be performed from a scanning line corresponding to said largest number.
Claim 7
Dependent Claim
54 words
The wavelet transform coding method of claim 1, wherein said step of adaptively choosing said scanning start point further comprises: choosing said scanning start point in each of said frequency subbands based on an energy distribution of those of said transform coefficients that have not yet been quantized in each of said frequency subbands.
Claim 8
Dependent Claim
93 words
The wavelet transform coding method of claim 6, wherein said step of adaptively choosing said start points further comprises: calculating a plurality of squared values of said transform coefficients on each of a number of scanning lines in each of said frequency subbands; calculating a corresponding sum of said squared values of said transform coefficients on said each of said scanning lines; and detecting a largest sum from among said sums and deciding said scanning start point so as to start scanning from one of said scanning lines corresponding to said largest sum.
Claim 9
Dependent Claim
93 words
The wavelet transform coding method of claim 6, wherein said step of adaptively choosing said start points further comprises: calculating a number of absolute values of said transform coefficients on each of said scanning lines in each of said frequency subbands; calculating a corresponding sum of said absolute values of said transform coefficients on said each of said scanning lines; and detecting a largest sum from among said sums to allow for choosing said scanning start point such that said scanning may be performed from a scanning line corresponding to said largest sum.
Claim 10
Dependent Claim
39 words
The wavelet transform coding method of claim 1, wherein said step of adaptively choosing said scanning pattern comprises: adaptively choosing a sequence of scanning for each of said frequency subbands in accordance with a locality of said input signal.
Claim 11
Dependent Claim
40 words
The wavelet transform coding method of claim 9, wherein said step of choosing said sequence of scanning is based on an energy distribution of said transform coefficients before said coefficients have yet been quantized in each of said frequency subbands.
Claim 12
Dependent Claim
88 words
The wavelet transform coding method of claim 10, wherein said step of choosing said sequence of scanning further comprises: calculating squared values of said transform coefficients in each of said frequency subbands; calculating an average value from said squared values of said transform coefficients in each of said frequency subbands; and choosing said scanning pattern such that the scanning in each of said frequency subbands is accomplished in an order of said average values, from the largest of said average values to the smallest of said average values.
Claim 13
Dependent Claim
87 words
The wavelet transform coding method of claim 10, wherein said step of choosing said sequence of scanning further comprises: calculating absolute values of said transform coefficients in each of said frequency subbands; calculating, from said absolute values of said transform coefficients, an average value for each of said frequency subbands; and choosing said scanning pattern such that scanning in each of said frequency subbands is accomplished in an order of said average values, from the largest of said average values to the smallest of said average values.
Claim 14
Dependent Claim
37 words
The wavelet transform coding method of claim 9, wherein said step of choosing said sequence of scanning further comprises: choosing said sequence based on a distribution of significant transform coefficients after said transform coefficients have been quantized.
Claim 15
Dependent Claim
104 words
The wavelet transform coding method of claim 13, wherein said step of choosing said sequence of scanning further comprises: calculating a number of transform coefficients in each of said frequency subbands; calculating a number of significant transform coefficients in each of said frequency subbands; calculating a unique ratio in each of said frequency subbands by dividing the number of transform coefficients thereof by the number of significant transform coefficients thereof; and deciding said scanning pattern such that scanning in each of said frequency subbands is based on an order of said ratios, from the largest of said ratios to the smallest of said ratios.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2000-08-11 | 2001-02-10 | 2001-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-08-11 | 2005-02-10 | 2005-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-08-11 | 2009-02-10 | 2009-08-12 | $7700.00 | Window Closed / Lapsed |