Patent EP0475251A2 successfully refreshed from Google Patents.
EP0475251A2
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Coding apparatus for digital image data
Assignee: Mitsubishi Electric Corp
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Filing: 1991-09-03
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Granted: —
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Expires: 2011-09-03
Abstract
Abstract A coding apparatus being designed for reduction and variable-length-coding of digital image data, wherein the image data is once variable-length-coded thereby to obtain a variable length code and, the optimum weighting factor and/or quantizing level is selected based on the coding amount (number of bits) of the obtained variable length code. The image data is further variable-length-coded again with the selected weighting factor and quantizing level. The weighting factor and quantizing level are selected so that the recording density in a recording medium becomes maximum.
Inventors
- 👤 Manabu c/o Denshi Shohin Kaihatsu Tsukamoto
- 👤 Takashi c/o Denshi Shohin Kaihatsu Itou
- 👤 Yoshiko C/O Denshi Shohin Kaihatsu Hatano
- 👤 Yoshinori C/O Denshi Shohin Kaihatsu Asamura
- 👤 Ken C/O Denshi Shohin Kaihatsu Onishi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 15:44
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/76; H04N5/91; H04N5/92; H04N5/926; H04N5/9261; H04N5/9264; H04N19/00; H04N19/10; H04N19/102; H04N19/124; H04N19/126; H04N19/134; H04N19/146; H04N19/15; H04N19/169; H04N19/17; H04N19/176; H04N19/189; H04N19/192; H04N19/60; H04N19/13; H04N19/152; H04N19/30; H04N19/90; H04N19/91
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
158 words
A coding apparatus for reducing and coding digital image data, comprising: formatting means for formatting said image data into blocks per a plurality of picture elements; orthogonal transforming means for performing orthogonal transform on the formatted image data; first weighting means for performing weighting on coefficients obtained by said orthogonal transforming means; first quantizing means for quantizing the weighting-performed data; first coding means for performing variable length coding on the quantized data; selecting means for obtaining the coding amount of a variable length code obtained by said first coding means and selecting a weighting factor on the basis of the obtained coding amount; second weighting means for performing weighting on the coefficients obtained by said orthogonal transforming means with the weighting factor selected by said selecting means; second quantizing means for quantizing the data weighting-performed by said second weighting means; and second coding means for performing variable length coding on the data quantized by said second quantizing means.
Claim 2
Dependent Claim
36 words
A coding apparatus according to Claim 1, wherein said selecting means selects a weighting factor smaller than the weighting factor of said first weighting means when the obtained coding amount is larger than a predetermined amount.
Claim 3
Dependent Claim
51 words
A coding apparatus according to Claim 1, further comprising delay means provided between said orthogonal transforming means and said second weighting means and for inputting an output from said orthogonal transforming means to said second weighting means with the timing delayed more than the inputting timing to said first weighting means.
Claim 4
Dependent Claim
16 words
A coding apparatus according to Claim 1, wherein said orthogonal transform is DCT (Discrete Cosine Transform).
Claim 5
Dependent Claim
133 words
A coding apparatus for reducing and coding digital image data, comprising: formatting means for formatting said image data into blocks per a plurality of picture elements; orthogonal transforming means for performing orthogonal transform on the formatted image data; first quantizing means for quantizing coefficients obtained by said orthogonal transforming means; first coding means for performing variable length coding on the quantized data; selecting means for obtaining the coding amount of a variable length code obtained by said first coding means and selecting a quantizing level on the basis of the obtained coding amount; second quantizing means for quantizing the coefficients obtained by said orthogonal transforming means with the quantizing level selected by said selecting means; and second coding means for performing variable length coding on the data quantized by said second quantizing means.
Claim 6
Dependent Claim
23 words
A coding apparatus according to Claim 5, wherein said second quantizing means has a plurality of quantizing tables of different quantizing step widths.
Claim 7
Dependent Claim
29 words
A coding apparatus according to Claim 6, wherein said selecting means selects one quantizing table from said plurality of quantizing tables on the basis of the obtained coding amount.
Claim 8
Dependent Claim
36 words
A coding apparatus according to Claim 5, wherein said selecting means selects a quantizing level coarser than the quantizing level of said first quantizing means when the obtained coding amount is larger than a predetermined amount.
Claim 9
Dependent Claim
51 words
A coding apparatus according to Claim 5, further comprising delay means provided between said orthogonal transforming means and said second quantizing means and for inputting an output from said orthogonal transforming means to said second quantizing means with the timing delayed more than the inputting timing to said first quantizing means.
Claim 10
Dependent Claim
16 words
A coding apparatus according to Claim 5, wherein said orthogonal transform is DCT (Discrete Cosine Transform).
Claim 11
Dependent Claim
116 words
A coding apparatus for reducing and coding digital image data to record the data on a recording medium, comprising: first quantizing means for quantizing said image data; first coding means for performing variable length coding on the quantized data; selecting means for obtaining the coding amount of a variable length code obtained by said first coding means and selecting a quantizing level on the basis of the obtained coding amount so that the recording density in said recording medium becomes maximum; second quantizing means for quantizing said image data with the quantizing level selected by said selecting means; and second coding means for performing variable length coding on the data quantized by said second quantizing means.
Claim 12
Dependent Claim
30 words
A coding apparatus according to Claim 11, further comprising storing means for storing said image data, wherein said second quantizing means quantizes said image data stored by said storing means.
Claim 13
Dependent Claim
45 words
A coding apparatus according to Claim 11, wherein said second quantizing means has a plurality of quantizing tables of different quantizing step widths, and said selecting means selects one quantizing table from said plurality of quantizing tables on the basis of the obtained coding amount.
Claim 14
Dependent Claim
121 words
A coding apparatus for reducing and coding digital image data to record the data on a recording medium, comprising: quantizing means for quantizing a first image data which is a part of said image data; coding means for performing variable length coding on the quantized data; and selecting means for obtaining the coding amount of a variable length code obtained by said coding means and selecting a quantizing level on the basis of the obtained coding amount so that the recording density in said recording medium becomes maximum, wherein said quantizing means quantizes a second image data which is a part of said image data and adjacent to said first image data with the quantizing level selected by said selecting means.
Claim 15
Dependent Claim
118 words
A coding apparatus for reducing and coding digital image data to record the data on a recording medium, comprising: first quantizing means for quantizing said image data; first coding means for performing variable length coding on the quantized data; selecting means for selecting a quantizing level on the basis of the coding amount of a variable length code obtained by said first coding means and the coding amount of a variable length code of the other image data prior to said image data; second quantizing means for quantizing said image data with the quantizing level selected by said selecting means; and second coding means for performing variable length coding on the data quantized by said second quantizing means.
Claim 16
Dependent Claim
26 words
A coding apparatus according to Claim 15, wherein said selecting means selects one quantizing level so that the recording density in said recording medium becomes maximum.
Claim 17
Dependent Claim
45 words
A coding apparatus according to Claim 15, wherein said second quantizing means has a plurality of quantizing tables of different quantizing step widths, and said selecting means selects one quantizing table from said plurality of quantizing tables on the basis of the obtained coding amount.
Claim 18
Dependent Claim
118 words
A coding apparatus for reducing and coding digital image data to record the data on a recording medium, comprising: first quantizing means for quantizing said image data; first coding means for performing variable length coding on the quantized data; selecting means for selecting a quantizing level on the basis of the coding amount of a variable length code obtained by said first coding means; decoding means for decoding the variable length code obtained by said first coding means; second quantizing means for quantizing the image data obtained by said decoding means with the quantizing level selected by said selecting means; and second coding means for performing variable length coding on the data quantized by said second quantizing means.
Claim 19
Dependent Claim
37 words
A coding apparatus according to Claim 18, further comprising storing means for storing the variable length code obtained by said first coding means, wherein said decoding means decodes the variable length code stored by said storing means.
Claim 20
Dependent Claim
26 words
A coding apparatus according to Claim 18, wherein said selecting means selects a quantizing level so that the recording density in said recording medium becomes maximum.
Claim 21
Dependent Claim
45 words
A coding apparatus according to Claim 18, wherein said second quantizing means has one plurality of quantizing tables of different quantizing step widths, and said selecting means selects one quantizing table from said plurality of quantizing tables on the basis of the obtained coding amount.
Claim 22
Dependent Claim
140 words
A coding apparatus for reducing and coding digital image data to record the data on a recording medium, comprising: first quantizing means for quantizing said image data; first coding means for performing variable length coding on the quantized data; second coding means for performing variable length coding on the data obtained by said first coding means in a coding method different from that of said first coding means thereby to obtain a variable length code; selecting means for selecting a quantizing level on the basis of the coding amount of the variable length code obtained by said second coding means; second quantizing means for quantizing the data obtained by said first coding means with the quantizing level selected by said selecting means; and third coding means for performing variable length coding on the data quantized by said second quantizing means.
Claim 23
Dependent Claim
34 words
A coding apparatus according to Claim 22, further comprising storing means for storing the data obtained by said first coding means, wherein said second quantizing means quantizes the data stored by said storing means.
Claim 24
Dependent Claim
26 words
A coding apparatus according to Claim 22, wherein said selecting means selects one quantizing level so that the recording density in said recording medium becomes maximum.
Claim 25
Dependent Claim
45 words
A coding apparatus according to Claim 22, wherein said second quantizing means has a plurality of quantizing tables of different quantizing step widths, and said selecting means selects one quantizing table from said plurality of quantizing tables on the basis of the obtained coding amount.
References Cited (Backward Citations)
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