JPH0970042A - Image coder, image coding method, image coding/ transmission method and image recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimize a parameter (minimum value (MIN) and dynamic range (DR)) at the decoder side so that the decoding error between an original signal and a decoded value becomes small. SOLUTION: A maximum value detection section 2 detects a maximum value (MAX) of a (3×3) blocks, a minimum value detection section 3 detects a minimum value (MIN). A subtractor 4 generates a dynamic range (DR), a subtractor section 5 subtracts the MIN from an input picture element value (y) and normalized. A step width calculation section 6 calculates a quantity step width Δfrom the DR and a quantization section 7 uses the width Δ to generate a 4-bit quantization value (x). A least square estimate section 8 generates a decoded value y' from the values x, y, to obtain an optimum dynamic range (DR') minimizing the square sum of the error (y'-y) and the optimum minimum value (MIN'). A framing section 11 applies framing processing to the x, DR', MIN' and the result is recorded in a recording medium 15 via an error correction code addition section 12, a modulation section 13 and a recording section 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image coding apparatus, an image coding method, an image coding transmission method and an image recording medium for coding a digital image signal in order to compress the data amount of the digital image signal. In particular, the present invention relates to an image coding apparatus, an image coding method, an image coding transmission method, and an image recording medium that code a digital image signal and transmit additional information together with coded information.

[0002]

2. Description of the Related Art FIG. 7 is a block diagram showing an example of an image coding apparatus for compressing a digital image signal. Figure 7
The image encoding device shown in FIG. 2 uses ADRC (Adaptive Dynamic Renge Coding) that divides an input image signal into blocks in a predetermined block unit and adaptively encodes pixels in the block according to the dynamic range of the block. It is an encoding device.

ADRC is disclosed in Japanese Patent Application Laid-Open No. 61-
It is proposed in Japanese Patent No. 14498. ADRC will be briefly described with reference to FIG. 7. The input image signal input from the input terminal 120 is supplied to the block division unit 121. Then, in the block division unit 121, the input image signal is, for example, 3 pixels × 3 lines (hereinafter (3 ×
3)), which is divided into blocks each including 9 pixels. Then, the output signal from the block division unit 121 is
Maximum value detection unit 122 and minimum value detection unit 1 for each block
23 respectively.

The maximum value detector 122 detects the maximum value MAX of the pixel values included in the block, and the minimum value detector 123 detects the minimum value MIN. The maximum value MAX from the maximum value detection unit 122 is calculated by the subtraction unit 124.
Is supplied to. Further, the minimum value MIN from the minimum value detection unit 123 is supplied to the subtraction unit 124, the subtraction unit 125, and the framing unit 128, respectively.

In the subtracting section 124, the minimum value MIN is subtracted from the maximum value MAX to generate the dynamic range DR. Then, the dynamic range DR is determined by the quantization step width calculation unit 126 and the framing unit 12.
8 respectively. Quantization step width calculation unit 12
In 6, the quantization step width Δ is calculated from the dynamic range DR supplied from the subtraction unit 124, and the calculated quantization step width Δ is supplied to the quantization unit 127.

Further, the subtracting unit 125 is supplied with 9 pixels of the (3 × 3) block from the block dividing unit 121, and by subtracting the minimum value MIN from the pixel values of the 9 pixels, each pixel value is obtained. Normalization is performed on the other hand. The normalized pixel values are supplied to the quantizer 127. In the quantizer 127, each normalized pixel value is quantized with a quantization step width Δ, and as a quantized value x,
Each is supplied to the framing unit 128.

In the framing unit 128, the dynamic range DR and the minimum value MIN supplied for each block are subjected to framing together with the quantized value x of 9 pixels of the block as an output signal. Is output. Then, this output signal is recorded on a recording medium such as a disk, or transmitted via a transmission path.

[0008]

However, on the decoding side, using the parameters of the block to be transmitted,
When decoding the quantized value of the block, in the sense that the decoding error between the original signal value and the decoded restored value is minimized, the quantized value of the block is calculated using the parameter of the block obtained first. There is no guarantee that the decoding is optimal, and in some cases, the decoding error becomes large and the decoded image deteriorates.

Therefore, an object of the present invention is to provide a parameter (for example, in the case of ADRC) first determined for obtaining a quantized value on the encoding side so that a decoding error between an original signal value and a restored value becomes small. The image coding apparatus, the image coding method, the image coding transmission method, and the image recording medium capable of reducing the decoding error by optimizing the maximum value MAX, the minimum value MIN, or the dynamic range DR). To provide.

[0010]

In order to achieve the above object, the present invention is an image coding method for coding and transmitting an input digital image signal so as to reduce the amount of generated data of the input digital image signal. In, the input digital image signal is divided into blocks made up of a plurality of pixels, a plurality of pixels in each block are coded for each block, coded data and parameters are generated, and a decoding error of coded data Image coding method adapted to optimize parameters generated for each block so as to minimize the sum of squares, and image coding apparatus, image coding transmission method and recording corresponding to the image coding method It is a medium.

Further, in the image coding method of the present invention, the coding step further detects, for each block, a maximum value of a plurality of pixels and a minimum value of the plurality of pixels, and determines the maximum value and the minimum value. The dynamic range, which is the difference between the values, is detected, the pixel values of the plurality of pixels that are normalized using the value that defines the dynamic range are quantized, and the quantized values of the plurality of pixels are generated. , An image coding method for optimizing the parameters of each block so as to minimize the sum of squares of the decoding error of the quantized value, and an image coding apparatus and image coding transmission corresponding to the image coding method. A method and a recording medium.

Further, in the image coding method of the present invention, the optimizing step further indicates the maximum value, the minimum value and the dynamic range of each block so as to minimize the sum of squares of the decoding error of the quantized value. At least 2 of information
One is an image coding method adapted to optimize one, an image coding apparatus corresponding to the image coding method, an image coding transmission method, and a recording medium.

As described above, according to the present invention, after the block parameter is obtained, decoding is performed using the parameter to obtain the error between the restored value and the true value, and the parameter is adjusted so as to minimize the error. Therefore, the restoration error between the original signal value and the restoration value can be further reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a block diagram of a first embodiment of an image coding apparatus of the present invention. The input image signal is supplied to the block division unit 1 via the input terminal IN. In the block division unit 1, the input image signal is
For example, it is divided into (3 × 3) blocks and
3) Input pixel value y consisting of 8 bits of 9 pixels in the block
Are supplied to the maximum value detection unit 2, the minimum value detection unit, the subtraction unit 5, and the least squares estimation unit 8, respectively.

The maximum value detection unit 2 detects a value having the maximum pixel value level among the 9 pixels included in the (3 × 3) block, and the maximum value MAX is supplied to the subtraction unit 4. . Further, in the minimum value detection unit 3, (3 × 3)
Of the nine pixels included in the block, a value having the minimum pixel value level is detected, and the minimum value MIN is used as the subtraction unit 4
And the subtraction unit 5 respectively.

In the subtracting section 4, the maximum value MAX to the minimum value M
IN is subtracted to generate the dynamic range DR. The dynamic range DR is supplied to the quantization step size calculator 6. In addition, the subtraction unit 5 subtracts the minimum value MIN from the input pixel value y of the 9 pixels of the (3 × 3) block from the block division unit 1, and normalizes the minimum value MIN of the 9 pixels of the (3 × 3) block. Pixel values are generated.
The normalized pixel values of 9 pixels in the (3 × 3) block are supplied to the quantization unit 7.

The quantizing step width calculation unit 6 calculates the quantizing step width Δ based on the supplied dynamic range DR, and the calculated quantizing step width Δ is
It is supplied to the quantizer 7. The quantizer 7 performs 4-bit quantization on the pixel values of 9 pixels of the (3 × 3) block normalized by the supplied quantization step width Δ. The quantized value x consisting of 4 bits of 9 pixels in the (3 × 3) block is the least squares estimation unit 8 and the framing unit 11.
Is supplied to each.

Then, the least squares estimation unit 8 quantizes the input pixel value y of the 9 pixels of the (3 × 3) block which is the input image signal and the quantized 9 pixels of the quantized (3 × 3) block. The value x is supplied, and the least squares estimation unit 8 supplies the input pixel value (true value) y and the quantized value x supplied for each block.
By using the least squares method, the difference between the decoded value y ′ of the quantized value of each block and the true value y corresponding to the decoded value y ′ (y
′ -Y) Optimized dynamic range DR ′ and optimized minimum value MIN to minimize the sum of squares
Estimate ´. That is, the relationship of the following expression (1) is established between the decoded value y ′ of the input pixel value y and the quantized value x.

Y ′ = x × DR / n + MIN (1) (where n is the number of quantization bits)

Then, the optimized dynamic range DR 'is obtained by the following equation (2).

DR ′ = n · Δ ′ (2) (where Δ ′ is the optimized quantization step width)

Further, assuming that the number of pixels in the block is m, the optimized quantization step width can be obtained by the following equation (3).

Δ ′ = (m · Σxy−Σx · Σy) / (m · Σx ² − (Σx) ² ) (3)

Further, the optimized minimum value MIN 'is obtained by the following equation (4).

MIN ′ = (Σy−Δ ′ · Σx) / m (4)

Then, the optimized dynamic range DR ′ and the optimized minimum value MIN ′ are supplied to the framing unit 11. The framing unit 11 framing the quantized value x from the quantization unit 7, the optimized dynamic range DR ′ and the optimized minimum value MIN ′ from the least squares estimation unit 8 for each block, and framing signals. Is supplied to the error correction code addition unit 12.

The error correction code addition section 12 adds an error correction code to the framing signal and supplies it to the modulation section 13. The modulator 13 modulates the framing signal to which the error correction code is added by using a modulation method such as an EFM modulation method. Then, the modulated signal is recorded by the recording unit 1.
4 and is recorded in the recording medium 15 such as a disc in the recording unit 14.

Further, in the case of transmitting the modulated signal via the transmission line 17, the present invention is constituted by the transmission unit 16 instead of the recording unit 14. Then, the modulation unit 13 modulates the framing signal to which the error correction code is added by using a modulation method optimal for transmission, and supplies the framing signal to the transmission line 17 via the transmission unit 16. A number of techniques are already known for the framing technique and the modulation technique, so that they are omitted here, but any technique may be used.

Next, the details of the least squares estimation unit 8 of the first embodiment will be described with reference to FIGS. 2 and 3. FIG. 3 is an example of an actual configuration for obtaining the optimized dynamic range DR ′ and the optimized minimum value MIN ′ by the method of least squares, and FIG. 2 calculates the constants required for the configuration. This is an example of the configuration.

As described above, the data x used in this first embodiment is the quantized value, and the data y'is the restored value of the data x. Further, the true value of the data y ′ is y, and the number of pixels in the block is m. Therefore,
The least squares estimation unit 8 uses the supplied pixel value y and the quantized value x for each block to convert the quantized value of each block into a decoded value y ′ and a decoded value y ′ by the least square method. An optimized minimum value MIN ′ and an optimized dynamic range DR ′ that minimize the sum of squares of the error (y′−y) from the corresponding true value are estimated.

First, the data x is supplied from the input terminal 21 shown in FIG. 2, and the data x is supplied to the register 22. Further, the data y is supplied to the register 24 via the input terminal 23. The counter 25 counts the number of pixels for each block according to the clock, and counts the number of pixels m.
Is supplied to the terminal 28 via the registers 26 and 27.

The multiplier 29 multiplies the 4-bit data x supplied from the register 22 by the 8-bit data y supplied from the register 24 to obtain 12
The bit data xy is added to the adder circuit 3 via the register 30.
1 is supplied. In this adder circuit 31, the supplied 1
The 2-bit data xy is supplied to the adder 31a. The data output from the adder 31a is stored in the register 3
1b and 31c. The data xy supplied from the register 30 and the data output from the adder 31a are added by the adder 31a via the register 31b. Data of 18 bits is output from the adder circuit 31 and supplied as data Σxy to the terminal 33 via the register 32. That is, the adder circuit 31
Generates Σxy in block units.

The 4-bit data x supplied from the register 22 is supplied to the adder circuit 35 via the register 34. In the adder circuit 35, the supplied data x of 4 bits is supplied to the adder 35a. The data output from the adder 35a is supplied to the registers 35b and 35c. The data x supplied from the register 34 and the data output from the adder 35a are added by the adder 35a via the register 35b. The adder circuit 35 outputs 10-bit data,
The data Σx is supplied to the terminal 37 via the register 36. That is, the adder circuit 35 generates Σx in block units.

The 10-bit data Σx from the adder circuit 35 is supplied to the multiplier 38. The multiplier 38 calculates the square of the data Σx and supplies it to the terminal 40 via the register 39 as 20-bit data (Σx) ² .

The 8-bit data y supplied from the register 24 is supplied to the adder circuit 42 via the register 41. In the adder circuit 42, the supplied data y of 8 bits is supplied to the adder 42a. The data output from the adder 42a is supplied to the registers 42b and 42c. The data y supplied from the register 41 and the data output from the adder 42a are added by the adder 42a via the register 42b. 14-bit data is output from the adder circuit 42,
The data Σy is supplied to the terminal 44 via the register 43. That is, the adder circuit 42 generates Σy in block units.

The multiplier 45 calculates the square of the 4-bit data x supplied from the register 22, and supplies 8-bit data x ² to the adder circuit 47 via the register 46. In this adder circuit 47, the supplied 8
The data x ² consisting of bits is supplied to the adder 47a. The data output from the adder 47a is stored in the register 4
7b and 47c. The data x ² supplied from the register 46 and the data output from the adder 47a are added by the adder 47a via the register 47b. 14-bit data is output from the adder circuit 47, and is supplied to the terminal 49 via the register 48 as data Σx ² . That is, the adder circuit 47
Generates Σx ² in block units.

Further, as shown in FIG. 2, the input terminal 50 is
The counter 25 is connected to the clear terminals of the registers 31b, 35b, 42b and 47b, the input terminal 51 is connected to the clear terminals of the registers 27, 32, 36, 39, 43 and 48, and each register is connected to these input terminals 50. Controlled on a block-by-block basis by signals provided to and 51.

FIG. 3 shows a general configuration example of the actual least squares method. The pixel number m supplied to the terminal 28 is supplied to the reciprocal circuit 61, the multiplier 64, and the multiplier 71, respectively. The reciprocal circuit 61 calculates the reciprocal (1 / m) of the supplied pixel number m, and supplies the reciprocal (1 / m) to the terminal 63 via the register 62. In the multiplier 64,
The data Σxy supplied to the terminal 33 is multiplied by the number of pixels m, and the data mΣxy is supplied to the subtractor 66 via the register 65.

The Σx supplied to the terminal 37 is supplied to the multiplier 67 and the multiplier 74, respectively, and the data Σy supplied to the terminal 44 is supplied to the multiplier 67. In the multiplier 67, the data Σx and the data Σy are multiplied,
The data ΣxΣy is supplied to the subtractor 66 via the register 68. The subtractor 66 subtracts the data ΣxΣy from the data mΣxy, and outputs the output data mΣxy−Σ
xΣy is multiplied by the multiplier 79 via the registers 69 and 70.
Is supplied to.

The multiplier 71 multiplies the data Σx ² supplied to the terminal 47 by the number of pixels m, and the register 72
The data mΣx ² is supplied to the subtractor 73 via the. The multiplier 74 calculates the square of the data Σx, and the data (Σx) ² is supplied to the subtractor 73. Subtractor 73
Then, the data (Σx) ² is subtracted from the data mΣx ² , and the output data mΣx ² − (Σx) ² is supplied to the reciprocal circuit 77 via the register 76. Inverse circuit 7
7, the reciprocal of data mΣx ² − (Σx) ² (1 / (mΣx ² − (Σx) ² )) is calculated, and the reciprocal (1 / (mΣx ² − ( Σx)
² )) is supplied to the multiplier 79.

In the multiplier 79, the data mΣxy−ΣxΣ
y is multiplied by the data 1 / (mΣx ² − (Σx) ² ) to obtain the data (mΣxy−ΣxΣy) / (mΣx ² −
(Σx) ² ) is supplied to the multipliers 81 and 89 via the register 80, respectively. In the multiplier 81, the terminal 3
Data Σx and data (mΣxy−ΣxΣ
y) / (mΣx ² − (Σx) ² ), and as a result, data (mΣxΣxy− (Σx) ² Σy) /
(MΣx ² − (Σx) ² ) is supplied to the subtractor 83 via the register 82.

In the subtractor 83, the data (mΣxΣxy) from the register 82 is converted from the data Σy supplied to the terminal 44.
Subtraction of − (Σx) ² Σy) / (mΣx ² − (Σx) ² ) is performed, and as a result, data m is output via the register 84.
(Σx ² Σy−ΣxΣxy) / (mΣx ² − (Σ
x) ² ) is supplied to the multiplier 85. In the multiplier 85,
1 / m from the terminal 63 and the data m (Σx ² Σy−ΣxΣ
xy) / (mΣx ² − (Σx) ² ) is performed,
As a result, the data (Σx ² Σy−ΣxΣxy) / (mΣ
x ² − (Σx) ² ) becomes the optimized minimum value MIN ′. Then, the generated minimum value MIN ′ is supplied to the output terminal 87 via the register 86 and output.

At the terminal 88, the quantization step size calculator 6
The preset value 2 ⁿ corresponding to the number of quantization bits used in is supplied. In the multiplier 89, the terminal 88
2 ⁿ (n is the number of quantized bits) and the data (mΣxy−ΣxΣy) / (mΣx ² − (Σx) ² ) are supplied to the data 2 ⁿ (mΣxy−Σ).
xΣy) / (mΣx ² − (Σx) ² ) is the optimized dynamic range DR ′. The generated dynamic range DR ′ is stored in the registers 90, 91 and 92.
It is supplied to the output terminal 93 via and is output. In this way, the optimized minimum value MIN ′ and the optimized dynamic range DR ′ can be obtained.

FIG. 4 shows the optimized maximum value MAX 'and the optimized dynamic range D together with the quantized value.
The image coding apparatus of the 2nd Example which transmits R'is shown. In the description of the second embodiment, the same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the subtraction unit 19, from the maximum value MAX, (3 ×
3) Input pixel value y consisting of 8 bits of 9 pixels in the block
Are subtracted, and the input pixel values of 9 pixels are each normalized. The normalized pixel value of 9 pixels is supplied to the quantization unit 7. The quantizer 7 supplies a quantized value consisting of 4 bits of 9 pixels of a (3 × 3) block to the least squares estimator 9 and the framing unit 11, respectively.

Then, the least-squares estimation unit 9 inputs the input pixel value y of the 9 pixels of the (3 × 3) block which is the input image signal and the 9 pixel pixels of the quantized (3 × 3) block. A quantized value x is provided. This least squares method estimation unit 9
Using the input pixel value (true value) y and the quantized value x supplied for each block, the decoded value y ′ of the quantized value of each block and the true value corresponding to the decoded value y ′ are obtained by the method of least squares. Estimate the optimized dynamic range DR ′ and the optimized maximum value MAX ′ that minimize the sum of squares of the error (y′−y). That is, the decoded value y of the input pixel value y
The relation of the following expression (5) is established between ′ and the quantized value x.

Y ′ = MAX−x × DR / n (5) (where n is the number of quantization bits)

Then, assuming that the number of pixels in the block is m, the optimized dynamic range DR 'is obtained by the above equation (2) using the above equation (3). Further, the optimized maximum value MAX ′ is obtained by the following equation (6) using the above equation (3).

MAX ′ = MIN ′ + DR ′ = (Σy−Δ ′ · Σx) / m + n · Δ ′ = (Σy + (n−Σx) Δ ′) / m (6)

Then, the optimized dynamic range DR 'and the optimized maximum value MAX' are supplied to the framing unit 11. The framing unit 11 framing the quantized value x from the quantizing unit 7, the optimized dynamic range DR ′ and the optimized maximum value MAX ′ from the least squares estimation unit 9 for each block.

FIG. 5 shows a third embodiment of the image coding apparatus for transmitting the optimized maximum value MAX 'and the optimized minimum value MIN' together with the quantized value. In the description of the third embodiment, the same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the subtracting section 5, as in the embodiment of FIG.
The minimum value MIN is subtracted from the input pixel value y consisting of 8 bits of 9 pixels in the (3 × 3) block, and the pixel value of 9 pixels is normalized. The normalized pixel value of 9 pixels is supplied to the quantization unit 7. The quantizer 7 uses (3 ×
3) The quantized value consisting of 4 bits of 9 pixels of the block is supplied to the least squares estimation unit 10 and the framing unit 11, respectively.

Then, the least-squares estimation unit 10 inputs the input pixel value y of 9 pixels of the (3 × 3) block which is the input image signal and the 9 pixel pixels of the quantized (3 × 3) block. The quantized value x is supplied to the least squares estimation unit 10
Is a true value corresponding to the decoded value y ′ and the decoded value y ′ of the quantized value of each block by the least squares method using the input pixel value (true value) y and the quantized value x supplied for each block. Optimized minimum value MIN 'and optimized maximum value MAX for minimizing the square sum of the error (y'-y) with the value
Estimate ´. That is, the relationship of the following expression (7) is established between the decoded value y ′ of the input pixel value y and the quantized value x.

Y ′ = x × (MAX-MIN) / n + MIN (7) (where n is the number of quantization bits)

When the number of pixels in the block is m, the optimized minimum value MIN 'is given by the above-mentioned equation (3).
Is calculated by the above-described equation (4). In addition, the optimized maximum value MAX ′ is obtained by the above-mentioned equation (3).
Is calculated by the above-mentioned equation (6). Then, the optimized minimum value MIN ′ and the optimized maximum value MAX ′ are supplied to the framing unit 11. The framing unit 11 framing the quantized value x from the quantization unit 7, the optimized minimum value MIN ′ and the optimized maximum value MAX ′ from the least squares estimation unit 10 for each block.

Next, FIG. 6 shows an example in which the image coding apparatus of the present invention is applied to a hierarchical coding apparatus. The input image signal from the input terminal 101 is supplied to the averaging unit 102 and the subtracting unit 104, respectively. In the averaging unit 102, for example, the supplied input image signal is added to four pixels in units of (2 × 2) blocks, and the added value is averaged to ¼. The averaged pixels are supplied to the interpolation unit 103 and the high efficiency encoding unit 108, respectively.

The interpolating unit 103 interpolates the pixels thinned out by averaging, for example, using a class classification adaptive processing technique, and the pixels are supplied to the subtractor 104. As described above, regarding the interpolation method using the class classification adaptive processing technique, for example, Japanese Patent Application Laid-Open No.
It is proposed in Japanese Patent No. 328185. Also,
The interpolation unit 103 may use a known interpolation method other than the method using the class classification adaptive processing technique.

The subtractor 104 subtracts the interpolated pixel from the input pixel value y, and supplies the residual signal to the high efficiency encoder 105. This high efficiency coding unit 1
In the same manner as in the above-described embodiment of the present invention, reference numeral 05 designates A that optimizes at least two parameters of the dynamic range DR, the minimum value MIN and the maximum value MAX.
It is a high-efficiency coding unit by DRC.

That is, the high-efficiency coding unit 105 generates a quantized value x and an additional code (for example, the optimized dynamic range DR 'and the optimized minimum value MIN' in the first embodiment). Then, the generated quantized value x and the additional code are supplied to the variable length coding unit 106.
In the variable length coding unit 106, the supplied quantized value x
And the additional code are subjected to variable length coding such as Huffman coding and run length coding, and the variable length coded data is transmitted from the output terminal 107 as the coded data of the lower layer.

Similarly, in the high efficiency encoding unit 108, the averaged pixels supplied from the averaging unit 102 are supplied to the high efficiency encoding unit 108. This high efficiency encoding unit 108
Is an ADR that optimizes at least two parameters of the dynamic range DR, the minimum value MIN and the maximum value MAX as in the above-described embodiment of the present invention.
It is a high-efficiency coding unit using C.

That is, the high-efficiency coding unit 108 generates the quantized value x and the additional code (for example, the optimized dynamic range DR 'and the optimized minimum value MIN' in the first embodiment). Then, the generated quantized value x and the additional code are supplied to the variable length coding unit 109.
In the variable length coding unit 109, the transmitted quantized value x
And the additional code are subjected to variable-length coding such as Huffman coding and run-length coding, and the variable-length coded data is transmitted from the output terminal 110 as coded data of the upper layer.

In the first, second and third embodiments of the present invention, the parameters to be transmitted are optimized dynamic range DR ', optimized minimum value MIN' and optimized maximum value MAX. 'Of at least 2
Although one parameter is transmitted, the present invention is not limited to this, and two parameters including at least the optimized quantization step width Δ ′ may be transmitted.

That is, according to the present invention, at least the two parameters to be transmitted may be optimized in the least squares estimation section and the two optimized parameters may be transmitted together with the quantized value.

Further, in the first and third embodiments of the present invention, the subtraction unit 5 subtracts the minimum value MIN from the quantized value of 9 pixels, but the present invention is not limited to this, and the second Similarly to the embodiment described above, the input pixel value of 9 pixels may be subtracted from the maximum value MAX.

In the second embodiment of the present invention, the subtraction unit 19 subtracts the quantized value of 9 pixels from the maximum value MAX, but the present invention is not limited to this, and the first embodiment is not limited to this. Similarly, the minimum value MIN may be subtracted from the quantized value of 9 pixels.

Further, the block division unit of the present invention divides the input image signal into two-dimensional blocks of (3 × 3) blocks, but the present invention is not limited to this, and other than (3 × 3) blocks. It may be composed of blocks, or the input image signal may be composed of three-dimensional blocks.

Further, in the embodiment of the present invention, the ADRC
However, the present invention is not limited to this, and DCT (Discre
When te Cosine Transform) is used, optimization is performed on the DC component and GBTC (Grobal Block Trancation) is performed.
When using Coding), it is possible to perform optimization on the average value and standard deviation.

Although the embodiment of the present invention is a coding apparatus for digital image signals, the present invention is not limited to this, and can be applied to data such as digital audio signals.

Various modifications and application examples can be considered without departing from the gist of the present invention. Therefore,
The gist of the present invention is not limited to the embodiments.

[0070]

According to the present invention, on the encoding side, the parameter first obtained for obtaining the quantized value is optimized by the least square method so that the decoding error between the original signal value and the restored value becomes small. It has become. Therefore, according to the present invention,
On the decoding side, the error between the restored value and the original signal value can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of an image coding apparatus according to the present invention.

FIG. 2 is a diagram showing a configuration example of a least squares method estimation unit according to the present invention.

FIG. 3 is a diagram showing a configuration example of a least squares estimation unit according to the present invention.

FIG. 4 is a block diagram showing a second embodiment of the image coding apparatus according to the present invention.

FIG. 5 is a block diagram showing a third embodiment of the image coding apparatus according to the present invention.

FIG. 6 is a block diagram showing an example in which the image encoding device of the present invention is used in a hierarchical encoding device.

FIG. 7 is a block diagram of a conventional ADRC.

[Explanation of Codes] 1 ... Block division unit, 2 ... Maximum value detection unit, 3 ...
..Minimum value detecting units 4, 5, ... Subtracting unit, 6 ... Step width calculating unit, 7 ... Quantizing unit, 8 ... Least square method estimating unit, 11 ... Framing unit, 12 ... Error correction code addition section, 13 ... Modulation section, 14 ... Recording section, 15 ... Recording medium, 16 ... Transmission section, 17 ...
・ Transmission path

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kunio Kawaguchi 6-735 Kitashinagawa, Shinagawa-ku, Tokyo Sony Corporation

Claims (12)

[Claims] 1. An image coding apparatus for coding the input digital image signal so as to reduce the amount of generated data of the input digital image signal, wherein the input digital image signal is divided into blocks composed of a plurality of pixels. A division unit, an encoding unit that encodes a plurality of pixels in the block for each block to generate encoded data and parameters, and a sum of squares of decoding errors of the encoded data is minimized. As described above, the image encoding device, comprising: an optimization unit that optimizes the parameters generated for each block. 2. The image coding apparatus according to claim 1, wherein the coding unit detects, for each block, a maximum value of the plurality of pixels and a minimum value of the plurality of pixels in the block. A first detection unit for detecting a dynamic range that is a difference between the maximum value and the minimum value; and a plurality of pixels that are normalized using a value that defines the dynamic range. The pixel value is quantized and consists of a quantizer that generates the quantized values of the plurality of pixels. The optimizing unit minimizes the sum of squared decoding errors of the quantized values.
An image coding apparatus characterized by optimizing parameters of each block. 3. The image coding apparatus according to claim 2, wherein the optimizing unit minimizes a sum of squares of decoding errors of the quantized values.
An image coding apparatus characterized by optimizing at least two of information indicating a maximum value, a minimum value, and a dynamic range of each block. 4. An image coding method for coding the input digital image signal so as to reduce the amount of generated data of the input digital image signal, wherein the input digital image signal is divided into blocks composed of a plurality of pixels. A step of encoding a plurality of pixels in the block for each block, generating encoded data and parameters, and minimizing the sum of squares of the decoding error of the encoded data, And a step of optimizing a parameter generated for each block. 5. The image coding method according to claim 4, wherein the step of generating the coded data and parameters includes, for each block, a maximum value of the plurality of pixels in the block, and Detecting a minimum value of a plurality of pixels, detecting a dynamic range that is a difference between the maximum value and the minimum value, and detecting a dynamic range of the plurality of pixels normalized using a value that defines the dynamic range. Quantizing a pixel value to generate quantized values of the plurality of pixels, and the optimizing step includes minimizing a sum of squares of decoding errors of the quantized values.
An image coding method comprising the step of optimizing the parameters of each block. 6. The image coding method according to claim 5, wherein the optimizing step minimizes a sum of squares of decoding errors of the quantized values.
An image coding method comprising a step of optimizing at least two of information indicating a maximum value, a minimum value and a dynamic range of each block. 7. An image coding transmission method for coding and transmitting the input digital image signal so as to reduce the amount of generated data of the input digital image signal, wherein the input digital image signal is divided into blocks composed of a plurality of pixels. A step of dividing, a step of encoding a plurality of pixels in the block for each block to generate encoded data and a parameter, and a sum of squares of decoding errors of the encoded data is minimized. Thus, the image coding is characterized by the steps of optimizing the parameters generated for each block, and transmitting the coded data and the optimized parameters for each block. Transmission method. 8. The image coding transmission method according to claim 7, wherein the step of generating the coded data and the parameter includes, for each block, a maximum value of the plurality of pixels in the block, Detecting a minimum value of the plurality of pixels, detecting a dynamic range that is a difference between the maximum value and the minimum value, and the plurality of pixels normalized using a value defining the dynamic range Quantizing the pixel value of, and generating the quantized values of the plurality of pixels, the optimizing step includes minimizing the sum of squares of the decoding error of the quantized value,
Image coding transmission, characterized in that it comprises a step of optimizing parameters of each block, and said transmitting step comprises a step of transmitting a plurality of quantized values and the optimized parameters for each block. Method. 9. The image coding transmission method according to claim 8, wherein the optimizing step minimizes the sum of squares of the decoding error of the quantized value.
The method comprises the step of optimizing at least two pieces of information indicating the maximum value, the minimum value, and the dynamic range of each block, and the transmitting step includes the optimized maximum value, the optimized minimum value, and the optimized value. An image coding transmission method, comprising: transmitting at least two pieces of information indicating the generated dynamic range as a parameter together with a plurality of quantized values for each block. 10. An image recording medium in which the input digital image signal is coded so as to reduce the amount of generated data of the input digital image signal, and the coded signal is recorded. A recording unit for recording the coded signal, wherein the coded signal divides the input digital image signal into blocks composed of a plurality of pixels, and codes a plurality of pixels in the block for each block. It is characterized by comprising the encoded data obtained by the above, and an optimization parameter obtained by optimizing the parameter generated for each block so as to minimize the sum of squares of the decoding error of the encoded data. Image recording medium. 11. The image recording medium according to claim 10, wherein the coded data detects a maximum value of the plurality of pixels and a minimum value of the plurality of pixels in the block for each block. , A plurality of pixels obtained by detecting a dynamic range that is a difference between the maximum value and the minimum value, and quantizing pixel values of the plurality of pixels normalized using a value that defines the dynamic range. Is a quantized value of, and the optimization parameter is such that the sum of squares of the decoding error of the quantized value is minimized,
An image recording medium, which is a parameter obtained by optimizing a parameter of each block. 12. The image recording medium according to claim 11, wherein the optimization parameter minimizes the sum of squares of the decoding error of the quantized value.
An image recording medium, which is a parameter obtained by optimizing at least two of information indicating a maximum value, a minimum value, and a dynamic range of each block.