JP2001045485A - Moving picture encoding apparatus and method, decoding apparatus and method, and image recording / reproducing apparatus - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the coding efficiency while suppressing the overall processing amount in moving image coding, and to perform appropriate image reproduction according to the search speed when searching for images. Realize. SOLUTION: A block dividing unit 1 for dividing an input image 100 into a plurality of blocks, and an error between a block image located at the same position of a previous frame stored and held in a frame memory 14 and a current encoding target block. An error detection unit 12 for detecting, an encoding mode control unit 2 for selectively controlling whether to perform encoding of the encoding target block according to the detected error, and a wavelet transform encoding for each block image. And a circuit unit for performing wavelet transform coding. A circuit unit for wavelet transform coding includes a wavelet transform unit 4, a scanning unit 5, a quantization unit 6, and an entropy coding unit 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving picture encoding apparatus and method, a decoding apparatus and method, and an image recording / reproducing apparatus which can be used in a system for efficiently transmitting or storing images. The present invention relates to a moving picture encoding apparatus and method, a decoding apparatus and method using a block-based wavelet transform in a compression / decompression part, and an image recording / reproducing apparatus.

[0002]

2. Description of the Related Art Conventional typical image compression methods include:
ISO (International Organization)
for Standardization)
(Joint Photographic Coding Experts Group). The JPEG method is a method for mainly compressing and coding a still image using DCT (Discrete Cosine Transform). If a relatively high bit is allocated, a good encoded / decoded image is obtained. It is known to provide However, in this method, if the number of coded bits is reduced to some extent, block distortion peculiar to DCT becomes remarkable, and deterioration is subjectively noticeable.

[0003] Apart from this, recently, there has been research on a method of dividing an image into a plurality of bands by a filter combining a high-pass filter and a low-pass filter called a filter bank, and performing encoding for each band. It is thriving. Above all, wavelet coding is regarded as a promising new technology to replace DCT because it does not have the drawback that block distortion becomes noticeable due to high compression, which is a problem in DCT.

At present, in products such as electronic still cameras and video movies, the JPEG system or the MPEG (Mo
In many cases, a ving Picture Image Coding Exparts Group (DV) method or a so-called DV (Digital Video) method is adopted, and each of these compression coding methods uses DCT as a transform method. It is presumed that the above products based on the wavelet transform will appear in the market in the future, but studies for improving the efficiency of the coding method are being actively conducted by various research institutions. In MPEG, the coding efficiency is improved by performing motion compensation prediction between a previous frame and a block called a macroblock to be coded.

[0005]

By the way, as a technique of image compression / decompression required for an electronic still camera, a video movie, or the like, a wavelet transform, which is considered to have higher compression efficiency than DCT, is used for processing by MPEG. It is desired to obtain a good image while omitting the process of motion compensation prediction, which occupies the most part.

In view of such circumstances, the present invention has a frame memory means for compressing / decompressing a moving image in particular, so that the encoding efficiency can be improved while suppressing the entire processing amount. Focusing on the point that one of the outstanding features of the wavelet transform is that it can support multiple resolutions, when performing a video search with a moving picture compression recording / decompression device equipped with the image compression / decompression device of the present invention, Moving image encoding apparatus and method, decoding apparatus and method capable of performing a search that could not be realized by a conventional video recorder or the like by selectively decoding a predetermined band component according to the speed, It is another object of the present invention to provide an image recording / reproducing apparatus.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problem, a moving picture coding apparatus and method according to the present invention divide an input picture into a plurality of blocks and store the divided pictures in a picture memory.
A block image at the same position of the held previous frame,
Detecting an error with the current coding target block, selecting whether to perform coding of the coding target block according to the detected error or not, and performing wavelet transform coding for each block image. Features.

Here, the image memory may store and hold an image obtained by performing an inverse wavelet transform decoding on an encoded output obtained by the wavelet transform encoding.

Further, the moving picture decoding apparatus and method according to the present invention input or read a coded bit stream, perform wavelet inverse transform decoding, output a decoded picture, and extract a target area from the obtained decoded picture. The decoded image stored in the image memory is stored and held in the image memory, and the decoded image of the previous frame stored in advance in the image memory is transmitted or decoded by the inverse wavelet transform decoding unit in accordance with the supplied encoding control signal. It is characterized in that it is selected whether or not to send the image.

When performing the inverse wavelet transform decoding, the quantized transform coefficients are inversely quantized and returned to the transform coefficients, and the transform coefficients are inversely scanned (inverse scanning).
Then, a transform coefficient to be decoded is extracted from the obtained transform coefficients, and inverse wavelet transform is performed on the obtained decode coefficients.

Further, the image recording / reproducing apparatus according to the present invention further comprises means for converting an input image into a plurality of bands by a filter bank means comprising a plurality of low-pass filters and a high-pass filter. Scanning the transform coefficients for each band, quantizing, entropy encoding means for recording an encoded bit stream on a recording medium, and an image compression apparatus comprising: reading an encoded bit stream from the recording medium; An image decompression device having means for performing entropy decoding, inverse quantization, inverse scanning, and inverse transform by the filter bank means, and outputting a decoded image. Is characterized by having a search means for reading out a corresponding band component from an encoded bit stream recorded in.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an apparatus and a method for encoding a moving image of an image according to the present invention;

FIG. 1 shows an example of the configuration of an image moving picture coding apparatus according to a first embodiment of the present invention. The image moving picture coding apparatus shown in FIG. 1 includes a block dividing unit 1 for dividing an input image 100 into a plurality of blocks, and a same position of a previous frame stored and held in a frame memory 14 as an image memory. And an error detecting unit 12 for detecting an error between the block image and the current block to be coded, and outputting the current block to be coded without coding or wavelet transform coding according to the detected error. Encoding mode control unit 2 for selecting and controlling an encoding mode for performing coding, an encoding target area extracting unit 3 for extracting an encoding target area in accordance with a control signal of the encoding mode, A wavelet transform unit 4 for performing a wavelet transform;
It has a transform coefficient scanning unit 5 for scanning wavelet transform coefficients, a quantization unit 6 for quantizing the scanned coefficients, and an entropy encoding unit 13 for entropy encoding the quantized coefficients and outputting an encoded bit stream. It is configured. As will be described later, the wavelet transform unit 4 has means for symmetrically expanding the pixels inside the block and performing a convolution operation within a range that can be filtered outside the block.

In the moving picture coding apparatus shown in FIG. 1, an input image 100 is first input to a block dividing unit 1, and a plurality of block images 10
It is divided into 1 and sent to the error detection unit 12. The error detecting unit 12 reads the block image 115 at the same position as the block image 101 read from the decoded image of the previous frame stored and held in the frame memory 14, the block image 101 from the block dividing unit 1, Between the error 10
2 and sends the detected error 102 to the coding mode control unit 2. The encoding mode control unit 2 determines one of two encoding modes depending on the magnitude of the error 102.

That is, when the error 102 is larger than a predetermined threshold value (error 102> threshold value), it is determined that the content of the block image has greatly changed. Output an encoded bit stream. On the other hand, when the error 102 is equal to or smaller than the predetermined threshold (error 102 ≦ threshold), since the block image hardly changes, the wavelet transform coding is skipped and the block image 115 in the frame memory 14 is decoded. What is necessary is just to hold | maintain as an image as it is. Therefore, the operation in the former case will be described in detail below. Note that the threshold may be determined in advance before the encoding unit. Also, the encoding mode control unit sends the encoding identification information 1
14 is sent out.

The encoding target area extraction unit 3 includes a lock image 101 from the block division unit and an encoding mode control unit 2
Is sent. The encoding target area extraction unit 3 extracts a block image 101 to be subjected to a subsequent wavelet transform. At this time, the region of the block image 101 to be extracted changes depending on the filtering (convolution operation) of the wavelet transform described in the later embodiment. The information on the filtering method of the wavelet transform refers to the control information 103 from the coding mode control unit 2.

The block image 104 to be encoded extracted by the encoding target area extracting unit 3 is sent to a wavelet transform unit 4, and the wavelet transform unit 4 performs filtering (convolution operation) of wavelet transform. The transform coefficients 105 obtained as a result are input to the scanning unit 5, which scans (scans) the wavelet transform coefficients. For example, it is assumed here that the wavelet transform coefficients are scanned from left to right (horizontal direction) and from top to bottom (vertical direction).

The transformed transform coefficient 106 is quantized in the quantizing section 6 and a quantized coefficient 107 is output. Here, as the quantization means, for example, as shown in the following Expression 1, a normally used scalar quantization may be used.

Q = x / Δ (Equation 1) In Equation 1, x is a wavelet transform coefficient value, Δ
Is a quantization index value.

The quantized coefficient 107 from the quantizer 6 obtained by the scalar quantization or the like is entropy-encoded by the entropy encoder 13 and an encoded bit stream 116 is output. As means used in the entropy coding unit 13, there are arithmetic coding means in addition to variable length coding means, and research results have been reported by each research institution regarding these entropy coding means. May be used.

In a local decoding (local decoding) loop, which is the other path, the quantization coefficient 107 is inversely quantized again and the transform coefficient 108 is output. Further, through the inverse scanning unit 8, the conversion coefficient 109 of the original two-dimensional array is obtained.
Get. Next, coefficients to be decoded are extracted from the transform coefficients 109, and the extracted transform coefficients 110 are subjected to inverse wavelet transform to output a decoded image 111.
The specific operation of the decoding target coefficient extraction unit 9 will be described in an embodiment described later. Finally, the area image 112 extracted from the decoded image 111 is written into the frame memory 14.

The above is the basic configuration and operation of the moving picture coding apparatus according to the first embodiment.

Here, the general wavelet transform coding means includes the wavelet transform unit 4, the scanning unit 5, the quantization unit 6, and the entropy coding unit 13 shown in FIG.
The general inverse wavelet transform decoding means includes the inverse quantization unit 7, the inverse scanning unit 8, and the inverse wavelet transform unit 10 in FIG.

Next, an example of a specific configuration of the wavelet transform unit 2 and the inverse wavelet transform unit 10 according to the first embodiment of the present invention will be described with reference to the drawings.

First, FIG. 2 shows a configuration of a normal wavelet transform unit. This shows a configuration example in which octave division, which is the most common wavelet transform among several methods, is performed over a plurality of levels. In the case of FIG. 2, the number of levels is three (level 1 to level 3), and the image signal is divided into a low band and a high band, and only the low band component is hierarchically divided. I have. FIG. 2 illustrates a wavelet transform for a one-dimensional signal (for example, a horizontal component of an image) for convenience.
By expanding this to two dimensions, it is possible to cope with a two-dimensional image signal.

Next, the operation will be described. The input image signal 120 to the wavelet transform unit shown in FIG. 2 is first band-divided by a low-pass filter 21 (transfer function H ₀ (z)) and a high-pass filter 22 (transfer function H ₁ (z)) and obtained. The resolution of the low-frequency component and the high-frequency component is reduced by a factor of two, respectively, by the corresponding downsamplers 23a and 23b (level 1). The outputs at this time are the L component 121 and the H component 126. Here, L indicates a low range in Low, and H indicates a high range in High. 2, the low-pass filter 21, the high-pass filter 22,
And the two downsamplers 23a and 23b constitute a level 1 circuit section 201.

The low-frequency components of the signals decimated by the downsamplers 23a and 23b, that is, only the signal from the downsampler 23a are further subjected to level 2 signals.
Are divided into bands by the low-pass filter and the high-pass filter of the circuit unit 202, and the resolution is thinned by a factor of two by the corresponding downsampler (level 2). The circuit unit 202 including the level 2 low-pass filter, the high-pass filter, and the down-sampler includes the level 1 low-pass filter 2
1, high-pass filter 22 and down-sampler 23a,
A configuration similar to that of the circuit unit 201 composed of 23b is used.

By performing such processing up to a predetermined level, band components obtained by hierarchically dividing the low-frequency components into bands are sequentially generated. The band components generated at level 2 are the LL component 122 and the LH component 125. FIG. 2 shows an example in which band division is performed up to level 3, and the output from the down sampler on the low-pass filter side of the level 2 circuit section 202 is the level 3 of the same configuration as the circuit section 201 described above.
Is supplied to the circuit unit 203 of the first embodiment. Thus level 3
As a result of band division into LLL component 123 and LLH component 12
4. An LH component 125 and an H component 126 are generated.

Next, a specific configuration example of the wavelet inverse transform unit that performs the reverse operation of the wavelet transform unit shown in FIG. 2 will be described with reference to FIG. The inverse wavelet transform unit in FIG. 3 can be used as the inverse wavelet transform unit 10 in FIG.

Each band component 123, 124, 125, 1, which is the output of the wavelet transform unit 2 described in FIG.
When the signal 26 is input to the inverse wavelet transform unit in FIG. 3, first, the LLL component 123 and the LLH component 124 are upsampled to double the resolution by the upsamplers 24a and 24b, respectively. Subsequently, the low-pass component is filtered by the low-pass filter 25 and the high-pass component is filtered by the high-pass filter 26, and the adder 27 combines the two band components. By the circuit unit 206 so far, the inverse conversion as the reverse process of the conversion in the level 3 circuit unit 203 in FIG. 2 is completed, and the LL component 127 which is the band component on the low frequency side of the level 2 is obtained. Can be By repeating this process up to level 1 thereafter, a final decoded image 129 after inverse conversion is output. That is, the level 2 circuit section 207 and the level 1 circuit section 208 have the same configuration as the level 3 circuit section 206, and the output of the level 3 circuit section 206 is lower than that of the level 2 circuit section 207. And the output of the level 2 circuit section 207 is sent as the low-frequency side input of the level 1 circuit section 208, respectively. The above is the basic configuration of the normal wavelet inverse transform unit.

FIG. 4 illustrates band components obtained as a result of band division of a two-dimensional image up to level 2. The notation of L and H in FIG. 4 is different from the notation of L and H in FIGS. 2 and 3 which deal with one-dimensional signals. That is, in FIG. 4, first, four components LL, LH, HL, and HH are divided by level 1 band division (horizontal and vertical directions). Here, LL means that both horizontal and vertical components are L. LH means that the horizontal component is H and the vertical component is L. Next, the LL component is subdivided again, and further LLLL, LLHL,
LLLH and LLHH are generated. As described above, in addition to hierarchically dividing low-frequency components, the entire band is equally divided.

Next, a moving picture coding apparatus according to a second embodiment of the present invention will be described. The overall configuration of the second embodiment is the same as that of the moving picture encoding apparatus shown in FIG. 1, but is a more specific example of the encoding target area extraction unit 3 in FIG. Prior to the description of the encoding target region extraction unit and the wavelet transform operation related thereto,
Referring to FIG. 5, a description will be given of a case where filtering is applied to pixels surrounding the block by the tap length of the filter when performing the wavelet transform for each block. That is, the filtering is performed while overlapping with the adjacent block.

FIG. 5 shows a block R _T to be coded and a range R _F covered by filtering when performing an overlap type block-based wavelet transform. 5, a, b, c, d, e, f, h, i, j, k, l, and m all represent pixels. For example, when filtering the pixel c in the horizontal direction, three pixels d, e, and f are read from the block image on the right and convolved with a predetermined filter coefficient. Similarly, for example, when filtering the pixel j in the vertical direction, three pixels of k, l, and m are read from the lower block image, and a predetermined filter coefficient is convolved with them.

Therefore, the encoding target area extraction unit according to the second embodiment reads out the pixels of the adjacent block around the block to the extent that the influence of the filtering by the wavelet transform means affects the encoding target area. Enlarge the area. The above is the description of the operation of the wavelet transform performed by the encoding target area extracting unit 3 and the wavelet transforming unit 4 according to the second embodiment.

Next, a third embodiment of the present invention will be described. The overall configuration of the third embodiment is the same as that of the video encoding apparatus shown in FIG. 1, but is a more specific example of the encoding target area extraction unit 3 of FIG. In the third embodiment, as already described in the second embodiment, it is necessary to prepare encoding target pixels around the block to the extent that the influence of the filtering by the wavelet transform unit is exerted. . In the second embodiment, the means for directly reading out the pixels of the adjacent block is used. However, in the third embodiment, the pixel values inside the block are symmetrically expanded so as to have a mirror image relationship at the block boundary. Perform filtering. That is, in the third embodiment, no overlap area is provided between the images of adjacent blocks, and the convolution operation is performed by symmetrically expanding the wavelet transform coefficients inside the block within the range that can be filtered outside the block. I have to. FIGS. 6 and 7 show this. FIG. 6 shows a process of performing wavelet division while performing a convolution operation of symmetric expansion on an original image. FIG. 7 shows a specific example around a block.
Each is shown.

FIG. 6 is a diagram for explaining the concept of wavelet coding by symmetric convolution. The original image shown in (A) of FIG. 6 is divided into block images as shown in (B), and then, for each block image, up to the range covered by the filter processing shown by the broken line in (C). Perform symmetric expansion of pixels in the region.

FIG. 7 specifically shows this target extension, and shows a region R _{T of} a block to be coded or decoded.
Horizontal c, b, a pixel column of a inner is in the boundary of the block boundary, symmetrically a, b, the order of c, it is found that it is extended to a range R _F over which the filtering. Similarly, in vertical direction, f in a block region R _T, e, the pixel columns of d, and the boundary of the block boundaries are expanded symmetrically d, e, the sequence of f to the extent R _F over which the filtering .
It is known that if such a symmetric expansion of the mirror image relationship is performed, only the same number of wavelet transform coefficients as the number of pixels in the block image will be generated. That is, there is an advantage that there is no redundancy.

Subsequently, WT (wavelet transform) is applied to each symmetrically expanded block shown in FIG. 6C. As a result, as described with reference to FIG. 4, the signal is divided into, for example, four band components (see FIG. 6D). The hatched portion in FIG. 6D is the above-mentioned low-range LL component. Further, the block of the low frequency component (LL) in the hatched portion is shown in FIG.
(E), the symmetric extension is performed in the same manner, and the wavelet transform (WT) is performed. After that, the same operation
This is repeated up to a predetermined number of wavelet divisions. The above is the description of the operation of the wavelet transform with the symmetric extension for each block in the encoding target region extracting unit and the wavelet transform unit according to the third embodiment.

Next, a fourth embodiment of the present invention will be described. The fourth embodiment shows a specific example of the encoding target area extracting means and the wavelet transform means associated therewith in the video encoding apparatus having the basic configuration shown in FIG. In the fourth embodiment, as the wavelet transform means, a method of performing a convolution operation by setting all pixels within the range that is outside the block to be filtered to 0 is used. Also in this case, it is not necessary to use the pixels of the adjacent block in the original screen. Next, the operation will be described.

FIG. 8 is a diagram showing the range that the filtering outside the block covers. In FIG. 8, outside the block to be coded or decoded R _T , by setting the range R _{F over} which filtering in the horizontal direction can be all set to 0, c, b, a, 0, 0, 0 is obtained. By setting all the ranges R _F covered by the vertical filtering to 0, f, e, d, 0,
It becomes 0,0. A convolution operation of the wavelet filter coefficient is performed on this.

Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, as a wavelet transform unit, pixels within a range that is outside of a block and that is subjected to filtering are symmetrically expanded so as to have a point-symmetric relationship with pixel values on a block boundary. Are expanded. FIG. 9 illustrates this, and shows two examples of (a) and (b) in FIG. In the figure, X [0], X [1], X [2], X [3], X [4], X [5], X
The eight sample points [6] and X [7] are the pixels (1
(Only in the dimensional direction).

On the other hand, the pixel at the sample point shown by the dotted line is
The pixel value of X [0] or X [7] is calculated as a point-symmetric reference value. In the case of FIG. 9A, the point Pa indicating the pixel value at the sample position of the sample point X [0] on the block boundary is set as a point-symmetric reference point. For example, the sample point x [1] outside the block is used. Is obtained by calculating equidistant points on an extended line extending from the sample point X [1] having a point-symmetric positional relationship within the block so as to pass through the reference point Pa. That is, the sample point x [1] is located symmetrically with respect to the reference point Pa with respect to the sample point X [1]. Similarly, the reference point P
The sample point x [2] is centered on a and the sample point X [2]
, And the sample point x [3] is at the point symmetric position of the sample point X [3]. The same applies when the pixel value at the sample point of X [7] at the other boundary of the block is used as a point-symmetric reference point.

Next, the case of FIG. 9B will be described. The difference from the case of FIG. 9A is that the reference point Pb, which is the center of point symmetry, is shifted from the sample position by a distance of a half sample. In other words, a point Pb indicating a pixel value equal to the sample point X [0] at a position where the sample position of the sample point X [0] at the block boundary is shifted outside the block by a distance of a half sample is set as a point-symmetric reference point. And Therefore, the sample point x located at a position one sample away from the sample point X [0] outside the block.
[0] has the same value as the sample point X [0] because it is located symmetrically with respect to the sample point X [0] about the reference point Pb. As a result, each value of a point inside the block boundary (for example, X [0]) and an outside point (for example, x [0]) become the same, and connection at the block boundary can be made smooth.

As described above, by performing pixel expansion using the point symmetry relationship by any of the methods shown in FIGS. 9A and 9B, the pixels inside the block can be used without using the pixel values of the adjacent block. The convolution operation can be performed by expanding the value to a range where filtering by wavelet transform is performed outside the block.

Next, a sixth embodiment of the present invention will be described. In the sixth embodiment, in particular, the permutation coefficient extraction unit 9 to be decoded, the wavelet inverse transformation unit 10 linked therewith, and the decoded image region extraction This is a specific example of the unit 11. In FIG. 1, the quantization coefficient 107 is inversely quantized by the inverse quantization unit 7 to obtain a transform coefficient 108. Conversion factor 10
8 is inverse-scanned, and only the decoding target coefficient extraction unit 9 extracts only the decoding target from the conversion coefficients 109 rearranged into a two-dimensional image array.

The extracted coefficient 110 is subjected to inverse wavelet transform, and a decoded image 111 is output from the inverse wavelet transform unit 10. Further, an area image to be decoded is extracted from the decoded image 111, and is written into the frame memory 14 as 112. This is the sixth
4 is an operation description of local decoding means inside the encoding device according to the embodiment.

Next, a seventh embodiment of the present invention will be described. The seventh embodiment corresponds to a modification of the sixth embodiment. In the seventh embodiment, the decoding target coefficient extracting unit performs filtering of inverse wavelet transform outside the block. In this case, the transform coefficients of the adjacent blocks are read out to a range covered by the filter. That is, this corresponds to the case where a, b, c, d, e, and f are regarded as transform coefficients in FIG. Then, the wavelet inverse transform is performed by performing a convolution operation on the read transform coefficient outside the block and the transform coefficient of the block.
Then, from the decoded image restored by the inverse wavelet transform, only the region to be decoded may be extracted by the decoded image region extraction unit at the subsequent stage.

Next, an eighth embodiment of the present invention will be described. The eighth embodiment is equivalent to a modification of the sixth embodiment. In the eighth embodiment, the decoding target coefficient extraction unit performs filtering of inverse wavelet transform outside the block. In this case, the coefficients are symmetrically expanded so as to have a mirror image relationship at the block boundary up to the range covered by the filter. In the decoding target coefficient extraction unit, the convolution operation of the wavelet inverse transform is performed in the wavelet inverse transform unit including the expanded transform coefficient.

FIG. 10 illustrates this series of operations, and shows a process of performing a wavelet inverse transform by symmetrically expanding the low-frequency and high-frequency transform coefficient components so as to have a mirror image relationship. I have.

In FIG. 10 (A), the wavelet transform coefficients of the four band components LL, LH, HL, HH are symmetrically expanded as shown in FIG. 10 (B), and each is subjected to the inverse wavelet transform (IWT). ). As a result, as shown in FIG. 10C, each block image is decoded and output. For the symmetric extension, the method of the third embodiment described above with reference to FIG. 7 may be used. However,
In the description of the wavelet transform described in the third embodiment, a, b, c,... In FIG. 7 indicate pixels, but in the present wavelet inverse transform, these represent wavelet transform coefficients. You have to be careful.

An advantage of using the inverse wavelet transform of the symmetric extension is that the inverse transform and decoding can be performed completely independently of the neighboring blocks.
In the case of a relatively high bit rate (low compression rate), deterioration of the boundary between blocks can hardly be detected.

Next, a ninth embodiment of the present invention will be described. In the ninth embodiment, when the inverse decoding of the wavelet is performed outside the block as the decoding target coefficient extracting unit, the convolution operation is performed by setting all the wavelet transform coefficients within the range that the filtering can reach outside the block to 0. I do. Next, the operation will be described.

FIG. 11 is a diagram for specifically explaining this. For example, four band components shown in FIG.
The wavelet transform coefficients of LL, LH, HL, and HH are left as they are, and as shown in FIG. Each block is subjected to inverse wavelet transform (IWT). Thus, each block image is decoded and output. The convolution operation of the inverse wavelet transform at this time is referred to as linear convolution.

The linear convolution means is as described with reference to FIG. 8 and will not be described. As an advantage of this linear convolution, there is an excellent feature that a block boundary is not detected even under a low bit rate (high compression). This is because the effect of linear interpolation by wavelet filtering is obtained at the boundary by making the coefficient of the boundary with the adjacent block equal to 0, and the boundary is smoothly connected.

Also, with this wavelet inverse transform means, since it is not necessary to overlap and read out the wavelet transform coefficients of adjacent blocks, it is possible to perform inverse transform and decoding completely independently of the neighboring blocks. No.

Therefore, as the inverse wavelet transform means, the convolution operation is performed by setting all wavelet transform coefficients within the range that is outside the block to be filtered to 0, thereby achieving high image quality under high compression and partial block decoding. It is an excellent thing that has both of the realizations.

Next, a tenth embodiment of the present invention will be described. The tenth embodiment corresponds to a modification of the sixth embodiment. In the tenth embodiment, filtering of inverse wavelet transform is performed outside the block as the decoding target coefficient extraction unit. When performing a wavelet inverse transform, the transform coefficients outside the block are extended so that the point is symmetrical across the block boundary up to the range covered by the filter, and the obtained transform coefficients and the transform coefficients inside the block are included. It is. The specific expansion method is as shown in FIG. 9 described above, but differs in that the pixel value is expanded in FIG. 9, but the transform coefficient value is expanded in the present embodiment. The subsequent operation is the same as in the eighth embodiment.

Next, an eleventh embodiment of the present invention will be described. This embodiment is an embodiment of a wavelet decoding apparatus and method for an image to which an encoded bit stream obtained by performing the above-described image wavelet encoding is supplied.

FIG. 12 is a block diagram showing a schematic configuration of a moving picture decoding apparatus according to the eleventh embodiment, which corresponds to the moving picture coding apparatus shown in FIG.

In FIG. 11, an image wavelet decoding device inputs or reads out an encoded bit stream and performs entropy decoding on an entropy decoding unit 16.
And an inverse quantization unit 7 for inversely quantizing the obtained quantization coefficient
And a transform coefficient inverse scanning unit 8 for inversely scanning the obtained transform coefficients to return to the original coefficient order, and a decoding target coefficient extracting unit 9 for extracting decoding target coefficients of the inverse-scanned coefficients. Wavelet inverse transform unit 10 that generates block images by inverse wavelet transform of coefficients to be decoded, and decoded image region extracting unit 1 that extracts decoded image regions
1 and a decoding mode control unit 15 and a frame memory 14. Next, the operation will be described.

In FIG. 11, encoding mode information 104
Is received, the decoding mode control unit 15 selects whether to skip the decoding and output the block image stored and held in the frame memory 14 as it is as the output 119 or to perform decoding. When skipping the decoding, the decoding mode control unit 15 sends a control signal 118 to the frame memory 14 to output the stored and held block image as it is. When performing the latter decoding, a control signal is issued from the decoding mode control unit 15 to the entropy decoding unit 16, and the subsequent operation is performed.

That is, when performing the above decoding, first, the entropy decoding unit 16
16 is subjected to entropy decoding, and the quantized coefficient 113 is reproduced. The quantized coefficient 113 is sent to the inverse quantization unit 7 and inversely quantized, and becomes a transform coefficient 108. Conversion factor 1
08 is sent to the inverse scanning unit 8 and subjected to reverse scanning to become the original two-dimensional array of wavelet transform coefficients 109. A coefficient to be decoded is extracted from the transform coefficient 109 by the decoding coefficient extracting unit 9, and the extracted transform coefficient 110 is output to the inverse wavelet transform unit 1.
0, and undergoes inverse wavelet transform to obtain a decoded image 1
11 is obtained. From the decoded image 111, the region image 112 extracted by the decoded image region extraction unit 11 is
The data is written to the frame memory 14. Needless to say, the entropy decoding means must be integrated with the means used in the entropy encoding means in the encoding apparatus.

Next, a twelfth embodiment of the present invention will be described. The twelfth embodiment is a specific example of the decoding target coefficient extraction unit 9 in the eleventh embodiment described above. In the wavelet inverse transform, the transform coefficients up to the range affected by the filtering outside the block are considered. To
Any one of the above-described second to fifth embodiments may be used.
It is obtained by applying to a conversion coefficient instead of a pixel. That is, the transform coefficients outside the block are obtained by reading from an adjacent block, expanding symmetrically at a block boundary, setting to 0, or expanding point-symmetrically around the block boundary, and calculating the wavelet inverse. The conversion is performed. This needs to be linked to the operation of the coded image area extraction unit 3 of the moving picture coding apparatus of FIG. Further, the decoded image area extraction unit 11 which is a component of the video decoding apparatus needs to have a unit for extracting a target block area from the decoded image restored by the inverse wavelet transform unit.

Next, a thirteenth embodiment of the present invention will be described. In the thirteenth embodiment, in the moving picture coding apparatus shown in FIG. 1, all blocks to be coded are coded once by a wavelet transform coding once in a plurality of frames. That is, as described above, the moving picture coding apparatus of FIG. 1 codes a picture in units of blocks, and stores and holds the picture in the frame memory when there is little change in the pixels in the block such as the movement of the subject. The block image at the same position of the pre-encoded frame thus obtained is used as a decoded image as it is, and when the change is large, the subsequent wavelet transform encoding means is performed.

However, if the wavelet transform coding means is applied to all blocks every predetermined number of frames, the accumulation of errors is eliminated and a high quality decoded image can be always provided. Therefore, in the thirteenth embodiment, all blocks to be coded are subjected to wavelet transform coding for each predetermined number of frames by predetermined means or in the form of external input.

Next, a fourteenth embodiment of the present invention will be described. This fourteenth embodiment is characterized in that a filter bank means comprising a plurality of low-pass filters and a high-pass filter converts an input image into a plurality of bands, Scan, quantize,
An image compression device comprising means for recording an encoded bit stream on a recording medium by means of entropy encoding, and reading the encoded bit stream from the recording medium, entropy decoding, inverse quantization, inverse scanning, and An image compression / expansion device comprising an image decompression device having means for performing inverse conversion by the filter bank means and outputting a decoded image, the image data being recorded on the recording medium in accordance with a search speed. It has a search means for reading out a corresponding band component from an encoded bit stream.

FIG. 13 is a block diagram showing an image recording / reproducing apparatus according to the fourteenth embodiment.
3 includes an external input control unit 38, a CCD unit 39,
It includes an AD conversion unit 30, an encoding unit 31, a decoding unit 37, a recording medium control unit 34, a writing unit 32, a reading unit 33, a recording medium 40, and a display unit 35. Next, the operation will be described.

The encoding unit 31 is a unit for performing the wavelet transform encoding means described in the embodiment, and has a wavelet band dividing means for an image, a scanning means for transform coefficients, a quantization means, and an entropy encoding means. are doing. On the other hand, the decoding unit 27 includes entropy decoding means, inverse quantization means, inverse scanning means, and wavelet band synthesis means.

For the encoding unit 31 and the decoding unit 37,
As shown in FIG. 13, the image input units and the recording units on the recording medium are connected. Normally, an image is input as an optical signal 131 to a CCD section 39 such as a camera, and the CCD signal 132 is AD-converted by an AD converter 30 to obtain a digital image signal 13.
Converted to 3. This digital image signal 133 is
Depending on the characteristics of D, for example, the signal may be output as separate signals of R, G, and B, or may be one signal.

The digital image signal 133 is subjected to a wavelet transform coding process in the coding unit 31 to generate a coded bit stream 134. The encoded bit stream 134 is sent to the decoding unit 37,
, The decoded image 135 is output via the display unit 35 and the display image 136 is output. On the other hand, the encoded bit stream 134 is sent to the writing unit 32, and together with the write control signal,
As 1, it is sent to the recording medium control unit 34, multiplexed with the control information to become a recording signal, and written to the recording medium 40. A signal 139 is recorded and reproduced between the recording medium 40 and the recording medium control unit 34 in accordance with the recording format of the recording medium 40. Here, as the recording medium 40, in addition to a magnetic tape, an optical disk such as a CD-ROM, a CD-R, and a DVD-ROM can be used.

On the other hand, a case where the apparatus reads out an encoded bit stream of an image recorded on the recording medium 40 and performs a high-speed search will be described below. The external signal 137 holds, for example, information on the search speed. This information is decoded by the external input control unit 38, and the control signal 138 is transmitted to the recording medium control unit 34. The drive system of the recording medium 40 is operated from the recording medium 40 to the recording medium control unit 34 in accordance with the search speed, and the signal 13 of the encoded bit stream according to the recording format of the recording medium 40 is output.
9 is read out and encoded bit stream 140 (including additional information and header information) via the recording medium control unit 34
Is sent to the reading unit 33. The pure coded bit stream 142 (having no additional information or header information) output from the reading unit 33 is decoded by the decoding unit 37, and the decoded image 135 is transmitted from the decoding unit 135 as described above.
The above is the operation at the time of the search.

Next, reading of an encoded bit stream at the time of a search will be described. In this embodiment, in order to take advantage of using a wavelet encoding unit that hierarchically divides an image as an encoding unit in the encoding unit, an encoded bit stream recorded on a recording medium 40 is used. Then, means for selecting and reading out a signal corresponding to a predetermined band component in accordance with the search speed is used. That is, the corresponding band component is read from the coded bit stream recorded on the recording medium 40 in accordance with the search speed. Specifically, for example, when the search speed is high, the low band component is read. Read only the coded bit stream corresponding to the band of the low-frequency component, and conversely, if the search speed is low, the coded bit stream corresponding to the band of the low-frequency component and the high-frequency component Is read to decode the band image. More detailed configurations and operations will be described in the following embodiments.

Next, a fifteenth embodiment of the present invention will be described. The apparatus according to the fifteenth embodiment decodes the band image of the low band component when the search speed is high, and decodes the band image of the low band and the high band component when the search speed is low. The overall configuration shown in FIG. 13 can be used.

Normally, it is necessary to reproduce a large number of image frames at a predetermined time during a search, so that it is difficult to read and decode all of the coded bit stream in terms of hardware. Therefore, measures such as skipping frames at certain intervals or decoding only a part of an image are usually taken.

However, in the fifteenth embodiment, a search means which decodes all frames and does not impair the impression of the entire image is realized. That is, FIG.
As described above, the use of the wavelet encoding means makes it easy to obtain a decoded image from only low-frequency components (for example, the LLLL component). If the reading speed of the stream cannot be sufficiently ensured, only the coded bit stream corresponding to the band of the low frequency component can be read, and the decoding unit 37 in FIG. 13 can generate a decoded image.

On the other hand, in the case of a low-speed search or when the reading speed of the encoded bit stream can be sufficiently ensured,
An encoded bit stream corresponding to the bands of the middle and high frequency components in addition to the low frequency components is read out, and the decoding unit 37 can generate a decoded image. By the above means, decoding using one or a plurality of optimum bands can be realized according to the search speed or the read speed of the encoded bit stream.

In this case, the decoded image may be decoded with the size of the predetermined band component in the above-described wavelet transform. This is, for example, LLLL
When only the coded bit stream corresponding to the component is read and decoded, the size of the image included in the LLLL band component is one-fourth in both the horizontal and vertical directions of the original image, as is clear from FIG. Therefore, the display image 136 has the original 1 /
4 (1/4 in length ratio and 1/16 in area ratio) are displayed.

On the other hand, as another method, the decoded image may be generated as a decoded image having the same size as the original image and using a predetermined band component. In this case, a decoded image using only the LLLL component does not have a high-frequency component, and therefore has a slightly blurred image quality with reduced resolution. However, since much of the energy of the image is concentrated in the low-frequency component, the general characteristics of the image can be sufficiently grasped.

Next, a sixteenth embodiment of the present invention will be described. While the fourteenth and fifteenth embodiments are coding / decoding devices including an image input unit and a display unit, the sixteenth embodiment is, as shown in FIG.
This is a configuration of an apparatus provided with only a portion for reading and decoding the recording medium 40. In other words, it is a device suitable for image receivers and portable players without an encoder. Next, the configuration and operation will be described.

The apparatus shown in FIG. 14 includes a recording medium 40, a control unit 45, an encoded bit stream reading unit 46, and a decoding unit 37. External input information 137
According to the control information 145 and 147 from the control unit 45, the encoded bit stream reading unit 46
An encoded bit stream 148 including additional information, header information, and the like is read from the recording medium 40, and a pure encoded bit stream 149 including no additional information, header information, and the like is read.
Is output. This purely encoded bit stream 149
Is decoded by the decoding unit 37 to generate a decoded image 130.
Is output. The operation of the decoding unit 37 is as described in the fourteenth,
The description is omitted because it is similar to that described in the fifteenth embodiment.

Next, a seventeenth embodiment of the present invention will be described. The seventeenth embodiment is a moving picture coding apparatus in a case where an input picture is an interlaced picture.

The television broadcast we are currently familiar with is an interlaced image using interlaced scanning, and is composed of odd and even fields. FIG.
Is a diagram illustrating this, and the lines La ₁ , La ₂ ,.
.. Are odd fields, lines Lb ₁ , Lb ₂ ,.
Means an even field.

In the interlaced image, odd fields and even fields are alternately arranged for each line as in the left frame (Frame) structure in FIG. 15, and if this is encoded as a frame image, the efficiency is increased. May fall. FIG. 16 shows this. As shown in FIG. 16, in the case of a frame image of an interlaced image, if the motion of the subject is large, there is a time difference between the odd field and the even field, so that the left frame (Frame) structure in FIG. It appears that there is a shift between the image of the odd field and the image of the even field. This leads to a decrease in efficiency in performing the subsequent-stage encoding. On the other hand, the division into the field structure on the right side of FIG. 16 eliminates a shift for each line and prevents a decrease in efficiency.

Next, the actual operation will be described with reference to FIG. First, the interlaced image 100 of the input image is converted into an odd-numbered field image 155 by the field division unit 56.
And an even-numbered field image 156. These odd field image 155 and even field image 1
56 is encoded by the encoding unit 57, and the encoded bit stream 157 and the encoding mode information 158 are transmitted.

Here, for the specific operation of the encoding section 57, the encoding constituting means described in the first embodiment may be used as it is. That is, as described with reference to FIG. 1, each unit from the block dividing unit 1 to the entropy encoding unit 13 may be provided. With the above configuration, it is possible to realize a moving image encoding unit having high encoding efficiency without reducing the efficiency even for interlaced images.

Next, a seventeenth embodiment of the present invention will be described. This seventeenth embodiment corresponds to a decoding device corresponding to the encoding device of the seventeenth embodiment. Next, the operation will be described with reference to FIG. The decoding unit 58 which has received the coded bit stream 157 and the coding mode information 158 outputs a decoded image 151 of an odd field and a decoded image 152 of an even field using a decoding unit. The decoded image 151 of the odd field and the decoded image 152 of the even field are synthesized by the field synthesizing unit 59, and the synthesized image 153 of both fields, that is, the frame shown in FIG. 15 or FIG. Return to structure image.

As a specific configuration of the decoding section 58, the decoding circuit configuration described in the eleventh embodiment may be used as it is. That is, each component from the entropy decoding unit 16 to the frame memory 14 in FIG.
Used as decoding means.

With the above configuration, the coded bit stream of the interlaced image is decoded for each field,
A decoded image can be generated for each field, and a field image can be generated by synthesizing it with a frame image.

As specific application examples of the embodiment of the present invention, an electronic camera, a portable / mobile image transmitting / receiving terminal (PD)
A), a printer, a compressor / decompressor for a satellite image, a medical image or the like, or a software module thereof, a game compression / decompression device used in a game or three-dimensional CG, or a software module thereof.

The present invention is not limited to only the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

[0091]

According to the present invention, the input image is divided into a plurality of blocks, and the error between the block image at the same position of the previous frame stored and held in the image memory and the current block to be coded is obtained. By detecting whether or not to perform coding on the block to be coded according to the detected error and performing wavelet transform coding for each block image. Since the simple prediction means for each block is used without using the compensation prediction means, the processing amount can be extremely small. Here, the background portion hardly moves in a normal moving image, so that the present invention works effectively in such a portion, and the compression efficiency is increased.

Further, since the motion compensating means can be greatly simplified, conventionally, the motion compensating means is provided by dedicated hardware (LSL).
In contrast to I), the present invention can be implemented by software.

[0093] Also, using the encoding means in block units,
As for the pixels at the portion where the filter protrudes out of the block at the time of the wavelet transform coding, a means in which the distortion of the block boundary is inconspicuous is used.

Further, according to the image recording / reproducing apparatus of the present invention, means for converting an input image into a plurality of bands by a filter bank means comprising a plurality of low-pass filters and a high-pass filter; An image compression device comprising means for scanning, quantizing, and entropy-encoding transform coefficients for each of the bands to record an encoded bit stream on a recording medium, and reading the encoded bit stream from the recording medium And an image decompression device having means for performing entropy decoding, inverse quantization, inverse scanning, and further performing inverse transformation by the filter bank means and outputting a decoded image. Since there is a search means for reading out the corresponding band component from the coded bit stream recorded on the recording medium, the coded bit stream recorded on the recording medium is provided. It reads the stream, when performing a search of the decoded image can be read only optimum band components tailored to search speed can be decoded to obtain a consistently high-quality decoded image without frame dropping.

Further, since the decoded image can have the resolution of the band component in addition to the size of the original image, the variation of the decoded image increases, and the decoded image can be used properly according to the application.

Therefore, according to the present invention, both high image quality under high compression and realization of partial block decoding are provided, and the wavelet transform means and the wavelet inverse transform means can be matched. Encoding and high quality decoding.

Further, in the case of an interlaced image,
By separately encoding the odd-field image and the even-field image and encoding them separately, high encoding efficiency can always be maintained even when a subject with a large motion exists in the image.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a video encoding device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic configuration (up to level 3) of a normal wavelet transform unit.

FIG. 3 is a block diagram showing a schematic configuration (up to level 3) of a normal wavelet inverse transform unit.

FIG. 4 is a diagram for describing band division (division level = 2) of a two-dimensional image.

FIG. 5 is a diagram for explaining a convolution operation at the time of overlap type wavelet encoding.

FIG. 6 is a diagram for explaining the concept of wavelet coding for performing a symmetric convolution operation of pixels.

FIG. 7 is a diagram for explaining the concept of a symmetric convolution operation.

FIG. 8 is a diagram for explaining the concept of a linear convolution operation.

FIG. 9 is a diagram for explaining the concept of a point-symmetric convolution operation.

FIG. 10 is a diagram for explaining the concept of wavelet decoding for performing symmetric convolution of wavelet transform coefficients.

FIG. 11 is a diagram for explaining the concept of wavelet decoding for performing a linear convolution operation of wavelet transform coefficients.

FIG. 12 is a block diagram illustrating a schematic configuration of a video decoding device according to an eleventh embodiment of the present invention.

FIG. 13 is a block diagram illustrating a schematic configuration of an image recording / reproducing apparatus according to a fourteenth embodiment of the present invention.

FIG. 14 is a block diagram illustrating a schematic configuration of an image decoding device according to a sixteenth embodiment of the present invention.

FIG. 15 is a diagram illustrating a frame image and a field image in the case of an interlaced image.

FIG. 16 is a diagram for explaining a frame image and a field image in the case of an interlaced image.

FIG. 17 is a block diagram illustrating a schematic configuration of an image encoding device for encoding an interlaced image.

FIG. 18 is a block diagram illustrating a schematic configuration of an image decoding device for decoding an interlaced image.

[Explanation of symbols]

1 block division unit, 2 coding mode control unit, 4
Wavelet transform unit, 5 scanning unit, 4
6 quantization unit, 7 inverse quantization unit, 8 inverse scanning unit, 9 decoding target coefficient extraction unit, 10 wavelet inverse transformation unit, 11 decoded image region extraction unit, 12 error detection unit, 13 entropy encoding unit, 14 frame memory 15, decoding mode control unit, 16 entropy decoding unit, 21 low-pass filter for analysis,
22 high-pass filter for analysis, 23a, 23b
1/2 downsampler, 24a, 24b 2x upsampler, 25 low-pass filter for synthesis,
26 high-pass filter for synthesis, 31, 57 coding unit, 32 writing unit, 33 reading unit, 3
4 Recording medium control unit, 35 display unit, 37, 57
Decoding unit, 38 external input / control unit, 39 CCD unit,
40 recording medium, 45 control unit, 46 coded bit stream reading unit, 56 field division unit,
59 field synthesis unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C053 FA22 FA24 FA25 GA11 GB22 GB26 GB32 HA29 LA01 LA03 LA14 5C059 KK03 MA24 MA32 MC11 MC38 ME01 ME11 PP04 PP25 RE06 SS10 SS15 SS19 SS23 SS24 SS28 TA16 TB08 TC03 TD05 TD12 UA02 UA05 UA11 5J064 AA02 BA09 BA15 BC02 BC16 BD03

Claims (34)

[Claims] 1. A block dividing means for dividing an input image into a plurality of blocks, and detecting an error between a block image at the same position of a previous frame stored and held in an image memory and a current encoding target block. Error detection means for performing coding, coding mode control means for selectively controlling whether or not to perform coding of a coding target block according to the detected error, and wavelet transform for performing wavelet transform coding for each block image A moving picture coding apparatus comprising coding means. 2. The apparatus according to claim 1, further comprising: a wavelet inverse transform decoding means for performing an inverse wavelet transform decoding on the encoded output obtained by said wavelet transform encoding means. 2. The moving picture coding apparatus according to claim 1, wherein the moving picture coding apparatus stores and holds an image. 3. The wavelet transform encoding means,
Wavelet transform means for performing a wavelet transform for each block image, scanning means for scanning wavelet transform coefficients, quantization means for quantizing the coefficients after scanning, and a coded bit stream by entropy encoding the quantized coefficients. 2. The moving picture encoding apparatus according to claim 1, further comprising: an entropy encoding unit that outputs the video signal. 4. Prior to the wavelet transform means,
4. An encoding target area extracting means for determining a current encoding target block area in accordance with information from said encoding mode control means and extracting pixels of the encoding target area. The moving picture encoding device according to the above. 5. The encoding target area extracting section expands the encoding target area by reading pixels of an adjacent block around the block to a range where the influence of the filtering by the wavelet transform section is exerted. 5. The moving picture coding apparatus according to claim 4, wherein: 6. The encoding target area extracting means sets the pixel values inside the block to a mirror image relationship at the block boundary to the extent to which the influence of the filtering by the wavelet transform means surrounds the block. The moving picture coding apparatus according to claim 4, wherein the coding target area is expanded by performing symmetric expansion. 7. The encoding target area extraction unit expands the encoding target region by inserting 0 values around the block to a range where the influence of the filtering by the wavelet transform unit is exerted. The moving picture coding apparatus according to claim 4, wherein 8. The encoding target area extracting means sets the pixel values inside the block to a point symmetrical relation at the block boundary to the extent to which the influence of the filtering by the wavelet transform means is applied around the block. 5. The moving picture coding apparatus according to claim 4, wherein the coding target area is expanded by performing symmetric expansion. 9. An inverse wavelet transform decoding means for performing inverse wavelet transform decoding on the quantized wavelet transform coefficients from the wavelet transform encoding means, and converting the image from the inverse wavelet transform decoding means into the image In addition to storing and holding in a memory, the inverse wavelet transform decoding means includes an inverse quantization means for inversely quantizing the quantized transform coefficient to return to a transform coefficient, an inverse scanning means for inversely scanning the transform coefficient, and 2. The moving picture coding apparatus according to claim 1, further comprising wavelet inverse transform means for performing an inverse wavelet transform on the obtained transform coefficients. 10. A decoding target coefficient extracting means for extracting a transform coefficient to be decoded is provided before the inverse wavelet transform means, and a decoded image area extracting means is provided after the inverse wavelet inverse transform means. The moving picture coding apparatus according to claim 9, wherein 11. The decoding target coefficient extraction unit expands a decoding target coefficient region by reading transform coefficients of an adjacent block around the block to the extent that the filtering by the wavelet inverse transformation unit affects. The moving picture coding apparatus according to claim 10, wherein 12. The decoding-target-coefficient extracting unit causes the transform coefficients inside the block to have a mirror image relationship at a block boundary to the extent that the filtering by the inverse wavelet transform unit affects the block. 11. The moving picture coding apparatus according to claim 10, wherein a coefficient area to be decoded is expanded by performing symmetric expansion. 13. The decoding target coefficient extraction unit expands a decoding target coefficient region by inserting 0 values around the block to a range affected by the filtering by the wavelet inverse transformation unit. The moving picture coding apparatus according to claim 10, wherein: 14. The decoding target coefficient extracting means sets the transform coefficients inside the block in a point symmetrical relation at the block boundary to the extent to which the influence of the filtering by the wavelet inverse transform means surrounds the block. 11. The moving picture coding apparatus according to claim 10, wherein the coefficient area to be decoded is expanded by performing symmetric expansion. 15. The moving picture coding apparatus according to claim 10, wherein said decoded picture area extracting means extracts a target block area from the decoded picture restored by said inverse wavelet transform means. 16. The apparatus according to claim 1, further comprising means for dividing the interlaced image as the input image into odd fields and even fields before the means for dividing the input image into a plurality of blocks. Video encoding device. 17. A step of dividing an input image into a plurality of blocks, and a step of detecting an error between a block image at the same position of a previous frame stored and held in an image memory and a current encoding target block. A step of selecting whether or not to perform coding of the current block in accordance with the detected error; and a step of performing wavelet transform coding for each block image. Encoding method. 18. The method according to claim 18, further comprising the step of performing inverse wavelet transform decoding on the coded output obtained in the step of performing the wavelet transform encoding, wherein the image memory is obtained by performing the inverse wavelet transform decoding in the image memory. 18. The moving picture coding method according to claim 17, wherein the obtained picture is stored and held. 19. A wavelet inverse transform decoding means for inputting or reading an encoded bit stream, performing wavelet inverse transform decoding and outputting a decoded image, and decoding for extracting a target area from the decoded image obtained by the wavelet inverse transform decoding means. An image area extracting means, an image memory for storing and holding the obtained decoded image, and, according to the supplied encoding control signal, sending out a decoded image of a previous frame previously stored in the image memory, or A decoding mode control unit for selecting whether to transmit an image decoded by the inverse transform decoding unit. 20. The inverse wavelet transform decoding means includes an inverse quantization means for inversely quantizing the quantized transform coefficient to return to a transform coefficient, an inverse scanning means for inversely scanning the transform coefficient, and an obtained transform. 20. The decoding apparatus according to claim 19, further comprising: decoding coefficient extraction means for extracting a transform coefficient to be decoded from the coefficients; and wavelet inverse transform means for performing an inverse wavelet transform on the obtained decoding coefficient. Video decoding device. 21. The decoding target coefficient extraction unit expands a decoding target coefficient region by reading transform coefficients of an adjacent block around the block to a range where the influence of the filtering by the wavelet inverse transformation unit is exerted. 21. The moving picture decoding apparatus according to claim 20, wherein: 22. The decoding-target-coefficient extracting unit sets the transform coefficients inside the block to a mirror image relationship at the block boundary to the extent that the filtering by the inverse wavelet transform unit affects the block. 21. The moving image decoding apparatus according to claim 20, wherein a coefficient area to be decoded is expanded by performing symmetric expansion. 23. The decoding target coefficient extraction unit expands a decoding target coefficient region by inserting 0 values around the block to a range where the influence of the filtering by the wavelet inverse transformation unit is exerted. 21. The moving picture decoding apparatus according to claim 20, wherein: 24. The decoding target coefficient extracting means sets the transform coefficients inside the block to a point symmetrical relation at the block boundary to the extent to which the influence of the filtering by the wavelet inverse transform means surrounds the block. 21. The moving picture decoding apparatus according to claim 20, wherein a coefficient area to be decoded is expanded by performing symmetric expansion. 25. The moving picture decoding apparatus according to claim 20, wherein said decoded picture area extracting means extracts a target block area from the decoded picture restored by said wavelet inverse transform means. 26. The coded bit stream has an coded bit stream of an odd field image and a coded bit stream of an even field image, and the coded bit stream of the odd field image and the coded bit stream of the even field image. 20. The moving picture decoding apparatus according to claim 19, wherein an encoded bit stream is decoded by the inverse wavelet transform decoding means, respectively, and an odd field decoded picture and an even field decoded picture are synthesized. 27. A step of inputting or reading an encoded bit stream, performing inverse wavelet transform decoding on the encoded bit stream and outputting a decoded image, and extracting a target area from the decoded image obtained by the inverse wavelet transform decoding. Storing and holding the decoded image in the image memory; and transmitting the decoded image of the previous frame previously stored in the image memory according to the supplied encoding control signal, or decoding the decoded image by the inverse wavelet transform decoding means. Selecting whether to send the decoded image. 28. The step of performing the inverse wavelet transform decoding includes the following steps: an inverse quantization step of inversely quantizing the quantized transform coefficient to return to a transform coefficient; and an inverse scanning step of inversely scanning the transform coefficient. 28. A decoding method according to claim 27, further comprising: a decoding coefficient extraction step for extracting a decoding coefficient to be decoded from the obtained conversion coefficients; and a wavelet inverse transforming step for performing an inverse wavelet transform on the obtained decoding coefficient.
The moving picture decoding method according to the above. 29. A filter bank means comprising a plurality of low-pass filters and a high-pass filter,
An image compression apparatus comprising: means for converting an input image into a plurality of bands; and means for recording a coded bit stream on a recording medium by means for scanning, quantizing, and entropy coding the transform coefficients for each band. And an image decompression device comprising: means for reading an encoded bit stream from the recording medium, performing entropy decoding, inverse quantization, inverse scanning, and further performing inverse transformation by the filter bank means, and outputting a decoded image. An image recording / reproducing apparatus comprising: a search unit that reads a corresponding band component from an encoded bit stream recorded on the recording medium in accordance with a search speed. 30. When the search speed by the search means is high, only the coded bit stream corresponding to the low-frequency component band is read out, and the low-frequency component band image is decoded by the image decompression device. 30. The image recording / reproducing apparatus according to claim 29, wherein when the search speed is low, an encoded bit stream corresponding to the band of the low band and the band of the high band component is read to decode the band image. 31. The image recording / reproducing apparatus according to claim 30, wherein the decoded band image is decoded at a resolution of a predetermined band component. 32. The image recording / reproducing apparatus according to claim 30, wherein the decoded band image is decoded by using a predetermined band component at a resolution of an original image. 33. The search means reads out a predetermined code word from a recording medium on which an encoded bit stream is recorded by a search speed from a control means or control from an external input, and outputs a decoded image. The image recording / reproducing apparatus according to claim 29, wherein: 34. scanning a transform coefficient for each of a plurality of bands;
The encoded bit stream is read from the recording medium on which the encoded bit stream obtained by quantization and entropy encoding is recorded, and entropy decoding, inverse quantization, inverse scanning, and inverse transform by the filter bank means are performed. And a search means for reading out a corresponding band component from an encoded bit stream recorded on the recording medium in accordance with a search speed.