JP2002176561A - Image processor, image processing method, and computer readable memory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processor, an image processing method and a computer readable memory which restore an image from an encoded image while keeping image quality regardless of a lower resolution. SOLUTION: An image signal is encoded by an encoding part 2, and a display resolution of a decoded image signal based on its encoded fundamental code string is set by a resolution setting part 8, and the image feature value of the decoded image signal is determined on the basis of this set resolution. A code string constitution part 3 generates a decoding object code string corresponding to the determined image feature value on the basis of the fundamental code string.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus and method for processing an input image signal, and a computer readable memory.

[0002]

2. Description of the Related Art In recent years, digital image signals have been stored or transmitted in an electronic format and used for display, printing, and the like due to improvements in computer performance and increase in the capacity of storage media. I have. On the other hand, due to the spread of digital image signals on the Internet,
Such digital image signals are required to have higher image quality than before.

In such a flow, medical images which have been processed as analog signals in the medical field are now being treated as digital signals.
As a medical image, for example, the number of pixels in the vertical and horizontal directions is 25, respectively.
It has a resolution of 00 pixels or more, and the accuracy of each pixel is represented by 12 bits per pixel. In order to store an image having a high resolution and a high pixel precision as it is, a large-capacity storage medium is required, and the image is compression-coded as necessary.

[0004] After the images thus compressed and coded are decoded, they are displayed on a display device such as a monitor at the time of diagnosis. However, as described above, these medical images usually have a high resolution and therefore have a high resolution. Cannot display the entire image at the resolution of the monitor.

Therefore, in order to observe the entire image, it is necessary to convert the decoded image to a resolution that can be displayed on a monitor and display the converted image. On the other hand, in recent years, image coding using discrete wavelet transform (hereinafter, referred to as DWT) has been put to practical use. In such an encoding method, a subband structure by DWT is used, and some subbands are used. , A low-resolution image can be obtained. Furthermore, by performing bit-plane coding on the DWT coefficients, it is possible to realize progressive coding for improving the image quality stepwise during decoding. Regarding such a method, for example, ISO / IEC 15444-1 (hereinafter referred to as an international standard for still images)
JPEG2000) and its related standards, detailed description is omitted.

[0006]

However, as described above, when a low-resolution image is restored using a sub-band structure in the compression coding method using DWT, the frequency band of the image is limited. However, the image quality generally deteriorates. Furthermore, when this function is combined with the above-described bit plane coding, the degree of image quality degradation differs depending on the filter used for DWT, and there is a problem that image quality cannot be guaranteed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has an image processing apparatus and method capable of restoring an image from an encoded image while maintaining image quality even at a low resolution.
It is an object to provide a computer readable memory.

[0008]

An image processing apparatus according to the present invention for achieving the above object has the following arrangement.
That is, an image processing device that processes an input image signal, the encoding unit encoding the image signal, and the display resolution of a decoded image signal based on the basic code sequence encoded by the encoding unit. Setting means for setting, determining means for determining an image feature amount of the decoded image signal based on the display resolution set by the setting means, and a decoding target code string corresponding to the image feature amount determined by the determining means And generating means for generating based on the basic code string.

Preferably, the coding means generates the code sequence by sequentially coding transform coefficients obtained by performing discrete wavelet transform on the image signal from an upper bit plane to a lower bit plane.

Preferably, the image feature amount is a code amount to be decoded.

Preferably, the image feature value is an objective image quality evaluation reference value to be decoded.

Preferably, the generation means includes a storage means for storing the basic code string, and the generation means is determined by the determination means among the basic code strings stored in the storage means. The decoding target code sequence is generated by reading a code sequence corresponding to the image feature amount from the storage unit.

Preferably, the apparatus further comprises decoding means for generating a decoded image signal based on the basic code string, and transmission means for transmitting the basic code string read from the storage means to the decoding means. Means for controlling a code string transmitted from the transmission means to the decoding means, wherein the generation means includes an image feature determined by the determination means among basic code strings read from the storage means. The code string corresponding to the amount is transmitted from the transmission means to the decoding means using the control means, thereby generating the decoding target code string.

Preferably, the control unit controls the decoding unit based on the display resolution.

Preferably, the control means controls the decoding means based on the image feature amount.

Preferably, when the display resolution set by the setting unit is 1/4 of the image signal, the code amount determined by the determining unit is one unit with respect to the data amount of the image signal. / 15 or more.

Preferably, when the display resolution set by the setting means is の of the image signal, the code amount determined by the determining means is 1 to the data amount of the image signal. / 20 or more.

Preferably, the image feature value determined by the determining means is changed by a discrete wavelet transform filter used in the decoding means.

An image processing apparatus according to the present invention for achieving the above object has the following arrangement. That is, an image processing apparatus that processes an input image signal, the encoding unit encoding the image signal, and a decoded image signal generated based on a basic code sequence encoded by the encoding unit. Decoding means, setting means for setting a display resolution of the decoded image signal, and decoding control means for controlling the decoding means based on the display resolution set by the setting means.

Preferably, the decoding control means includes:
The decoding means is controlled based on an image feature amount of the decoded image signal associated with the display resolution.

An image processing system according to the present invention for achieving the above object has the following arrangement. That is, an image processing system that processes an input image signal, the encoding unit encoding the image signal, and the display resolution of a decoded image signal based on a basic code string encoded by the encoding unit. Setting means for setting, determining means for determining an image feature amount of the decoded image signal based on the display resolution set by the setting means, and a decoding target code string corresponding to the image feature amount determined by the determining means And generating means for generating based on the basic code string.

An image processing method according to the present invention for achieving the above object has the following arrangement. That is, an image processing method for processing an input image signal, comprising: an encoding step of encoding the image signal; and a display resolution of a decoded image signal based on the basic code sequence encoded in the encoding step. A setting step of setting, a determining step of determining an image feature amount of the decoded image signal based on the display resolution set in the setting step, and a decoding target code string corresponding to the image feature amount determined in the determining step Is generated based on the basic code string.

An image processing method according to the present invention for achieving the above object has the following arrangement. That is, an image processing method for processing an input image signal, wherein an encoding step of encoding the image signal and a decoded image signal are generated based on the basic code sequence encoded in the encoding step. A decoding step of setting a display resolution of the decoded image signal; and a decoding control step of controlling the decoding step based on the display resolution set in the setting step.

A computer readable memory according to the present invention for achieving the above object has the following configuration. That is,
A computer readable memory storing a program code of image processing for processing an input image signal, the program code of an encoding step of encoding the image signal, and a basic code encoded in the encoding step A program code of a setting step of setting a display resolution of a decoded image signal based on a column, and a program code of a determining step of determining an image feature amount of the decoded image signal based on the display resolution set in the setting step. A program code for a generation step of generating a decoding target code string corresponding to the image feature amount determined in the determination step based on the basic code string.

A computer readable memory according to the present invention for achieving the above object has the following configuration. That is,
A computer readable memory storing a program code of image processing for processing an input image signal, the program code of an encoding step of encoding the image signal, and a basic code encoded in the encoding step A program code for a decoding step of generating a decoded image signal based on the sequence; a program code of a setting step for setting a display resolution of the decoded image signal; and the decoding step based on the display resolution set in the setting step. And a program code of a decoding control step for controlling

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. <First Embodiment> FIG. 1 is a diagram showing the overall configuration of an image processing apparatus according to a first embodiment.

In FIG. 1, an image input unit 1 is a predetermined image input device. In the medical field, the image input unit 1 corresponds to, for example, an X-ray imaging device, a CT or the like. The encoding unit 2 compression-encodes the input image signal, and outputs the image signal to the subsequent code sequence forming unit 3. The encoding unit 2 is capable of compression codes of a plurality of types of compression rates. In the first embodiment, in particular, the compression codes of the compression rates corresponding to the plurality of types of display resolutions which can be set by a resolution setting unit 8 described later And the following code string forming unit 3
Output to The code sequence forming unit 3 generates an input code sequence (basic code sequence) into a code sequence rearranged into a format satisfying a predetermined function, and outputs the code sequence to the code sequence storage unit 4. The code string storage unit 4
A storage device such as a hard disk that stores the input code string corresponds to the storage device.

The resolution setting unit 8 sets a display resolution for decoding and displaying the above-described code string by an input (not shown), and sets image feature amounts (image quality, S / N) of an image to be decoded in accordance with the set display resolution. Ratio, code amount, etc.), and outputs them to the code sequence forming unit 3 and the decoding unit 6. Here, examples of the input to the resolution setting unit 8 include a display setting from a doctor through an input device such as a mouse and a keyboard connected to a computer.

The code sequence forming unit 3 reads out the code sequence of the image signal to be processed from the code sequence storage unit 4 and outputs it to the transmission unit 5. Here, the transmission unit 5 corresponds to a network.
When the image processing apparatus shown in FIG. 1 is realized by one computer, a bus interposed between the hard disk and the CPU corresponds. The decoding unit 6 decodes the input code string to restore an image signal, and outputs the image signal to the image output unit 7. The image output unit 7 is, for example, a display device such as a monitor connected to a computer, and displays an image having the display resolution set by the resolution setting unit 8.

Hereinafter, the operation of each component of the image processing apparatus will be described in detail.

The digital image signal generated by the image input unit 1 is output to the encoding unit 2. Here, the digital image signal may be either a color image signal or a monochrome grayscale image signal, but in the following description, a monochrome grayscale image signal is assumed as the digital image signal. When the digital image signal is a color image signal, the processing described below may be similarly performed on each color component.

The encoding unit 2 converts the input digital image signal into a resolution setting unit 8 by transform encoding using DWT.
Performs compression encoding at various compression rates corresponding to display resolutions that can be set in. Here, the encoding method is JPEG2000
However, the present invention is not limited to this, and a DWT is applied to the digital image signal, and the obtained transform coefficient is a code sequence having a progressive characteristic obtained by a method such as bit plane coding, that is, a discrete sequence. Any code sequence can be used as long as it can generate a code string having progressive characteristics obtained by sequentially encoding the wavelet-transformed transform coefficients from the upper bit plane to the lower bit plane. Note that the compression / encoding method in JPEG2000 is described in detail in ISO / IEC 15444, and will not be described here.

The basic coded sequence obtained by compression coding is rearranged into a code sequence having a predetermined progressive characteristic in the subsequent code sequence forming unit 3 and output to the code sequence storage unit 4. Here, the structure of the code string is JPEG
Layer-resolution level-component-2000
Position progressive shall be used.

Here, an outline of the structure of the code string will be described with reference to FIG.

FIG. 2 is a diagram showing an outline of the configuration of the code string according to the first embodiment.

In FIG. 2A, a digital image signal is divided into a plurality of tiles, and a main header MH, a header TH relating to each tile, and coded data BS are arranged corresponding to the number of tiles. In the first embodiment, since the digital image signal is not divided into tiles, actually, TH0 and B0 in FIG.
Only S0 exists. Further, as shown in FIG. 2A, the main header MH includes information such as an image size, a tile size, the number of components, and coding parameters.

FIG. 2B shows the tile header TH.
As shown in (1), information such as a tile length and an encoding parameter for each tile is included.

FIG. 2C shows the arrangement of the code strings in the first embodiment. The code strings are arranged in order from the upper layer to the lower layers (Layer L-1, Layer L-2,
.., Layer 0: L is a positive integer). Each layer has a subband (LL, HL2, L
H2, HH2, HL1, LH1, and HH1). Further, the code related to each subband includes the code of the code block included in the subband and the packet header PH including the designation of the coding path and the code of each code block.

In the first embodiment, it is assumed that the code string shown in FIG. 2C is composed of layers corresponding to a predetermined compression ratio.

Next, the relationship between the layer and the compression ratio will be described with reference to FIG.

FIG. 3 is a diagram showing the relationship between layers and compression ratios in the first embodiment.

In the figure, the code string has 10 layers (Layer 9) to Layer 0 (Layer 9).
0)), and lossless decoding is possible when all the layers from the highest layer 9 to the lowest layer 0 are decoded.

On the other hand, the code amount of the uppermost layer 9 corresponds to a compression ratio 1/20 with respect to the data amount of the input image. Further, the code amount relating to layers 9 to 7 is a compression rate of 1/1.
Corresponds to 0. The encoding unit 2 configures the layers such that the code amount corresponding to the predetermined compression ratio corresponds to the boundary of the predetermined layer.

The code string generated as described above is stored in the code string storage unit 4.

Next, the procedure for decoding and displaying the stored code string will be described.

The resolution setting section 8 sets the resolution of an image to be displayed and output on the image output section 7 by a predetermined method. As described above, the input method is set by a doctor who observes the image by a predetermined method such as a mouse / keyboard. However, since a plurality of images are simultaneously displayed on the screen, the image is input at a lower resolution than the original resolution. Shall be displayed.

The resolution setting unit 8 reads out from the storage means (not shown) the input display resolution and the image feature amount (compression ratio) of the decoded image corresponding to the display resolution determined in advance by a predetermined method, and determines the read image resolution. Output to the code string forming unit 3. Here, the determined compression ratio is a compression ratio that can maintain a sufficient image quality when an image is displayed at a display resolution. At the same time, the resolution setting unit 8 outputs the display resolution to the decoding unit 6.

The code sequence forming unit 3 outputs a code sequence of a layer corresponding to the compression rate determined by the display resolution set by the resolution setting unit 8. For example, if the compression rate determined by the display resolution set by the resolution setting unit 8 is 1
If it is / 20, it outputs the layer 9 to the transmission unit 5 if it is 1/10.

The decoding unit 6 receives the code string from the transmission unit 5 and performs decoding. In the first embodiment, the decryption unit 6
This is a decoder defined by EG2000, and decoding is performed by a method defined in the standard. Regarding the inverse discrete wavelet transform (hereinafter referred to as IDWT), the display resolution previously input from the resolution setting unit 8 is used. The inverse conversion process is performed for the number of levels.

FIG. 4 shows the situation at this time.
The input image is subjected to two-level DWT and encoded. In contrast, the display resolution is the size shown in the figure,
IDWT is performed only one level. As a result, an image having a resolution of 1/2 of the original length and width is restored and output to the image output unit 7.

As described above, according to the first embodiment, each sub-band (LL, HL)
2, LH2, HH2, HL1, LH1, HH1), and outputs a code string of a layer corresponding to a compression ratio determined by the set display resolution. As a result, even if the display resolution is changed, it is possible to display an image having the required image quality. <Second Embodiment> In the first embodiment, the code string forming unit 3
Output a code string corresponding to the input compression ratio, but similar effects can be obtained by different modes. To realize this, the decoding unit 6 according to the second embodiment has a configuration as shown in FIG.

FIG. 5 is a diagram showing a detailed configuration of the decoding unit according to the second embodiment.

In the figure, the header of the input code sequence is analyzed by a code sequence analysis unit 601, and the analysis result is output to a control unit 605. The control unit 605 controls the operation of the decoding unit 6, stops input of a code string when a predetermined layer is detected, and controls the whole so that a decoded image is generated only from the code input at that time.

On the other hand, the encoded data itself is decoded by an entropy decoding unit 602, an inverse quantization unit 603, and an inverse discrete wavelet transform unit 604. Since these details are described in detail in the JPEG2000 standard, the description is omitted here.

Prior to the image display, the doctor inputs the display resolution, and the resolution setting unit 8 determines the compression ratio based on the display resolution, as in the first embodiment, but in the second embodiment, The display resolution and the compression ratio determined based on the display resolution are output to the decoding unit 6.

The code sequence analysis unit 601 analyzes the header of the input code sequence and sequentially outputs the input layers to the control unit 605. On the other hand, the control unit 605 controls the entropy decoding unit 602 to stop decoding when the layer corresponding to the compression rate determined based on the display resolution input from the resolution setting unit 8 is read.

In the second embodiment, it is assumed that which layer configured at the time of encoding corresponds to which compression ratio is stored in advance as information known by the encoder and the decoder.

By interrupting the decoding operation in this way, a predetermined number of layers are restored from the upper layer, and the IDWT performs the inverse conversion by the level corresponding to the display resolution in the same manner as in the first embodiment. The image is displayed at the display resolution specified in.

In the second embodiment, the code string analyzing unit 601 analyzes the code string and detects the boundary of the layer corresponding to the predetermined compression ratio. However, the code amount may be simply counted. The same effect can be obtained by setting the end of the code string when the counted code reaches a predetermined amount. In this case, the decoding operation is interrupted when an amount of codes corresponding to a predetermined compression rate calculated from the size of the original image is read, and the image is displayed.

Furthermore, the layers formed at the time of encoding do not necessarily have to correspond to the compression ratio. A layer is formed in advance based on a predetermined method, for example, an image feature amount indicating an objective image quality evaluation reference value such as an S / N ratio and a sharpness, and decoding is stopped at a predetermined layer or transmission is interrupted. An image having an image quality corresponding to the image feature amount can be displayed at a required display resolution.

The inventors of the present application have conducted the following experiments regarding the relationship between the resolution and the compression ratio, and the details will be described.

The images were printed on a silver halide film and evaluated by a plurality of image evaluators. The pixel size of the silver halide film was 80 μ, and the image used was an X-ray image taken by a flat panel sensor having 160 μ pixels.

Experiment 1: Lossle of JPEG2000
The encoded data encoded by the ss encoding is decoded at a resolution of 1/2, ie, equivalent to 320 μ pixels, and this low-resolution image is enlarged by a factor of 2 by Replication, and the degradation from the original image is reduced by a compression ratio. Were used as parameters.

Result of Experiment 1: Image deterioration was gradually confirmed with an image having a compression ratio of 1/20.

Experiment 2: Lossle of JPEG2000
The encoded data encoded by the ss encoding is decoded with a resolution of 1/4, that is, 640 .mu. pixels, and this low-resolution image is enlarged four times by the replication, and the deterioration from the original image is reduced by the compression ratio. Were used as parameters.

Result of Experiment 2: Image degradation was gradually confirmed in an image with a compression ratio of 1/15, and degradation was clearly confirmed in a 1/20 image.

As shown by the above experimental results, it can be seen that the compression ratio at which image quality degradation can be confirmed changes depending on the resolution. The results of this experiment were confirmed on a total of 10 images such as an image of lung cancer and an image of silicosis.

As described above, according to the second embodiment, each sub-band (LL, HL)
2, LH2, HH2, HL1, LH1, HH1). Then, decoding is performed while controlling the code string input to the decoding unit 6 based on the set display resolution. As a result, even if the display resolution is changed, it is possible to display an image having the required image quality.

The relationship between the compression ratio and the layer described above may be changed by a filter at the time of encoding. JPEG2
In the 000 standard, different DWT filters are used for irreversible coding and lossless coding, but a determination method according to these coding modes may be selected in advance.

Finally, an outline of the processing executed in the first and second embodiments will be described with reference to FIG.

FIG. 6 is a flowchart showing processing executed by the image processing apparatus of the present invention.

First, in step S101, the image input unit 1
The encoding unit 2 encodes the input image signal so as to obtain a code string including a layer corresponding to each image feature amount determined according to the display resolution settable by the resolution setting unit 9. Then, the obtained basic code sequence is output to the code sequence forming unit 3. The code sequence forming unit 3 stores the input basic code sequence in the code sequence storage unit 4.

In step S102, the resolution setting unit 8
The image feature amount of the decoded image is determined by setting the display resolution of the image to be decoded.

In step S103, a code string corresponding to the determined image feature is generated. In the first embodiment, a code string corresponding to the determined image feature amount is generated by acquiring a layer including a corresponding code string from the code string storage unit 4. Further, in the second embodiment, the code sequence forming unit 3 reads the layer group stored in the code sequence storage unit 4 from the upper layer, sequentially outputs the layer group to the transmission unit 5, and outputs the layer group input from the transmission unit 5. Input control to the decoding unit 6
The decoding unit 6 generates a code string corresponding to the determined image feature amount.

In step S104, the code string generated in step S102 is decoded by the decoding unit 6. This is because, in the first embodiment, the code string input from the transmission unit 5 is
To decrypt. Further, in the second embodiment, a code sequence sequentially input from the transmission unit 5 to the decoding unit 6 is controlled, and the controlled code sequence is decoded by the decoding unit 6.

In step S105, the image signal decoded by the decoding unit 6 is displayed on the image output unit 7.

An object of the present invention is to supply a storage medium storing a program code of software for realizing the functions of the above-described embodiments to a system or an apparatus, and to provide a computer (or CPU or MPU) of the system or the apparatus. Can also be achieved by reading and executing the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the function of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R / RW, DVD-ROM / RAM, magnetic tape, non-volatile memory card, ROM and the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) Or perform some or all of the actual processing in collaboration with other application software, etc.
It goes without saying that a case where the function of the above-described embodiment is realized by the processing is also included.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instruction of the program code, It goes without saying that the CPU included in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

When the present invention is applied to the storage medium, the storage medium stores program codes corresponding to the above-described flowchart shown in FIG.

[0083]

As described above, according to the present invention,
The present invention has been made in view of the above problems, and can provide an image processing apparatus and method capable of restoring an image from an encoded image while maintaining image quality even at a low resolution, and a computer readable memory.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an overall configuration of an image processing apparatus according to a first embodiment.

FIG. 2 is a diagram illustrating an outline of a configuration of a code string according to the first embodiment.

FIG. 3 is a diagram illustrating a relationship between layers and a compression ratio according to the first embodiment.

FIG. 4 is a diagram for explaining an inverse discrete wavelet transform level according to the first embodiment.

FIG. 5 is a diagram illustrating a detailed configuration of a decoding unit according to a second embodiment.

FIG. 6 is a flowchart illustrating a process executed by the image processing apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image input part 2 Encoding part 3 Code sequence construction part 4 Code sequence storage part 5 Transmission part 6 Decoding part 7 Image output part 8 Resolution setting part 601 Code sequence analysis part 602 Entropy decoding part 603 Dequantization part 604 Inverse discrete wavelet Conversion unit 605 Control unit

Continued on the front page F term (reference) 5C059 KK01 MA00 MA24 MA35 SS20 SS23 SS26 TA39 TC25 TC36 UA02 UA05 UA11 5C078 BA57 BA58 DB19

Claims (29)

[Claims] An image processing apparatus that processes an input image signal, comprising: an encoding unit that encodes the image signal; and a decoding unit that decodes a decoded image signal based on a basic code sequence encoded by the encoding unit. Setting means for setting the display resolution, based on the display resolution set by the setting means,
Determining means for determining an image feature amount of the decoded image signal, and generating means for generating a decoding target code string corresponding to the image feature amount determined by the determining means based on the basic code string. Image processing device. 2. The coding unit according to claim 1, wherein the coding unit generates the code sequence by sequentially coding transform coefficients obtained by performing discrete wavelet transform on the image signal from an upper bit plane to a lower bit plane. Item 1
An image processing apparatus according to claim 1. 3. The image processing apparatus according to claim 1, wherein the image feature amount is a code amount to be decoded. 4. The image processing apparatus according to claim 1, wherein the image feature amount is an objective image quality evaluation reference value to be decoded. 5. The image processing apparatus according to claim 1, wherein the generating unit includes a storage unit configured to store the basic code sequence, wherein the generating unit determines an image feature determined by the determining unit out of the basic code sequences stored in the storage unit. The image processing apparatus according to claim 1, wherein the decoding target code sequence is generated by reading a code sequence corresponding to the amount from the storage unit. 6. A decoding unit that generates a decoded image signal based on the basic code sequence, and a transmission unit that transmits the basic code sequence read from the storage unit to the decoding unit, wherein the generation unit includes: Control means for controlling a code string transmitted from the transmission means to the decoding means, wherein the generation means corresponds to the image feature amount determined by the determination means among the basic code strings read from the storage means The image processing apparatus according to claim 5, wherein the code string to be decoded is generated by transmitting the code string to be transmitted from the transmission means to the decoding means using the control means. 7. The image processing apparatus according to claim 6, wherein the control unit controls the decoding unit based on the display resolution. 8. The apparatus according to claim 6, wherein the control unit controls the decoding unit based on the image feature amount. 9. The code amount determined by the determining means is 1/15 or more of the data amount of the image signal when the display resolution set by the setting means is １ ／ of the image signal. The image processing apparatus according to claim 3, wherein 10. The code amount determined by the determination unit is 1/20 or more of the data amount of the image signal when the display resolution set by the setting unit is に 対 し て of the image signal. The image processing apparatus according to claim 3, wherein 11. The image processing apparatus according to claim 1, wherein the image feature amount determined by the determining unit changes by a discrete wavelet transform filter used in the decoding unit. 12. An image processing apparatus that processes an input image signal, comprising: an encoding unit that encodes the image signal; and a decoded image signal based on a basic code sequence encoded by the encoding unit. Decoding means for generating a display resolution of the decoded image signal, based on the display resolution set by the setting means,
An image processing apparatus comprising: a decoding control unit that controls the decoding unit. 13. The image processing apparatus according to claim 12, wherein the decoding control unit controls the decoding unit based on an image feature amount of the decoded image signal associated with the display resolution. apparatus. 14. An image processing system that processes an input image signal, comprising: an encoding unit that encodes the image signal; and a decoding image signal based on a basic code sequence encoded by the encoding unit. Setting means for setting the display resolution, based on the display resolution set by the setting means,
Determining means for determining an image feature amount of the decoded image signal, and generating means for generating a decoding target code string corresponding to the image feature amount determined by the determining means based on the basic code string. Image processing system. 15. An image processing method for processing an input image signal, comprising: an encoding step of encoding the image signal; and a decoding image signal based on a basic code sequence encoded in the encoding step. A setting step of setting a display resolution, based on the display resolution set in the setting step,
A determining step of determining an image feature amount of the decoded image signal, and a generating step of generating a decoding target code sequence corresponding to the image feature amount determined in the determining step based on the basic code sequence. Image processing method. 16. The coding step according to claim 1, wherein the coding step generates the code sequence by sequentially coding transform coefficients obtained by performing discrete wavelet transform on the image signal from an upper bit plane to a lower bit plane. Item 16. The image processing method according to Item 15. 17. The image processing method according to claim 15, wherein the image feature amount is a code amount to be decoded. 18. The image processing method according to claim 15, wherein the image feature amount is an objective image quality evaluation reference value to be decoded. 19. The generating step includes a storing step of storing the basic code string, wherein the generating step includes, among the basic code strings stored in the storing step, the image feature determined in the determining step. The image processing method according to claim 15, wherein the decoding target code sequence is generated by reading a code sequence corresponding to the amount from the storage step. 20. A decoding step for generating a decoded image signal based on the basic code string, and a transmitting step for transmitting the basic code string read from the storage step to the decoding step, wherein the generating step includes: A control step of controlling a code string transmitted from the transmission step to the decoding step, wherein the generation step corresponds to the image feature amount determined in the determination step among the basic code strings read from the storage step 20. The image processing method according to claim 19, wherein the code string to be decoded is generated by transmitting the code string to be transmitted from the transmission step to the decoding step using the control step. 21. The image processing method according to claim 20, wherein said control step controls said decoding step based on said display resolution. 22. The image processing method according to claim 20, wherein the control step controls the decoding step based on the image feature amount. 23. The code amount determined in the determining step is 1/15 or more of the data amount of the image signal when the display resolution set in the setting step is １ ／ of the image signal. The image processing method according to claim 17, wherein 24. The code amount determined in the determining step is 1/20 or more of the data amount of the image signal when the display resolution set in the setting step is の of the image signal. The image processing method according to claim 17, wherein 25. The image processing method according to claim 15, wherein the image feature amount determined in the determining step is changed by a discrete wavelet transform filter used in the decoding step. 26. An image processing method for processing an input image signal, comprising: an encoding step of encoding the image signal; and a decoded image signal based on a basic code sequence encoded in the encoding step. And a setting step of setting a display resolution of the decoded image signal.Based on the display resolution set by the setting step,
A decoding control step of controlling the decoding step. 27. The image processing apparatus according to claim 26, wherein the decoding control step controls the decoding step based on an image feature amount of the decoded image signal associated with the display resolution. Method. 28. A computer readable memory storing an image processing program code for processing an input image signal, wherein: a program code for an encoding step for encoding the image signal; Program code of a setting step of setting the display resolution of the decoded image signal based on the converted basic code string, based on the display resolution set by the setting step,
A program code of a determining step of determining an image feature amount of the decoded image signal, and a program code of a generating step of generating a decoding target code string corresponding to the image feature amount determined in the determining step based on the basic code string. A computer readable memory comprising: 29. A computer-readable memory storing an image processing program code for processing an input image signal, wherein: a program code for an encoding step for encoding the image signal; A program code of a decoding step of generating a decoded image signal based on the converted basic code sequence, a program code of a setting step of setting a display resolution of the decoded image signal, and a display resolution set by the setting step. hand,
A program code for a decoding control step for controlling the decoding step.