JPH1127667A - Image coder and image decoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct continuous processing of coding and/or decoding of an image efficiently even when number of times of execution commands to the hardware implemented for each processing of image coding and/or decoding by entirely controlling control of a signal processing means and inter-communication between a coding control means and the signal processing means based on a coding control signal. SOLUTION: In this image coder 10, images being image information are continuously supplied to an image input section 1. A 1st control section 12 supplies image information in a memory 2 to an input filter 11s of a signal processing section 11. On the other hand, a 1st control section 12 generates and provides an output of a coding command to be written in a coding command register 13 of a 2nd control section 13. The 2nd control section 13 controls a signal processing section 11 in response to data to the coded command to be written. Thus, a series of coding processing is repetitively executed by one instruction and number of interrupt is reduced to one, then the processing time is reduced and efficient coding is implemented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reads supplied image information through image input means, and reduces various types of redundancy of the image information by signal processing using hardware and software. The reduced image information is information-compressed and encoded, and the supplied encoded information of the image is read through the reception input unit, and the encoded information of the image is converted by signal processing using hardware and software. The present invention relates to an image encoding device and an image decoding device for decoding, and is particularly suitable for use in a system of an information transmitting device and / or a receiving device, such as a video conference system.

[0002]

2. Description of the Related Art Televisions and video monitors, for example,
One screen (frame) is constituted by causing the pixels arranged on the screen to emit light in accordance with the supplied image signal (image information). Therefore, information of pixels of a moving image or a still image generally has a high correlation with information of neighboring pixels with respect to a focused pixel, and includes high redundancy. In image signal processing, especially in the case of moving images, high-speed processing of a huge amount of image information is required, so even if information redundancy is minimized and information is greatly reduced, it is equivalent to the source image. It is desired that the image be restored. Image encoding devices and image decoding devices encode and decode images so as to satisfy the above-mentioned requirements.

For example, image coding includes intra-frame coding and inter-frame coding. Intra-frame encoding is
Using orthogonal transform of highly correlated image information that is energy concentrated in a specific frequency component, for example, using discrete cosine transform (DCT), the transform coefficients obtained by DCT are quantized and encoded. Do. In addition, inter-frame coding is performed by detecting, as a motion vector, a movement between frames before and after a frame to be coded, and obtaining difference information between the frames by, for example, DCT
The orthogonal transform such as is performed, and the transform coefficient obtained by the DCT is quantized and encoded.

On the other hand, in decoding an image, coded data is subjected to inverse quantization, and the obtained data is subjected to an inverse DCT (Inverse Discrete Cosine Transform: hereinafter, IDCT).
Is performed). The image data subjected to the IDCT processing is supplied to an output filter. The output filter performs a filtering process on the image data and outputs the result. An output image signal is obtained by such a decoding process.

Here, the signal processing for the DCT, IDCT, and motion vector detection described above requires enormous calculations. Hardware configured to perform processing in accordance with a signal processing algorithm in order to speed up signal processing, such as a DSP (Digital) for efficient signal processing
Signal Processor) is used. This DSP is performed by software control from a control unit provided in the device. When performing software control, an execution instruction command from the control unit is always written in a register provided in advance in hardware. The hardware operates according to the content of the execution instruction command, and upon completion of the operation, the hardware outputs an interrupt signal to the control unit. The control unit sucks up the operation result of the hardware by so-called interrupt processing to which the interrupt signal is supplied.

[0006]

When an image is displayed, the image display device completes the required image processing within a predetermined standard time, and the processed image information is supplied to a display or the like and displayed. There must be. Therefore, high-speed image processing is always required. This request is also applied to the image encoding / decoding process. However, in the case of image encoding / decoding processing, processing involving software is known as inefficient processing. For example, writing an execution instruction command to hardware or interrupting a control unit takes longer than the signal processing time of the hardware, that is, the execution time, and usually requires a plurality of times to complete a series of image processing. Has become. Further, every time image encoding / decoding processing is repeated, processing such as writing of an execution instruction command to hardware occurs every time, which is inefficient.

The present invention solves the above-mentioned drawbacks of the prior art, and reduces the number of execution instruction commands to hardware performed each time the image is encoded and / or decoded. It is an object of the present invention to provide an image encoding device and an image decoding device capable of efficiently performing continuous decoding processing.

Another object of the present invention is to provide an image encoding method capable of efficiently performing image decoding processing.

[0009]

According to the present invention, supplied image information is read through image input means, and various types of redundancy possessed by the image information are processed by signal processing using hardware and software. An image encoding apparatus for compressing the reduced image information and encoding the reduced image information by passing the image information through an electronic circuit to perform a plurality of signal processings; and First encoding control means for performing an encoding control signal for performing signal processing in accordance with a program, collectively controlling the overall operation of the apparatus, and collectively controlling the operation of the signal processing means; The storage means is used for storing the encoding control signal supplied from the means, and the control of the signal processing means and the first encoding control means and the signal processing are performed in accordance with the encoding control signal from the storage means. And having a second encoding control means for collectively controlling the mutual communication between the means.

According to the present invention, there is provided an image decoding apparatus for reading encoded information of a supplied image via a reception input means, and decoding the encoded information of the image by signal processing using hardware and software. Comprises: a first decoding control means for performing signal processing on the encoded information of the image according to a program, and generating a decoding control signal for collectively controlling the overall operation control and signal processing operation of the apparatus; A decoding signal processing means for performing a plurality of signal processings by passing a signal processing result of the decoding control means of the above into an electronic circuit, and a decoding control storage means for storing a decoding control signal supplied from the first decoding control means. To control signal processing according to the decoding control signal from the decoding control storage means and collectively control the mutual communication between the first decoding control means and the decoded signal processing means. And having a second decoding control unit.

Further, according to the present invention, the supplied image information is read through the image input means, and various types of redundancy of the image information are reduced by signal processing using hardware and software. The reduced image information is information-compressed and encoded, and the supplied image encoding information is read via the reception input means, and the image encoding information is decoded by signal processing using hardware and software. The image encoding and image decoding apparatus performs signal processing on the image information in accordance with a program by passing the image information through an electronic circuit, and performs signal processing on the image information according to a program. First encoding control means for generating an encoding control signal for collectively controlling the operation control and the operation of the signal processing means;
The storage means is used for storing an encoding control signal supplied from the first encoding control means, and the control of the signal processing means and the first encoding control means are performed in accordance with the encoding control signal from the storage means. A second encoding control unit for collectively controlling mutual communication with the signal processing unit, and a signal processing unit that performs signal processing on the supplied encoded information of the image according to a program;
First decoding control means for generating a decoding control signal for collectively controlling the overall operation control and signal processing operation of the device;
Decoding signal processing means for performing a plurality of signal processings by passing a signal processing result of the first decoding control means into an electronic circuit; and decoding control for storing a decoding control signal supplied from the first decoding control means. A second decoding control means for controlling signal processing in accordance with the decoding control signal from the decoding control storage means and collectively controlling mutual communication between the first decoding control means and the decoded signal processing means using the storage means; And characterized in that:

Here, the signal processing means of the image coding apparatus includes an input filter means for performing a filtering process on image information, and a first redundancy for reducing spatial redundancy with respect to an output of the input filter means. Reducing means, redundancy restoring means for restoring spatial redundancy with respect to the output of the first redundancy reducing means, and second redundancy reducing means for reducing temporal redundancy of image information. The first encoding control means includes a quantization function block for quantizing the processing result of the first redundancy reducing means, an encoding function block for encoding the output of the quantization function block, and a quantization function block. And an inverse quantization function block that inversely quantizes the output of

Further, it is preferable that at least bits corresponding to each processing of the signal processing means are arranged in the operation order in the storage means of the second encoding control means.

In the first decoding control means of the image decoding apparatus,
A decoding function block for decoding encoded information of the supplied image; and an inverse quantization function block for inversely quantizing an output of the decoding function block. It is preferable to include an inverse transform unit for performing inverse transform on the processing, and an output filter unit for performing a filtering process on an output of the inverse transform unit.

It is desirable that the decoding control storage means of the second decoding control means of the image decoding apparatus have at least bits corresponding to each processing of the decoded signal processing means arranged in the order of operation.

In the image encoding and / or image decoding apparatus, the first encoding control means generates an encoding control signal for collectively controlling the overall operation control of the apparatus and the operation of the signal processing means during encoding. The coding control signal supplied from the first coding control means is stored in the storage means of the second coding control means, and the control of the signal processing means and the first control are performed in accordance with the coding control signal from the storage means. The image information is encoded by collectively controlling the mutual communication between the encoding control means and the signal processing means, and the overall operation control and decoding signal processing operation of the apparatus are collectively controlled by the first decoding control means in decoding. A decoding control signal is generated, a decoding control signal supplied from the first decoding control means is stored in a decoding control storage means of the second decoding control means, and a decoding signal corresponding to the decoding control signal from the decoding control storage means is generated. By controlling the processing and intercommunication between the first decoding control means and the decoded signal processing means collectively to decode the encoded information of the image, the software side required for the image encoding and / or image decoding processing Thus, the number of times of write access from the user and interrupt access to the software side can be reduced, and encoding can be continuously performed by only one write.

Further, according to the present invention, the supplied image information is read through the image input means, and various types of redundancy of the image information are reduced by signal processing using hardware and software. An image coding method for compressing the reduced image information by information compression is a coding control for collectively instructing a plurality of signal processes for sequentially performing an inverse transformation process for the spatial redundancy reduction process on the image information. A control signal generation step of generating a signal, a storage step of storing the encoding control signal generated in the control signal generation step, and a signal processing of the image information according to the encoding control signal stored in the storage step And a signal processing step of performing

The image encoding method collectively instructs a plurality of signal processes for sequentially performing an encoding control signal generated in a control signal generating step on the image information from an inverse transform process for a process of reducing spatial redundancy. By generating an encoding control signal to perform the signal processing of the image information in the signal processing step according to the encoding control signal stored in the storage step, 1
When performing continuous image processing by only writing once, the number of write accesses from software and interrupt accesses to software required for image encoding and / or image decoding can be reduced.

[0019]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an image encoding apparatus and an image decoding apparatus according to the present invention; In the present embodiment, configurations and operations of an image encoding device and an image decoding device will be described with reference to FIGS. The image coding apparatus reads the supplied image information through the image input unit 1, and reduces various types of redundancy of the image information by signal processing using hardware and software, and reduces the reduced image information. A device for compressing and encoding information, which is used, for example, in a configuration of a part of a transmission device.

FIG. 1 shows a block configuration of the image encoding apparatus 10. The image encoding device 10 basically includes a signal processing unit 11, a first control unit 12, and a second control unit 13. The signal processing unit 11 includes a discrete cosine transform unit (Discrete Cosine Transform: hereinafter) as a plurality of processing units that pass supplied image information through an electronic circuit to perform signal processing.
11a, motion vector search section (Motion Est)
imation: hereinafter referred to as ME section 11b, Inverse Discrete Cosine Transform section: hereinafter ID
A CT unit), an input filter 11d, and an output filter 11e.

The DCT unit 11a applies a discrete cosine transform to the image information supplied via the input filter 11d as an orthogonal transform for reducing spatial redundancy. For image information having a strong correlation between adjacent pixels, reduction of spatial redundancy (information compression) depending on the fineness of the image is performed by orthogonal transform (DCT) in which energy is concentrated in a specific frequency component.

The ME unit 11b often compresses information by reducing the temporal redundancy included in the image information because the time change of the image information when image information is continuously supplied is often limited. I have. For this information compression, the ME unit 11
b detects a motion vector of each part moving in the screen, and obtains a prediction error signal between a prediction value based on motion compensation prediction or inter / intra prediction and image information of the next image.

The IDCT unit 11c performs an inverse orthogonal transform (IDC) to restore the orthogonal transform performed in the DCT unit 11a.
T).

The input filter 11d divides the image information supplied from the memory 2 in FIG. 1 into a plurality of pixels, for example, 8 × 8 pixels (one block) as preprocessing. The input filter 11d further samples these four blocks as a macroblock. The output filter 11e adjusts the size of the output image according to the size of the output device, for example.

The first control section 12 controls the overall operation of the image encoding apparatus 10 by a CPU (Central Processing Unit) and generates an encoding command as an encoding control signal for collectively controlling the operation of the signal processing section 11. I do. Also, the first control unit 12
Performs signal processing according to a program on image information by software. The first control unit 12 includes a quantization function unit 12a and a coding function unit 12b as signal processing functions.
, And an inverse quantization function unit 12c. The first control unit 11 supplies a storage address of an area for storing image information in the memory 2 and a signal processing option to the signal processing unit 11 via the second control unit 13.

The quantization function unit 12a approximates the signal level supplied from the signal processing unit 11 to a discrete value (bit value) corresponding to the quantization level. The quantization function unit 12a sends the obtained value to the encoding function unit 12b.

The encoding function unit 12b performs a process of assigning a binary code to each quantization level obtained by the quantization function unit 12a. This process encodes the image information.

On the other hand, the inverse quantization function unit 12c performs a process reverse to the process performed by the quantization function unit 12a to return the discrete value of the quantization function unit 12a to the original signal level. .

The second control unit 13 uses the encoded command register 13a shown in FIG. 2 for storing the encoded command supplied from the first control unit 12, and this encoded command register 13a
In response to the encoding command register from the controller, the control of the signal processing unit 11 and the mutual communication between the first control unit 12 and the signal processing unit 11 are collectively controlled. The second control unit 13 includes an interface for mediating access between the first control unit 12 and each unit in the signal processing unit 11. For this reason, the second control unit 13
Allows the first control unit 12 to access registers and memories included in each unit of the signal processing unit 11, interrupt the first control unit 12 when a series of signal processing performed by the signal processing unit 11 ends, and the like. The second control unit 13 includes a signal processing unit 11 in advance.
Are controlled according to the data in the encoding command register 13a.

The coding command register 13a is basically arranged in a bit order in consideration of the operation order. The encoding command indicates whether each unit of the signal processing unit 11 operates. When the data is "1" in each bit, the second control unit 13 is set to operate each unit of the signal processing unit 11 corresponding to the bit, and not to operate when the data is "0".

Next, the operation of the image encoding device 10 will be described.
Images are continuously supplied to the image input unit 1 of the image encoding device 10 as image information. The data is supplied to the memory 2 via the image input unit 1 under the control of the first control unit 12. Next, the first control unit 12 supplies the image information in the memory 2 to the input filter 11d of the signal processing unit 11. Here, the input filter 11d and the output filter 11e are controlled by the second control unit 13 so that the input filter 11d and the output filter 11e become operable with the activation of the device 10. The input filter 11d divides the supplied image information of one screen into macroblocks.

On the other hand, the first controller 12 generates and outputs an encoded command to be written into the encoded command register 13a of the second controller 13. Encoding commands are at least three bits wide. The second control unit 13 writes the supplied encoded command into the encoded command register 13a. The second control unit 13 controls the signal processing unit 11 according to, for example, the data “... 111” of the written encoded command. This data “... 111” is stored in the IDCT unit 11c of the signal processing unit 11,
This means that the unit 11b and the DCT unit 11a are sequentially operated.

In the signal processing for the first image, the discrete cosine transform is performed on the macroblock of the original signal divided by the input filter 11d.
When the image information of the next image is supplied from the memory 2, the second control unit 13 performs the signal processing on the IDCT unit 11 c, the ME unit 11 b,
The DCT unit 11a operates sequentially.

First, after DCT processing is performed on the first image, DCT processing is performed.
The output from the unit 11a is supplied to the IDCT unit 11c. IDCT part 11
c performs an inverse discrete cosine transform under the control of the second control unit 13 and outputs the result to the ME unit 11b. ME 11b is an input filter
The motion vector of each part of the image is detected based on the macroblock of the next image (current image) supplied from 11c and the previous image supplied from the IDCT unit 11c, that is, the reference image. The difference between the image based on the prediction obtained by moving the image and the reference image, that is, the prediction error
Send to part 11a. The ME unit 11b reduces temporal redundancy by this signal processing. The next signal processing, DCT unit 11a,
The DCT is added to the prediction error supplied according to the control of the second control unit 13.
Processing is performed to obtain a conversion coefficient. As a result, the spatial redundancy of the transform coefficients is reduced. The second control unit 13 interrupts the first control unit 12 upon completion of a series of signal processing, and supplies the data obtained by the signal processing unit 11 to the first control unit 12.

The supplied data is quantized by the quantization function unit 11a based on the quantization level and sent to the encoding function unit 11b. The encoding function unit 11b performs an encoding process such as variable-length encoding on the quantized value, generates an encoded stream, and outputs the encoded stream to the transmission unit 4. The transmission unit 4 sends the encoded stream to the outside under the control of the first control unit 11.

The DCT unit 11a transmits the calculation result to the first control unit.
Output to the 11 quantization function unit 11a and the IDCT unit 11c.
If the second control unit 13 controls so as to also supply the inverse quantization function, the inverse quantization function unit 11c displayed on the first control unit 12 in FIG. 1 becomes unnecessary. If the DCT unit 11a supplies the output only to the first control unit 12, the quantization function unit 11a supplies the output to the inverse quantization function unit 11c and performs a process of returning to the original transform coefficient. First
The control unit 11 controls to supply the transformed coefficients restored from the inverse quantization function unit 11c to the IDCT unit 11c.

The IDCT unit 11c sends a processing result to the ME unit 11b to form a new reference image based on the supplied data.
In this manner, the image encoding device 10 performs a series of image encoding processes.

Therefore, the image encoding device 10 performs signal processing necessary for encoding based on an instruction performed only once from the first control unit 12, and interrupts the first control unit 12 by one.
It only needs to be performed once, and the overhead of command execution can be reduced. As in the image encoding method described in the present embodiment, signal processing is executed from the IDCT unit 11c, thereby reducing command execution overhead and simultaneously executing a command instruction and an interrupt only once. Can be realized.

Here, the image encoding device 20 shown in FIG. 3 is shown as a comparative example. The image encoding device 20 includes an input filter 21, a changeover switch SW, a DCT unit 22, a quantization unit 23, an encoding unit 24, an inverse quantization unit 25, an IDCT unit 26, a motion compensation / memory unit 2
7. It has an adder 28 and an encoding control unit 29.

When this configuration is compared with the image encoding apparatus 10, the encoding control unit 29 corresponds to the first control unit 12 and the second control unit 13 in FIG. 1, and the motion compensation / memory unit 27 is the signal processing unit 11 Of the ME unit 11c. As shown in FIG. 3, the changeover switch SW, the quantization unit 23, and the encoding unit 24 are an encoding control unit.
The quantization unit 23, the encoding unit 24, and the inverse quantization unit 25 are controlled to perform signal processing by software.

Next, the operation of the image encoding device 20 will be briefly described. Image information from an image input unit (not shown) is supplied to the input filter 21. The input filter 21 samples and divides the screen into a desired image size, for example, a macroblock in which four 8 × 8 pixel blocks are grouped. The output end of the input filter 21 is connected to the addition input end of the adder 28, one end a of the changeover switch SW, and the motion compensation / memory unit 27.

The DCT unit 22 performs discrete cosine transform on each macroblock of the image supplied via the changeover switch SW and supplies the result to the quantization unit 23. In this supply, although not shown, the DCT unit 22 interrupts the encoding control unit 29. By this interrupt processing, DC is applied to the quantization unit 23.
The processing result from the T unit 22, that is, the conversion coefficient is supplied. The quantization unit 23 quantizes the transform coefficients and encodes the
To the inverse quantization unit 25. The encoding unit 24 includes an encoding control unit 29
For example, variable-length coding is performed to generate a coded stream. On the other hand, the inverse quantization unit 25 returns the quantized discrete value to the original transform coefficient, and outputs it to the IDCT unit 26.

The IDCT unit 26 performs an inverse discrete cosine transform on the basis of the transform coefficient supplied according to the instruction of the encoding control unit 29, and outputs the result to the motion compensation / memory unit 27. The motion compensation / memory unit 27 loads the image supplied from the IDCT unit 26 into the memory as a reference image.

Next, the motion compensation / memory unit 27 detects the motion vector in each part of the image by comparing the next image from the input filter 21 with the reference image. Motion compensation / memory unit 27
Supplies the detected motion vector to the encoding control unit 29 (not shown), and outputs the stored reference image to the subtraction input side of the adder. Further, the next image from the input filter 21 is added to the adder 28. With these inputs, the adder 28 supplies a difference signal between the reference image and the next image to the other end b of the changeover switch SW. On the other hand, the next image from the input filter 21 is supplied to the terminal a of the changeover switch SW. The changeover switch SW switches according to the control of the encoding control unit 29.

The code control unit 29 uses the supplied motion vector, for example, and selects the terminal b when the motion vector is smaller than a certain threshold value (the difference from the previous image is small). Is larger (the difference from the previous image is larger), the selector switch SW is controlled so as to select the terminal a side. The selected signal is sent from the changeover switch SW
It is supplied to the DCT unit 22. By repeating the DCT, quantization and coding, inverse quantization, IDCT, and motion compensation (motion vector search: ME) processing, image information supplied continuously is encoded.

By the way, as described above, the image encoding device 20 includes the motion compensation / memory unit 27, the IDCT unit 26, and the DCT
The unit 22 is executed by hardware, and the other quantization units 23,
The encoding unit 24 and the inverse quantization unit 25 are processed by software. For this reason, the encoding process of the input image is generally performed in the order of the motion compensation / memory unit 27, the DCT unit 22, the [quantization unit 23, the encoding unit 24, the inverse quantization unit 25], and the IDCT unit 26. In this case, software processing is performed during hardware processing. At this time, when one encoding process is performed, a notification of an execution instruction is issued before the operation of the motion compensation / memory unit 27 and the IDCT unit 26 starts, and an interrupt is issued.
This is performed when the signal processing of the DCT unit 22 and the IDCT unit 26 is completed.

The image coding apparatus 10 of the present embodiment repeatedly executes a series of coding processes with one instruction (execution instruction) and reduces the number of interrupts to one. The processing time can be shortened as compared with the twenty encoding processes, and the encoding of the input image can be performed efficiently.

Next, the configuration and operation of the image decoding apparatus according to the present invention will be described with reference to FIGS. The image decoding device reads the encoded information of the supplied image via the reception input unit 5 and decodes the encoded information of the image by signal processing using hardware and software. Used.

FIG. 4 shows a block configuration of the image decoding device 30. The image decoding device 30 includes a first decoding control unit 31,
It comprises a decoded signal processing unit 32 and a second decoding control unit 33.

The first decoding control section 31 generates a decoding command for controlling the overall operation of the image decoding apparatus 30 and for controlling the decoding signal processing operation collectively. Further, the first decoding control unit 31 performs a decoded signal process on the supplied coded stream of the image according to a program. The first decoding control unit 31 has a decoding function unit 31a and an inverse quantization function unit 31b.

The decoding function unit 31a decodes an encoded stream of an image, for example, which has been subjected to variable length encoding and supplied from the memory 6. The decoding function unit 31a sends the decoded discrete value (bit value) to the inverse quantization function unit 31b.

The inverse quantization function section 31b returns the output from the decoding function section 31a to the original signal level by the inverse quantization processing. This signal level is the same as the transform coefficient obtained by the DCT processing in the image encoding device. The inverse quantization function unit 31b of the first decoding control unit 31 supplies the obtained transform coefficient to the decoded signal processing unit 32.

The decoded signal processing section 32 has an IDCT section 32a and an output filter 32b as a plurality of decoding processing sections for performing a plurality of signal processings by passing a signal processing result of the first decoding control section 31 through an electronic circuit. doing.

The IDCT unit 32a is provided, for example, in the image encoding device 10
The inverse orthogonal transform (for example, IDCT) is performed to restore the orthogonal transform performed in the DCT unit 11a. IDCT part 32
a supplies an output to an output filter 32b under the control of a second decoding control unit 33 described in detail later.

The output filter 32b supplies the output from the IDCT unit 32a as a group of image information for each macroblock. Therefore, the output filter 32b expands the image information supplied so as to correspond to each pixel position on the screen by filtering. Do. The output filter 32b sends the image information thus restored to the image output unit 7 under the control of the first decoding control unit 31.

The second decoding control unit 33 uses the decoding command register 33a (see FIG. 5) to store the decoding command supplied from the first decoding control unit 31, and
a, and collectively controls the mutual processing between the first decoding control unit 31 and the decoded signal processing unit 32.

The second decoding control unit 33 has an interface for mediating access between the first decoding control unit 31 and each unit in the decoded signal processing unit 32. For this reason, the second decoding control unit 33 accesses the register and the memory of each unit of the decoded signal processing unit 32 from the first decoding control unit 31 and performs the first decoding at the end of a series of signal processing performed by the decoded signal processing unit 32. Interruption to the decoding control unit 31 and the like become possible. The operation order of the second decoding control unit 33 is set in advance so as to control the decoded signal processing unit 32 according to the data in the decoding command register 33a.

The decoding command register 33a is basically arranged in a bit order in consideration of the operation order. The decoding command indicates whether or not each unit of the decoded signal processing unit 32 operates. When the data in each bit is "1", the second
The decoding control unit 33 is set so that each unit of the decoded signal processing unit 32 corresponding to the bit is operated, and is not operated when the data is “0”.

Next, the operation of the image decoding device 30 will be described. The first decoding control unit 31 of the image decoding device 30 is a receiving unit shown in FIG.
5 is supplied to the memory 5 with the coded stream of the image supplied continuously to the memory 5. Next, the first decoding control unit 31 converts the encoded stream in the memory 5 into a decoding function unit 31 of the first decoding control unit 31.
Put in a. The decoding function unit 31a decodes, for example, one screen of image information encoded into a variable length code. The decoded discrete value is subjected to an inverse quantization process in an inverse quantization function unit 31b. The output of the inverse quantization function unit 31b is generally the same as the transform coefficient obtained after DCT processing. Inverse quantization function
The output of the IDCT unit 32b is controlled by the second decoding control unit 33.
supplied to a. The IDCT unit 32a performs inverse discrete cosine transform under the control of the second decoding control unit 33, and outputs the image information restored to the output filter 32b.

At this time, the first decoding control unit 31 generates a decoding command to be written in the decoding command register 33a of the second decoding control unit 33 shown in FIG. Decryption commands are at least two bits wide. The second decoding control unit 33 writes the supplied decoding command into the decoding command register 33a. Second decryption control unit 33
Is, for example, the data "...
The decoded signal processing unit 33 is controlled according to “11”. This data "... 11" is used by the decoded signal processing unit 32 in the subsequent repetitive processing.
This means that the output filter 32b and the IDCT unit 32a are sequentially operated.

Since the restored image information is image information for each macro block, the output filter 32b expands the image information by filtering so as to correspond to each pixel position on the screen. Under the control of the second decoding control unit 33, the output filter 32b gives an interrupt to the first decoding control unit 31 at the end of the expansion processing, which means completion of image restoration. First
The decoding control unit 31 controls the image information thus restored to be sent to the image output unit 7. The image output unit 7 sends out the restored image to the outside.

Accordingly, the image encoding device 30 performs signal processing necessary for decoding based on an instruction performed only once from the first decoding control unit 31, and interrupts the first decoding control unit 12 only once. And the overhead of command execution performed during the repetitive processing can be reduced. Further, as described in the present embodiment, by executing the signal processing from the output filter 32b, the image decoding can be repeatedly performed only once for each of the command instruction and the interrupt.

Next, a comparative example of the image decoding apparatus for this embodiment will be described. This image decoding device 40 includes a decoding unit
41, an inverse quantization unit 42, an IDCT unit 43, and an output filter 44.

When this configuration is compared with the image decoding device 30, the decoding unit 41 and the inverse quantization unit 42 correspond to the first decoding control unit 31 in FIG. 4, and each unit of the decoded signal processing unit 32
It corresponds to the IDCT unit 32a and the output filter 32b. Although not shown, the decoding unit 42 and the inverse quantization unit 43 shown in FIG. 6 are controlled by a decoding control unit to perform signal processing by software.

The operation of the image decoding device 40 will be briefly described. The image decoding device 40 inputs the coded stream of the image continuously supplied to the decoding unit 41. The decoding unit 41 decodes, for example, one screen of image information encoded into a variable length code. An inverse quantization process is performed on the decoded discrete value by the inverse quantization unit 42. The inverse quantization unit 42 is generally the same as the transform coefficient after DCT processing, and supplies this output to the IDCT unit 43.
The IDCT unit 43 performs inverse discrete cosine transform under control and outputs image information restored to the output filter 44.

Here, the image decoding device 40 executes the IDCT unit 43 and the output filter 44 by hardware, and the other decoding unit 41 and inverse quantization unit 42 perform processing by software. For this reason, in the decoding process of the coded stream of the input image, usually, when performing one decoding process, the [decoding unit 41, the inverse quantization unit 42], the IDCT unit 43,
The processing is performed in the order of the output filter 44. By the way, when the decoding process is performed in this order, the image decoding device 40 writes an execution instruction (decoding command) in the IDCT unit 43 after the software process, and interrupts the process after the output filter 44 finishes the process. That is, each time the decoding process is repeated, writing and interruption must be performed once each.

On the other hand, the image decoding device 30 includes, for example, an output filter 32b, a [decoding function unit 31a, and an inverse quantization function unit 31b.
] And the IDCT unit 32a. At this time, in the order in which software processing was entered during hardware processing,
The execution instruction is notified by the motion compensation / memory unit 27 and IDCT, respectively.
The interrupt is issued before the operation of the unit 26 starts, and the interrupt is sent to the DCT unit 22
This is performed when the signal processing of the IDCT unit 26 ends.

The image decoding device 30 of this embodiment repeatedly executes a series of decoding processes with one instruction (execution instruction), so that the processing time is shorter than the decoding process of the image decoding device 40 of the comparative example and the input time is shorter. The encoded stream of the image to be decoded can be efficiently decoded.

In the above-described embodiment, the image encoding device 10 and the image decoding device 30 are separate devices. However, an image encoding / decoding device combining these two devices simultaneously encodes and decodes an image. It can be performed efficiently. This device is effective when incorporated in, for example, a transmitting / receiving device of a so-called video conference system as a two-way communication device.

Although the present embodiment has described the apparatus configuration for performing hybrid coding and decoding using transform coding and motion compensation prediction, the present invention is not limited to the above-described embodiment. Alternatively, another encoding may be performed using the concept of the present invention.

With such a configuration, the image encoding device, the image decoding device, and the image encoding method repeatedly execute a series of encoding and / or decoding processes with one instruction (execution instruction). In any of the processes, the processing time can be reduced, and the encoding of the input image and / or the decoding of the encoded stream of the image can be performed efficiently.

[0072]

As described above, according to the image encoding apparatus and the image decoding apparatus of the present invention, the encoding control signal for collectively controlling at least the operation of the signal processing means is generated by the first encoding control means in encoding. Then, this encoding control signal is
The image information is stored in the storage means of the encoding control means, and the control of the signal processing means and the mutual communication between the first encoding control means and the signal processing means are collectively controlled in accordance with the encoding control signal. In the encoding and decoding, the first decoding control means generates a decoding control signal for collectively controlling at least the decoding signal processing operation, and stores the decoding control signal in the decoding control storage means of the second decoding control means. Controlling the decoding signal processing according to the signal and collectively controlling the mutual communication between the first decoding control means and the decoding signal processing means to decode the coded information of the image, and perform image coding and / or image decoding By reducing the number of write accesses from the software side and interrupt accesses to the software side required for processing, encoding and / or decoding of a series of images can be performed with only one instruction (execution instruction). Since thereby processing iterations performed can be performed decoding of any of the images is also shortened by entering the processing time in the processing coded and / or image encoded stream efficiently.

According to the image encoding method of the present invention,
A coding control signal for collectively instructing a plurality of signal processes for sequentially performing the coding control signal generated in the control signal generating process from the inverse transform process is generated, and a signal is generated according to the coding control signal stored in the storage process. In the processing step, signal processing of image information is performed to reduce command execution overhead, and image encoding is performed by reducing the number of write accesses from software and interrupt accesses to software required for image encoding. As a result, the encoding processing time can be shortened and efficient encoding can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an embodiment of an image encoding device according to the present invention.

FIG. 2 is a schematic diagram illustrating an example of an encoded command register of a second control unit illustrated in FIG.

FIG. 3 is a block diagram illustrating a configuration of a comparative example with respect to the image encoding device illustrated in FIG. 1;

FIG. 4 is a block diagram illustrating a configuration of an embodiment of an image decoding device according to the present invention.

FIG. 5 is a schematic diagram illustrating an example of a decoding command register of the decoding signal processing unit illustrated in FIG. 4;

6 is a block diagram illustrating a configuration of a comparative example with respect to the image decoding device illustrated in FIG. 4;

[Explanation of symbols]

 10 image encoding device 11 signal processing unit 12 first control unit 13 second control unit 30 image decoding device 31 first decoding control unit 32 decoded signal processing unit 33 second decoding control unit

Claims (12)

[Claims] An image information to be supplied is read via an image input means, and various kinds of redundancy of the image information are reduced by signal processing using hardware and software, and the reduced image information is read. In an image coding apparatus for compressing and coding information, the apparatus includes signal processing means for passing the image information through an electronic circuit and performing a plurality of signal processes; and performing signal processing on the image information according to a program. A first encoding control unit for generating an encoding control signal for collectively controlling the operation of the apparatus and the operation of the signal processing unit; and encoding supplied from the first encoding control unit. The storage means is used for storing the control signal, and the control of the signal processing means and the mutual communication between the first coding control means and the signal processing means are performed in accordance with the coding control signal from the storage means. An image encoding apparatus comprising: a second encoding control unit that performs collective control. 2. The image encoding apparatus according to claim 1, wherein the signal processing unit includes: an input filter unit that performs a filtering process on the image information; and a spatial redundancy with respect to an output of the input filter unit. First redundancy reducing means for reducing, redundancy restoring means for restoring spatial redundancy with respect to an output of the first redundancy reducing means, and second redundancy reducing means for reducing temporal redundancy of the image information The first encoding control unit includes: a quantization function block that quantizes a processing result of the first redundancy reduction unit; and an output of the quantization function block. An image coding apparatus comprising: a coding function block that performs quantization; and an inverse quantization function block that performs inverse quantization on an output of the quantization function block. 3. The image encoding apparatus according to claim 1, wherein at least bits corresponding to each processing of said signal processing means are arranged in an operation order in said storage means of said second encoding control means. An image encoding device, characterized in that: 4. An image decoding apparatus which reads supplied encoding information of an image via a reception input means and decodes the encoding information of the image by signal processing using hardware and software, wherein the apparatus comprises: First decoding control means for performing signal processing on the encoded information of the image according to a program, and generating a decoding control signal for collectively controlling the overall operation of the apparatus and the signal processing operation; Decoding signal processing means for performing a plurality of signal processes by passing a signal processing result of the control means into an electronic circuit; decoding control storage means for storing a decoding control signal supplied from the first decoding control means; Control of signal processing according to the decoding control signal from the decoding control storage means;
An image decoding apparatus comprising: a decoding control means for controlling the mutual communication between the decoding control means and the decoded signal processing means. 5. The image decoding apparatus according to claim 4, wherein said first decoding control means comprises: a decoding function block for decoding the supplied coded information of the image; An inverse quantization function block for transforming the spatial signal, wherein the decoded signal processing means comprises: an inverse transform means for performing an inverse transform on the spatial redundancy reduction process; and an output filter for performing a filtering process on an output of the inverse transform means. And an image encoding device. 6. The image decoding device according to claim 4, wherein the decoding control storage means of the second decoding control means includes:
An image encoding apparatus, characterized in that at least bits corresponding to each processing of the decoded signal processing means are arranged in an operation order. 7. The supplied image information is read via an image input means, and various types of redundancy of the image information are reduced by signal processing using hardware and software. Image encoding and image encoding for compressing and encoding information, reading encoded information of the supplied image via a reception input unit, and decoding the encoded information of the image by signal processing using hardware and software. In the decoding device, the device includes: a signal processing unit that performs a plurality of signal processes by passing the image information through an electronic circuit; performs a signal process on the image information according to a program; and controls an overall operation of the device. And a first encoding control unit for generating an encoding control signal for collectively controlling the operation of the signal processing unit; and a first encoding control unit supplied from the first encoding control unit. Storage means for storing the encoding control signal, and controlling the signal processing means in accordance with the encoding control signal from the storage means and controlling the signal processing means between the first encoding control means and the signal processing means. Second encoding control means for collectively controlling intercommunication; signal processing for supplied encoded information of the image according to a program; and decoding control for collectively controlling the overall operation of the apparatus and the signal processing operation. First decoding control means for generating a signal, decoded signal processing means for performing a plurality of signal processes by passing a signal processing result of the first decoding control means into an electronic circuit, and first decoding control means A decoding control signal supplied from the decoding control storage means, and control of signal processing according to the decoding control signal from the decoding control storage means and the first
And a second decoding control means for collectively controlling mutual communication between the decoding control means and the decoded signal processing means. 8. The image encoding and decoding apparatus according to claim 7, wherein the signal processing unit includes: an input filter unit that performs a filtering process on the image information; and a spatial redundancy with respect to an output of the input filter unit. A first redundancy reducing unit for reducing redundancy, a redundancy restoring unit for restoring spatial redundancy with respect to an output of the first redundancy reducing unit, and a second redundancy reducing unit for reducing temporal redundancy of the image information. The first encoding control unit includes: a quantization function block that quantizes a processing result of the first redundancy reduction unit; and an output of the quantization function block. An image encoding and decoding apparatus, comprising: an encoding function block for encoding; and an inverse quantization function block for inversely quantizing an output of the quantization function block. 9. The image encoding and decoding apparatus according to claim 7, wherein at least a bit corresponding to each processing of said signal processing means is stored in a storage means of said second encoding control means in an operation order. An image encoding / decoding device, which is provided. 10. The image encoding and decoding apparatus according to claim 7, wherein said first decoding control means comprises: a decoding function block for decoding coding information of the supplied image; and an output of said decoding function block. An inverse quantization function block that inversely quantizes the spatial redundancy, wherein the decoded signal processing unit performs an inverse transform for inversely transforming the spatial redundancy reduction process, and performs a filtering process on an output of the inverse transform unit. An image encoding and decoding apparatus, comprising: 11. The image encoding and decoding apparatus according to claim 7, wherein at least a bit corresponding to each processing of said decoded signal processing means is stored in a decoding control storage means of said second decoding control means. An image encoding and decoding device, which is arranged in the order of operation. 12. The supplied image information is read via an image input means, and various types of redundancy of the image information are reduced by signal processing using hardware and software, and the reduced image information is read. An image encoding method for compressing and encoding information, the method comprising: an encoding control signal for collectively instructing a plurality of signal processes for sequentially performing the inverse transformation process for the spatial redundancy reduction process on the image information. Generating a control signal, generating a control signal, storing the encoded control signal, and performing a signal processing of the image information according to the encoded control signal stored in the storage step. Performing a signal processing step.