JPH0795567A - Picture coder and decoder - Google Patents

Abstract

PURPOSE:To realize miniaturization and to reduce cost by providing a frame memory in a video telephone set or the like, using the frame memory for two field memories in the case of 2-way picture communication and using the frame memory for a frame memory in the case of transmission of a high definition picture to reduce the number of memories considerably and circuits for memory control remarkably. CONSTITUTION:When a request of 2-way picture transmission is received between two video telephone sets interconnected by a transmission line, one frame memory is used for two independent field memories 4A, 12A to attain transmission and reception. When a request of transmission of a picture with high resolution is received between the telephone sets, the two field memories 4A, 12A are integrated into one frame memory.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image encoding / decoding device for transmitting a still image or the like bidirectionally or unidirectionally using a transmission line.

[0002]

2. Description of the Related Art The structure of a conventional image coding / decoding apparatus will be described with reference to FIG. FIG. 6 is a block diagram showing the configuration of a conventional image encoding / decoding device.

In FIG. 6, 1 is an image input terminal for inputting an image from a camera or the like, 2 is an image input section connected to the image input terminal 1, and 3 is an A / D converter connected to the image input section 2. Is. Further, 4 is a transmission frame memory connected to the A / D converter 3, 5 is an encoder connected to the transmission frame memory 4, and 6 is a code data buffer connected to the encoder 5. Further, 7 is a transmission controller including a transmitter 7a and a receiver 7b. Reference numeral 8 is a transmission data terminal connected to the transmission controller 7.

Reference numeral 9 is a received data terminal to which protocolized transmission data is input, 10 is a decoded data buffer connected to the transmission control unit 7, and 11 is a decoded data buffer 10.
A decoder 12 connected to the decoder 12 and a reception frame memory 12 connected to the decoder 11. Further, 13 is a D / A converter connected to the receiving frame memory 12, and 14 is a D / A converter.
An image output unit connected to the / A converter 13 and an image output terminal 15 connected to the image output unit 14. Furthermore, 1
Reference numeral 6 is a system control unit that controls the above-described units.

Next, the operation of the above-mentioned conventional image encoding / decoding device will be described. First, the image input terminal 1
An image from a camera or the like is input from the image input device, and after Y / C separation or the like is performed in the image input unit 2, digital sampling is performed by the A / D converter 3 and the transmission frame memory 4
Accumulated in.

The image data accumulated in the transmission frame memory 4 is highly efficiently encoded by the encoder 5, and then input to the transmission controller 7 via the code data buffer 6. The transmission unit 7a of the transmission controller 7 sends out the protocolized transmission data from the transmission data terminal 8 according to the connected transmission line.

Further, the protocolized transmission data input from the reception data terminal 9 is converted into code data by the reception section 7b of the transmission controller 7 and passed through the decoding data buffer 10 to the decoder 11. Is entered. The coded data is decoded in the decoder 11 and stored in the receiving frame memory 12.

The image data read from the receiving frame memory 12 is converted into an analog signal by the D / A converter 13, and converted into a TV (television) signal or the like by the image output section 14, and the image output terminal is supplied. It is output from 15 to a monitor or the like.

[0009]

In the conventional image coding / decoding device as described above, in the case of the TV telephone device in which both of them see each other's images, the frame memories are required for the transmission and the reception. However, there is a problem in that it is difficult to reduce the size and cost.

The present invention has been made in order to solve the above-mentioned problems. In the image encoding / decoding apparatus, one frame memory is held and two frame memories are used for bidirectional image communication. It can be used as a single field memory, and as a frame memory when transmitting high-definition images, the number of memories can be significantly reduced, and the memory control circuit can also be significantly reduced. It is an object of the present invention to obtain an image encoding / decoding device that can realize a small size and a low price, such as being possible.

[0011]

An image coding / decoding device according to claim 1 of the present invention comprises the following means:
The first and second field memories are composed of one frame memory. [1] Image input means for inputting image data and digitally sampling. [2] A first field memory that stores the digitally converted image data. [3] Image encoding means for encoding the accumulated digital image data. [4] Image decoding means for inputting and decoding received data. [5] A second field memory for accumulating the decoded reception data. [6] Image output means for converting the accumulated received data into an analog signal for output.

An image coding / decoding device according to a second aspect of the present invention is provided with the following means, and the first and second field memories are composed of one frame memory. [1] Image input means for inputting image data and digitally sampling. [2] A first field memory that stores the digitally converted image data. [3] Image encoding means for encoding the accumulated digital image data. [4] Image decoding means for inputting and decoding received data. [5] A second field memory for accumulating the decoded reception data. [6] Image output means for converting the accumulated received data into an analog signal for output. [7] When bidirectional image transmission is performed, the image input means and the first field memory are connected to each other, and the second field memory is connected.
When the high-resolution image transmission is performed by connecting the field memory and the image output means, the image input means and the first and second field memories are connected, and the first and second fields are connected. Switching means for connecting the memory and the image output means.

An image coding / decoding device according to a third aspect of the present invention is provided with the following means, and the first and second field memories are composed of one frame memory. [1] Image input means for inputting image data and digitally sampling. [2] A first field memory that stores the digitally converted image data. [3] Image encoding means for encoding the accumulated digital image data. [4] Image decoding means for inputting and decoding received data. [5] A second field memory for accumulating the decoded reception data. [6] Image output means for converting the accumulated received data into an analog signal for output. [7] Image quality setting means for independently setting the image quality of the data stored in the first and second field memories.

An image coding / decoding device according to a fourth aspect of the present invention is provided with the following means, and the first and second field memories are composed of one frame memory. [1] Image input means for inputting image data and digitally sampling. [2] A first field memory that stores the digitally converted image data. [3] Image code decoding means for encoding the accumulated digital image data, inputting and decoding the received data, and performing the encoding and decoding in time division. [4] A second field memory for accumulating the decoded reception data. [5] Image output means for converting the accumulated received data into an analog signal for output.

[0015]

In the image coding / decoding device according to the first aspect of the present invention, the first and second field memories are
It is composed of individual frame memories. Also,
Image data is input and digitally sampled by the image input means, the digitally converted image data is accumulated by the first field memory, and the accumulated digital image data is encoded by the image encoding means. To be done. Further, the image decoding means receives and decodes the received data, the second field memory stores the decoded received data, and the image output means stores the stored received data in an analog form. It is converted and output.

In the image coding / decoding apparatus according to the second aspect of the present invention, the first and second field memories are composed of one frame memory. Further, the image data is inputted and digitally sampled by the image input means, and the digitally converted image data is accumulated by the first field memory,
The accumulated digital image data is encoded by the image encoding means. Further, the image decoding means receives and decodes the received data, the second field memory stores the decoded received data, and the image output means stores the stored received data in an analog form. It is converted and output. When bidirectional image transmission is performed by the switching unit, the image input unit and the first field memory are connected, and the second field memory and the image output unit are connected to each other, and a high resolution image is displayed. When image transmission is performed, the image input means is connected to the first and second field memories, and the first and second field memories are connected to the image output means.

In the image coding / decoding apparatus according to the third aspect of the present invention, the first and second field memories are composed of one frame memory. Further, the image data is inputted and digitally sampled by the image input means, and the digitally converted image data is accumulated by the first field memory,
The accumulated digital image data is encoded by the image encoding means. Further, the image decoding means receives and decodes the received data, the second field memory stores the decoded received data, and the image output means stores the stored received data in an analog form. It is converted and output. Then, the image quality of the data stored in the first and second field memories is independently set by the image quality setting means.

In the image coding / decoding device according to the fourth aspect of the present invention, the first and second field memories are composed of one frame memory. Image data is input and digitally sampled by the image input means, and the digitally converted image data is stored in the first field memory. Furthermore, the accumulated digital image data is encoded by the image encoding / decoding means, the received data is input and decoded, and the encoding and decoding are performed in time division. Then, the decoded reception data is accumulated by the second field memory, and the accumulated reception data is analog-converted and output by the image output means.

[0019]

EXAMPLES Example 1. The configuration of the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention, which corresponds to a TV telephone device or the like, and includes an image input terminal 1 to an A / D converter 3,
The code data buffer 6 to the decoded data buffer 10, and the D / A converter 13 to the image output terminal 15 are the same as those of the above-described conventional device. In each figure, the same reference numerals indicate the same or corresponding parts.

In FIG. 1, 17 is an image input section 2 and A.
A selector connected to the / D converter 3 and 4A is a selector 1
7 and an ODD field memory connected to the encoder / decoder 18 (described later). Reference numeral 18 denotes an encoder / decoder that serves as an encoder or a decoder depending on the operation direction.

Reference numeral 12A is an EVEN field memory connected to the selector 17 and the encoder / decoder 18, and 19 is an image output unit 14, ODD field memory 4A and EVE.
It is a selector connected to the N field memory 12A. 16A is a system control unit that controls each unit.

By the way, the image input means according to claim 1 of the present invention is the same as the image input section 2 and the A / D in the first embodiment.
The first aspect of the present invention, which comprises the converter 3,
This field memory corresponds to the ODD field memory 4A in the first embodiment, and the image encoding means according to claim 1 of the present invention is the encoder / decoder 18 in the first embodiment.
The image decoding means according to claim 1 of the present invention corresponds to the decoding part of the encoder / decoder 18 in the first embodiment, and the image decoding means according to claim 1 of the present invention. The field memory 2 corresponds to the EVEN field memory 12A in the first embodiment, and the image output means according to claim 1 of the present invention is composed of the D / A converter 13 and the image output unit 14 in the first embodiment. Has been done.

The switching means according to claim 2 of the present invention is composed of selectors 17 and 19 in the first embodiment.

The image quality setting means according to claim 3 of the present invention corresponds to the system control section 16A in the first embodiment.

Further, the image code decoding means according to claim 4 of the present invention is the code / decoder 18 in the first embodiment.
Equivalent to.

Next, the operation of the above-described first embodiment will be described with reference to FIG. FIG. 2 is a timing chart showing the operation of the first embodiment of the present invention.

In FIG. 2, (a) shows the encoder / decoder 1.
8, (b) is the code data buffer 6, (c) is the transmitter 7a of the transmission controller 7, (d) is the decoded data buffer 10,
(E) shows the operation of the receiving unit 7b of the transmission controller 7.

Image input terminal 1 to A / D converter 3 and D /
Input / output and digital conversion of image data from the A converter 13 to the image output terminal 15 are the same as the conventional operation.

When bidirectional image communication is performed by a user's selection of a switch or the like (not shown), the selector 17 is controlled by the system controller 16A.
Is connected to the terminal B and the selector 19 is connected to the terminal G to use the ODD field memory 4A for transmission and the EVEN field memory 12A for reception.

As shown in FIGS. 2 (a) and 2 (b), OD
The image data accumulated in the D field memory 4A is encoded by the encoder / decoder 18 and accumulated in the encoded data buffer 6. Further, as shown in FIG. 2 (c), the code data accumulated in the code data buffer 6 is transferred from the transmission data terminal 8 to the transmission line after being subjected to appropriate protocol processing by the transmission section 7a of the transmission controller 7. Sent out.

On the other hand, as shown in FIGS. 2 (e), 2 (d) and 2 (a), the coded data input from the reception data terminal 9 is input to the decoded data buffer 10 and the coded / decoder 18 is used. It is decoded and stored in the EVEN field memory 12A. Then, from the EVEN field memory 12A through the selector 19, the D / A converter 1
3 is converted into an analog signal and output from the image output terminal 15 via the image output unit 14.

At this time, the encoder / decoder 18 first executes the encoding of the transmission data and then the decoding of the reception data, and switches each operation in time division. In this case, when the encoding / decoding speed is sufficiently higher than the transmission speed, it seems that image communication is pseudo bidirectionally performed. This state is shown in FIG.

Next, the operation of transmitting a high-resolution image by the user's selection of a switch or the like (not shown) will be described.

The image input from the image input terminal 1 is digitally converted by the A / D converter 3 via the image input section 2. At this time, the image input unit 2 determines whether the image currently being input is the ODD field or the EVEN field, and based on this information, the selector 17 transfers the image to the ODD field memory 4A via the terminal B. Data is stored or image data is stored in the EVEN field memory 12A via the terminal C, and stored in each memory.

The image data accumulated in each memory is input to the encoder / decoder 18 as frame data, and is subjected to appropriate protocol processing by the transmission controller 7 via the code data buffer 6 and then transmitted data. Output from the terminal 8 to the transmission line.

On the other hand, when the transmission data is input from the reception data terminal 9, protocol processing is performed by the transmission controller 7 and input to the encoder / decoder 18 via the decoded data buffer 10. The encoder / decoder 18 decodes the input image data as frame data and stores it in the ODD field memory 4A and the EVEN field memory 12A according to the data in the ODD field or the EVEN field. Then, the image output unit 14 outputs the data in the memory corresponding to each field to the selector 1
9 is selected, converted into an analog signal by the D / A converter 13, and output from the image output terminal 15 to a monitor or the like.

In the first embodiment, an image taken by a camera or the like is digitally sampled and written in a frame memory, and then encoded and transmitted through a digital line or the like, and the received transmission data is decoded and the above-mentioned frame is transmitted. In a TV telephone device which writes in a memory and then converts it into an analog signal for display on a monitor or the like, the frame memory is replaced by an ODD field memory 4A and an EVEN field memory 12A
And ODD field memory 4A for transmission, E
The VEN field memory 12A is assigned for reception to enable bidirectional image communication.

In addition, the ODD field memory 4A and EV
By using the EN field memory 12A in combination as a frame memory, a high-resolution image can be transmitted in one direction and the resolution in the vertical direction can be increased.

In addition, the number of pixels in the horizontal direction (horizontal resolution) can be independently set for the two field memories 4A and 12A by the system control unit 16A by the operation of the user's switch or the like, so that transmission can be performed. The image quality of reception can be set independently.

Further, although the encoder / decoder 18 is a type that cannot perform encoding and decoding at the same time, it encodes or decodes image code data at a speed higher than the transmission speed, and performs encoding / decoding at the time. By performing division, bidirectional image communication is possible.

That is, in the first embodiment, as described above, the TV telephone device or the like has one frame memory and uses the frame memory as two field memories when bidirectional image communication is performed. Also, when transmitting high-definition images, by using it as a normal frame memory, the number of memories can be significantly reduced, and the memory control circuit can also be greatly reduced, thus reducing size and cost. Aim to achieve.

In the first embodiment, one frame memory is used as two independent field memories 4A and 12A when there is a request for bidirectional image transmission between two TV telephone devices connected on a transmission line. However, it enables transmission and reception. Furthermore, the horizontal resolution can be set independently for each of the field memories 4A and 12A. On the other hand, if there is a request for high-resolution image transmission between the above devices, the two field memories 4A and 12 are
By configuring A as one frame memory, it is possible to transmit a high-resolution image in one direction.

Therefore, according to the first embodiment, bidirectional image communication and unidirectional high-resolution image communication are possible by only possessing one frame memory, and the apparatus is downsized and the price is low. Can be realized.

Example 2. The configuration of the second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a block diagram showing a configuration of the second embodiment of the present invention, which corresponds to a personal computer, a workstation, etc., and an image input terminal 1
-A / D converter 3, ODD field memory 4A, code data buffer 6, decoded data buffer 10, EVEN
Field memory 12A, D / A converter 13-image output terminal 15, system control unit 16A, and selector 17-
The selector 19 is similar to that of the first embodiment described above.

In FIG. 3, 20 is a storage control unit connected to the code data buffer 6 and the decoded data buffer 10, and 21 is a storage unit connected to the storage control unit 20.

Next, the operation of the above-described second embodiment will be described. The second embodiment shown in FIG. 3 is the same as the first embodiment shown in FIG.
The transmission controller 7 is replaced by a storage controller 20 and applied to an image storage device. The operations for encoding and decoding are the same as those of the device shown in FIG.

When recording / reproducing a high-resolution image,
The ODD field memory 4A and the EVEN field memory 12A are used as a frame memory. When the image data is encoded and stored and is decoded and displayed in real time, the ODD field memory 4A is used for encoding and the EVEN field memory 12A is used for compounding to enable the above operation.

Example 3. The configuration of the third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram showing the configuration of the third embodiment of the present invention. The image input terminal 1 to the A / D converter 3, the encoder 5 to the decoder 11, and the D / A converter 13 to the image. The output terminal 15 is similar to that of the above-mentioned conventional device.

In FIG. 4, 17 is the image input unit 2 and A.
A selector connected to the / D converter 3 and 4A is a selector 1
7 and an ODD field memory connected to the decoder 11. 12A is a decoder 11 and a selector 1
Reference numeral 7 is an EVEN field memory, and reference numeral 19 is a selector connected to the image output unit 14, the ODD field memory 4A and the E field memory 12A. Further, 16A is a system control unit that controls each unit.

In the third embodiment, the encoder / decoder 18 shown in FIG. 1 is separated into an encoder 5 and a decoder 11. By configuring the apparatus as in the third embodiment, it is possible to increase the image frame rate (the rate of how many images can be transmitted per second) during bidirectional image communication, and a more real-time image can be obtained. It is possible to approach.

Example 4. The configuration of the fourth embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram showing the configuration of Embodiment 4 of the present invention, which corresponds to a personal computer, a workstation, etc., and the image input terminal 1
-A / D converter 3, ODD field memory 4A, encoder 5, code data buffer 6, decoded data buffer 1
0, decoder 11, EVEN field memory 12A,
The D / A converter 13 to the image output terminal 15, the system controller 16A, the selector 17 and the selector 19 are the same as those in the third embodiment.

In FIG. 5, 20 is a storage control unit connected to the code data buffer 6 and the decoded data buffer 10, and 21 is a storage unit connected to the storage control unit 20.

In the fourth embodiment, the encoder / decoder 18 shown in FIG. 3 is separated into an encoder 5 and a decoder 11. By configuring the apparatus as in the fourth embodiment, it is possible to increase the image frame rate during image storage (rate of how many images can be stored per second), and bring the image closer to a real-time image. Is possible.

[0054]

The image encoding according to claim 1 of the present invention
As described above, the decoding device inputs the image data and digitally samples the image input means, the first field memory for storing the digitally converted image data, and the encoded digital image data. Image encoding means for converting the received data, image decoding means for inputting and decoding the received data, second field memory for storing the decoded received data, and analog conversion of the stored received data Since the first and second field memories are composed of one frame memory, the number of memories can be significantly reduced, and a memory control circuit is also provided. There is an effect that it is possible to realize a small size and a low price, such as a large reduction.

As described above, the image coding / decoding apparatus according to the second aspect of the present invention is such that the image input means for inputting the image data and digitally sampling the image data, and the first image storing means for accumulating the digitally converted image data. 1 field memory, image coding means for coding the accumulated digital image data, image decoding means for inputting and decoding the received data, and second for accumulating the decoded received data Field memory, image output means for converting the stored received data into an analog signal and outputting the image data. When bidirectional image transmission is performed, the image input means and the first field memory are connected to each other, and When two field memories are connected to the image output means and high-resolution image transmission is performed, the image input means and the first and second image input means are connected.
And a switching means for connecting the first and second field memories to the image output means, and the first and second field memories are connected to each other.
Since it is composed of one frame memory, bidirectional image communication and unidirectional high resolution image communication can be realized, and it is possible to achieve miniaturization and cost reduction. .

As described above, the image coding / decoding apparatus according to the third aspect of the present invention includes the image input means for inputting the image data and digitally sampling the image data, and the first image storing means for accumulating the digitally converted image data. 1 field memory, image coding means for coding the accumulated digital image data, image decoding means for inputting and decoding the received data, and second for accumulating the decoded received data Field memory, image output means for converting the stored received data into an analog signal and outputting it, and image quality setting means for independently setting the image quality of the data stored in the first and second field memories. Comprises the first
Since the second field memory is composed of one frame memory, the number of memories can be significantly reduced, and the memory control circuit can be significantly reduced. There is an effect that can be realized. Further, there is an effect that the transmission image quality and the reception image quality can be set independently.

As described above, the image coding / decoding device according to the fourth aspect of the present invention is such that the image input means for inputting the image data and digitally sampling the image data, and the first image storing means for accumulating the digitally converted image data. 1 field memory, encoding the accumulated digital image data,
Image code decoding means for inputting and decoding received data and performing the encoding and decoding in time division, a second field memory for storing the decoded received data, and the stored received data Image conversion means for analog-converting and outputting, and since the first and second field memories are composed of one frame memory,
The number of memories can be significantly reduced, and the number of memory control circuits can also be significantly reduced. Therefore, it is possible to achieve miniaturization and cost reduction. Further, there is an effect that it is possible to perform an operation as if bidirectional image communication is performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a timing chart showing the operation of the first embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a second embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a third embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a fourth embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a conventional image encoding / decoding device.

[Explanation of symbols]

 1 Image Input Terminal 2 Image Input Section 3 A / D Converter 4A ODD Field Memory 5 Encoder 6 Code Data Buffer 7 Transmission Controller 8 Transmit Data Terminal 9 Receive Data Terminal 10 Decoded Data Buffer 11 Decoder 12A EVEN Field Memory 13 D / A converter 14 Image output unit 15 Image output terminal 16A System control unit 17 Selector 18 Encoder / decoder 19 Selector 20 Storage control unit 21 Storage unit

Claims (4)

[Claims] 1. An image input unit for inputting image data to digitally sample, a first field memory for storing the digitally converted image data, an image encoding unit for encoding the stored digital image data, An image decoding means for inputting and decoding the received data, a second field memory for accumulating the decoded received data,
And an image output unit for converting the accumulated received data into an analog signal and outputting the converted data, wherein the first and second field memories are composed of one frame memory. apparatus. 2. An image input means for inputting image data to digitally sample, a first field memory for storing the digitally converted image data, an image encoding means for encoding the stored digital image data, An image decoding means for inputting and decoding the received data, a second field memory for accumulating the decoded received data,
An image output unit for converting the stored received data into an analog signal and outputting it, and, in the case of performing bidirectional image transmission, the image input unit and the first field memory are connected to each other, and the second field memory is connected. When the image output means is connected to perform high-resolution image transmission, the image input means is connected to the first and second field memories, and the first and second field memories and the image are connected. An image encoding / decoding device comprising switching means for connecting to output means, wherein the first and second field memories are composed of one frame memory. 3. Image input means for inputting image data to digitally sample, first field memory for storing the digitally converted image data, image encoding means for encoding the stored digital image data, An image decoding means for inputting and decoding the received data, a second field memory for accumulating the decoded received data,
Image output means for converting the accumulated received data into analog data and outputting it, and image quality setting means for independently setting the image quality of the data accumulated in the first and second field memories are provided. An image encoding / decoding device in which the second field memory is composed of one frame memory. 4. An image input unit for inputting image data and digitally sampling it, a first field memory for storing the digitally converted image data, encoding the stored digital image data, and inputting received data. Image decoding means for performing time-divisional encoding and decoding, a second field memory for accumulating the decoded reception data, and an analog conversion of the accumulated reception data for output. An image encoding / decoding device, comprising: an image output unit for performing the operation, wherein the first and second field memories are composed of one frame memory.