JPH10164572A - Dynamic image encoder and decoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dynamic image encoder and decoder, capable of adjusting an image in an arbitrary area desired to be noticed to be a high quality image, from a remote place. SOLUTION: Relating to a moving image decoder 2, qualutcture guilty adjusting information is inputted to a picture quality adjusting information input circuit 22 from outside, the information is transmitted to a moving image encoder through a multiple separation circuit 20. A memory control circuit 13 receiving this information through the multiple separation circuit 15 of the encoder 1 writes the information in a eqidere guilty adjusting memory 12. An encoding control circuit 11 reads the information from the memory 12 and controls a moving image encoding circuit 10 to improve the picture sgfe of a block shown by the information at the time of encoding the moving image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving picture coding apparatus and a decoding apparatus, and more particularly to a moving picture coding apparatus and a decoding apparatus used for a video conference terminal or a remote picture monitoring apparatus.

[0002]

2. Description of the Related Art A conventional moving picture coding apparatus employs, for example, an ITU-T Recommendation H.264 as a moving picture coding algorithm capable of transmitting at a fixed bit rate. 261 is used. This method uses motion compensation interframe coding, DCT (Discrete Cosine Tran).
It has a buffer memory that performs image compression by transform coding, quantization, and variable-length coding, smoothes the generated image information, and transmits it at a constant bit rate. That is, when transmitting at a fixed bit rate, it is necessary to control the amount of generated image information corresponding to the rate in order to prevent the buffer memory from becoming excessive or insufficient.

The amount of generated information of an image after variable-length encoding dynamically changes depending on the degree of movement of the image and the picture. When this image data is transmitted through a transmission path having a constant bit rate, it is necessary to temporarily store the image data in a buffer memory for smoothing, read out the data at a constant speed, and flow the transmission data through the transmission path. The amount of image data stored in the buffer memory is hereinafter referred to as a buffer occupancy.

[0004] It is possible to reduce the amount of generated information by increasing the image coding parameter P, and to increase the amount of generated information by reducing the image coding parameter P.

Therefore, when the buffer occupancy is large, the parameter P is increased, and conversely, when the buffer occupancy is small, the parameter P is decreased to control the buffer occupancy so that the buffer occupancy does not exceed or underflow. .

[0006] Generally, the quality of a moving image is evaluated by parameters of image quality and image smoothness of each image having a trade-off relationship with each other. That is, if the image quality of each image is improved, smoothness is lacking, and if the motion is smoothly controlled, the image of each image is degraded.

Therefore, this type of encoding apparatus is intended to maintain a constant ratio between the two parameters and to automatically realize uniform moving picture quality for any input picture.

However, depending on the moving image, a function for improving image quality for a specific image area may be required.

A technique for achieving this object is disclosed in Japanese Unexamined Patent Publication No.
No. 53567 (hereinafter referred to as Prior Art 1) and Japanese Patent Application Laid-Open No. 5-95541 (hereinafter referred to as Prior Art 2).

FIG. 3 is a configuration diagram of the prior art 1. This prior art 1 includes a time axis filter 101 and a spatial filter 10.
2, an encoder 103, a face area detecting unit 104, a moving area detecting unit 105, an inverter 106, and an AND circuit 1
07.

According to this circuit, a moving image input from the input terminal 108 is encoded by the encoder 103 via the time axis filter 101 and the spatial filter 102, and is output from the output terminal 109 to the outside.

Further, at the time of encoding, if the input moving image is a face area, the output of the face area detection unit 104 becomes high level, so that both the outputs of the inverter 106 and the AND circuit 107 become low level. Time axis filter 101
And the spatial filter 102 is also turned off. Therefore, in this case, the face area is clearly displayed.

On the other hand, when the input moving image is a moving area other than the face area (for example, in the case of a person's body), the outputs of the inverter 106 and the AND circuit 107 are both at a high level. Both 101 and the spatial filter 102 are turned on. Therefore, in this case, the moving area portion is displayed with noise, minute movement, and fine patterns cut out.

When the input moving image is neither a face area nor a moving area (for example, in the case of a background), the output of the inverter 106 is at a high level and the output of the AND circuit 107 is at a low level. Only the time axis filter 101 is turned on. Therefore, in this case, this area is displayed with noise and minute movement cut off.

FIG. 4 is a configuration diagram of the prior art 2. This prior art 2 includes a moving image encoding unit 111 and a transmission buffer unit 1
12, a video decoding unit 113, a display unit 114, an object tracking unit 115, a quantization control unit 116, and a coordinate detection unit 117.

According to this circuit, the coordinate detecting section 117 has a sensor disposed on the video monitor of the display section 114, and senses the position of the target object by pointing it on the video monitor, Output as coordinate information 118.

The coordinate information 118 is input to the object tracking unit 115, and the object tracking unit 115 cuts out the area of the target object at the same position from the coordinate information 118 and the input video signal 119. Follow
The corrected coordinate information of the tracked target object area is output, and the quantization control unit 116 calculates the quantization step size from the corrected coordinate information from the object tracking unit 115 and the remaining amount of data in the transmission buffer 112. Then, by giving a small quantization step to the region of the target object that has been focused and tracked, the distortion of the image of the region of the tracked target object can be reduced and the image can be improved.

[0018]

However, these prior arts 1 and 2 are techniques for improving image quality limited to a predetermined point of interest, such as a face area or a moving object, in which parameters are changed. There was a disadvantage that it could not be done.

For example, when the apparatus is used for remotely monitoring a dangerous place, an arbitrary area to be focused on is specified remotely, high-quality coding is performed only on a specified specific image area, and other areas are specified. Regions may need to be transmitted with low quality coding.

SUMMARY OF THE INVENTION An object of the present invention is to provide a moving picture coding apparatus and a decoding apparatus capable of remotely adjusting an image in an arbitrary area of interest to high quality.

[0021]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an encoding means for encoding a moving image according to its motion, and a code obtained by the encoding means at a constant speed. Selection means for selecting the code for transmission, transmission means for transmitting the code extracted by the selection means to the video decoding device, and image quality adjustment information transmitted from the video decoding device Image quality adjustment information receiving means for receiving the image quality adjustment information, and image quality adjustment means for changing the code selection ratio of the specific image area based on the image quality adjustment information obtained by the image quality adjustment information reception means. An image encoding device is configured.

Another aspect of the present invention is a moving picture code receiving means for receiving a moving picture code transmitted from a moving picture coding apparatus, and a decoding means for decoding a code obtained by the moving picture code receiving means. Means, image quality adjustment information input means for externally inputting image quality adjustment information for increasing the code amount of a specific image area of a moving image decoded by the decoding means, and image quality input to the image quality adjustment information input means A moving picture decoding apparatus including image quality adjustment information transmitting means for transmitting adjustment information to the moving picture coding apparatus.

According to the present invention, based on the image quality adjustment information transmitted from the moving picture decoding apparatus, the image quality adjusting means changes the code selection ratio of the specific image area to the selection means. That is, the image quality adjusting means controls the selection means so as to increase the amount of codes to be taken in the specific image area. Then, the moving image code whose image quality has been adjusted by the image quality adjusting means is transmitted by the transmitting means.

According to another aspect of the present invention, when the moving picture decoding apparatus receives the moving picture code transmitted from the moving picture coding apparatus by the receiving means, the moving picture decoding apparatus decodes the moving picture code by the decoding means. . Then, the image quality adjustment information input means externally inputs image quality adjustment information for increasing the code amount of a specific image area of the decoded moving image, and the image quality adjustment information transmitting means sends the image quality adjustment information to the moving image encoding apparatus. Send.

[0025]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a configuration diagram of a preferred embodiment of a moving picture encoding device and a decoding device according to the present invention.

The moving picture coding apparatus and the decoding apparatus according to the present invention are provided with a moving picture coding apparatus 1 for inputting a moving picture 51 and performing high-efficiency coding, and transmitted from the moving picture coding apparatus 1. A moving image decoding device 2 that receives the highly efficient encoded data 61 and reproduces the moving image.

The moving picture coding apparatus 1 comprises a moving picture coding circuit 10 for performing high efficiency coding of a moving picture, and a coding control circuit 1 for giving coding parameters to the moving picture coding circuit 10.
1, an image adjustment memory 12 for storing information of an area for improving image quality and a degree of image quality, a memory control circuit 13 for performing image quality parameter writing control on the image adjustment memory 12,
A buffer memory 14 for temporarily storing encoded moving images for smoothing and transmitting at a constant bit rate the highly efficient encoded data generated in the moving image encoding circuit 10, and a high efficiency code from the buffer memory 14. And a demultiplexing circuit 15 for multiplexing the coded data and separating the image quality adjustment information (dp) 52 from the transmission signal 57 transmitted from the opposing video decoding device 2.

Next, the operation of the moving picture coding apparatus 1 will be described. The video encoding circuit 10 is, for example, an ITU-T
Recommendation H. 261 is a circuit that implements high-efficiency coding except for redundancy in the space domain and the time domain by the motion compensation / interframe coding method specified in H.261, and performs orthogonal transform (DCT) and quantization on the motion compensation interframe difference signal. And performs variable-length coding.

This moving picture coding circuit 10 is, for example, 8 ×
The image is decomposed into small blocks of 8 pixels, and high-efficiency encoding processing such as orthogonal transformation and quantization is performed for each small block.

The output 53 of the moving picture coding circuit 10 is input to the demultiplexing circuit 15 as data 54 at a constant bit rate after being smoothed in the buffer memory 14.

The encoding control circuit 11 includes a buffer memory 14
The encoding parameter (P) 56 is obtained from the buffer occupancy 55 obtained from
Is output to the moving picture coding circuit 10.

The coding parameter (P) 56 serves as information for controlling the quantization characteristics of the moving picture coding circuit 10.
That is, when the encoding parameter (P) 56 is a large value, coarse quantization is performed, and the image quality of each image is deteriorated, but the motion is smooth. On the other hand, when the encoding parameter (P) 56 is small, the control for fine quantization is performed, and the image quality of each image is improved, but the image lacks smooth motion.

The encoding control circuit 11 keeps the relationship between these two parameters at a constant ratio so as to automatically realize uniform moving picture quality for any input picture.

The value of the encoding parameter (P) 56 is determined by the degree of image movement and the type of picture.

The operation up to this point is the same as in the prior art. The present invention is characterized by having an image quality adjustment memory 12 and a memory control circuit 13 for controlling the encoding control circuit 11 to adjust the image quality.

Next, the operation of the image quality adjustment memory 12 and the memory control circuit 13 will be described.

The demultiplexing circuit 15 separates the image quality adjustment information (dp) 52 from the transmission signal 57 from the video decoding device 2, and the image quality adjustment information (dp) 52 is input to the memory control circuit 13. . The image quality adjustment information (dp) 52 includes image area information (α) specifying a specific image area and image quality adjustment value information (β) specifying an image quality adjustment value.

The memory control circuit 13 writes the image quality adjustment information (dp) 52 into the image quality adjustment memory 12.

FIG. 2 is a block (memory address) of the image quality adjustment information (dp) 52 stored in the image quality adjustment memory 12.
FIG.

The image quality adjustment memory 12 is divided into small blocks of, for example, 8 × 8 pixels, and corresponds to small blocks for which the moving picture coding circuit 10 performs coding processing. The hatched portion shown in FIG. 6 indicates the block number of the block in which the image quality adjustment information (dp) 52 is stored, that is, the high image quality setting area (α) in one moving image screen, and the image quality is set in the block. Image quality adjustment value information (β) for specifying a value is stored.

Then, the encoding control circuit 11 gives the (P-dp) parameter which becomes a high image quality control value in the high image quality setting area to the moving image encoding circuit 10, and low image quality for the other areas. A (P + dp) parameter serving as a control value is given to the moving image encoding circuit 10. Note that P and dp are positive real numbers.

That is, in the high image quality setting area, the parameter P
The image quality is improved because it is smaller by dp, and the image quality is degraded in other areas because the parameter is larger by dp than P.

On the other hand, the moving picture decoding apparatus 2 receives the high efficiency coded picture data 61 transmitted from the moving picture coding apparatus 1 and separates the data. Inverse DC is applied to the separated image data 62
A moving image decoding circuit 21 that outputs a moving image 63 reproduced by performing high-efficiency decoding such as T and inverse quantization, and image quality adjustment information that externally improves the image quality of a specific image region of the reproduced moving image 63 (Dp) 52 and an image quality adjustment information input circuit 22 for outputting the image quality adjustment information (dp) 52 to the demultiplexing circuit 20. Further, the demultiplexing circuit 20
Has a function of assembling information 57 to be transmitted to the moving picture coding apparatus 1 into a multiplexed frame and multiplexing the image quality adjustment information (dp) 52 at a predetermined bit position of the frame.

Thus, by specifying the image area to be focused on from the moving picture decoding apparatus 2 side with the picture quality adjustment information (dp) 52 and transmitting it to the moving picture coding apparatus 1, the picture of the area is provided with high image quality. Can be displayed.

[0045]

According to the present invention, encoding means for encoding a moving picture according to its motion and selection of the codes for transmitting the code obtained by the encoding means at a constant speed are selected. Selecting means for performing, transmitting means for transmitting the code extracted by the selecting means to the video decoding device, and image quality adjustment information receiving means for receiving the image quality adjustment information transmitted from the video decoding device; A video encoding apparatus including an image quality adjustment unit that changes the code selection ratio of a specific image area to the selection unit based on the image quality adjustment information obtained by the image quality adjustment information receiving unit. It is possible to transmit an image of an arbitrary area to be adjusted with high quality.

According to another aspect of the present invention, a moving picture code receiving means for receiving a moving picture code transmitted from a moving picture coding apparatus, and decoding a code obtained by the moving picture code receiving means. Decoding means, image quality adjustment information input means for externally inputting image quality adjustment information for increasing the code amount of a specific image area of a moving image decoded by the decoding means, and input to the image quality adjustment information input means. And a video decoding apparatus including image quality adjustment information transmitting means for transmitting the image quality adjustment information to the video coding apparatus, so that it is possible to remotely adjust an image of an arbitrary region of interest to high image quality. Become.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a preferred embodiment of a video encoding device and a decoding device according to the present invention.

FIG. 2 is a schematic explanatory diagram showing blocks of image quality adjustment information stored in an image quality adjustment memory of the video encoding device according to the present invention.

FIG. 3 is a configuration diagram of Prior Art 1.

FIG. 4 is a configuration diagram of prior art 2.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 moving image encoding device 2 moving image decoding device 10 moving image encoding circuit 11 encoding control circuit 12 image adjustment memory 13 memory control circuit 14 buffer memory 15, 20 demultiplexing circuit 21 moving image decoding circuit 22 image quality adjustment information Input circuit

Claims (6)

[Claims] An encoding means for encoding a moving image according to its motion, a selection means for selecting the code to transmit the code obtained by the encoding means at a constant speed, Transmitting means for transmitting the code extracted by the selecting means to the video decoding device; image quality adjustment information receiving means for receiving the image quality adjustment information transmitted from the video decoding device; A moving image encoding apparatus comprising: an image quality adjusting unit that causes the selecting unit to change a code selection ratio of a specific image area based on the image quality adjusting information obtained by the unit. 2. The sorting means according to claim 1, wherein said sorting means temporarily stores a code obtained by said encoding means, and a sorting control means which controls the sorting of said code based on the code amount stored in said storing means. 2. The moving picture coding apparatus according to claim 1, comprising: 3. The moving picture coding apparatus according to claim 2, wherein said code amount is determined by a degree of motion of the picture and a type of picture. 4. The image quality adjustment information according to claim 1, wherein the image quality adjustment information includes image area information specifying the specific image area and image quality adjustment value information specifying an image quality adjustment value. Video encoding device. 5. A moving picture code receiving means for receiving a moving picture code transmitted from a moving picture coding apparatus, a decoding means for decoding a code obtained by the moving picture code receiving means, and the decoding Image quality adjustment information input means for externally inputting image quality adjustment information for increasing the code amount of a specific image area of a moving image decoded by the means, and image quality adjustment information input to the image quality adjustment information input means A moving picture decoding apparatus, comprising: image quality adjustment information transmitting means for transmitting to a coding apparatus. 6. The moving picture decoding apparatus according to claim 5, wherein said image quality adjustment information includes image area information specifying said specific image area and image quality adjustment value information specifying an image quality adjustment value. .