JPH11252567A - Coder for image signal, its method, decoder for image signal and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration in the image quality resulting from misusing a motion vector in the case that decoding is applied to an image signal subjected to high efficiency compression coding by using motion compensation prediction and signal processing using a motion vector is applied to the image signal subjected to decoding. SOLUTION: The device is provided with a coding means 12 that applies coding using motion compensation prediction to an image signal, an information generating means 13 that generates information denoting reliability of a motion vector used for the motion compensation prediction by the coding means 12, and a multiplexer means 14 that multiplexes the information denoting the reliability of the motion vector generated by the information generating means 13 onto the image signal coded by the coding means 12. Since the information denoting the reliability of the motion vector used for the motion compensation prediction is multiplexed on the image signal subjected to high efficiency coding processing by using the motion compensation prediction according to the configuration, deterioration in the image quality due to misuse of the motion vector is prevented when signal processing using the motion vector is applied to the image signal decode-processed by a decoder side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image signal encoding apparatus and method for performing a high-efficiency compression encoding process on a digitized image signal using motion compensation prediction, and a high-efficiency compression encoding process. TECHNICAL FIELD The present invention relates to an image signal decoding apparatus and method for performing a decoding process on an image signal subjected to a decoding process, and in particular, to an improvement of a device which performs signal processing using a motion vector on the decoded image signal. About.

[0002]

2. Description of the Related Art As is well known, in various media systems which digitize an image signal and send it to a transmission system or record it on a recording medium, the image signal is transmitted or recorded. In order to reduce the information amount of the image signal, band compression processing is performed on the image signal. At present, various standards of the high-efficiency compression coding method have been proposed as the band compression processing technology so that the original image signal can be faithfully reproduced without deterioration as much as possible.

[0003] For example, in a storage media system, MPE is used as a method for performing high-efficiency compression encoding processing on a moving image signal.
The G (Moving Picture Image Coding Experts Group) standard is widely adopted. According to the MPEG standard, a motion-compensated predictive encoding process for reducing the redundancy in the time axis direction of an image signal and an orthogonal transform encoding process for reducing the redundancy in the spatial axis direction of the image signal are performed. A combined high efficiency compression coding scheme is used.

That is, according to the high-efficiency compression coding method based on the MPEG standard, based on a motion vector of an object detected by comparing the preceding and succeeding frames,
A prediction signal is generated by motion-compensating the image signal of the previous frame, and a difference between the prediction signal and the image signal of the current frame is generated as a prediction error signal. Then, by encoding a transform coefficient obtained by orthogonally transforming the prediction error signal,
An encoding process with high compression efficiency can be realized.

[0005] On the other hand, image signals subjected to the high-efficiency compression encoding process as described above are generally interlaced scans. Therefore, simply performing the decoding process simply results in interlacing such as line flicker and pairing. The image quality is degraded due to the interference. For this reason, conventionally, on the decoding side, a signal of a scanning line missing in interlaced scanning is generated by interpolation processing to convert the signal into a non-interlaced scanning image signal.

By the way, when the interlaced scanning image signal subjected to the high-efficiency compression encoding process as described above is subjected to scanning line conversion processing on the decoding side into a non-interlaced scanning image signal, the interpolation signal is converted to a non-interlaced scanning image signal. To generate
Motion-adaptive signal processing for changing characteristics according to the motion of an image is required. Therefore, conventionally, for performing scanning line conversion processing for motion compensation, for example, Japanese Patent Application Laid-Open No. 8-46929 is used.
An encoding / decoding system such as that disclosed in Japanese Patent Laid-Open Publication No. H10-21064 has been considered.

The encoding / decoding system performs signal processing for extracting a motion vector in a form suitable for scan line conversion processing for motion compensation on the encoding side, and performs decoding on the decoding side for the decoded motion vector. , A signal processing for selecting a motion vector in a form suitable for the scan line conversion processing of the motion compensation is performed, and the scan line conversion processing of the motion compensation is performed using the selected motion vector, thereby achieving high-definition and high-definition. To reproduce the best images.

[0008]

However, in the conventional image signal encoding / decoding system as described above, the motion vector included in the encoded stream does not always correspond exactly to the motion of the image. Not necessarily. Therefore, if the decoded motion vector is simply considered to be correct and the decoding side actively uses the motion vector to perform the scan line conversion process, an erroneous interpolation signal is generated and the image quality is degraded. The problem arises.

That is, there is no requirement that the motion vector be accurate, and in most cases, the motion vector is not generated by following the movement of the moving object itself, and the position of the similar object between the preceding and following frames is determined. It is just searching and generating. For this reason, a motion vector that is not actually suitable for the motion-compensated scanning line conversion processing is often erroneously detected on the decoding side as a motion vector suitable for the motion-compensated scanning line conversion processing, and the Deterioration will occur.

Further, in the above description of the related art, when performing a scan line conversion process using a motion vector, an incorrect interpolation signal is generated if the motion vector is inaccurate, thereby deteriorating the image quality. However, this is not limited to only the scan line conversion processing. For example, in signal processing such as frame number conversion processing using motion vectors or three-dimensional noise reduction processing, if the motion vector is inaccurate, the Of course, degradation occurs.

Therefore, the present invention has been made in view of the above circumstances, and when performing high-efficiency compression encoding processing on an image signal using motion compensation prediction, the image signal decoded on the decoding side is used. It is an object of the present invention to provide a very good image signal encoding apparatus and method capable of preventing image quality deterioration due to erroneous use of a motion vector when performing signal processing using a motion vector. .

Further, the present invention decodes an image signal that has been subjected to a high-efficiency compression encoding process using motion compensation prediction, and performs signal processing using a motion vector on the decoded image signal. It is therefore an object of the present invention to provide a very good image signal decoding apparatus and method capable of preventing image quality deterioration due to erroneous use of a motion vector.

[0013]

According to the present invention, there is provided an image signal encoding apparatus for performing an encoding process on an image signal using motion compensation prediction, and an encoding apparatus for performing motion compensation prediction in the encoding means. Information generating means for generating information indicating the reliability of the motion vector, and multiplexing means for multiplexing the information indicating the reliability of the motion vector generated by the information generating means into an image signal coded by the coding means. Is provided.

[0014] Further, according to the image signal encoding method of the present invention, information representing the reliability of a motion vector used for motion compensation prediction is added to an image signal that has been subjected to high-efficiency encoding processing using motion compensation prediction. It is intended to be multiplexed.

According to the above configuration and method, information representing the reliability of the motion vector used for the motion compensation prediction is multiplexed on the image signal that has been subjected to the high efficiency coding processing using the motion compensation prediction. With this configuration, when signal processing using a motion vector is performed on an image signal decoded on the decoding side, it is possible to prevent deterioration in image quality due to erroneous use of a motion vector.

Further, the image signal decoding apparatus according to the present invention provides an image signal which has been subjected to encoding processing using motion compensation prediction, by adding information representing the reliability of the motion vector used for motion compensation prediction to the encoded image signal. Separating the coded image signal and the information indicating the reliability of the motion vector from the image signal obtained by multiplexing the coded image signal and the decoding means for performing a decoding process on the coded image signal separated by the separating means. Signal processing is performed on the image signal decoded by the decoding means using a motion vector included in the encoded image signal and information indicating the reliability of the motion vector separated by the separation means. And a signal processing means for applying.

Further, according to the picture signal decoding method of the present invention, the coded picture signal which has been subjected to the coding processing using the motion compensation prediction is provided with information indicating the reliability of the motion vector used for the motion compensation prediction. Is separated from the coded image signal and information representing the reliability of the motion vector from the multiplexed image signal, and is included in the coded image signal in an image signal obtained by performing a decoding process on the coded image signal. Signal processing is performed using a motion vector and information indicating the reliability of the motion vector.

According to the above configuration and method, the encoded image signal and the information indicating the reliability of the motion vector are separated from the input image signal, and the encoded image signal is subjected to a decoding process. Since the image signal is subjected to signal processing using the motion vector included in the encoded image signal and information indicating the reliability of the motion vector, signal processing using the motion vector is performed on the decoded image signal. , It is possible to prevent the image quality from deteriorating due to erroneous use of the motion vector.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a transmission system for digitized image signals will be described below in detail with reference to the drawings. In FIG. 1, reference numeral 11 denotes an encoding device to which a digitized image signal is supplied. The image signal supplied to the encoding device 11 is supplied to an encoding circuit 12, and subjected to a high-efficiency compression encoding process that combines a motion compensation prediction encoding process and an orthogonal transform encoding process.

The encoding device 11 has a motion vector related information generating circuit 13. The motion vector related information generation circuit 13 monitors how the encoding circuit 12 has performed the high-efficiency compression encoding process on the image signal, and checks the reliability of the motion vector used in the motion compensation prediction encoding process. Generates information representing degrees.

The image signal output from the encoding circuit 12 and subjected to the high-efficiency compression encoding process, and the information indicating the reliability of the motion vector output from the motion vector related information generating circuit 13 include: The signal is supplied to the multiplexing circuit 14 and multiplexed.

The multiplexing circuit 14 is provided with the encoding circuit 1
2 is a video packet, and the information representing the reliability of the motion vector output from the motion vector related information generating circuit 13 is a private packet. It is multiplexed as an MPEG TS (Transport Stream) as shown and output to the transmission path 15.

Here, the motion vector related information generating circuit 13 includes, for example, a first mode in which the motion detecting process is executed with high accuracy and a second mode in which the motion detecting process is simplified and executed with low accuracy in the encoding circuit 12, for example. When the first mode is selected, the reliability of the motion vector is set to a high level. For example, when the motion vector is represented by 8 bits, the level is set to "255". Is selected, the reliability of the motion vector is low. For example, information set to a level of "0" when represented by 8 bits is repeatedly multiplexed as a private packet in the TS. In this case, the information indicating the reliability of the motion vector can be changed in the middle as needed, regardless of the mode.

The encoding method of the encoding circuit 12 is MP
In the case of EG, if a TC (Time Code) included in a GOP (Group of Picture) header is referred to as a setting range of the information indicating the reliability of the motion vector, the motion vector in frame units is obtained. Can be set. At this time, in addition to referring to TC, TR (Temporal Referral) included in the picture header is used.
ence), the reliability can be expressed with higher accuracy.

Further, by setting a slice number (position) as a setting range of information representing the reliability of a motion vector, the reliability of a motion vector can be set in units of slices. By setting, for example, when coding processing is performed using motion compensation prediction, it is possible to set the reliability of a motion vector in macroblock units according to the magnitude of the prediction error. By doing so, for example, even if the prediction error is small due to the limitation of the code amount despite the large prediction error value, on the decoding side,
In fact, it can be seen that the prediction error was large.

As described above, the information representing the reliability of the motion vector is multiplexed into the image signal by the encoding device 11, and the data stream sent to the transmission line 15 is supplied to the decoding device 16. The data stream supplied to the decoding device 16 is supplied to a separation circuit 17,
Video packets and private packets are separated based on the PID (Program Identifier).

The image signal transmitted as a video packet is supplied to a decoding circuit 18 and subjected to a decoding process, whereby the image signal is decoded into an original image signal and output to a signal processing circuit 19. . At this time, the decoding circuit 18
Outputs the motion vector included in the input video packet to the signal processing circuit 19. Information indicating the reliability of the motion vector transmitted as the private packet is supplied to the signal processing circuit 19.

The signal processing circuit 19 uses the motion vector supplied from the decoding circuit 18 for the interlaced scanning image signal supplied from the decoding circuit 18 so as to become a non-interlaced scanning image signal. Is subjected to a scanning line conversion process, and is output as a decoded image signal. In this case, the signal processing circuit 19 determines whether to use the motion vector supplied from the decoding circuit 18 for the scan line conversion process based on the information indicating the reliability of the motion vector supplied from the separation circuit 17. Is defined.

That is, in the signal processing circuit 19, in addition to the motion vector, TC,
The TR included in the picture header, the slice number included in the slice header, and the like are received at the same time.
7, the reliability of the motion vector is determined from a predetermined threshold value by referring to the reliability of the motion vector for each of the setting ranges separated in step 7, ie, for the entire stream, frame, slice, and macroblock. Is high, the scan line conversion process is performed using the motion vector supplied from the decoding circuit 18, and if the reliability of the motion vector is lower than a preset threshold, the decoding circuit The scan line conversion process is performed by a method that does not use the motion vector supplied from.

According to the above-described embodiment, in the encoding device 11, information indicating the reliability of the motion vector used in the motion compensation prediction encoding process is added to the image signal subjected to the high efficiency compression encoding process. Is multiplexed and transmitted, and the decoding device 16 determines whether or not to use a motion vector based on information indicating the reliability of the motion vector when performing a scan line conversion process on the decoded image signal. Since the determination is made, it is possible to prevent the image quality from being deteriorated due to erroneous use of the motion vector.

In the above embodiment, the signal processing circuit 19 performs the scanning line conversion processing using the motion vector. However, the signal processing by the signal processing circuit 19 includes the scanning line conversion processing. The present invention is not limited to this, and signal processing such as frame number conversion processing or three-dimensional noise reduction processing using a motion vector may be used.

Further, in the above embodiment, whether to use a motion vector for signal processing is determined based on information indicating the reliability of the motion vector. However, the present invention is not limited to this. It is a matter of course that information indicating the reliability of the motion vector may be used in order to determine the mixture ratio between the image signal processed using the image signal and the image signal processed without using the motion vector. . It should be noted that the present invention is not limited to the above-described embodiment, and can be variously modified and implemented without departing from the scope of the invention.

[0033]

As described in detail above, according to the present invention,
When performing high-efficiency compression encoding using motion compensation prediction on an image signal, when the signal processing using a motion vector is performed on the image signal decoded on the decoding side, the motion vector is incorrectly used. It is possible to provide a very good image signal encoding apparatus and method capable of preventing image quality deterioration due to image quality.

Further, according to the present invention, a video signal subjected to a high-efficiency compression coding process using motion compensation prediction is decoded, and a signal processing using a motion vector is performed on the decoded video signal. , It is possible to provide a very good image signal decoding apparatus and method capable of preventing image quality deterioration due to erroneous use of a motion vector.

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining an embodiment of an image signal encoding apparatus and method and an image signal decoding apparatus and method according to the present invention;

FIG. 2 is an exemplary view for explaining a data structure according to the embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Encoding device, 12 ... Encoding circuit, 13 ... Motion vector related information generation circuit, 14 ... Multiplexing circuit, 15 ... Transmission line, 16 ... Decoding device, 17 ... Demultiplexing circuit, 18 ... Decoding circuit, 19 ... Signal processing circuit.

Claims (7)

[Claims] An encoding means for performing an encoding process on an image signal using motion compensation prediction, and an information generation means for generating information indicating the reliability of a motion vector used for the motion compensation prediction in the encoding means. And multiplexing means for multiplexing information representing the reliability of the motion vector generated by the information generating means onto the image signal encoded by the encoding means. Encoding device. 2. The encoding unit is switchable between a mode in which the motion detection processing of the image signal is performed with a first accuracy and a mode in which the motion detection process is performed with a second accuracy lower than the first accuracy. The information generating unit sets the reliability of the motion vector to a first level in a state where the encoding unit is switched to a mode in which the motion detection process of the image signal is performed with a first accuracy; Setting the reliability of the motion vector to a second level lower than the first level in a state where the encoding unit is switched to a mode in which the motion detection processing of the image signal is performed with the second accuracy. The image signal encoding apparatus according to claim 1, wherein: 3. The image signal according to claim 1, wherein the information generation unit sets the reliability of the motion vector to a lower level as the prediction error in the motion compensation prediction of the encoding unit increases. Encoding device. 4. An image signal obtained by multiplexing information representing the reliability of a motion vector used in the motion compensation prediction with an image signal that has been subjected to high-efficiency encoding processing using motion compensation prediction. Encoding method. 5. An image signal obtained by multiplexing information representing the reliability of a motion vector used for the motion compensation prediction on an encoded image signal that has been subjected to encoding processing using motion compensation prediction, and Separating means for separating a coded image signal and information indicating the reliability of the motion vector, decoding means for performing a decoding process on the coded image signal separated by the separating means, and decoding by the decoding means The processed image signal, a motion vector included in the encoded image signal,
An image signal decoding device, comprising: signal processing means for performing signal processing using information indicating the reliability of the motion vector separated by the separation means. 6. The image processing apparatus according to claim 1, wherein the signal processing unit includes, when the reliability of the motion vector is at the first level, the image signal decoded by the decoding unit and included in the encoded image signal. Performing signal processing using a motion vector, and when the reliability of the motion vector is at a second level lower than the first level, the image signal subjected to the decoding process by the decoding unit is The image signal decoding apparatus according to claim 5, wherein the signal processing is performed without using a motion vector included in the encoded image signal. 7. An image signal obtained by multiplexing information representing the reliability of a motion vector used in the motion compensation prediction onto an encoded image signal that has been subjected to encoding processing using motion compensation prediction, and The encoded image signal and the information indicating the reliability of the motion vector, the image signal obtained by performing a decoding process on the encoded image signal, the motion vector included in the encoded image signal, the motion vector Signal processing using information representing the reliability of the image signal.