JPH0779416A - Image signal transmission device - Google Patents

Abstract

(57) [Summary] [Structure] The composite color video signal VS is divided into a main image part signal series MS in the form of a component and a mask signal series YM in the upper and lower non-image area of the screen. Highly efficient coding is performed on the MS and YM with coding parameters having different characteristics, and the coded data series V
Generates 2. The system identifying section 2 identifies the NTSC system and the EDTV system based on the presence / absence of an identification control signal, and generates a control signal VMD necessary for encoding. [Effect] Both the NTSC system and the EDTV system can be coded according to the characteristics of the signal, the compression efficiency is high, and
It is possible to realize a transmission device of an image signal with little deterioration in image quality due to encoding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image signal transmitting apparatus, and more particularly to converting a composite color video signal of NTSC system or EDTV system into a signal of component form and compressing the information amount by high efficiency encoding. The present invention relates to an image signal transmission device suitable for transmission and reception.

[0002]

2. Description of the Related Art Research and development of an EDTV system, which is compatible with the current TV system, that is, the NTSC system, is being pursued to improve the image quality of TV images and widen the screen. In the EDTV system, a wide screen is realized by a letterbox system in which non-image areas are provided above and below the screen and a horizontally long image having a horizontally long aspect ratio is arranged in the main image area. Further, in the non-image area above and below the screen, vertical high-frequency components, etc., which cannot be transmitted in the main image area and which are necessary for image quality improvement, are superimposed as auxiliary signals to realize high image quality and high definition.
The EDTV system signal is composed of a composite color video signal of a composite form similar to that of the NTSC system, and achieves both transmission path compatibility and receiver compatibility.

On the other hand, in the field of image signal transmission or recording, a high-efficiency coding technique is used to compress the information amount to about several tenths, and a high quality image is obtained at a bit rate of several Mbps to several + Mbps. Devices for transmission have been put to practical use.

In these devices, redundancy in the time domain and the horizontal / vertical spatial domain is realized by a high efficiency coding technique utilizing the statistical property of the image signal, for example, interframe predictive coding, orthogonal transform coding and the like. The degree of efficiency is removed, and encoding with a high compression rate is realized. These high efficiency coding techniques
Application to material transmission using communication satellites, or material encoding in future digital broadcasting, storage media systems, etc. is under consideration.

In these high-efficiency encodings, component encoding (encoding a luminance signal and two color difference signals) is adopted. Various transmission devices for converting an NTSC composite color video signal into a component signal for encoding have been conventionally devised.

[0006]

In the above conventional device,
High-efficiency coding is performed with coding parameters based on the statistical properties of images. Therefore, it is possible to efficiently encode a signal in the main picture area of the EDTV system. On the other hand, the signals in the non-image area on the upper and lower sides of the screen have completely different characteristics from the signals in the main image area, but they are encoded with the same parameters. For this reason, there is a problem that a component important for improving the image quality is lost, and in the EDTV reproduction image, a remarkable image quality deterioration occurs due to the encoding.

An object of the present invention is NTSC system, EDTV.
An object of the present invention is to provide an image signal transmission apparatus that performs encoding with high compression efficiency on both types of composite color video signals and that the deterioration of image quality due to encoding is extremely small.

[0008]

In order to achieve the above object, the present invention provides a system identification means for determining whether the composite color video signal is of the NTSC system or the EDTV system. Also, two types of image coding means having different coding parameters or coding methods are provided. For the signals in the main picture area of the NTSC system and the EDTV system, the first image coding means, EDTV
The signals in the upper and lower non-image areas of the screen are subjected to high-efficiency coding adapted to the respective signals by the second image coding means.

[0009]

In the present invention, for the signals in the main picture area of the NTSC system and the EDTV system, that is, the image signals,
The first image coding means performs high-efficiency coding adapted to the properties of the image similar to the conventional technique. On the other hand, with respect to the signals in the upper and lower non-image areas of the screen of the EDTV system, that is, the auxiliary signal, the second image encoding means finely quantizes the component important for improving the image quality of the EDTV reproduced image. Performs high-efficiency coding suitable for the nature of the auxiliary signal. Therefore, according to the present invention, it is possible to realize a transmission apparatus that can encode both an image signal and an auxiliary signal with characteristics that match the characteristics of each signal, has high compression efficiency, and has very little deterioration in image quality due to encoding. it can.

In the present invention, the NTSC system or EDT is used.
It is necessary to identify the V system and perform encoding. However, in the EDTV system, information such as the type of auxiliary signal is added to a specific scanning line as an identification control signal. Therefore, it is possible to discriminate between the NTSC system and the EDTV system by detecting the presence or absence of the discrimination control signal. Then, encoding is performed based on this identification result, and NTSC
It is possible to realize high-efficiency coding that conforms to the characteristics of each signal in both the H.264 and EDTV systems.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to the block diagram shown in FIG. This is suitable for encoding the first and second image encoding means with encoding parameters having the same encoding method but different characteristics.

In the transmission section of FIG. 1A, the composite color video signal VS is input to the AD conversion section 1 and the system identification section 2.
The AD converter 1 samples at a frequency four times as high as the color subcarrier fsc and converts it into a digital signal. Method identification unit 2
Then, the presence or absence of the identification control signal is detected to detect the NTSC system, E
The system identification of the DTV system is performed and the system control signal VMD is generated.

The main signal preprocessing unit 3 performs YC separation and color demodulation signal processing, and a main image component signal sequence M
S (luminance signal Y, color difference signals CB, CR) is generated. The mask section signal pre-processing section 4 converts the signals of the upper and lower non-picture area of the EDTV system screen into a mask section component signal series YM (a luminance signal YM and a color difference signal are all zero signals).
Output as. The selection unit 5 selects the signal sequence MS in the NTSC system, the signal sequence YM in the non-image area above and below the screen in the EDTV system, and the signal sequence MS in the main image area to display the component image. The signal sequence VC is generated.

The encoding preprocessing unit 6 combines a field image of interlaced scanning to generate a frame image, a sub-sampling process for thinning out the sampling points of the color difference signals in half horizontally and vertically, and encoding. Performs signal processing such as image format conversion to obtain the encoded image signal V
1 is generated.

FIG. 2 shows an example of a coded image format. FIG. 10A is an explanatory diagram of an EDTV system signal, in which a horizontally long image is arranged in the main image area and upper and lower non-image area areas UM and D are arranged.
Superimpose an auxiliary signal on M. FIG. 2B shows a coded image format in which the type 1 has the same form as the EDTV system, and the types 2 and 3 perform the coding in a form in which the non-image area is integrated in the lower part or the upper part. The color difference signal in the non-image area is a signal with zero component.

In the image coding unit 7, for example, CCITT
Recommendation H. 261 or high-efficiency coding processing by video coding conforming to the moving picture coding standard MPEG for storage media is performed to generate a coded data series V2. In addition, according to the system control signal VMD, NTSC system and EDT
The main image area of the V system and the non-image area of the EDTV system are coded using coding parameters having different characteristics, and the processing equivalent to the first and second image coding means is realized. To do.

The channel coding unit 8 performs predetermined processing such as packetization for dividing data in units of several tens of bytes, addition of error correction code, digital modulation (QPSK, 16QAM, etc.), and the transmission data signal V3. To generate.

On the other hand, in the receiving section shown in FIG. 2B, the transmission data signal V3 is input to the channel decoding section 9 and subjected to a predetermined decoding process to decode the coded data series V2. The image decoding unit 10 performs signal processing opposite to the encoding, and decodes the encoded image signal V1.

The post-encoding processing unit 11 performs signal processing such as image format reverse conversion and conversion of a frame image into a field image of in-italy scanning, and decodes the component image signal series VC. In the distribution unit 12, according to the system control signal VMD, the NTSC system and the EDTV system are used.
Main image component signal sequence M in the main image area of the system
It is distributed to the mask part component signal series YM in the non-image area of the S and EDTV systems.

The main signal post-processing unit 13 multiplexes the color-modulated carrier color signal with the luminance signal to synthesize the video signal MV of the main image area.
Generate S. Further, the mask section signal post-processing section 14 reproduces the signal YM as an auxiliary signal to generate the video signal BVS in the non-picture area.

In the process unit 15, the two signals are combined and subjected to processing such as addition of predetermined synchronizing signals, identification control signals, DA conversion, etc. to decode the composite color video signal VS of NTSC system or EDTV system.

As described above, according to this embodiment, the NTSC system,
It is possible to realize an image signal transmission device that encodes any composite color video signal of the EDTV system with high compression efficiency and with very little deterioration in image quality due to encoding.

A second embodiment of the present invention will be described with reference to the block diagram shown in FIG. This is suitable for realizing the first and second image coding means by different coding methods.

In the transmission section of FIG. 1A, the composite color video signal VS is input to the AD conversion section 1 and the system identification section 2.
The AD converter 1 performs sampling at a frequency four times as high as the color subcarrier fsc and converts it into a digital signal. Also,
The system identification unit 2 detects the presence / absence of an identification control signal,
The system control signal VMD is generated by discriminating between the TSC system and the EDTV system.

The main signal preprocessing unit 3 performs YC separation and color demodulation signal processing, and a main image component signal sequence M
S (luminance signal Y, color difference signals CB, CR) is generated. Further, the mask part signal pre-processing part 4 outputs the signals of the upper and lower non-image part regions of the EDTV system screen as a mask part component signal series YM (luminance signal YM, color difference signals are all zero component signals). .

The precoding unit 6 performs signal processing such as frame composition for composing field images of interlaced scanning to generate a frame image and coded image format conversion to generate a coded image signal V1. And
In the image encoding unit 7, for example, CCITT Recommendation H.264. 26
1 or high-efficiency coding processing by video coding conforming to the moving picture coding standard MPEG for storage media, and a coded data series V by the first picture coding means.
Generates 2.

The mask signal coding preprocessing section 16 performs signal processing such as grouping of signal components of the non-picture area UM and DM at the top and bottom of the screen and conversion of coded image format to generate a coded mask signal V10. To do. The mask signal encoding unit 17 performs high efficiency encoding processing such as DPCM encoding and orthogonal transform encoding, and generates an encoded data sequence V11 by the second image encoding means.

The multiplexing unit 18 time-divisionally multiplexes the coded data series V2 and V11 by the system control signal VMD to generate the coded data series V12. Then, in the channel coding unit 8, packetization of data, addition of error correction code, digital modulation (for example, QPSK,
A predetermined signal processing such as 16QAM) is performed to generate the transmission data signal V3.

On the other hand, in the receiving section shown in FIG. 9B, the transmission data signal V3 is input to the channel decoding section 9, where it is subjected to a predetermined decoding process to decode the coded data series V12. Then, the demultiplexing unit 19 separates the coded data series V2 by the first image coding means and the coded data series V11 by the second image coding means.

The image decoding unit 10 performs a decoding process opposite to the coding process to decode the coded image signal V1. Then, the post-coding processing unit 11 performs signal processing such as image format reverse conversion and conversion of a frame image into a field image of interlaced scanning to decode the main image part component signal series MS. The main signal post-processing unit 13 multiplexes the color-modulated carrier color signal with the luminance signal to obtain NTS.
Video signal MV in the main picture area of C system and EDTV system
Generate S.

The mask signal decoding unit 20 performs a decoding process opposite to the coding, and decodes the coded mask signal V10. The mask signal coding post-processing unit 21 performs signal processing such as image format inverse conversion, and decodes the mask component signal sequence YM. Then, in the mask portion signal post-processing portion 14, the auxiliary signal is reproduced by the signal YM and the ED signal is reproduced.
The video signals BVS of the upper and lower non-image areas of the TV system are generated.

In the process section 15, the two signals are combined, a predetermined synchronizing signal and an identification control signal are added, the analog signal is converted by DA conversion, and the composite color video signal VS of NTSC system or EDTV system is decoded. To do.

As described above, according to this embodiment, the NTSC system,
It is possible to realize an image signal transmission apparatus that has high compression efficiency and has extremely little deterioration in image quality due to encoding for any EDTV-type composite color video signal.

The structures of the main block parts in these embodiments will be described below. FIG. 4 is an explanatory diagram of an embodiment of the main signal processing unit 3 and the main signal post-processing unit 13.
In the pre-processing unit of FIG. 9A, the YC separation unit 22 separates the luminance signal Y and the carrier color signal C, for example, by performing a separation process of luminance and color signals with a horizontal / vertical two-dimensional characteristic. The color demodulation unit 23 synchronously detects the carrier color signal C with the color subcarrier fsc and generates color difference signals CB and CR.

On the other hand, in the post-processing section of FIG. 7B, the color modulating section 24 quadrature-phase amplitude-modulates the color subcarrier fsc with the color difference signals CB and CR to generate the carrier color signal C. Then, the adder 25 adds the carrier color signal C to the luminance signal Y to generate the video signal MVS of the main image area.

Next, FIG. 5 shows an explanatory view of an embodiment of the mask part signal pre-processing part 4 and the mask part signal post-processing part 14. Each of them is configured by a combination of the memory unit 26, the WT control unit 27, and the RD control unit 28, and writing of signals to the memory and reading of signals are realized by controlling the WTCT and RDCT signals, respectively. That is, in the pre-processing unit, the signals UM and DM in the non-image area above and below the screen are written in the memory, and the U of the encoded image format is read from the memory.
The signal is read during the period of the M and DM regions (see FIG. 2). In the post-processing, the operation opposite to that of the pre-processing section is performed, and the ED
The video signals BVS of the upper and lower non-image areas of the TV system are generated.

Next, FIG. 6 shows a block diagram of an embodiment of the precoding unit 6 and the postcoding unit 11. In the pre-encoding unit 6 of FIG.
Then, two field images of interlaced scanning are combined to generate a frame image. Since the visual characteristic with respect to the color difference is lower than that with the luminance, the sub-sampling process is performed on the color difference signal by the sub-sampling unit 30 to thin out the number of sampling points in half in the horizontal and vertical directions. In the block data generation unit 31, for example, CCIT
Recommendation H.T. 261, Moving Picture Coding Standard M for Storage Media
Macroblock for PEG video coding (4 luminance blocks and 2 chrominance blocks, each block is 8 pixels x 8
The encoded image signal V1 is generated in units of lines.

In the post-encoding processor 11 shown in FIG. 9B, the block data distributor 32 separates the luminance block and the color difference block. In the interpolation unit 33,
Sampling point interpolation processing that doubles the number of sampling points in each vertical direction is performed. The frame distributor 34 synthesizes macroblock data to decode a frame image, decomposes it into two field images, and generates an interlaced scanning component image signal sequence VC.

Next, the image coding unit 7 and the image decoding unit 1
FIG. 7 shows an example diagram of No. 0. This is based on CCITT Recommendation H.264. 261, MPEG standard for moving picture coding for storage media
It performs high-efficiency coding in accordance with.

In the image coding unit 7 shown in FIG. 9A, the switch 37 is provided with a terminal b, a P picture, and a B picture (interframe prediction + DCT) when the coding mode is e-picture (intra-frame DCT coding). In the case of (encoding), the encoding process is performed by connecting to the terminal a.

The encoded image signal V1 is sent to the frame memory unit 3
Enter in 5. In the subtraction unit 36, the frame memory unit 35
The prediction signal PS is subtracted from the output signal of P to produce the prediction error signal PE in the coding mode of P and B pictures. DCT
The section 38 performs an operation using a discrete cosine transform matrix of 8 rows and 8 columns to generate a transform coefficient signal C2. Quantizer 3
At 9, quantization processing is performed to generate a quantized coefficient signal C3. It should be noted that the quantization is performed with different characteristics by the quantization control signal QCT so that the DC and low frequency components in the mask portion signal and the DC and low frequency components in the main image portion signal are small. The VCL unit 40 performs variable length coding and run length coding to generate a variable length code signal C4. Then, the data is written in the buffer unit 41. On the other hand, the signal is read from the buffer unit at a constant speed and the encoded data sequence V2 is generated. The coding control unit 42 creates the necessary quantization control signal QCT according to the scheme control signal VMD and the buffer capacity.

On the other hand, the quantized coefficient signal C3 is inversely quantized by the inverse quantization section 43 to decode the transformed coefficient signal. The inverse DCT unit 44 performs a matrix operation using a discrete cosine transform inverse matrix to decode the signal C1. Then, the addition unit 45 adds the output signal from the switch 37, decodes the coded image signal V1 ′, and inputs the decoded image signal V1 ′ to the frame memory unit 35. The MC prediction signal generation unit 47 performs motion compensation signal processing on the output signal of the frame memory based on the motion vector information MV extracted by the motion vector detection unit 46 to generate a prediction signal PS.

In the image decoding section 10 shown in FIG.
The encoded data sequence V2 is written in the buffer unit 41. The variable length code C4 read from the buffer unit is the inverse VC.
The L unit 48 performs a predetermined decoding process to decode the quantized coefficient signal C3. The inverse quantization unit 43 performs inverse quantization processing and decodes the transform coefficient signal C2. Inverse DCT unit 44
Then, the matrix operation by the discrete cosine transform inverse matrix is performed,
Decode the signal C1. The adding unit 45 adds the prediction signal PS to the signal C1 and decodes the coded image signal in the coding mode of P and B pictures. The switch 37 is connected to the terminals b, P and B in the e-picture coding mode, and outputs the coded image signal V1. Also, M
The C prediction signal generation unit 47 performs motion compensation signal processing on the output signal of the frame memory unit 35 based on the motion vector information MV to generate a prediction signal PS. In addition, the decoding control unit 49 uses signals (QC) necessary for decoding processing.
T, MV, VMD, etc.).

Next, FIG. 8 shows an embodiment of the channel coding unit 8 and the channel decoding unit 9. In the channel coding unit 8 shown in FIG. 4A, the coded data sequence V2 is divided by the packetization unit 50 into block data in units of several tens of bytes, for example. The FEC adding unit 51 adds an error correction code for correcting a code error generated in the transmission medium. In the modulator 52, digital modulation (for example,
QPSK, 16QAM, etc.) to generate the transmission data signal V3.

In the channel decoding section 9 shown in FIG. 9B, the demodulation section 53 performs digital demodulation processing. FEC
The correction unit 54 corrects a code error using the error correction code. Then, the depacketizing unit 55 integrates the block data and decodes the original encoded data series V2.

Next, FIG. 9 shows an embodiment of the mask signal coding unit 17 and the mask signal decoding unit 20 in the second embodiment. This is an example of orthogonal transform coding using a Hadamard transform matrix.

The mask signal encoder 17 shown in FIG.
Then, the coded mask signal V10 is input to the ADM conversion unit 56 and is calculated by a Hadamard transform matrix in units of, for example, 8 pixels to generate a transform coefficient signal C5. The quantizing unit 57 performs quantization with the characteristic that the quantization error of the DC and low frequency components is small, for example, and generates the quantization coefficient signal C6. The VLC unit 58 performs entropy coding to generate a coded data series V11.

The mask signal decoding unit 20 shown in FIG.
Then, the inverse VLC unit 59 performs decoding to the original fixed length code and decodes the quantized coefficient signal C6. Inverse quantizer 60
Then, the inverse quantization process is performed, and the inverse ADM conversion unit 61 performs an operation using the Hadamard transform inverse matrix to obtain the encoded mask signal V1.
Decode 0.

The coding can also be realized by DPCM coding, discrete cosine transform coding, or the like.

Further, FIG. 10 shows an example of an image format for encoding the signals in the non-picture area on the upper and lower sides of the screen. The encoding is performed in a form in which the signals of the upper and lower non-image area regions UM and DM are combined. In the UM and DM regions, as shown in the figure, auxiliary signals of three scanning lines are time-divisionally multiplexed for each line (for example, L1, L2, L).
3). Therefore, in the horizontal one-dimensional encoding, the encoding is performed in the image format as it is. On the other hand, in horizontal and vertical two-dimensional coding, for example, 8 pixel × 8 line orthogonal transform coding, time series conversion is performed, and the image is converted into a highly correlated image format in the vertical direction for coding. As a result,
It is possible to perform encoding with high compression efficiency of information amount.
Note that these image format conversions are performed by the mask signal coding preprocessing unit 16 and the mask signal coding postprocessing unit 21 shown in FIG.

The components other than the above-mentioned block portion can be realized in the capacitor by the conventional technique, and the description thereof will be omitted.

In the description of the embodiment, the image coding of the signal in the main picture area is CCITT Recommendation H.264. 261, the video coding of the moving picture coding standard MPEG for storage media is shown as an example. However, the present invention can be applied to various other forms of high efficiency coding.

[0053]

According to the present invention, the NTSC system and EDT are used.
It is possible to realize an image signal transmission device that has high compression efficiency for both V-type composite color video signals and has little deterioration in image quality due to encoding.

The image signal transmitting apparatus of the present invention can be applied to digital broadcasting, digital recording, etc., and can also re-record high-quality TV images by efficiently transmitting them.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram of an image format in FIG.

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

FIG. 4 is an explanatory diagram of an embodiment of a main signal pre-processing unit and a main signal post-processing unit.

FIG. 5 is an explanatory diagram of a mask section signal pre-processing section and a mask section signal post-processing section.

FIG. 6 is a block diagram of an embodiment of a precoding unit and a postcoding unit.

FIG. 7 is a block diagram of an embodiment of an image encoding unit and an image decoding unit.

FIG. 8 is an explanatory diagram of an embodiment of a channel encoding unit and a channel decoding unit.

FIG. 9 is an explanatory diagram of an embodiment of a mask signal encoding unit and a mask signal decoding unit.

FIG. 10 is an explanatory diagram of an example of an image format of a mask portion signal.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... AD conversion part, 2 ... system identification part, 3 ... main signal pre-processing part, 4 ... mask part signal pre-processing part, 5 ... selection part, 6 ... coding pre-processing part, 7 ... image coding part, 8 ... Channel coding unit, 9 ... Channel decoding unit, 10 ... Image decoding unit, 11
Encoding post-processing section, 12 ... Distributing section, 13 ... Main signal post-processing section, 14 ... Mask section signal post-processing section, 15 ... Process section.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Ishikura 1-280 Higashi Koigakubo, Kokubunji City, Tokyo Central Research Laboratory, Hitachi, Ltd. (72) Inventor Masahiro Kageyama 1-280 Higashi Koigakubo, Kokubunji City, Tokyo Hitachi Ltd. Central Research Center

Claims (6)

[Claims] 1. An image signal transmission device for highly efficiently encoding and transmitting a composite color video signal, means for identifying a method of the composite color video signal, the composite color video signal being a luminance signal and two color difference signals. A means for converting into a component image signal sequence, a first image encoding means for highly efficient encoding the component image signal sequence, and a second image encoding means are provided, and in the NTSC system composite color video signal, the first image encoding means is provided. Image encoding means, in the EDTV system composite color video signal, the main image area is encoded by the first image encoding means, and the upper and lower non-image area of the screen are encoded by the second image encoding means. An image signal transmission device, which transmits the converted image data. 2. The image coding method according to claim 1, wherein the first image coding means and the second image coding means use the same high-efficiency coding method to improve image quality with different coding characteristics. An image signal transmission device that realizes fine quantization of important components. 3. The high efficiency coding method according to claim 2,
CCITT Recommendation H. 261 is an image signal transmission apparatus which is an encoding method compliant with the H.261 video encoding or moving image encoding standard MPEG for storage media. 4. The image signal transmission device according to claim 1, wherein the first image coding means and the second image coding means are realized by different high efficiency coding systems. 5. The method according to claim 4, wherein the first image coding means is CCITT Recommendation H.264. 261 is a high-efficiency coding method conforming to the video coding or the moving picture coding standard MPEG for storage media, and the second image coding means is Hadamard transform coding, discrete cosine transform coding,
Alternatively, an image signal transmission device realized by a high-efficiency coding method by DPCM coding. 6. The image signal transmission device according to claim 1, wherein the system identification of the composite color video signal is performed by detecting the presence or absence of an identification control signal.