DD284324A5 - TRANSFER PROCEDURE AND RECIPIENT FOR A TRANSMISSION PROCEDURE - Google Patents

Abstract

The invention relates to a UEbertragungsverfahren and a receiver for a UEbertragungsverfahren for a temporally and locally high-resolution image signal. Such a signal is divided into two signal components with respect to band-limited transmission channels, which are transmitted via two separate channels. In this case, the first signal component represents a standard TV signal and the second component a locally high-resolution image signal. As the second signal component, a signal with the same high local resolution as the input signal is transmitted. The temporal resolution is reduced. The invention is applicable to a compatible television broadcasting system for an HDTV signal. bandlimited transmission channels; two signal components; two separate channels; compatible television transmission system; HDTV signal}

Description

Transmission method and receiver for a transmission method

Field of application of the invention

The invention relates to a transmission method for a temporally and spatially high-resolution image and a receiver for the transmission method.

Characteristic of the known state of the art

In the proceedings of the HDTV Colloquium 1987, Ottawa, 04.-08.10.1987 is by William E. Glenn and Karen G. Glenn of the Hew York Institute of Technology under "Improved HDTV with Compatible Transmission" on pages 4,5 »1 -4.5.12 a transmission system has been proposed, which allows both the reception of a high-definition television signal, hereinafter called HDTV signal, as well as a standard television signal, hereinafter referred to as standard TV signal. For this purpose, a HDTV signal supplied by a source is split by means of a digital signal processor by a two-dimensional local filtering in such a way that a standard TV signal and a signal which delivers the high local frequency components of the HDTV signal result as a result,

These two signals are transmitted separately via two separate band-limited channels, one channel transmitting the standard TV signal and the second channel acting as a supplemental channel transmitting the high local frequency components of the HDTV signal.

On the side of the receiver, the standard TV signal can then be received by means of a standard TV receiver.

A suitable HDTV receiver is capable of reconstructing and reproducing the image provided by the source by outputting the signals of both channels.

From the information of the additional channel alone can be reconciled and reproduce no spatially high-resolution image.

Aim of the invention

The aim of the invention is to avoid overages in the prior art.

Explanation of the essence of the invention

The invention has for its object to provide a transmission method and a receiver for the transmission method for a high-definition television signal, which allows for existing band limited transmission channels on the receiver side, the reconstruction of image information even at -4npfang only one channel.

According to the invention the object is achieved in that a second transmission channel transmits a locally high-resolution, temporally low-resolution image signal.

Another feature is that the second transmission channel transmits at most each image 2n-1 of the temporally and spatially high-resolution image signal, and that the image signal of the second transmission channel encodes for data reduction

and is transmitted ·

Another Kerkmal is characterized in that information about the coding type is transmitted and · a motion vector is detected and transmitted.

Ss is advantageous in that additional information is transmitted in the second transmission channel, which contains information about the first transmission channel.

A receiver for a transmission method is characterized in that the receiver includes a transcoder with a deinterlacer, which generates an image without interlacing to increase the picture format of a standard TV signal by field-dependent line transfer and interpolation.

In another embodiment, the transcoder includes a vertical transcoder filter and / or a horizontal transcoder filter for sample rate conversion. In addition, the receiver includes an HD decoder which decodes the received signals, performs a block reconstruction according to the received encoding mode, and supplies the information on motion vectors to an image regeneration circuit.

In accordance with another embodiment, the image regeneration circuit generates an image signal having an increased frame rate by means of decoded coder mode information and / or data of the motion vectors.

To generate an image 2n, the image 2n-1 or 2n + 1 shifted by half the motion vector is used in blocks.

In order to generate an image 2n, the images 2n-1 and 2n + 1, which are shifted in opposite directions by half the motion vector, are interpolated pixel by pixel.

According to another embodiment, to generate an image 2n in an intraframe coding of a block of the images 2n-1 or 2n + 1, a point-by-point averaging of the block of the image 2n-1 is performed with the corresponding local Зіоск of the image 2n + 1.

The receiver is further characterized as including a spatio-temporal filter and in that the spatio-temporal filter includes a summer whose β'άϊΐββ are connected to the outputs of the image regeneration circuit and the transcoder. The output of the summer is fed to a weighting circuit. Moreover, a multiplier is connected to the output signals of the transcoder and a weighting circuit and a multiplier to the output signals of the HD decoder and the weighting circuit. The outputs of the multipliers are connected via an adder.

Another feature of the receiver is that in order to avoid motion defects and to take over the local resolution of the HDTV signal pixel by pixel, the absolute gray value differences of the image 2n block by block over a window and from the weighting factor (a) of each pixel of the image 2n determined becomes.

According to another embodiment, the non-interlaced image generated from the standard TV signal is weighted by the weighting factor (a) and the 1n weighted image 2n.

factor (1-a) multiplied by pixels.

Ss is advantageous in that the weighting factor (a) = 1 when the weighted sum of the absolute gray value differences is above a threshold.

Below this threshold, the weighting factor (a) increases in proportion to the weighted sum of the absolute gray value differences.

According to another embodiment, to determine the weighting factor (a) additional data is extracted from the HD decoder, in particular via the transmission mode, the quantization status and / or motion information.

According to the invention, an evaluation circuit is provided for the additional information, which automatically connects the first transmission channel when the second transmission channel is received

 The ünpfanger contains two receiving devices.

On the transmitter side, an HDTV signal with high spatial and temporal resolution is split into two signals. The first signal has a low local but high temporal resolution and can be converted into a standard TV signal, e.g. As PAL, Secam, UTSC or D2-KAC or digitally with or without data reduction, implemented and transmitted over a first band-limited channel.

The second signal has a high local but low temporal resolution. This can be z. B, by omitting

Images, preferably every other image. By a corresponding coder, it may, for. B. converted into an HD-MAC signal or directly digitally transmitted with or without data reduction over a second band-limited channel.

With the help of the first channel, a complete local time and high-yellowed image signal can be received on the receiver side.

Compared to the prior art, a complete picture signal which is temporally low-resolution and locally high-resolution can be received via the second channel, from which an adequate locally high-resolution picture signal, referred to below as the HD signal, can be reconstructed by suitable decoding and image regeneration measures.

The Regeneratxonsmaßnahmen serve to reconstruct the information lost by the receiver side by omitting images, especially in moving sequences, largely st st »

In order to regenerate a complete HDTV signal, both channels must be evaluated on the receiver side. For this purpose, the temporally high-resolution image information of the first channel is used in particular for motion defects in the reconstruction of the HD image.

The signal of the second channel is added information via the corresponding first channel. This information can be evaluated on receipt of the second channel by the receiver to the effect that this is

automatically enables the reception of the first channel.

Advantageously, therefore, in the transmission method according to the invention, the introduction of an HDTV transmission method compatible with the conventional transmission method results, wherein the first channel provides an image signal with a resolution corresponding to today's television standard and the second channel delivers a complete image signal of high spatial resolution.

embodiments

Sin embodiment will be explained below with reference to the drawing in detail

 Ss show:

Pig. 1: 2 channel HDTV transmission system;

Fig. 2: a transcoder in the transmitter (encoder);

Pig. 3: a transcoder in the receiver (decoder);

4: an HD encoder (in the transmitter);

Fig. 5: an HD decoder (in the receiver);

6 shows an image regenerator;

Pig. Fig. 7: an example of the puncturing manner of an image regenerator;

Pig. 8: a local-temporal filter.

Fig. 1 shows a 2-channel HDTV transmission system. One of

a source-generated HDTV signal is a first transmission path consisting of a transcoder 1, a TV encoder 2, a TV decoder 3 and a transcoder 4, and a second transmission path, consisting of an image suppression circuit 5, an HD encoder 6, an HD decoder 7 and an image regeneration circuit 8 supplied.

The transcoder 1 of the first transmission link reduces the horizontal resolution of the picture by 2: 1 and the vertical resolution by 3i2 by means of appropriate filtering. In addition, the non-interlaced HDTV signal is converted into a Zsilensprungetes signal, the zeitlicne resolution is maintained. The output signal of the transcoder 1 is fed to the TV encoder 2, which generates a standard TV signal, for example in PAL, Secam, NTSC or D2-MAC, and whose output is connected to a first transmission channel. However, if the output signal of the transcoder z. B. stored on a digital recorder, it is either directly or via a data reduction means on the first transmission, i. Given a recording channel.

In the receiver of the first transmission channel, the incoming standard TV signal in the TV decoder 3 is decoded. At the output of the TV decoder 3 then the standard TV signal is reproduced.

The HDTV signal supplied to the second link is subjected to an omission of pictures to match a band-limited second transmission channel. only every second image transmitted. It is conceivable for signals with static image content, the suppression of more than

only every second image, so that the then released channel capacity for the encoding and transmission of the remaining images is available. The output signal of the image suppression circuit 5 passes through the HD encoder 6 to a second transmission channel. The HD encoder generates either an analog signal, eg. As HD-KAG, or a digital signal that is transmitted directly or after data reduction over the channel.

In the receiver of the second transmission channel, the incoming signal is supplied to the HD decoder 7. The output of the HD decoder 7 is connected to the image regeneration circuit 8 which, by utilizing a motion estimation by block comparison, performs a reconstruction of the images dropped out on the receiver side. At the output of bilcregenerationsschaltung 8 is then an HD signal with high spatial resolution and a frame rate of z. B. 50 Hz reproducible, but with possible errors in the moving image content.

In order to minimize these errors in the area of moving picture parts and thus to achieve the high temporal resolution of the input HDTV signal, an inversion of the sampling rate conversion of the transcoder 1 is carried out by means of the transcoder 4 from the standard TV signal. Both signals, that of the transcoder 4 and the 3ildregenerationsschaltung 8, are fed to a combination filter 9, which provides by appropriate Y / ichtung an HDTV output signal from high temporal and spatial resolution.

Fig. 2 describes the transcoder 1 in the transmitter. The incoming HDTV signal is fed to a horizontal transcoder filter 9.

A basic procedure for this is used in stalking,? .j Bierling, K: "Changing the sampling rate of video signals by rational factors", Proc, EUSIPCO ^f 83, Signal Processing II: Theories and Applications, EURASIP 1983, pp. 171-174. Thereafter, the signal passes through a vertical transcoder filter 10 which lowers the vertical sampling rate by 3: 2. The output signal then passes through a vertical low pass followed by an interleaver 11 which performs a 2: 1 subfield dependent vertical sub-scan to produce an interlaced image signal.

If the HDTV signal at the input of the transcoder 1 z _o B. 1440 * 864 active pixels per image with a refresh rate of 50 Hz and progressive scan of 1: 1, the image format in the following stages is reduced «

1. 720 * 864, 50 Hz, 1: 1

2. 720 * 576, 50 Hz, 1: 1

3. 720 * 576, 50 Hz, 2: 1

Fig. 3 shows the transcoder 4 in the receiver. The incoming standard TV signal, in the form of digital samples, is supplied to a deinterlacer 12, which by image frame-dependent line transfer and interpolation of the interstitial lines from a picture signal in the format 720 * 576, 50 Hz, 2: 1 an image signal in the format 720 * 576 , 50 Hz, 1: 1, this signal is fed to a vertical transcoder filter 13, which regenerates by vertical sampling rate conversion by 2: 3 a signal in the format 720 * 864, 50 Hz, 1: 1. Kittel's subsequent horizontal transcoder filter 14 with a horizontal sample rate conversion of 1: £ arises

The HDTV signal in its format comparable signal with 1440 * 864, 50 Hz, 1: 1.

4 shows the HD encoder 6. The HDTV input signal passing through the image suppression circuit 5 is supplied to both a mode selection circuit 23 and a block search circuit 31

In the mode selection circuit 23, either an intra or intraframe mode is selected by comparing the input signal with the output of the block search circuit 31 for encoding the input signal. The coding is done e.g. uniform for a block containing 8 * 8 pixels. For example, if the deviations of the current BiM to the previous image are large, then intraframe encoding is performed. In the other case, interframe coding is used for data reduction. In interframe mode, the image signal is predicted along determined motion vectors, and the difference signal is passed between the original and prediction signals. In intraframe mode, the input signal itself is forwarded. The block search circuit determines a motion vector for each current block. The motion vector can z. B. from the minimum sum of the absolute values of the differences, the minimum sum of the alternating energy or minimum variance are determined.

Subsequent to the mode selection circuit ü3, the signal is supplied to a discrete cosine transformer 24. Its output is sorted in a sorter (scanner) 25 and then supplied to a weighting circuit 26 and a quantizer 27. The output of the quantizer 27 is both a coder 28 and for reconstruction

the image signal is supplied via an inverse weighting circuit 36, an inverse sampler 35 and an inverse discrete cosine transformer 34 to a block reconstruction circuit 33 whose output is connected to an image memory 32.

The coder 28 receives as input quantized weighted transform coefficients in order determined by the sampling. Sr performs variable length coding for data reduction and provides coded coefficients and addresses as output. This is fed to a video multiplexer and buffer memory 29 _o

The data stored in the image memory 32 are data of the previous picture its _β v / required ground in order to determine a motion information for a current block. This is a z. B. 8 * 8 pixels comprehensive block of the current image in a z. 3. 16 * 16 pixel search range of the previous image varies in position within the 16 * 16 block using so-called block matching until a position of the current block is found in the previous block where the smallest deviations are detected As a result, a vector which is supplied to the mode selection circuit 23 and a coder 30 is detected. This coder З0 also carries out a variable-length coding and forwards the coded motion vector for temporary storage "in addition to the corresponding signal data to the video multiplexer and buffer memory 29. For controlling the quantization, the buffer memory 29 is connected to the quantizer 27.

The result of the InOd us selection is supplied to the video multiplexer and buffer memory 29 and for correct block reconstruction of the 31ockrekonstruktionsschaltung 33.

The output signal of the buffer memory 29 is fed to the second transmission channel at a constant data rate »

Fig. 5 shows the HD decoder 7 with a buffer memory and video demultiplexer 15. »Each output of the buffer memory leads to a decoder 16 or 21. An output of the decoder 16 leads via an inverse weight 17» an inverse scanner 18 and an inverse discrete The output of the block reconstruction circuit 20 leads to the image regeneration circuit 8 as well as to an image or block memory 22. The output of the decoder 21 with the decoded motion vectors also leads to another input of the biodiode er Blockspeicxiers 22nd

In decoder 16, the addresses and coefficients are decoded back to their original form. The same goes through the decoder 21 for the motion vectors.

From the buffer memory 15, an information line 54 leads to the block reconstruction circuit 20 with the information as to whether the block has been coded in interframe or intraframe mode. A further line 56 leads from the buffer memory 15 to the decoder 16, which transmits buffer status and information about the quantizer status.

Pig. 6 represents the image regeneration circuit 8. The output signal of the HD decoder 7 is sent to an image memory 38.

guided. An output of the image memory 38 leads to an image interpolation circuit 37, another output to an image memory 39 and a multiplexer 40 ".

Other inputs of the image interpolation circuit 37 carry more data from the HD decoder 7, z. B. the motion vectors 53 and the encoder mode information 54 »so information about inter- or intraframe coding. An output of the image interpolation circuit 37 leads to the Lultiplexer 40 »At the output of the Lultiplexers 40 is an HD signal with 1440 * 864 pixels, 50 Hz, 1: 1 can be tapped, hereinafter called HDTV-TV signal.

The operation of the image regenerator 8, Pig. 6 is illustrated in FIG. 7 with reference to a one-dimensional example.

Each image 2n + 1 output from the HD decoder is stored in the image memory 38 of the image regenerator, and the previously transmitted image 2n-1 is held in the image memory 39. The intermediate picture 2n has been left out from the picture suppressing circuit 5 on the transmitting side.

An input carries the output signal 46 of the image memory 39 with the image information 49 and 50. The second input carries the output signal 48 of the image memory 38. The output signal -47 with the image information 51 is supplied to the multiplexer 40 ,

If block 52 of the image currently being processed has been transmitted via the channel in intraframe mode, block 51 of the intermediate image is transmitted via the channel.

2n from image 2n-1 and image 2n + 1 determined directly on a block basis by point-by-point averaging of the image contents. This is not shown in Fig. 7.

If, on the other hand, an interframe coding is present, then the 3-motion vector 53 of the block 52 is known from the HD decoder. For block 51 of the image to be interpolated, the block 50 of the image 2n-1 (46) offset by half the motion vector 54 is adopted.

Furthermore, the image 2n can be generated by pixel-wise interpolation of the images 2n-1 and 2n + 1 shifted in opposite directions by half the motion vector.

FIG. 8 shows the spatial-temporal filter 9. The TV image produced by the transcoder 4, which is temporally high-resolution, spatially interpolated and thus corresponding to the format of the HDTV image, is fed to a summer 41. The output of the Bildregenerationsshalt 8 is also supplied to the summer 41. The summer 41 determines the sum of the absolute gray value differences of the two differently regenerated image signals via a pointwise via a η * η window. The sum forms a value Z per window size Ώ. * n.

From the value Z, factors for weighting the TV and HD image signals are determined in the circuit 43. Thus, the TV signal in a multiplier 42 is multiplied by a, the HD signal in an ILU multiplier 44 by 1-a. Depending on the fourth Z , the weighting factor a can assume a value between 0 and 1.

If the value Z is large, d. H. it is in the image regenerator 8, Fig. 6, by large movements to faulty interpolation

results, the factor a = 1 and thus the image information of the TV signal is adopted. If, on the other hand, the value Z is very small, that is to say, if there is static picture content, then the data is taken from the HD signal, since this represents the original locally high resolution from source to sink

The multiplication results of the multipliers are supplied to a summer 45 whose output signal corresponds to the original HDTV signal.

The HD images transmitted in the second transmission channel are applied directly to the output of the combination filter 9, corresponding to a = 0 for the entire image.

The image regeneration process is performed by receiver-side evaluation of both channels. For this purpose, the images generated by the above image regeneration methods are combined as follows. The differences between the transcoded time-resolved, locally interpolated HDTV-TV signal, which corresponds in format to the HDTV image, and the HDTV-HD image produced by image interpolation are calculated point by point. n-window, the sum of the absolute gray value differences of the two differently regenerated image signals determined and weighted. The weighting determines a factor a in the range of 0 to 1. The HDTV-TV and HDTV-HD image signals are linked to the weighting factor a as follows: the HDTV-TV signal is multiplied by the factor a, the HDTV-HD signal by the factor 1-a.

Is it due to the image regeneration of the HDTV-HD signal

large movements have come to faulty interpolation results, then the factor a = 1 and thus the picture information of the HDTV-TV signal is adopted. If the value is very small, d. h., z. 3. static image content, the data will be taken from the HDTV-HD signal as it represents the original high resolution from source to sink.

According to the invention, the weighting factor a is set to 1 if the weighted sum of the absolute gray values exceeds a threshold value that is smaller than 1. 3is to this threshold value, the value of the weighting factor increases proportionally from 0 to 1.

In addition, the weighted addition of the two channels can be evaluated by evaluated HD decoder information, i. Information about the transfer mode, the quantization status or the movement of the block, improve.

Claims (20)

Pat claims 1. A transmission method for a temporally and spatially high-resolution image signal of high bandwidth for transmission over zv / ei transmission channels of lower bandwidth, wherein a first transmission channel image signals of a first ITorm low local resolution transmits, characterized in that a second transmission channel a spatially high-resolution, temporally low-resolution image signal transfers. 2. Transmission method according to claim 1, characterized in that the second transmission channel transmits at most each image 2n-1 of the temporally and spatially high-resolution image signal. 3. Transmission method according to claim 2, characterized in that the image signal of the second transmission channel is coded and transmitted for data reduction. 4. Transmission method according to claim 3, characterized in that information about the coding is transmitted and a motion vector is detected and transmitted. 5. Transmission method according to claim 1, characterized in that an additional information is transmitted in the second transmission channel containing information about the first transmission channel. 6 jümpf anger for a transmission method, characterized in that the receiver has a transcoder (4) with a Deinterlacer (12), which generates a non-interlaced image to increase the picture format of a standard TV signal by sub-picture-dependent line transfer and interpolation. 7. Receiver according to claim 6, dadurcn characterized in that the transcoder (4) contains a vertical i'transcoderfilter (13) and / or a horizontal transcoder filter (14) for sampling rate conversion. A receiver according to claim 6 or 7, characterized in that the receiver includes an HD decoder (7) which decodes the received signals, performs a block reconstruction according to the received coding mode and the information on motion vectors of an image regeneration circuit. (8j 37). 9. A receiver according to claim 8, characterized in that the image regeneration circuit (8; 37) generates an image signal with an increased frame rate by means of decoded coder mode information (54) and / or data of the motion vectors (53). 10. A receiver according to claim 9, characterized in that for generating an image 2n block by half the motion vector shifted image 2n-1 or 2n + 1 was used. 11. A receiver according to claim 9, characterized in that for generating an image 2n by the half of the motion vector oppositely shifted images 2n-1 and 2n + 1 are pixel-wise interpolated. 12. Receiver according to claim 9 ,. characterized in that in order to generate an image 2n in an intraframe coding of a block of the images 2n-1 or 2n + 1, a point-by-point averaging of the block of the image 2n-1 with the corresponding local block of the image 2n + 1 is performed. 13. A receiver according to claim 7 and / or 8, characterized in that the receiver includes a spatiotemporal PiI ter (9) that the spatio-temporal filter (9) includes a summer (41) whose inputs to the outputs the image regeneration circuit (8) and the transcoder (4) are connected such that the output signal (Z) of the summer (41) is supplied to a weighting circuit (43), that a multiplier (42) is connected to the output signals of the transcoder (4) and the Weighting circuit (43) and a multiplier (44) with the output signals of the HD decoder (7) and the weighting circuit (43) is connected, and the outputs of the multipliers (42; 44) via an adder (45) are connected. 14. A receiver according to claim 13, characterized in that to avoid motion defects and to take over the local resolution of the HDTV signal pixel by pixel the absolute gray value differences of the image 2n block by block over a window are summed and from the weighting factor (a) of each pixel of the image 2n is determined. 15. A receiver according to claim 14, characterized in that the image generated from the standard TV signal without line -A- jump with the weighting factor (a) pixel by pixel and the image 2n multiplied by 1-weighting factor (1-a) pixel by pixel. 16. A receiver according to claim 15, characterized in that the weighting factor (a) = 1, when the weighted sum of the absolute gray value differences is above a threshold. 17. A receiver according to claim 16, characterized in that below this threshold the weighting factor (a) increases in proportion to the weighted sum of the absolute gray value differences. 18. A receiver according to claim 14, characterized in that to determine the weighting factor (a) additional data from the HD decoder (7) are pulled out, in particular via the transmission mode, the quantization status and / or motion information. 19 receiver according to claim 6, characterized in that an evaluation circuit for the additional information is present, which automatically connects the first transmission channel upon receipt of the second transmission channel. 20. A receiver according to claim 19, characterized in that the receiver contains two receiving devices » For this 4 pages drawings