JPH0431477B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a television signal receiving device that has been subjected to band compression processing, and more specifically, it reduces the signal bandwidth by interframe sub-Nyquist sampling and improves image quality. This invention relates to a television signal receiving device in which the amount of movement between fields or frames is transmitted as a motion vector signal together with the image signal, and in addition, a subsample phase control signal corresponding to the motion vector signal is transmitted together with the image signal. It is.

Conventional Structure and Problems When transmitting a wideband image signal such as a high-definition television signal, a method has been proposed in which the signal bandwidth is reduced by sub-Nyquist sampling. This method is called a motion-compensated multiple sub-Nyquist sampling transmission method, and the sampling phase is offset between fields and frames, and the image signal is transmitted by performing processing such that the sampling phase goes around in four fields. Basically, the receiving side is equipped with a frame memory to store the transmitted image signal, and the signals of four fields transmitted sequentially are combined to create a single television image. However, in televisions that perform 2:1 interlaced scanning, the above-mentioned interframe offset subsampling processing and signal restoration processing are the basis of signal processing for each field. The method of transmitting image signals by performing inter-field and inter-frame offset subsampling processing does not cause any problems for signals such as still images, but for images with movement, it may cause problems on the receiving side. If the past pixel signals stored in the frame memory are used as they are, the combined image will become multiple images and the image quality will deteriorate significantly. On the receiving side, the position of the pixel signal one frame before is shifted using a motion vector signal and a sub-sample phase control signal to perform position correction on the past pixel signal, and then combined with the image of the current field. Occurrence of multiple images,
Alternatively, deterioration of resolution in moving images is prevented. Even if this motion vector signal, sub-sampled phase control signal, etc. are transmitted in the form of a code that allows error correction on the receiving side, the error correction ability of the error correction code may be affected by, for example, noise mixed in in the middle of the transmission path. Errors in excess of It is possible that the data may be missing. Therefore, on the receiving side, it is necessary to restore the motion vector signal and sub-sample phase control signal by some method in the event of signal loss or uncorrectable errors.

Conventional examples related to the present invention will be described below with reference to the drawings.

FIG. 2 shows an example of a device for restoring a sub-sampled phase control signal when errors cannot be corrected.

An error detection/correction circuit 1 supplies an error correction code including a motion vector signal and a sub-sample phase control signal to a signal input terminal _T11 , and corrects a correctable erroneous signal and detects the occurrence of an uncorrectable error. When the error detection signal output from the conductor 10 is determined to be non-error, the decoded motion vector signal output from the conductor 11 is sent via the switch 3 controlled by the control circuit 2. memory 4
The motion vector signal stored in the signal output terminal _T12 is simultaneously transmitted to the signal output terminal T12, and the motion vector signal is sequentially transmitted for each field. storing the decoded sub-sampled phase control signal output from the conductor 11 in the memory 6;
At the same time, it is operated to use a sub-sample phase control signal sent to the signal output terminal _T13 and sequentially transmitted for each field. On the other hand, if the error detection signal outputted from the conductor 10 is determined to be an uncorrectable error, the switch 3 is switched to the opposite side from when the error detection signal is determined to be non-error, and the signal is stored in the memory 4. The motion vector signal of one field before is selected again as the input signal of the memory 4, and simultaneously sent to the signal output terminal _T12 , and the error detection signal is also sent to the switch 5, which is controlled at the same time as the switch 3, to ensure that there is no error. If it is determined that
select the sub-sampled phase control signal of the previous frame stored in as the input signal of the memory 6 again,
At the same time, it is sent to the signal output terminal _T13 .

In conventional devices, the motion vector signal is zero, that is, in the case of a still image, and in the case of a moving image with complex movements other than the regulated movements of the camera, such as panning or tilting, the motion vector signal of the previous field and the inverted signal are used. There is no practical problem in substituting the sub-sampled phase control signal of the previous frame for the signal necessary for the current field, but for an image with motion that looks like it is actually being panned at a specific speed, When the moving speed is 4n + 2 times the sub-sampling interval, sub-sampling the point on the previous field and offset sub-sampling the point on the current field will synchronize the relationship between the moving speed and the offset, and therefore the sub-sampling interval will be Since the sample phase is the same in the two fields, there is a problem in that even if image signals subsampled over four fields are combined, one complete image cannot be obtained.

OBJECT OF THE INVENTION The present invention solves the above-mentioned problems of the conventional apparatus. Among the control signals included in the television signal and transmitted for each field, the sub-sampled phase control signal cannot be corrected by an error detection circuit. An object of the present invention is to provide a device that can accurately restore a sub-sample phase control signal by restoring the sub-sample phase control signal using a motion vector signal transmitted in the immediately previous field when it is determined that purpose.

According to the present invention, the amount of motion between frames or fields of an image is used as a motion vector signal, and the sub-Nyquist sampling phase on the transmitting side is used as a sub-sample phase control signal, and these signals are converted into a predetermined error correction code. When receiving a television signal that is transmitted to the receiving side along with an image signal in the form of a video signal, an error detection means detects whether or not the above-mentioned error correction code is erroneous, and performs motion vector signal and subsample phase control. a first one for delaying each of the signals by at least one field period;
and a second delay means, which inverts the signal polarity of the delayed sub-sampled phase control signal, which is the output signal of the second delay means, and further delays the signal by one field period; a first signal selection means for selecting one of the respective signals outputted by the second and third delay means; and a sub-sample phase control which is an output of the first signal selection means and an input signal of the second delay means. and a second signal selection means for selecting one of them by receiving each of the signals as input, and when the error detection means cannot correct an error, the signal outputted by this means is used to select the second signal. The selection means controls to select the output of the first signal selection means from the two inputs, and the first signal selection means selects the output of the first signal selection means according to the amount of motion of the image represented by the motion vector signal which is the output of the first delay means. and is controlled to select one of the outputs of the second and third delay means, and is configured to obtain a sub-sampled phase control signal from the output of the second signal selection means.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of a sub-sample phase control signal processing device based on the present invention.
In the figure, an error correction code including a motion vector signal and a subsample phase control signal is input to the signal input terminal.
When the error detection signal supplied from the conductor ₂₀ is determined to be non-error after being processed by the error detection/correction circuit 12 that corrects correctable signals and detects the occurrence of uncorrectable errors. control circuit 1
The switch 14 controlled by 3 is set to the a side,
The decoded motion vector signal supplied from the conductor 21 is stored in the memory 15, and at the same time the signal output terminal
The switch ₁₆ , which is controlled by the control circuit 13 at the same time as the switch 14, is also set to the a side, and the motion vector signal that is sent from the conductor 21 is set to the a side. The decoded sub-sample phase control signal is stored in the memory 17, and is simultaneously sent to the signal output terminal _T23 to operate so as to use the sub-sample phase control signal that is sequentially transmitted in each field. On the other hand, if the error detection signal supplied from the aforementioned conductor 20 is determined to be an uncorrectable error, the control circuit 13 causes the switch 14 to be switched to the switch b opposite to the case where the error detection signal is determined to be a non-error. The motion vector signal stored in the memory 15 one field before is selected again as the input signal of the memory 15, and simultaneously sent to the output terminal _T22 , and the control circuit 13 described above switches the motion vector signal to the switch 1.
For the switch 16 controlled at the same time as 4, the error detection signal is determined to be non-error.
Switch to the side. On the b side of the switch 16, a sub-sample phase control signal of one field before the field, which is the output of the memory 17 mentioned above, is connected to the field through an inverter 18 and a memory 23 for delaying the field by one field. On the other hand, one of the sub-sampled phase control signals of the previous frame is selected by the switch 22 and supplied. This switch 22 is controlled by a motion amount determining circuit 19 for determining the amount of motion of an image by inputting a motion vector signal outputted from the memory 15 mentioned above. For example, when the motion vector signal is zero, the motion amount determination circuit 19 controls the switch 22 to select the signal on the a side, and supplies the output signal from the memory 23, that is, one frame before the field in question. The sub-sampled phase control signal whose signal polarity has been inverted is supplied to the b-side terminal of the switch 16. In this case, if the control circuit 13 is supplied with an uncorrectable error detection signal via the conductor 20, the control circuit 13 controls the switches 14 and 16 to select the b side, and therefore the signal output terminal At _T23 , the sub-sampled phase control signal of one frame before the field is sent out with its signal polarity inverted. This state is maintained as long as the error correction code supplied to the signal input terminal T ₂₁ generates an uncorrectable error, and therefore the signal output terminal T ₂₃ receives one frame, that is, two frames.
A subsample phase control signal that is inverted for each field is sent out. On the other hand, if the motion vector signal is not zero, the motion amount determination circuit 19
The switch 22 is controlled depending on whether the sum of the amount of motion in the horizontal direction and the vertical direction is an even number or an odd number based on the motion vector signal from one field before supplied by the switch 22. memory 17
The output signal of the memory 23 to be supplied to the b side is selected so that the output signal of the memory 23 is selected, and if the number is even, the output signal of the memory 23 is selected to be supplied to the a side. This means that if the sum of the amounts of motion in the horizontal and vertical directions is an even number, the subsample phase control signal may be alternated every frame, just as in the case where the motion vector signal is zero; , is an odd number, it is necessary that the sub-sample phase control signal does not change, unlike the above-mentioned one, and for this reason, in the present invention, the motion vector signal of one field before is used for the field concerned. to switch between them. Specifically, the above-mentioned motion amount determination circuit 19 performs exclusive OR processing of the lowest bits of each of the horizontal motion vector signal and the vertical motion vector signal, and if the output is "0", it is an even number, and if the output is "1", it is an even number. If so, a circuit configuration that determines that the number is odd may be used.

In the above description, the memory 15 is used to delay one field period, but this memory is arranged in a plurality of fields, and the switch 22 is controlled by determining the amount of motion from the motion vector signals of the plurality of fields. You may.

Effects of the Invention The subsample phase control signal processing device according to the present invention is a device that performs restoration processing using at least the motion vector signal of the immediately previous field when it is determined that the subsample phase control signal cannot be error corrected. Even in the case where the sampling timing and the movement of the subject are synchronized, which is difficult to solve with the apparatus, the sub-sampled phase control signal can be successfully restored, and the practical effect is great.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a sub-sample phase control signal processing device according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional device. 12...Error detection/correction circuit, 13...Control circuit, 14, 16, 22...Switch, 15, 1
7, 23...Memory, 18...Inverter.

Claims (1)

[Claims] 1. Processing of a television signal in which a predetermined control signal including at least a motion vector signal between frames or fields of an image and a sub-sample phase control signal is time-division multiplexed during the blanking period. The apparatus includes an error detection means for receiving the control signal as an input and detecting an error thereof, and a second error detection means for receiving each of the motion vector signal and the sub-sampled phase control signal and delaying the signal by at least one field period. a third delay means configured to delay the output signal of the second delay means by one field period, invert the signal polarity, and send it out; the second delay means and the third delay means; a first signal selection means for receiving the respective output signals of the sub-sampled phase control signal as an input and selecting one of the signals; and a second signal selection means for receiving the first signal selection means and the sub-sampled phase control signal as inputs and selecting one of the signals. and the second signal selection means is controlled to select the output of the first signal selection means by the signal output from the error detection means when the error detection means cannot correct an error; The signal selection means selects one of the second and third delay means depending on the amount of motion of the image represented by the motion vector signal output from the first delay means, and A sub-sample phase control signal processing device characterized in that the sub-sample phase control signal is used as a sub-sample phase control signal. 2. If the motion vector signal includes a horizontal motion vector signal and a vertical motion vector signal, and the sum of these horizontal and vertical motion vector signals is an odd number, the first signal selection means selects the second delay means. A sub-sample phase control signal processing device according to claim 1, characterized in that: