JPH0334790A - Television signal reproducing device - Google Patents

Abstract

PURPOSE:To eliminate a noise bar and to attain a high speed reproduction of a video image without distortion by interpolating a video image of an interpolated part of the noise bar into the normal video image reproduced precedingly and correcting the deviation of the video image of the interpolated part and the current reproduced video image with information relating to a moving vector. CONSTITUTION:When a noised bar N is generated in a reproduction signal from a magnetic head at a high speed reproduction, since a high frequency level is lowered, a dropout detection circuit 14 detects the production of dropout. When the production of the dropout is detected, the write of a reproduction signal to a field memory 15 is inhibited while the dropout takes place. Thus, as a storage signal in the field memory 15, the reproduction signal written in the preceding field is left unerased for the period of the noise bar N. A horizontal moving vector data is extracted from the video signal and since the correction is implemented based on the horizontal moving vector data, the deviation between the replaced signal for the period of noise bar N and the signal not replaced is corrected.

Description

[Detailed description of the invention] The present invention will be explained in the following order.

Industrial application field Outline of the invention Prior art Problems to be solved by the invention Means for solving the problems □ Action Example G, Structure of one example G2 Operation during high-speed playback G, Description of other examples Effect of the Invention A: Industrial Application Field The present invention relates to a television signal reproducing device suitable for, for example, a VTR (video tape recorder) that reproduces high-definition television signals.

B. Summary of the Invention The present invention provides a reproduction device that reproduces a television signal including motion vector information such as a MUSE signal (use signal), and is capable of adjusting the reproduction speed so that the noise bar does not match from field to field when performing high-speed reproduction. , the noise bar is replaced with a previously played non-noise bar signal, and at the time of this replacement, it is corrected using motion vector information, so that images without noise bars are played back without distortion during high-speed playback. This is what I did.

C. Prior Art In recent years, video signal transmission systems that display high-resolution images called high-definition have been developed. In this high-definition system, the bandwidth of the video signal is N
Since it is much wider than standard broadcasting systems such as the TSC system, it has been proposed to compress the band and transmit it using a predetermined method. As this band compression method, the MUSE method using multiple subsampling is known. When recording this high-definition video signal on a VTR, etc., the video signal (band-compressed) using the MUSE method (
By recording the MUSE signal (hereinafter referred to as MUSE signal) as it is without demodulating it, the recording band can be made relatively narrow, and there is an advantage that the configuration of the recording apparatus can be simplified.

As a VTR that records and plays back such MUSE signals, 1
It has been proposed to perform so-called segment recording in which an image of a field is formed from signals of a plurality of tracks. That is, although the IUSE signal has a narrower bandwidth than the original high-definition signal, it has a bandwidth about twice that of a conventional television signal such as the NTSC system. For this reason, the first
Two magnetic heads (2A) and (2B) each having a different azimuth angle are mounted on a rotating head drum (1) as shown in Figure I.
Therefore, when recording the MUSH signal on the magnetic tape T,
As shown in Figure 12, A azimuth magnetic head (2A)
The horizontal line signals in the upper half of the image of one field are recorded, and the signals of the horizontal lines in the lower half of the image of one field are recorded by the B azimuth magnetic head (2B). In this way, the upper half of each field is recorded on the diagonal track formed by the magnetic head (2A), and the lower half of each field is recorded on the diagonal track formed by the magnetic head (2B), dividing the field into two. It is considered that segment recording is performed to increase the recording capacity of one field and compensate for the wide signal band.

D. Problems to be Solved by the Invention In general, VTRs perform fast-forward playback, in which the magnetic tape is played back at a faster running speed than normal, or rewind playback in the opposite direction. When performing fast-forward playback or rewind playback, each magnetic head (2A) and (2B) scans tracks recorded at different azimuth angles, resulting in noise bars in the reproduced image. Band-like noise occurs. To explain the principle behind the generation of this noise bar, for example, the 8th
As shown in the figure, if we perform quadruple speed playback using a magnetic tape in which track A of A azimuth and track B of B azimuth are alternately formed, the trajectory HA of the magnetic head (2A) of A azimuth is Recorded signals can be reproduced when scanning track A with A azimuth and when the trajectory H8 of the magnetic head (2B) with B azimuth is scanning over track B with B azimuth. However, each magnetic head (2A).

When (2B) is scanning tracks with different azimuth angles, the recorded signal cannot be reproduced, and the reproduced image at this time becomes a noise bar. As can be seen from this reproduction principle, the faster the reproduction speed, the greater the number of noise bars.

In conventional VTRs for the NTSC system, etc., in order to eliminate noise bars during high-speed reproduction, for example, a so-called double-speed reproduction magnetic head (2A) with a B azimuth is installed adjacent to a magnetic head (2A) with an A azimuth. The azimuth head is used as the double azimuth head, and the reproduction signals of the two magnetic heads constituting the double azimuth head are appropriately switched at high speed to produce tracks A at both azimuth angles.

It has been attempted to make it possible to reproduce the recorded signal of B.

However, when segment recording is performed using a MUSE signal VTR as described above, the image display positions are different between track A and track B, so the noise bar portion also corresponds to the recording signal of an adjacent track of a different azimuth. If it is replaced, it will be replaced with a completely different horizontal line signal, resulting in a distorted reproduced image.

For this reason, noise bars cannot be removed using a double azimuth head in a MUSE signal VTR. For example, as shown in Japanese Patent Application Laid-open No. 142881/1981, a noise bar removal method using a video signal memory is proposed. Proposed.

This removal method writes the reproduced video signal to memory during high-speed playback, and outputs the signal read from this memory as the reproduced signal.The part of the video signal corresponding to the noise bar is stored in the memory. In this noise bar section, a noise-free signal previously written to the memory is read out. According to such a removal method, a portion that becomes a noise bar is replaced with another previously reproduced video signal, and a reproduced signal without noise bars is obtained. However, when noise bars are removed using this kind of memory, the noise bar portion is replaced with a video signal that is at least several fields earlier (corresponding to high playback speed), so objects in the displayed image may move. In such cases, there is an inconvenience that the replaced part and the part where the noise bar originally does not occur are misaligned in the image, resulting in a distorted and unsightly image.

In view of the above, an object of the present invention is to provide a playback device for playing back MUSE signals, etc., which removes noise bars and displays images without distortion when performing high-speed playback. shall be.

E. Means for Solving the Problems The television signal reproducing apparatus of the present invention, as shown in FIG. Double speed setting means (23) for setting the playback speed to a value such that the playback speed does not occur; noise bar detection means (14) for detecting the position of noise bar occurrence; 1! : interpolation means (15) for interpolating noise bars with previously reproduced television signals; detection means (18) for detecting information regarding motion vectors; and the output of this detection means (18) and a reproduction speed value. and a correction means (17) for moving the image interpolated by the interpolation means (18) based on the above.

F Function According to such a configuration, the image of the interpolated part of the noise bar is interpolated to the previously reproduced normal image, and the deviation between the image of this interpolated part and the currently reproduced image is determined by information regarding the motion vector. The image is corrected, noise bars are removed, and distortion-free video is played back at high speed.

G. Embodiment Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 7.

G. Configuration of an Embodiment In this example, an example is shown in which the MUSE signal is applied to a VTR that records it as an analog signal, and segment recording is performed by dividing the L-field video signal into two tracks each having a different recording azimuth angle. It is something. FIG. 1 shows a reproduction signal processing circuit, and (11) in the figure shows a reproduction signal input terminal from a magnetic head, and this input terminal (11)
The reproduced signal obtained is supplied to the FM demodulation circuit (12). The FM demodulation circuit (12) demodulates the reproduced video signal that has been FM modulated for recording, and supplies the demodulated signal to the analog/digital converter (13). In addition, the reproduced signal immediately before being demodulated by this FM demodulation circuit (12) is supplied to a dropout detection circuit (14), and this dropout detection circuit (14) performs high frequency envelope detection of the reproduced signal, and the envelope detection value is When is less than a predetermined value, it is detected that dropout has occurred.

Then, the digital video signal converted by the analog/digital converter (13) is supplied to the field memory (15). This field memory (15) performs time axis correction of the input video signal for use as a time base collector, and also performs video correction during high-speed playback. That is, when the dropout detection circuit (14) detects dropout of the playback signal during high-speed playback, it supplies this dropout detection signal to the field memory (15) and writes the video signal during the dropout occurrence period. be prohibited.

The output video signal of the field memory (15) is then supplied to a control code extraction circuit (16) to extract the control code included in the reproduced video signal.

In this case, since the VTR of this example reproduces the MUSE signal, the control code extraction circuit (16) extracts the horizontal motion vector data etc. weighted with the video signal of the MUSE signal by time division multiplexing, and extracts the various codes. The extracted video signal is supplied to a shift register (17). Then, among the codes extracted by the control code extraction circuit (16), horizontal motion vector data is supplied to the motion vector detection circuit (18). This horizontal motion vector data is necessary when decoding the MIISE signal band-compressed by multiple subsampling into the original high-definition video signal. This method performs corrections.

As this horizontal motion vector data, the average value of the amount of motion and the direction of movement of each pixel per frame are converted into data, and this horizontal motion vector data is detected by a motion vector detection circuit (18). The detected motion amount and direction are supplied to the arithmetic circuit (19).

Furthermore, a dropout detection signal output from the dropout detection circuit (14) is supplied to this calculation circuit (one). Furthermore, a tape speed information signal output from a central control unit (hereinafter referred to as CPU) (23) that controls tape running of the VTR is supplied to this arithmetic circuit (19). When the tape speed information supplied to this arithmetic circuit (19) indicates that high-speed playback is in progress, when the dropout detection signal is supplied, the amount of motion in the supplied horizontal motion vector data is calculated. Correction is made based on the playback speed indicated by the tape speed information. For example, 1
Let the amount of movement per frame (2 fields) be X, and correct it again.

The corrected motion amount data is then supplied to the shift register (17) as shift amount data.

Further, the direction data accompanying the motion amount data is supplied to the shift register (17) as shift direction data. When this shift amount data and shift direction data are supplied to the shift register (17), at this time the shift register (
17) Shifting the video signal supplied to 17) by the direction and amount based on the data. The video signal subjected to this shift processing is then supplied to the multiplexer (20).

This multiplexer (20) is supplied with an HD signal, which is a synchronization signal of the MUSE signal, from a synchronization signal generation circuit (not shown) via an HD signal input terminal (24), and also receives a )(D period switching signal). It is supplied via the switching signal input terminal (25).The HD signal obtained at this terminal (24) is a signal as shown in Fig. 2A, and the gray level of the video signal is the same except when a pulse of the HD signal is obtained. The HD period switching signal is a signal that remains at a high level for a predetermined period centered around the supply timing of this HD pulse.

While this HD period switching signal is at a high level, the video signal supplied to the multiplexer (20) is replaced with the HD signal obtained at the terminal (24).

This HD signal insertion is performed for each horizontal line.

The video signal (MUSE signal) output from this multiplexer (20) is then transferred to a digital/analog converter (21).
) was converted into analog MU and SE signals and converted? The IIJSE signal is supplied to the video signal output terminal (22).

When the above-mentioned CPU (23) controls the tape running for high-speed playback (fast-forward playback, 2-rewind playback), the playback speed is set to a speed that is not an integral multiple of the normal speed. In this case, the playback speed in the forward or reverse direction with [,5] added, such as 4.5x speed or 10.5x speed, is set.

G2 operation during high-speed playback Next, we will explain the operation when performing high-speed playback with this VTR. First, as mentioned above, during this high-speed playback, the C
Under the control of P U (23), the reproduction speed is set to [, 5). For example, when performing fast-forward playback at 4.5x speed, the trajectories of the two magnetic heads (see Figure 11) on the tape during playback at 4.5x speed are A as shown in Figure 3. The trajectory HAl+HAz... by the azimuth magnetic head and the trajectory H1lI+HB□... by the B azimuth magnetic head each scan 4.5 tracks. here,
In this example, since segment recording of the video signal is performed, the upper half and lower half of the field image are recorded in the recording track A based on the A azimuth and the recording trunk B based on the B azimuth, respectively. Therefore, the trajectory IA
The images reproduced by I and H□ are assumed to be odd field images, and the trajectories HAz and HB! If the image reproduced by is an even field image, the reproduced image of an odd field is
As shown in Fig. 4, in the upper half of the image, a noise bar N occurs when the locus HA scans over the recording track B with azimuth B, and in the lower half of the image, the locus H□ scans over the recording track B with azimuth A. A noise bar N occurs when scanning over A. Furthermore, in the reproduced image of an even field, as shown in FIG. 5, a noise bar N occurs in the upper half of the image when the trajectory HAz scans the recording track B of B azimuth, and in the lower half of the image, a noise bar N occurs. H1l! A noise bar N is generated when the recording track A of A azimuth is scanned.

Here, it can be seen that the horizontal line where the noise bar N in the odd field is generated is different from the horizontal line where the noise bar N is generated in the even field. In this way, by selecting a playback speed that is not an integral multiple, the location where the noise bar N occurs differs for each field.

In this example, this point is utilized to remove the noise bar. When a noise bar N occurs in the reproduction signal from the magnetic head during high-speed reproduction, the high frequency level decreases, so the dropout detection circuit ( 14) detects the occurrence of dropout. When the occurrence of this dropout is detected, writing of the reproduced signal to the field memory (15) is prohibited while the dropout is occurring.

Therefore, as the stored signal in the field memory (15), the reproduced signal written in the immediately previous field is not erased and remains as it is in the section of the noise bar N. Therefore, as the output signal of the field memory (15), the section of the noise bar N is replaced with the reproduced video signal of the immediately previous field.

In this example, since horizontal motion vector data is extracted from this video signal and correction is performed based on this horizontal motion vector data, the difference between the replaced signal and the unreplaced signal in the section of the noise bar N is is corrected.

That is, when the output video signal of the field memory (15) is played back as is without correction, for example, during high-speed playback of an image in which a circular object is moving from left to right, the replacement is performed as shown in FIG. The image in section N' is an image 4 to 5 recording fields ago (when playing back at 4 or 5 times speed), and the object moves between these 4 to 5 fields.
The display will be shifted.

Here, in the circuit configuration of this example, the horizontal motion vector data of the field being played back is detected, and this detected data is multiplied by the playback speed as a coefficient. The amount of movement and the direction of movement are determined by an arithmetic circuit (19). Then, by shifting the image of the replaced section N' in the shift register (17) by the amount of movement determined by the arithmetic circuit (19), the amount of deviation of the image is corrected. By performing the correction in this way, for example, as shown in FIG.
A video signal is generated in which even a moving object is displayed in a substantially perfect shape.

Then, the video signal corrected by the shift register (17) is supplied to the multiplexer (20), and the HD signal newly obtained at the terminal (24) is transferred to the video signal (MUS).
By adding it to the E signal), it becomes a good MUSE signal. That is, when correction is performed by shift processing in the shift register (17) described above, the HD signal added to each horizontal line of the corrected video signal is also shifted, and the HD signal of the shifted horizontal line is inserted. The position shifts from its original position. Therefore, by using the HD period switching signal (FIG. 2B) obtained at the terminal (25), the signal in the range where the shifted HD signal exists is changed to the new HD signal obtained at the terminal (24) (FIG. 2A). ) to create an HD signal that is in phase with each horizontal line. Note that the sections other than the HD pulse of the signal to be replaced are set to gray level, but as long as the level is not noticeable at the time of reception, it may be set to a level such as black level.

Then, the MUS output from this multiplexer (20)
The E signal is converted into an analog MUSE signal by a digital/analog converter (21) and supplied to the output terminal (22), and the output MUSE signal is decoded into a high-definition video signal by a MUSE signal decoder. By supplying this signal to a video receiver, a good image without noise bars and distortion can be displayed even during high-speed playback.

G3 Description of other embodiments Note that in the above embodiment, V
Although an example in which the present invention is applied to a TR is shown, it can also be applied to a VTR that records one field of video signal on one track. In this case, the tape playback speed during high-speed playback should be set to even multiple speed (2
(x, 4x, 6x, etc.), the positions of the noise bars will not overlap for each field. For example, the head trajectories H,,H, in the case of 4x speed are shown in FIG. 8, and the head trajectories HA (odd field) and HN
Figures 9 and 10 show the reproduction state in an even field (even field).The position where the noise bar N is generated is completely different between the odd field and the even field, and the circuit configuration shown in the example in Figure 1 provides a good result. Noise bars can be removed.

Furthermore, it goes without saying that the present invention is not limited to the above-mentioned embodiments, and can take various other configurations.

Effects of the Invention According to the present invention, there is an advantage that a so-called noiseless search without noise bars can be performed during high-speed playback, and that even if the image during high-speed playback is a moving image, it will be good and free of distortion.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the television signal reproducing device of the present invention, FIG. 2 is a waveform diagram for explaining the embodiment, and FIG. 3 is an explanatory diagram showing the head trajectory of the embodiment. 4, 5, 6 and 7 are route diagrams for explaining the playback state of one embodiment, FIG. 8 is an explanatory diagram showing the head trajectory of another embodiment, and FIG. 9 10 are route maps for explaining the reproduction state of other embodiments, and FIGS. 11 and 12 are route maps for explaining segment recording. (I4) is a dropout detection circuit, <15> is a field memory, (17) is a shift register, (18) is a motion vector detection circuit, and (23) is a CPU. Agent Hidemori Matsukuma's condolence diagram Diagram showing the remains of the head car box Diagram 3 Diagram Diagram Completed Doctor Diagram A! ABABAB Now B↑9 'HA s ゝ日 A Diagram showing the footfall! 3 Ward 10 Figure 0 Figure Part 1]] Child showing anger Figure 12

Claims (1)

[Claims] In a television signal reproducing device that reproduces a television signal including information about motion vectors from a recording medium, when the television signal is reproduced at high speed, noise bars do not match from field to field. a double speed setting means for setting a playback speed value; a noise bar detection means for detecting the position of occurrence of the noise bar; an interpolation means for interpolating the noise bar with a previously reproduced television signal; A television signal reproducing apparatus comprising: a detection means for detecting information regarding vectors; and a correction means for moving the video interpolated by the interpolation means based on the output of the detection means and the reproduction speed value.