JPH0331036B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a television receiver in which an interlaced video signal is converted into a non-interlaced video signal and supplied to a picture tube to display a non-interlaced display. This is designed to reduce deterioration in image quality and resolution.

Generally, screen display using interlaced method is
When there are 525 scanning lines, 262.5 lines constitute one field, and by sending these at 60Hz, surface flicker is suppressed. Further, in order to obtain vertical resolution, the next field is scanned with a shift of 1/2 scan line interval.

However, in this case, even though macroscopically the number of images is 60 images/second, microscopically one scanning line lights up every 1/30 seconds, and the display cycle is 1/2.
It is 30 seconds. Therefore, the light emission of this one scanning line is visually perceived as flicker. That is, line flicker exists.

In order to reduce this line flicker, the display period of one scanning line may be made shorter than 1/30 second. Therefore, a television receiver that performs double-speed scanning with twice the horizontal frequency has been proposed.
In this case, the display period for both surfaces and lines is 1/60
seconds, and you won't notice any surface flicker or line flicker.

In order to perform double-speed scanning in which the horizontal frequency is doubled, the interlaced video signal is converted into a non-interlaced video signal in which the horizontal frequency is doubled and supplied to the picture tube.

As this conversion method, the methods shown in FIGS. 1, 2, and 3 have been proposed.

First, the system shown in Figure 1 predicts that the video signal of the previous scanning line and the next scanning line are the same, and uses the video signal of the previous scanning line as it is as an interpolation signal. This is a method of position prediction.

In the figure, 1 indicates an input terminal, and an interlaced video signal S _i is supplied to this input terminal 1. Further, 2 and 3 are 1H memories, respectively, and the read speed is twice the write speed. Further, 4 and 5 are respective changeover switches whose states are changed every 1H (one horizontal period), and when changeover switch 4 is changed to one side of memories 2 and 3, changeover switch 5 is changed to the other side. Can be switched.

In the example in FIG. 1, the video signal S _i supplied to input terminal 1 is sent to memories 2 and 3 alternately for 1H.
This memory 2
and 3, 1H of the video signal written in the previous 1H is read out twice from the other memories 3 and 2, and this is obtained at the output terminal 6. Therefore, in this case, the output terminal 6 receives a non-interlaced video signal in which the horizontal frequency is doubled, in which the video signal of each scanning line of the video signal S _i is repeated twice with a period of 1/2H. _SNI is obtained.

In addition, the system shown in FIG. 2 predicts that the video signal of the scanning line to be interpolated is equal to the video signal of the scanning line of the previous field, and uses this video signal as the interpolation signal.
This is a so-called pre-field prediction method.

In the same figure, 2A and 3A are 1H memory, respectively.
4A and 5A are changeover switches, respectively, and the memories 2 and 3 and changeover switches 4 and 5 shown in FIG.
It works the same way. Also, 2B and 3B are respectively
1H memories, 4B and 5B are changeover switches, respectively, which operate in the same way as memories 2 and 3 and changeover switches 4 and 5 shown in FIG.

Further, in the figure, 7 is a delay circuit having a delay amount of 1V (one field period).

8 is a changeover switch, which is switched every 1/2H and read from memory 2A or 3A.
The video signal for 1H and the video signal for 1H read out from the memory 2B or 3B are sequentially supplied to the output terminal 6 via this changeover switch 8 every 1/2H.

In the example shown in FIG. 2, the horizontal frequency is such that the video signal of each scanning line of the current field and the video signal of the corresponding scanning line of the previous field are obtained alternately every 1/2H at the output terminal 6. A non-interlaced video signal S _NI ′ is obtained in which the signal is doubled.

In addition, the system shown in Fig. 3 predicts that the video signal of the scanning line to be interpolated is the arithmetic average of the video signals of the scanning lines before and after it, and uses this video signal as the interpolation signal, which is the so-called arithmetic mean. It's a method.

In the same figure, 2C and 3C are 1H memory, respectively.
4C and 5C are changeover switches, respectively, and the memories 2 and 3 and changeover switches 4 and 5 shown in FIG.
It works the same way. Therefore, changeover switch 5C
From this, a video signal is obtained in which the video signal of each scanning line of the input video signal S _i is continuous twice with a period of 1/2H. This video signal is supplied to the synthesizer 10 via the delay circuit 9 having a delay amount of 1/2H, and this video signal is directly supplied to the synthesizer 10,
The arithmetic mean of these two video signals is output from the synthesizer 10 and supplied to the output terminal 6.

Therefore, in the example of FIG. 3, the output terminal 6
The horizontal frequency at which the video signal of each scanning line of the input video signal S _i and the arithmetic average of the two video signals, this video signal and the following video signal, are obtained alternately every 1/2H is A double non-interlaced video signal S _NI ″ is obtained.

If the non-interlaced video signals S _NI to S _NI '' with double the horizontal frequency obtained in this way are supplied to the picture tube and double-speed scanning is performed, surface flicker and line flicker will not be felt as described above. It disappears.

However, a television receiver in which double-speed scanning is performed using the non-interlaced video signals S _NI to S _NI '' as described above has the following drawbacks.

First, when using the non-interlaced video signal S _NI obtained by the pre-prediction method shown in Figure 1, two scanning lines of the same video signal continue, so diagonal lines becomes like a staircase. This is difficult to notice when looking at still images, but when it comes to moving images, it becomes a cause of considerable image quality deterioration. This increases as the screen size increases.

Next, a non-interlaced video signal obtained by the pre-field prediction method shown in Fig.
In the case of using S _NI ', the scanning lines of the video signal of the current field and the scanning lines of the video signal of the previous field are displayed alternately, so it is not ideal for images with strong temporal correlation, that is, still images. However,
In video images, there is a time lag within the image,
Image quality deteriorates.

Furthermore, a non-interlaced video signal 1 obtained by the average value prediction method shown in FIG.
In the case of using ``S _NI '', the video signal of the interpolated scanning line is the arithmetic average of the scanning lines before and after it, so the resolution in the vertical direction deteriorates due to this integral action. The fact that the line becomes step-like is somewhat relaxed compared to the case of the example in FIG.

These deteriorations in image quality and resolution are thought to be due to the fact that the interpolated scanning line video signal was not appropriate. For example, the video signal S _NI obtained by the pre-prediction method shown in the example in FIG. Even in cases where there is an interpolation signal, the video signal of one scanning line is always used as an interpolation signal.

The present invention has been made in view of this problem, and when non-interlaced display is used to prevent line flickering, the above-mentioned deterioration of image quality and
This is to reduce deterioration in resolution.

Hereinafter, an embodiment of the television receiver according to the present invention will be described with reference to FIG.
In FIG. 4, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

In this example, the non-interlaced video signal _SNI obtained by the changeover switch 5 and whose horizontal frequency is doubled is supplied to one fixed terminal 11a of the changeover switch 11. Here, the video signal
As described above, S _NI is a video signal in which each scanning line of the interlaced video signal S _i supplied to the input terminal 1 is consecutively repeated twice with a period of 1/2H. The other fixed terminal 11b of this changeover switch 11 has a blanking level voltage.
V _BL is supplied, and the output terminal 6 is led out from the movable terminal 11c of the changeover switch 11.

In addition, the video signal S _NI obtained from the changeover switch 5
is supplied to one input side of the correlator 12, and this video signal _SNI is supplied to the other input side of the correlator 12 via a delay circuit 13 having a delay amount of 1/2H.

The correlator 12 is composed of, for example, a subtracter, and subtracts the video signal S _NI supplied to one and the other input sides and a signal obtained by delaying this by 1/2H, and this subtracted output is controlled by the changeover switch 11. Supplied as a signal.

In this case, as described above, the video signal S _NI is the video signal of each scanning line of the input video signal S _i consecutively twice with a period of 1/2H, so this video signal S _NI and this When compared with a signal delayed by 1/2H, in the video signal period (1/2H) of the second scanning line where the video signal _SNI is repeated,
Since both are video signals of the same scanning line of the input video signal S _i , they are sure to match, but the video signal S _NI
In the period (1/2H) of the video signal of the first scanning line that is repeated, the input video signal S _i is based on the video signal of one scanning line and the previous scanning line, so the two do not necessarily match. do not. Therefore, during the period of the video signal of the first repeated scanning line of the video signal S _NI , the correlator 12 calculates the period of one scanning line of the corresponding input video signal S _i and the previous scanning line. A subtraction output corresponding to the amount of correlation of the video signal can be obtained.
In other words, during the period of the video signal of the interpolated scanning line of the video signal _SNI , a subtraction output is obtained that corresponds to the amount of correlation between the video signals of the scanning lines before and after this scanning line. The magnitude of this subtraction output becomes smaller as the amount of correlation increases, and becomes 0 when there is a perfect correlation.

The magnitude of the subtraction output is a predetermined level V _TH (When the magnitude of the subtraction output is below this level, the correlation between the video signals of one scanning line of the input video signal S _i and the scanning line before it is strong, and conversely, when it is above this level, the correlation is weak. (It can be said that.)
In the following cases, the movable terminal 11 of the changeover switch 11
c is connected to one fixed terminal 11a, and the video signal _SNI obtained from the changeover switch 5 is directly output to the output terminal 6.
be made so as to be obtained.

On the other hand, when this subtraction output is equal to or higher than the predetermined level _VTH , the movable terminal 11c of the changeover switch 11 is connected to the other fixed terminal 11b, and the changeover switch 5
The video signal S _NI obtained is the blanking level V _BL
It is said that In this case, the subtraction output is at the predetermined level V _TH
As is clear from the above, this is the period of the video signal of the interpolated scanning line of the video signal S _NI , and is when the correlation between the video signals of the scanning lines before and after this scanning line is weak. .

As a result, at the output terminal 6, a video signal _SNI1 is obtained, which is the video signal of the interpolated scanning line of the video signal _SNI , which is blanked when there is no correlation between the video signals of the scanning lines before and after it.

Although not shown, a non-interlaced video signal with twice the horizontal frequency obtained at this output terminal 6
_SNI1 is supplied to the picture tube via a signal processing circuit, and double-speed scanning is performed.

In the example shown in FIG. 4, it is assumed that an interlaced video signal S _i as shown in FIG. 5A is supplied to the input terminal 1, for example. In this video signal S _i, it is assumed that the correlation between the video signal S ₁ of the scanning line and the video signal S ₂ of the scanning line following it is weak.

In this case, the horizontal frequency of each scanning line of the input video signal S _i as shown in FIG. 5B is doubled by the changeover switch 5. A video signal _SNI is obtained. What is shown in Figure C is a signal obtained by delaying this video signal _SNI by 1/2H. The correlator 12 is supplied with the video signal S _NI and a signal delayed by 1/2H, and a subtracted output thereof is obtained at its output side.

Therefore, in this case, since the correlation between the video signal S ₁ of the scanning line of the input video signal S _i and the video signal S ₂ of the subsequent scanning line is weak, the video signal S of the first scanning line of the video signal S _NI The magnitude of the subtracted output obtained from the correlator 12 during period ₂ is equal to or greater than V _TH , and the video signal S ₂ of the first scanning line is blanked.
As a result, _a video signal _SNI1 is obtained at the output terminal 6, as shown _in FIG.

As is clear from the embodiments described above, according to the television receiver according to the present invention, the gain of the video signal of the interpolated scanning line is controlled according to the correlation amount of the video signal of the scanning line before and after the interpolated scanning line. Therefore, deterioration in image quality due to the video signal of the interpolated scanning line that is assumed to be correlated even when there is no correlation as in the conventional method is reduced. Also in this case,
Since the video signal of the interpolated scanning line is not obtained by arithmetic averaging of the video signals of the previous and subsequent scanning lines, there is no deterioration in resolution in the vertical direction.

Next, FIGS. 6, 7, and 9 show other embodiments of the present invention, respectively. These, the 6th
In the figures, FIGS. 7 and 9, parts corresponding to those in FIG. 4 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

First, the one shown in FIG. 6 uses three 1H memories. In the figure, 14, 15, and 16 are 1H memories, respectively, and the read speed is twice the write speed. Further, 17, 18, and 19 are changeover switches, which are switched every 1H (one horizontal period), and when the changeover switch 17 is switched to the memory 14, 15, and 16 side, the changeover switch 18 is switched to the memory 1 side.
At the same time, the changeover switch 19 is switched to the memory 15, 16, and 14 side.

In the example in FIG. 6, the video signal S _i supplied to the input terminal 1 is transferred from the memory 14→15→16→1
4... 1H worth of data is written every 1H. Then, the memory 16,
From 14 and 15, 1H of the written video signal is read out twice in succession with a period of 1/2H. Therefore, from the changeover switch 18, the 1H video signal of the video signal S _i supplied to the input terminal 1 is a non-interlaced video signal in which the horizontal frequency is doubled twice consecutively with a period of 1/2H. The video signal _SNI of the system is obtained. This video signal S _NI is supplied to one fixed terminal 11 a of the changeover switch 11 and also to one input side of the correlator 12 . Also, 1H written in memories 14, 15, and 16 is written in memories 15, 16, and 14.
From then on, 1H of the written video signal is 1/2
It is read twice consecutively with a period of H. Therefore, from the changeover switch 19, the 1H video signal of the video signal S _i supplied to the input terminal 1 is non-interlaced in which the horizontal frequency is doubled twice consecutively with a period of 1/2H. The video signal of the system can be obtained. This video signal is delayed by 1/2H×2 with respect to the video signal _SNI obtained from the changeover switch 18, and is supplied to the other input side of the correlator 12.

In the correlator 12, the video signal S _NI supplied to one and the other input sides and this is 1/2H×
The signal delayed by 2 is subtracted, and the subtracted output is supplied to the changeover switch 11 as a changeover control signal.

In the example shown in FIG. 6, when the video signal S _NI supplied to one and the other input sides of the correlator 12 is compared with a signal delayed by 1/2H×2, the repetition of the video signal S _NI In both the first and second scanning line video signal periods, the video signal S _NI and the signal delayed by 1/2H x 2 are respectively equal to one scanning line of the input video signal S _i . Since this is based on the video signal of the previous scanning line, the two do not necessarily match. Therefore, during the period of the video signal of the first repeated scanning line of the video signal S _NI , the correlator 12 calculates the period of one scanning line of the corresponding input video signal S _i and the previous scanning line. A subtraction output corresponding to the amount of correlation of the video signal can be obtained. In other words,
During the period of the video signal of the interpolated scanning line of the video signal _SNI , a subtraction output is obtained according to the amount of correlation between the video signals of the scanning lines before and after this scanning line. Also, the video signal
A similar subtracted output is obtained in the period of the video signal of the second scanning line in which _SNI is repeated, that is, the period of the video signal of the scanning line after the interpolated scanning line.

The rest of the structure is the same as the example shown in FIG.

After all, in the example of FIG. 6 as well, the output terminal 6 receives the video signal _SNI2 , which is blanked when the video signal of the interpolated scanning line of the video signal SNI has no correlation with the video signals of the scanning lines before and after _it. is obtained. still,
In the case of the example shown in FIG. 6, when the video signal of the interpolated scanning line is blanked, the video signal of the subsequent scanning line is also blanked.

In this way, also in the example shown in FIG. The same effects as in the illustrated example can be obtained.

Next, what is shown in FIG. 7 is that when the video signal of the first scanning line of the video signal S _NI that is repeated, that is, the video signal of the interpolated scanning line, is blanked, the video signal of the second scanning line is blanked. The video signal, that is, the video signal of the scan line after interpolation, is amplified and strengthened to compensate for the reduction in brightness due to blanking.

In the figure, a non-interlaced video signal _SNI obtained by the changeover switch 5 and whose horizontal frequency has been doubled is supplied to the first fixed terminal 20a of the changeover switch 20. This changeover switch 20
A blanking level voltage V _BL is supplied to the second fixed terminal 20b of. The output terminal 6 is led out from the movable terminal 20d of the changeover switch 20.

In addition, the video signal S _NI obtained from the changeover switch 5
is supplied to the third fixed terminal 20c of the changeover switch 20 via an amplifier 21 having a gain K, and this video signal _SNI is supplied to one input side of the correlator 12. The other input side of this correlator 12 receives the video signal S _NI obtained from the changeover switch 5.
The signal is supplied via a delay circuit 22 having a delay amount of 1H.

In the correlator 12, the video signal S _NI supplied to one and the other input sides and this is 1/2H×
The signal delayed by 2 is subtracted, and the subtracted output is supplied to the changeover switch 20 as a changeover control signal.

Since the video signal S _NI and a signal obtained by delaying this by 1/2H×2 are supplied to one input side and the other input side of the correlator 12, the subtraction output obtained from the correlator 12 is as in the case of the example in FIG. It's the same. That is, during the period of the video signal of the first repeated scanning line of the video signal _SNI , that is, the period of the video signal of the interpolated scanning line of the video signal _SNI , the correlator 12 outputs the corresponding input. A subtraction output is obtained in accordance with the amount of correlation between the scanning line of the video signal S _i and the previous scanning line, that is, the amount of correlation between the scanning lines before and after the interpolated scanning line of the video signal _{S NI} . The magnitude of this subtraction power becomes smaller as the amount of correlation increases, and becomes 0 when there is a perfect correlation.
becomes. Further, a similar subtraction output can be obtained during the video signal period of the first scanning line in which the video signal _SNI is repeated, that is, the video signal period of the scanning line after the interpolated scanning line.

In the changeover switch 20, when the subtraction output supplied as a changeover control signal is below a predetermined level V _TH (strong correlation), the movable terminal 20d is connected to the first fixed terminal 20a, and the video signal obtained by the changeover switch 5 is _SNI is made available directly to the output terminal 6.

On the other hand, when this subtraction output is equal to or higher than the predetermined level V _TH (correlation is weak), _the movable terminal 20d is is connected to the second fixed terminal 20b, the portion related to the subtraction output of the video signal of the first scanning line is set to the blanking level V _BL , and during the period of the video signal of the second scanning line, the movable terminal is connected to the second fixed terminal 20b. 20d is connected to the third fixed terminal 20c, and the portion related to the subtracted output of the video signal of the second scanning line is multiplied by K in the amplifier 21 and supplied to the output terminal 6. In this case, as mentioned above, the subtraction output is the same in the video signal periods of the first and second scanning lines that are repeated in the video signal _SNI , so if blanking is performed the first time, the second time is blanked. The corresponding portion will be amplified.

As a result, the video signal of the interpolated scanning line of the video signal S _NI (the video signal of the first repeated scanning line) is output to the output terminal 6. A video signal S _NI3 is obtained in which ranking is performed and the corresponding portion of the video signal of the scan line after this interpolated scan line is amplified.

In the example shown in FIG. 7, it is assumed that an interlaced video signal S _i as shown in FIG. 8A is supplied to the input terminal 1, for example. In this video signal S _i, it is assumed that the correlation between the video signal S ₁ of the scanning line and the video signal S ₂ of the scanning line following it is weak.

In this case, the horizontal frequency of each scanning line of the input video signal S _i as shown in FIG. 8B is doubled by the changeover switch 5. A video signal _SNI is obtained. What is shown in Figure C is a signal obtained by delaying this video signal _SNI by 1/2H×2. The correlator 12 is supplied with the video signal S _NI and a signal delayed by 1/2H×2, and a subtracted output thereof is obtained at its output side.

Therefore, in this case, since the correlation between the video signal S ₁ of the scanning line of the input video signal S _i and the following S ₂ is weak, the correlation between the video signal S ₂ of the first and second scanning lines of the video signal S _NI is weak. During the period, the magnitude of the subtraction output obtained from the correlator 12 is greater than or equal to V _TH , the video signal S ₂ of the first scanning line is blanked, and the video signal S ₂ of the second scanning line is amplified by K times. be done. In the end, a video signal _SNI3 as shown in FIG. 2D is obtained at the output terminal 6.

In the example shown in FIG. 7 as well, the gain of the video signal of the interpolated scanning line is controlled according to the correlation between the video signals of the scanning lines before and after it,
The same effects as in the illustrated example can be obtained. In the example shown in FIG. 7, when one of the video signals of two repeated scanning lines supplied to the picture tube is blanked, the signal level of the other one is amplified. Therefore, it is possible to compensate for the decrease in brightness that occurs when blanking is applied.

Next, what is shown in FIG. 9 is such that the gain of the video signal of the interpolated scanning line is controlled in an analog manner according to the amount of correlation between the video signals of the scanning lines before and after it.

In the figure, a non-interlaced video signal _SNI obtained by a changeover switch 5 and having a doubled horizontal frequency is supplied to the input side of a variable gain amplifier 23. An output terminal 6 is led out from the output side of this amplifier 23.

In addition, the video signal S _NI obtained from the changeover switch 5
is supplied to one input side of the correlator 12, and this video signal _SNI is supplied to the other input side of the correlator 12 via a delay circuit 22 having a delay amount of 1/2H×2. .

In the correlator 12, the video signal S _NI supplied to one and the other input sides and this is 1/2H×
The video signal delayed by 2 is subtracted, and the subtracted output is supplied to the above-mentioned amplifier 23 as a gain control signal.

In this case, the subtraction output obtained from the correlator 12 is the same as in the example of FIG.

In addition, in the example of FIG. 9, the subtraction output supplied to the amplifier 23 as a gain control signal is at a predetermined level.
When V _TH1 or less (strong correlation), the amplifier 23
The gain G of is set to 1, so that the video signal _SNI obtained at the changeover switch 5 is supplied to the output terminal 6 as is.

Furthermore, when the subtraction output is at a predetermined level V _TH2 (>V _TH1 ) or higher (there is almost no correlation), the video signal S _NI obtained at the changeover switch 5 is is amplifier 2
The gain G of the amplifier 23 is set to 0, and the portion related to the subtraction output of the video signal of the first scanning line is blanked, and during the period of the video signal of the second scanning line, the gain G of the amplifier 23 is K( >1), and the portion related to the subtracted output of the video signal of this second scanning line is multiplied by K times.

Furthermore, when the level of the subtraction output is within V _TH1 to V _TH2 (there is a correlation but it is weak), during the period of the video signal of the first repeated scanning line of the video signal _SNI obtained at the changeover switch 5, , gain G of amplifier 23
0<G<1, and the gain of the portion related to the subtracted output of the video signal of the first scanning line is multiplied by G and is weakened. In this case, the magnitude of the subtraction power is
The closer to V _TH1 , the closer the gain G of the amplifier 23 is to 1.
The closer it is to V _TH2, the closer it is to 0. Then, during the second scanning line video signal period, the amplifier 23
The gain G of is set to be G>1, and the portion related to the subtraction output of the video signal of this second scanning line is strengthened by a factor of G. In this case, the closer the magnitude of the subtracted output is to V _TH1 , the closer the gain G of the amplifier 23 is to 1.

After all, the video signal of the interpolated scanning line of the video signal S _NI (the video signal of the first repeated scanning line) is output to the output terminal 6 when there is no correlation between the previous and subsequent scanning lines or when the correlation is weak. Blanking, or a video signal whose level is weakened according to the amount of correlation, and at the same time the level of the corresponding part of the video signal of the scanning line after this interpolated scanning line is strengthened.
S _NI4 is obtained.

In this example in FIG. 9, for example, at input terminal 1,
Assume that a non-interlaced video signal S _i as shown in FIG. 10A is supplied. This video signal
In S _i , the period T ₁ of the video signal S ₁ of the scanning line is the corresponding period of the video signal S ₂ of the scanning line that follows it.
It is assumed that there is no correlation at all with the portion T ₂ and that the video signal S ₂ of the scanning line has a weak correlation with the video signal S ₃ of the scanning line that follows it.

In this case, the changeover switch 5 changes the video signal of each scanning line of the video signal S _i to 1/1 as shown in FIG.
A video signal _SNI is obtained in which the horizontal frequency is doubled twice consecutively with a period of 2H. Same figure C
What is shown in FIG. 2 is a signal obtained by delaying this video signal _SNI by 1/2H×2. The correlator 12 is supplied with the video signal S _NI and a signal delayed by 1/2H×2, and a subtracted output thereof is obtained at its output side.

Therefore, in this case, during the period _t1 of the video signal _S2 of the first scanning line of the video signal _SNI , the correlator 12
Since the magnitude of the subtracted output is equal to or larger than V _TH2 , the gain G of the amplifier 23 is set to 0, and the period t ₁ of the video signal S ₂ of the first scanning line is blanked. During the corresponding period t ₂ of the video signal S ₂ of the second scanning line, the gain G of the amplifier 23 is set to K (>1), and the gain G of the amplifier 23 is set to K (> ₁ ). The portion of period _t2 is intensified and brightness compensation is performed. Further, in the first period _t3 of the video signal _S3 of the scanning line of the video signal _SNI , the magnitude of the subtracted output of the correlator 12 is V _TH1 to V _TH2 , so the amplifier 23
The gain G of is set to be 0<G<1, and the video signal _S3 of this first scanning line is weakened. During period _t4 of the video signal _S3 of the second scanning line corresponding to this, the gain G of the amplifier 23 is set to G>1, and the video signal _S3 of the second scanning line becomes stronger. and brightness compensation is performed. Furthermore, in other periods other than those mentioned above, the magnitude of the subtracted output of the correlator 12 is less than V _TH1 , so the gain G of the amplifier 23 is set to 1, and the output terminal 6 is connected to the changeover switch 5. The resulting video signal _SNI is supplied as is.

As a result, a video signal _SNI4 as shown in FIG. 10D is obtained at the output terminal 6.

In this way, also in the example of FIG. 9, the gain of the video signal of the interpolated scanning line is controlled according to the amount of correlation between the video signals of the scanning lines before and after it.
The same effects as the example in FIG. 4 can be obtained.
In this example, brightness compensation is performed in the same manner as in the example shown in FIG. 7, so that reduction in brightness due to gain control is prevented.

Next, FIGS. 11 and 12 respectively show a television receiver using a two-beam type picture tube for non-interlaced display.

In the case of these examples in FIGS. 11 and 12, the first beam B _n1 and the second beam B _n2 are
As shown above, the scanning lines are scanned adjacent to each other with a spacing of 1/2 of the scanning line spacing in the interlaced method. FIGS. 13B and 13C show the scanning state of the first beam B _n1 and the second beam B _n2 on the screen 100 in odd-numbered fields and even-numbered fields.

When the number of scanning lines is 525, only 262.5 scanning lines are emitted in one field in the case of the 1-beam method, but in the case of the 2-beam method shown in the examples in Figures 11 and 12, the light is emitted in the next field. For the remaining 262.5 scanning lines that emit light, the second beam
It emits light by scanning with B _n2 , and all 525 scanning lines can be emitted within one field.
Therefore, non-interlaced display is performed in which the display period of each scanning line is 1/60 second. Here, the first
Figure 3A shows the beam scanning state on the screen 100 in the 1-beam method, where solid lines indicate odd fields,
Dashed lines represent even fields.

In the beam shown in FIG. 11, the first beam B _n1 and the second beam B _n2 are density-modulated with the same signal.

In the same figure, reference numeral 24 indicates an input terminal to which an interlaced video signal S _{i is} supplied. The first cathode K ₁ and the second cathode K ₂ are supplied with the first beam B _n1 and the second beam B _n2 .
Therefore, in this case, the first beam B _n1 and the second beam B _n2 are density-modulated with the same signal. In addition, in the same figure, 28 is a synchronous separation circuit, and 29 is a synchronous separation circuit.
30 is a horizontal deflection circuit, 31 is a vertical deflection circuit, and 32 is a vertical deflection coil.

In addition, what is shown in Fig. 12 is the second beam.
B _n2 is density-modulated with a signal obtained by arithmetic averaging of the video signal of one scanning line that density-modulates the first beam B _n1 and the video signal of the following scanning line.

In the figure, a video signal S _i supplied to an input terminal 24 is passed through a signal processing circuit 25, a delay circuit 33 having a delay amount of 1H, and an amplifier 26 to a picture tube 2.
7 _{, and the first beam B n1 is} density- _modulated by this signal. Further, the video signal from the signal processing circuit 25 and the video signal from the delay circuit 33 are arithmetic averaged in a combiner 34, and the arithmetic averaged signal obtained from the combiner 34 is sent to the picture tube 27 via an amplifier 35.
is supplied to the second cathode K ₂ according to the second beam B _n2 . Therefore, the second beam B _n2 is density-modulated with a signal obtained by arithmetic averaging of the video signal of one scanning line that modulates the density of the first beam B _n1 and the video signal of the following scanning line.

According to the television receivers shown in FIGS. 11 and 12, when there are 525 scanning lines, 525 scanning lines are emitted in one field, and non-interlaced display is performed, so that so-called line flicker does not occur. There is no.

However, in the case of the example in FIG. 11, the video signal of the interpolated scanning line, that is, the video signal that density-modulates the second beam B _n2 , is the video signal of the previous scanning line, that is, the first beam B _n1. Since two scanning lines of the same video signal continue on the screen 100, the diagonal lines become step-like and the image quality deteriorates. In the case of the example in FIG. 12, the video signal of the interpolated scanning line, that is, the video signal that density-modulates the second beam B _n2 , is the video signal of the scanning line before and after it, that is, the first beam B Since it is the arithmetic average of the two video signals modulating _n1 , it has the disadvantage that the resolution in the vertical direction deteriorates due to this integral action.

This deterioration in image quality and resolution is considered to be because the video signal for density modulating the second beam B _n2 was not appropriate. That is, for example, in the example of FIG. 11, even though there is no correlation between the video signal of one scanning line that modulates the first beam B _n1 and the video signal of the next scanning line that follows it, one scanning line This is because the second beam B _n2 is always modulated with the video signal.

FIG. 14 shows another embodiment of the present invention in which this point is taken into consideration.

In this figure, parts corresponding to those in FIG. 11 are denoted by the same reference numerals, and detailed explanation thereof will be omitted.

In the figure, the video signal from the signal processing circuit 25 is passed through a delay circuit 36 having a delay amount of 1H, and then sent to the first cathode K ₁ related to the first beam B _n1 of the picture tube 27 via the amplifier 37. It is also supplied to the second cathode K ₂ associated with the second beam B _n2 of the picture tube 27 via the variable gain amplifier 38 .

Further, the video signal from the delay circuit 36 is transmitted to the correlator 3
The video signal from the signal processing circuit 25 is supplied to the other input side of the correlator 39 . That is, the correlator 39 is supplied with the video signal of one scanning line that modulates the first beam B _n1 and the video signal of the next scanning line that follows it.

Since the correlator 39 is supplied with the video signal of one scanning line modulating the first beam B _n1 and the video signal of the next scanning line, the subtraction output obtained from the correlator 39 is as follows. It depends on the amount of correlation between the video signals of these scanning lines, and the smaller the amount of correlation, the more
Its size will be large.

In the amplifier 38, when the magnitude of the subtracted output supplied as a gain control signal is less than the predetermined level V _TH1 (at this time, the correlation is strong), the gain G
is set to be the same as the gain K _ref of the amplifier 37, and the same video signal is supplied to the first cathode K ₁ and the second cathode K ₂ at the same level.

Also, the magnitude of the subtraction output is at a predetermined level V _TH2 (>
V _TH1 ) or higher (there is almost no correlation), then
The gain G of the amplifier 38 is 0, and the second cathode
The video signal supplied to _K2 is blanked.

Furthermore, when the magnitude of the subtracted output is within V _TH1 to V _TH2 (there is a weak correlation when it is within this range), the gain G of the amplifier 38 is 0<G< _Kref ,
The level of the video signal supplied to the second cathode _K2 is weakened.

The rest of the structure is the same as the example in FIG. 11.

Since the example in Figure 14 is configured in this way,
The video signal of the scanning line supplied to the second cathode K ₂ related to the second beam B _n2 of the picture tube 27, that is, the video signal of the scanning line to be interpolated, is the video signal of the scanning line before and after it, that is, the first When there is no correlation between the video signals of the first and subsequent scanning lines supplied to the first cathode _K1 of the beam _Bn1 , or when the correlation is weak, the level is weakened according to blanking or the amount of correlation.

In the example of FIG. 14, the amplifier 37 also has a variable gain, as shown by the broken line, and supplies the output related to the subtracted output from the correlator 39 as a gain control signal, which is supplied to the second cathode _K2 as described above. When the video signal of the scanning line is blanked or its level is weakened according to the amount of correlation, the gain is increased and the level of the video signal of the scanning line supplied to the first cathode _K1 is strengthened to perform blanking etc. It may also be possible to compensate for the decrease in brightness due to

As described above, also in the example of FIG. 14, the gain of the interpolated scanning line video signal (the scanning line video signal that modulates the second beam) is determined by the correlation between the preceding and following scanning line video signals. Since it is controlled according to the amount, it is possible to obtain the same effect as the example shown in FIG.

In the case of this example in FIG. 14, a two-beam system is shown assuming a black and white system television receiver. In the case of color method,
There are two each of red, green, and blue beams, resulting in a 6-beam system, which can be configured similarly to the example in FIG. 14.

In addition, among the above-mentioned embodiments, in the examples shown in FIGS. 4, 6, and 7, the video signal is subjected to blanking processing, but this is performed on the picture tube side. You can also do that.

[Brief explanation of the drawing]

1 to 3 are configuration diagrams of essential parts for explaining a conventional non-interlaced display television receiver, and FIG. 4 is a configuration diagram showing an embodiment of a television receiver according to the present invention. 5 is a diagram for explaining the example in FIG. 4, FIGS. 6, 7, 9 and 14 are configuration diagrams showing other embodiments of the present invention, and FIGS. 8 and 10. 11 and 12 are diagrams showing examples of conventional two-beam television receivers, respectively, and FIG. 13 is an explanation thereof. FIG. 1 is an input terminal, 2 and 3 are each 1H memory, 4,
5 and 11 are respective changeover switches, 6 is an output terminal,
12 is a correlator, and 13 is a delay circuit.

Claims (1)

[Claims] 1. In a television receiver that converts an interlaced video signal into a non-interlaced video signal and supplies it to a picture tube to display a non-interlaced display, the gain of the video signal of the interpolated scanning line is calculated before and after the interlaced video signal. 1. A television receiver characterized in that control is performed according to the correlation amount of a video signal of a scanning line.