KR940000951B1 - Black and white level adaptive sharpness apparatus - Google Patents

Abstract

The sharpness apparatus for adjustment of white and black level comprises a delay for delaying the input signal, an edge stressing means for stressing the edge with adding the delay signal to original signal, a non-linear circuit for obtaining predetermined gain from edge stressing signal, a signal adder for producing required signal with adding the amplified non-linear signal to delayed signal, and gain controlling means, wherein it outputs gain control signal corresponding to original signal and controls thereby the gain of the signal generated in the edge stressing means, thereby making the white and black level increase more in the edge than in the center in the screen.

Description

Black and white level adaptive sharpness device.

1 is a system configuration diagram of conventional sharpness.

2 is an output waveform diagram of each part of FIG. 1;

3 is a frequency transfer characteristic diagram of the nonlinear side device of FIG.

4 is a block diagram of the present invention black, level adaptive sharpness system.

FIG. 5 is a detailed view of the first nonlinear characteristic circuit of FIG.

6 is a voltage transfer characteristic diagram of the second nonlinear characteristic element of FIG.

FIG. 7 illustrates the principle of noise signal attenuation for the second nonlinear characteristic element of FIG.

FIG. 8 is a tunnel diode characteristic diagram of FIG. 5 first nonlinear characteristic circuit; FIG.

9 is a characteristic diagram between an input voltage and an output voltage of a buffer unit in the first nonlinear characteristic circuit of FIG.

10 is an input / output characteristic diagram of a clamp portion in the first nonlinear characteristic circuit of FIG.

11 is an output waveform diagram of the fourth amplifying means and the fifth amplifying means.

12 is an input / output waveform diagram of each part of FIG.

FIG. 13 is an explanatory diagram for the operation of the first nonlinear characteristic circuit of FIG.

* Explanation of symbols for main parts of the drawings

100: first time delay means 101: edge emphasis waveform generating means

102: first nonlinear characteristic circuit unit 103: third amplification means

104: second signal summing means 105: gain adjusting means

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to image processing in a TV receiver, and in particular, by varying the degree of sharpness by a level averaged for a certain period of time, the sharpness of very bright and very dark areas is enhanced to sharpen the contents of the image. It relates to a black and white level adaptive sharpness device for processing.

The sharpness apparatus in the conventional TV receiver includes a first time delay means (100) for delaying and outputting an input signal (Xo) for a predetermined time, as shown in FIG. 1, and the first time delay means. Delaying and amplifying the signal delayed by a certain amount of time in the 100, and the second signal delayed and amplified and the first signal delayed by the first time delay means 100 and the original input signal Xo When the sum signal is inputted by the edge emphasis waveform generating means 101 which emphasizes and outputs the edge portion, and the sum signal from the edge emphasis waveform generating means 101 is clamped at a predetermined voltage, A non-linear characteristic circuit unit 102 for controlling and outputting a predetermined gain, a third amplifying means 103 for receiving an output signal from the non-linear characteristic circuit unit 102 and amplifying the signal to an arbitrary level and outputting the third amplifying means; (10 And a second signal delay means 104 which adds the signal amplified at an arbitrary level in 3) and the first signal delayed by the first predetermined time to the first time delay means 100 and outputs the desired signal.

The edge emphasis waveform generating means 101 is a first delay means 101a for inverting and amplifying the original input signal Xo to an arbitrary level and outputting the first delay through the first time delay means 100. The second time delay means 101b for delaying and outputting the signal again for a predetermined time, and the second amplification means for receiving the second delayed signal through the second time delay means 101b and inverting and amplifying the signal to an arbitrary level. And a second signal and a first signal obtained by inverting and amplifying to an arbitrary level through the input signal Xo and the second amplifying means 101c obtained by inverting and amplifying to an arbitrary level through the first amplifying means 101a. The first signal summing means 101d adds the first signal delayed by the time delay means 100 and inputs it to the nonlinear characteristic circuit unit 102.

As such, in the conventional TV receiver configured, the sharpness apparatus first inputs the signal Xo as a signal as shown in FIG. 2A, and the first time delay means 100 converts the input signal Xo into the second signal. As shown in (b), the second signal delay means is inputted to the second time delay means 101b and the first signal summing means 101c of the edge emphasis waveform generating means 101 by delaying for a predetermined time r. Input to 104.

The second time delay means 101b of the edge emphasis waveform generating means 101 delays the delayed signal by a predetermined time τ again through the first time delay means 100 and then delays the delayed signal by a predetermined time τ. Input is made to 101c.

That is, the signal input to the second amplifying means 101c is input as a signal delayed by a predetermined time 2τ with respect to the original input signal Xo.

The signal delayed by a predetermined time (2τ) in the second time delay means (101b) is amplified by -0.1 through the second amplification means (101c) of the edge emphasis waveform generating means 101, i.e. (d) of FIG. Likewise, the phase inversion and decrease by 0.5 times the input signal are input to the first signal summing means 101c.

On the other hand, the first amplifying means 101a of the edge emphasis waveform generating means 101 inverts and attenuates the input original signal Xo by 0.5 times as shown in FIG. Input is made to 101c.

Accordingly, the signal as shown in (c) of FIG. 2 amplified by the first amplifying means 101a of the first signal summing means 101 and (d) as shown in (d) of FIG. 2 amplified by the second amplifying means 101c. The signal and the signal delayed by a predetermined time (τ) through the first time delay means 100 are summed and input to the nonlinear characteristic circuit unit 102 as shown in FIG.

When the signal input through the first signal summing means 101d is equal to or greater than or equal to the constant voltage (± VS), the nonlinear characteristic circuit unit 102 adjusts the output to a constant gain and is within the constant voltage (± VS). By clinking, the signal input from the first signal summing means 101d is attenuated and input into the third amplifying means 103 in principle.

The third amplifying means 103 is attenuated by the nonlinear characteristic circuit unit 102 to be inverted and amplified by 0.5 times and input to the second signal summing means 104.

Therefore, the second signal summing means 104 sums up the signal input by being amplified by the third amplifying means 103 and the signal delayed by a predetermined time τ through the first time delay means 100 and finally, As shown in (f) of FIG. 2, a signal in which the contours of the rising edge and the falling edge portion are emphasized is output.

Here, the frequency transfer characteristics of FIG. 1 are as follows.

X5 = X2 + aX4

= Xo (t-τ) + a (X1 + X2 + X3)

= Xo (t-τ) + a (-0.5Xo + Xo (t-τ) -0.5Xo ((t-2τ)]

If the frequency conversion of the above equation,

X5 (f) = Xo (f) e ^-jw τ + a [0.5Xo (f) + Xo (f) e- _p ^w τ -0.5Xo (f) e ^-jw τ]

= Xo (f) e- _p ^w τ + aXo (f) (-0.5) [1-2e- _p ^w τ + e ^-jw τ]

= Xo (f) e- _p ^w (1-1 / 2 (a) (e ^jw τ ^{/ 2} -e ^-jw τ ^{2 /} ) ² )

= Xo (f) e- _p ^w τ (1-1 / 2 (a) (-2) ² sin ² 1/2 (wτ)]

(∵ sinθ = e ^j θ-e ^-j θ / 2j)

= Xo (f) e- ^jw τ [1 + 2a sin ² 1/2 (wτ)],

Since A = Xi (f) / Xo (f) = 1 + 2a sin ² 1/2 (wτ),

As shown in FIG. 3, the frequency transfer characteristic is such that sharpness is emphasized when the value of gain a is large, and high frequency is reduced when the value of gain a is negative.

Therefore, if the degree of sharpness is fixed to a certain gain (a), it shows a constant sharpness characteristic regardless of the degree of image. Therefore, sharpness in the very dark part or very bright part of the image is reproduced in the luminance of the screen when the image of the color receiver is reproduced. Since the range is limited, there is a problem in that the sharpness of the edge of the bright portion is lowered than the sharpness of the intermediate level.

Therefore, an object of the present invention is to find the average level value of the input signal level for a certain period of time, and then black and white level adaptive sharpness device to sharply process the content of the image by varying the degree of sharpness of very bright and very dark parts of the image. In providing.

Means for achieving the object of the present invention comprises a first time delay means for delaying the input signal for a predetermined time, the edge portion after receiving the sum and the original signal received from the signal obtained by delaying the first time delay means; A non-linear characteristic circuit unit for receiving the signal summed up by the edge-enhanced waveform generating means, clamping at a predetermined voltage, and outputting a control term with a constant gain above or below a predetermined voltage; A third amplifying means for receiving the signal output from the characteristic circuit section and amplifying the signal to an arbitrary level, a signal amplified to an arbitrary level by the third amplifying means, and a first signal delayed by the first predetermined time by the first time delay means; The input original in the sharpness device comprising second signal summing means for summing and outputting a desired signal. And a gain adjusting means for outputting a gain control signal in accordance with the signal level and adjusting the gain of the sum signal generated by the edge-enhanced waveform generating means according to the output gain control signal and inputting it to a nonlinear characteristic circuit. Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

4 is a block diagram of the adaptive black and white level adaptive sharpness system of the present invention. As shown in FIG. 4, the first time delay means 100 delays and outputs the input signal Xo for a predetermined time, and the first time. The delay means 100 delays and amplifies the signal delayed for a predetermined time again, and the second signal delayed and amplified and the first signal delayed by the first time delay means 100 and the original input signal ( Xo) is added to the edge emphasis waveform generating means 101 for emphasizing and outputting the edge portion, and the signal received from the edge emphasis waveform generating means 101 is input and clamped at a predetermined voltage, and fixed at a predetermined voltage above or below. A first nonlinear characteristic circuit unit 102 for controlling and outputting the gain, a third amplifying means 103 for receiving the signal output from the first nonlinear characteristic circuit unit 102 and amplifying and outputting the signal to an arbitrary level; 3 amplification Sharpness device comprising a second signal summing means 104 for outputting the signal amplified to an arbitrary level at the stage 103 and the first signal delayed by the first predetermined time delay in the first time delay means 100 as a desired signal After buffering and clamping the input signal Xo in, a gain control signal is output according to the level of the clamped signal, and the sum generated by the edge emphasis waveform generating means 101 according to the output gain control signal. And gain adjusting means 105 which adjusts the gain of the signal and inputs it to the first nonlinear characteristic circuit 102.

The edge emphasis waveform generating means 101 is a first delay means 101a for inverting and amplifying the original input signal Xo to a predetermined level and outputting the first delay through the first time delay means 100. The second time delay means 101b for delaying and outputting the signal again for a predetermined time, and the second amplification means for receiving the second delayed signal through the second time delay means 101b and inverting and amplifying the signal to an arbitrary level. And a second signal and a first signal obtained by inverting and amplifying the input signal Xo and the second amplifying means 101c, which are obtained by inverting and amplifying to an arbitrary level through the first amplifying means 101a. A first signal input means 101d is added to the first nonlinear characteristic circuit unit 102 by summing up the first signal delayed by the time delay means 100.

In addition, the gain adjusting means 105 receives a buffer 105a for buffering the original input signal Xo and a signal obtained by buffering the buffered signal through the buffering 105a and outputs a signal obtained by restoring only a DC component. The low pass filter means 105b of the resistor R1 and the condenser C1 and the level of the low frequency filtered signal of the low pass filtered signal in the low pass filter means 105b according to the level of the clamping pulse SSC input from the outside. The first clamping means (105c) and the signal obtained from the first clamping means (105c) for restoring the level of the orthogonal portion of the input is received and clipped within a predetermined voltage range, and a constant gain is obtained at a voltage outside the predetermined voltage range. First signal summing means 101d of the edge emphasis waveform generating means 101 in accordance with a second nonlinear characteristic circuit portion 105d for outputting a gain control signal so as to have a gain control signal output from the second nonlinear gain circuit portion 105d; From) And a fourth amplifying means 105e which variably amplifies the gain of the sum signal and inputs it to the first nonlinear characteristic circuit section 102.

The second nonlinear characteristic circuit portion 105d is a switching control means composed of a resistor R2 and a tunnel diode D1 that change and output the input current source Io according to the voltage obtained through the clamping means 105c. 10), a switching means 20 composed of a transistor TR1 and a resistor R3 switched by the current output from the switching control means 10 to output a reference power source, and output from the switching means 20. The second clamping means 30 is composed of a resistor R4-R6 and a transistor TR2 for linearly outputting the final output from the point determined by the reference power supply.

Thus, the operation and effects of the present invention configured as described in detail with reference to Figures 4 to 13 as follows.

First, when the original signal Xo from the outside is input to the buffer 105a of the first time delay means 100, the edge emphasis waveform generating means 101, and the gain adjusting means 105, the first time delay means ( Delaying the input signal (Xo) for a predetermined time (τ) is input to the second time delay means 101b and the first signal summing means 101c of the edge emphasis waveform generating means 101 and Input to the two signal summing means 104.

The second time delay means 101b of the edge emphasis waveform generating means 101 delays the signal delayed by a predetermined time τ through the first time delay means 100 again by a predetermined time τ and causes the second amplification means ( 101c).

That is, the signal input to the second amplifying means 101c is input as a signal delayed by a predetermined time 2τ with respect to the original input signal Xo.

The second time delay means 101b is amplified by −0.5 through the second amplification means 101c of the edge emphasis waveform generating means 101 of the signal delayed by a predetermined time (2τ), that is, 0.5 of the input signal Xo. Phase inversion and attenuation are doubled and input to the first signal summing means 101c.

On the other hand, the first amplifying means 101a of the edge emphasis waveform generating means 101 phase-inverts and attenuates the input original signal Xo by 0.5 times and inputs it to the first signal summing means 101c.

Accordingly, the first signal summing means 101b uses the signal amplified by the first amplifying means 101a, the signal amplified by the second amplifying means 101c, and the first time delay means 100. The delayed signal is summed and input to the fourth amplifying means 105e of the gain adjusting means 105 as shown in FIG.

On the other hand, the original signal Xo input to the gain adjusting means 105 is buffered as shown in FIG. 12A through the buffer 105a and input to the local filter means 105b.

The low pass filter means 105b processes the signal buffered through the buffer 150a into a resistor R1 and a capacitor C1 to restore only the instantaneous direct current component of the input signal to the first clamping means 105c. Will be entered.

The first clamping means 105c performs a clamping operation at a pedestal level between the horizontal driving mechanisms by a clamping pulse SSC inputted from the low pass filter means 105b as shown in FIG. The level of the DC component at the horizontal scan start point generated by the synchronous waveform and the low pass filter means 105b is recovered and output as shown in FIG.

The voltage output from the first clamping means 105c is input to the second nonlinear characteristic circuit portion 105c of the gain adjusting means 105, and as shown in FIG. If the voltage is between a and b, the voltage is clipped and output. If the voltage is outside the constant voltage range, that is, if the input level is less than or equal to b or more than b, the voltage is output with a constant gain and calculated as a waveform as shown in (d) of FIG.

On the other hand, the fourth amplifying means 105e of the gain adjusting means 105 for amplifying the signal as shown in FIG. 12E output from the first signal summing means 101d of the edge emphasis waveform generating means 101 is As shown in (d) of FIG. 12 output from the second nonlinear characteristic circuit section 105d, the amplification degree is changed and output by the gain control signal.

By the way, it can be seen that the signal waveform as shown in (e) of FIG. 12 output from the first signal summing means 101d adds the peaking waveform of the edge and the noise component.

Therefore, the fourth amplifying means 105e outputted under the control of the second nonlinear characteristic circuit portion 105d outputs the first signal having a large peak and a middle portion as shown in the waveform (f) of FIG. The second part is the peaking is small, and the third part, which is the tip, is output to the first non-linear characteristic circuit unit 102, the peaking size is larger than the peaking of 1.

The first nonlinear characteristic circuit unit 102 cuts to a zero level below a predetermined voltage (± VS) level according to the characteristics as shown in FIG. 6 and has a certain gain over the fourth amplification means 105e. When the picking signal passes through the nonlinear characteristic circuit unit 102, the level is cut as shown in FIG. 7, so that the output waveform of the fourth amplifying means 105e is controlled by noise as shown in FIG. The signal is converted into a signal waveform as shown in (g) of FIG. 12 and output.

A signal waveform such as (g) of FIG. 12 output from the first nonlinear characteristic circuit unit 102 is input to the third amplifying means 103, and the third amplifying means 103 is a kind of parking signal. Amplified by a predetermined amplification degree (a) is output to the second signal summing means 104.

The second signal summing means 104 sums up the signal input from the third amplifying means 103 and the input signal delayed by a predetermined time z by the first time delay means 100, and then (h) of FIG. Outputs the same signal waveform as

In the signal as shown in FIG. 12 (h) output from the second signal summing means 104, the waveforms of the black level and the white level have a high picking degree and the middle level have a relatively small picking degree.

In the above method, the output of the second nonlinear characteristic circuit portion 105d can be connected to the third amplifying means 103 to obtain the output waveform of FIG. The reason why the connection with 105e and the second nonlinear characteristic circuit portion 105d is used is that an input smaller than the cutting voltage VS of the second nonlinear characteristic circuit portion 105d has a first nonlinear characteristic circuit portion 102 as shown in FIG. (H) of Figure 12 of the final output is not picked when the input signal is inputted to the input signal. Since the voltage is input to the characteristic circuit section 102, a voltage larger than VS is input, so that the peaking is assured.

The nonlinear characteristic circuit portion 105d applied to the present invention has a voltage / current characteristic of the tunnel diode D1 when the input voltage is applied by the resistor R2 of the switching control means 10, as shown in FIG. As shown in FIG. 2, if the voltage of the tunnel diode D1 is changed from A to B, the current Id flowing through the tunnel diode D1 increases and decreases. _D + I _Q ) When the input voltage input by the resistor R2 changes and increases from A to B, the current I _Q decreases and increases. Therefore, the transistor TR1 of the switching means 20 appears to increase. As shown in FIG. 9, the output voltage of the emitter is reduced and increases, and the second output curve of the transistor TR2 of the second clamping means 30 that receives the voltage of the switching means 20 is input. Transistor (TR2) when output voltage decreases Off of the output level

[Equation 1]

In this case, since the transistor TR2 is turned on, the final output is linearly output as shown in FIG. 10 so that the overall input and output characteristics are the same as those of the first nonlinear characteristic circuit section 102 of FIG.

Therefore, the sharpness of the very bright or very dark part of the CRT is improved, and the part of the CRT bright or very dark part that is poor in reproduction power is emphasized in circuit, so that it is possible to display a constant sharpness regardless of the signal level. The CRT has a sharpness characteristic of black level or white level lower than that of the center level, but the circuit diagram of the present invention allows the sharpness characteristic of the black level or white level to be increased compared to the center level, so that the final output of the CRT is constant. Has the effect of having.

Claims (2)

A first time delay means for delaying an input signal for a predetermined time, an edge emphasis waveform generating means for receiving a signal obtained by being delayed by the first time delay means and an original input signal, adding and highlighting an edge portion; A nonlinear characteristic circuit unit for receiving the signal summed by the edge emphasis waveform generating means and clamping at a predetermined voltage, and adjusting and outputting a predetermined voltage above or below a predetermined voltage, and receiving the signal output from the first nonlinear characteristic circuit unit. A third amplifying means for amplifying and outputting at a level, a second amplifying means for outputting a desired signal by adding up a signal amplified to an arbitrary level by the third amplifying means and a first signal delayed by the first predetermined time A sharpness device comprising signal summing means, the sharpness device outputting a gain control signal in accordance with the input original signal level and Black and white level adaptive sharpness, characterized in that it comprises a gain control means for adjusting the gain of the sum signal generated by the edge-enhanced waveform generating means by the output gain control signal and inputting it to the first nonlinear characteristic circuit. Device. 2. The apparatus of claim 1, wherein the gain adjusting means comprises: a buffer for buffering the original input signal, a low pass filter means for receiving a signal obtained by being buffered through the buffer, and outputting a signal obtained by restoring only a DC component; First clamping means for restoring the level of the DC component at the horizontal scan start point of the low-pass filtered signal by the low-pass filter means according to the level of the clamping pulse SSC, and receiving a signal obtained from the first clamping means. A second nonlinear characteristic circuit portion for clipping within the range and outputting a gain control signal to have a constant gain at a voltage outside the constant voltage range, and the edge enhancement waveform generating means according to the gain control signal output from the second nonlinear characteristic circuit portion. A fourth variable variable amplification of the gain of the sum signal output from the first signal summing means and input to the first nonlinear characteristic circuit portion; A black characterized in that it consists of a unit width, the white level adaptive sharpening apparatus. 3. The first nonlinear characteristic circuit according to claim 2, wherein the first nonlinear characteristic circuit is switched by a switching control means for changing and outputting an input current source Io according to the voltage obtained through the clamping means, and switched by a current output from the switching control means. And a second clamping means for linearly outputting the final output from the point determined by the reference power output from the switching means.