KR100193093B1 - Automatic Noise Reduction Level Control during TVCR Tape Playback - Google Patents

Abstract

The present invention relates to a noise reduction device for reproducing a tape of a TVCR, and more particularly, to an apparatus for automatically adjusting a noise reduction level for reproducing a tape of a TVCR, which detects ambient brightness and automatically adjusts a noise reduction level when reproducing a tape according to ambient illumination. It is about.

The present invention relates to illuminance detecting means for detecting ambient illuminance, control means for automatically adjusting a noise reduction level during tape playback of a TVCR using information provided by the remote control and illuminance detecting means, and to control the control means. It is characterized in that the noise reduction means for reducing the high-frequency noise component in the luminance signal (Y), by reducing the noise reduction level by varying the ambient illumination to provide a smooth screen to reduce eye fatigue.

Description

Automatic Noise Reduction Level Control during TVCR Tape Playback

The present invention relates to a noise reduction device for reproducing a tape of a TVCR, and more particularly, to an apparatus for automatically adjusting a noise reduction level for reproducing a tape of a TVCR, which detects ambient brightness and automatically adjusts a noise reduction level when reproducing a tape according to ambient illumination. It is about.

In general, in a TVCR, a tape is read from a head of a video deck and processed by a Y / C processor to supply a composite video signal to a main signal processor, and the main signal processor processes a composite video signal to produce a color signal. R, G, and B) are output to the CRT.

When the TVCR tape is played back, the luminance signal Y contains high frequency noise. When the noise is high, the image quality is degraded and the screen is rough to the viewer.

In order to solve this problem, a TVCR is provided with a noise reduction device for tape playback. The noise reduction device of the conventional TVCR tape playback shown in FIG. 1 connects the capacitor C1 and the transistor Q1 to the luminance signal line output from the Y / C processing unit of the Y / C processor and turns on / off the transistor Q1. Controlled by a noise reduction switch, high is applied to the base of the transistor Q1 so that a certain amount of high frequency components included in the luminance signal Y are turned on while the transistor Q1 is turned on. It flows through the ground to ground to reduce noise. In the tape reduction of such a TVCR, the noise reduction device is always fixed at a constant noise reduction level.

However, there is a significant difference in how the viewer feels about the same amount of noise depending on the brightness of the surroundings.In general, when the surroundings are dark, the screen feels coarse with less noise, and when the surroundings are bright, the image quality is relatively good. Therefore, it is necessary to adjust the noise reduction level according to the ambient brightness. However, the conventional noise reduction device that always reduces a certain amount of high frequency components while the noise reduction switch is pressed has a disadvantage in that the noise reduction level cannot be adjusted according to the ambient brightness.

The present invention has been made to solve the above problems, and detects the ambient brightness by detecting the ambient brightness, and automatically adjusts the reduction level of the high frequency component included in the luminance signal (Y) according to the detected illumination The purpose is to provide a device for automatically adjusting the noise reduction level during tape playback.

To this end, the present invention provides an illuminance detecting means for detecting an illuminance of the surroundings, control means for automatically adjusting a noise level during tape playback of a TVCR using information provided by the remote control and illuminance detecting means, and control of the control means. And noise reduction means for reducing the high frequency noise component in the luminance signal (Y) by using the signal.

1 is a schematic diagram of a noise reduction apparatus for tape playback of a conventional TVCR.

Figure 2 is a block diagram of a noise reduction level automatic adjustment device during tape playback of a TVCR according to the present invention

3 is an operation flowchart of an apparatus for automatically adjusting noise reduction level during tape playback of a TVCR according to the present invention.

Explanation of symbols on the main parts of the drawings

10: illuminance detection unit 11: light sensor

12 illuminance detector 20 microprocessor

30: RAM40: noise reduction unit

41: D / A controller 50: main signal processor

60: Y / C Mixer 70: Y / C Processing Unit

80: Deck 90: Bandpass Filter

C1, C2: Capacitors Q1 to Q5: Transistors

V1: Varactors B1 to B4: Buffers

INV: Inverter

2 is a block diagram of an automatic noise level adjusting device for playing back a tape of a TVCR according to an exemplary embodiment of the present invention.

That is, a deck (50) reading a signal recorded on a tape through a head (not shown) by driving a video tape and a signal read from the deck (50) are processed to process a luminance signal (Y) and a chroma signal. Y / C processing unit 60 for separating (C), Y / C mixer unit 70 for synthesizing Y / C and supplying composite video signal CV to main signal processing unit 90, and Y / C A band pass filter 80 which passes only a signal of a specific band in the luminance signal Y of the C processing unit 70 and supplies it to the Y / C mixer 70 again, and a composite video signal input from the Y / C processor. And a main signal processor 90 for outputting color signals (R, G, B) to a CRT (not shown), and a microprocessor 20 for performing key operations of the remote controller and controlling the TVCR as a whole. In the TVCR, the illuminance detection for detecting the ambient illuminance from the light sensor 11 for detecting the brightness of the surrounding light and the output signal of the light sensor 11 An illumination intensity detection unit 10 including 12, a RAM 30 in which information on noise reduction level and noise reduction mode information is stored, and digital information on the noise reduction level of the microprocessor 20; Is converted into an analog and output by the D / A controller 41 and the output signal of the D / A controller 41 and the control signal of the microprocessor 20 to be output from the Y / C processing unit 100. A noise reduction unit including a varactor V1, a capacitor C2, transistors Q2 to Q5, and buffers B1 to B4 for filtering high frequency noise components included in the luminance signal Y. 40).

In addition, the microprocessor 20 recognizes a noise reduction key compared to the ambient illumination input from the remote controller, changes the current noise reduction mode, and stores the noise reduction level in the RAM 30, and stores a noise reduction level value corresponding to the noise reduction mode in RAM ( It further includes a function to read in 30 and output to the noise reduction unit 40.

The operation of the present invention having such a configuration will be described with reference to FIG.

When the viewer first selects the VCR key provided on the front panel of the remote control or the TVCR, and then presses the play key, the microprocessor 20 recognizes this and controls the TVCR to play the video tape.

Thus, the tape of the video deck 50 starts to run, and the information recorded on the tape is read from the head not shown and processed by the Y / C processor composed of the Y / C processing unit 60 and the Y / C mixer unit 70. When the composite video signal CV is supplied to the main signal processor 90, the main signal processor 90 processes the same and outputs color signals R, G, and B to a CRT (not shown) to reproduce an image.

At this time, the main signal processor 90 outputs the composite video signal CV to the Y / C processor 60. The Y / C processor 60 outputs the luminance signal Y and the chroma signal from the composite video signal CV. (C) is separated and output, and the output luminance signal Y is used for adjustment of sharpness and the like, and the chromaticity signal C is used for color and tint adjustment and the like.

At the same time, filtering is performed through the noise reduction unit 40 to reduce the high frequency noise component included in the luminance signal Y.

The filtering performed by the noise reduction unit 40 depends on the noise reduction mode.

If the noise reduction mode is not specified (normal mode), low is output to ports 1 and 2 (P1) and P2 to reduce a certain amount of noise.

Thus, the output of port 2 (P2) turns off transistor Q4, inverts at inverter INV, and applies transistor high to the base of transistor Q5 to turn transistor Q5 on. )

On the other hand, the output of port 1 (P1) turns off transistor Q2 and turns on transistor Q3. As a result, the luminance signal Y output from the Y / C processing unit 60 passes through the buffers B1 and B2, and is supplied to the band pass filter 80. At this time, a predetermined amount of high-frequency noise components are stored in the capacitor C2 and Flow is filtered through transistor Q5 to ground.

That is, since the transistor Q3 is in the on state and the transistor Q4 is in the off state, all of the luminance signals Y passing through the buffer B4 flow to the ground through the transistor Q3, and thus the buffers B1 and B2. The luminance signal Y is supplied to the band pass filter 80 only through.

On the other hand, if the current noise reduction mode stored in the RAM 30 is the noise reduction mode compared to the peripheral illumination, the microprocessor 20 uses the information on the viewing distance input from the illumination detection unit 10.

The illuminance detector 10 detects the brightness of the surroundings and applies the illuminance detector 12 to the illuminance detector 12, and the illuminance detector 12 detects the peripheral illuminance and outputs the peripheral illuminance to the microprocessor 20.

The microprocessor 20 reads the noise reduction level value corresponding to the peripheral illumination input from the illuminance detection unit 10 from the RAM 30 and outputs it to the D / A controller 41 of the noise reduction unit 40. In order to control (Q2 to Q5), high is output to ports 1 and 2 (P1) and P2.

Thus, the output of port 2 (P2) turns on transistor Q4 and turns off transistor Q5, the output of port 1 (P1) turns on transistor Q2 and turns off transistor Q3.

As a result, the luminance signal Y output from the Y / C processing unit 60 passes through the buffers B3 and B4 and is supplied to the band pass filter 80, where a predetermined amount of high frequency noise components are applied to the varactor V1. And through the transistor Q4 to ground.

That is, since the transistor Q2 is in the on state and the transistor Q3 is in the off state, all of the luminance signals Y passing through the buffer B1 flow to the ground through the transistor Q2, and thus the buffers B3 and B4. The luminance signal Y is supplied to the band pass filter 80 only through the transistor, and since the transistor Q5 is also turned off, the high frequency noise component of the luminance signal Y is filtered only through the varactor V1 and the transistor Q4. do.

The amount to be filtered depends on the noise reduction level value that the microprocessor 20 outputs to the D / A controller 41, and the D / A controller 41 analogizes the information (digital signal) on the input noise reduction level. Convert it to a signal and output it in the form of voltage.

Since the capacitor D1 has a characteristic that the capacitance changes according to the applied voltage, the microprocessor 20 changes the value of the noise reduction level outputted to the D / A controller 41, thereby causing a change in the luminance signal Y. The amount of reduction of high frequency noise components can be automatically adjusted.

Hereinafter, the operation of the automatic noise reduction level control apparatus during TVCR tape playback by the microprocessor 20 will be described with reference to the flowchart in FIG. 3.

When the TVCR plays back the tape, the microprocessor 20 periodically determines whether a noise reduction key has been input to a peripheral illuminance by a remote controller (not shown) for the purpose of noise reduction; Changing and storing a current noise reduction mode when a noise reduction key is input relative to a peripheral illumination level as a result of the determination; Reading a current noise reduction mode; Determining a current noise reduction mode; According to the determination result, a process of outputting a corresponding noise reduction level value is performed.

In detail, when the TVCR plays back the tape, the microprocessor 20 determines whether a noise reduction key is input from the remote control to reduce the high frequency noise component of the luminance signal Y while controlling the TVCR as a whole. S1).

As a result of the determination, if a noise reduction key is input relative to the ambient illuminance, the current noise reduction mode stored in the RAM 30 is changed and stored (S2).

That is, the noise reduction key compared to the ambient illumination of the remote controller is toggled so that the viewer can select / deselect the noise reduction compared to the ambient illumination whenever the key is pressed.

On the other hand, as a result of the determination of the step (S1), when the noise reduction key is not input to the ambient illuminance from the remote control or after performing the step (S2), the current noise reduction mode is read from the RAM 30 (S3). It is determined whether the noise reduction mode is a noise reduction mode compared to the ambient illumination (S4).

In the normal noise reduction mode, the high frequency component of the luminance signal Y input to the band pass filter 120 is controlled by outputting a low to ports 1 and 2 (P1) and P2 to control the transistors Q2 to Q5. Is reduced by a certain amount through the capacitor C2 and the transistor Q5 (S8).

On the other hand, in the determination result of the process (S4), if the noise reduction mode compared to the ambient illumination, the information on the ambient illumination input from the illumination detection unit 10 is read, and the value of the noise reduction level corresponding to the current ambient illumination is read from the RAM 30. come. At this time, the RAM 30 stores information on the noise reduction level compared to the peripheral illumination obtained experimentally. The microprocessor 20 outputs the noise reduction level value read from the RAM 30 to the D / A controller 71 of the noise reduction unit 40 and outputs high to the ports 1 and 2 (P1) and P2. By controlling the transistors Q2 to Q3 and the varactor V1, the high frequency component of the luminance signal Y input to the band pass filter 120 is reduced to be suitable for the ambient illuminance (S5 to S7).

Only signals of a specific frequency band among the luminance signals Y having reduced noise components pass through the bandpass filter 120 and are supplied to the Y / C mixer 110, and the Y / C mixer 110 is a composite image. By supplying a signal to the main signal processing unit 90, a screen on which noise is reduced to an appropriate level according to the ambient illumination is displayed on the CRT.

As described above, the present invention includes a noise reduction key in the remote control unit so that the microprocessor can recognize it, and has a peripheral illumination recognition unit to detect the ambient illumination to provide a microprocessor so that the microprocessor makes noise. It automatically adjusts the noise reduction level according to the reduction mode and the ambient light level, and changes the noise reduction level according to the ambient light level so that a smooth picture is always provided to reduce the eyestrain of the viewer.

The present invention has been described with reference to only one embodiment of the automatic noise level adjusting device according to the ambient illumination when playing back the tape of the TVCR as described in the claims, but is not limited to this, and those skilled in the art have many applications and modifications It will be possible.

Claims (4)

Deck 50 reading the signal recorded on the tape through the head to drive the video tape, and Y / C processing unit for processing the signal read from the deck 50 to separate the luminance signal (Y) and chroma signal (C) 60, a Y / C mixer 70 for synthesizing Y / C and supplying the composite video signal CV to the main signal processor 90, and a luminance signal Y of the Y / C processor 70. Bandpass filter 80 which passes only a signal of a specific band of the band) and supplies it to the Y / C mixer 70 again, and a composite video signal input from the Y / C processor to process a color signal (R, G) in a CRT. A TVCR comprising a main signal processor 90 for outputting B) and a microprocessor 20 for performing key operation of the remote controller and controlling the TVCR as a whole, an illumination detector for detecting ambient illumination ( 10); A RAM 30 in which information on the noise reduction level and the noise reduction mode information are stored; And a noise reduction unit (40) for filtering high frequency noise components in the luminance signal (Y) under the control of the microprocessor (20). The method of claim 1, wherein the illuminance detector (10) comprises: an optical sensor (11) for detecting the brightness of the surrounding light; And an illuminance detector (12) for detecting peripheral illuminance from the output signal of the optical sensor (11). The noise reduction unit (40) according to claim 1, further comprising: a D / A controller (41) for converting digital information about a noise reduction level into analog and outputting the analog information; The output signal of the D / A controller 41 which is operated by the control signal of the microprocessor 20 and filters the high frequency noise components included in the luminance signal Y output from the Y / C processing unit 100. And a capacitor (V1), a capacitor (C2), transistors (Q2 to Q5), and buffers (B1 to B4) whose capacitance changes due to the noise reduction level during TV playback. The method of claim 1, wherein the microprocessor 20 recognizes the noise reduction key compared to the ambient illumination input from the remote control, changes the current noise reduction mode and stores it in the RAM 30, noise reduction corresponding to the noise reduction mode Automatic noise reduction level control apparatus for TVCR playback, characterized in that it further comprises a function of reading the level value from the RAM (30) and output to the noise reduction unit (40).