KR0162418B1 - Apparatus for changing picture of digital tv - Google Patents

Abstract

The present invention relates to an apparatus for screen switching of digital TVs. In the related art, since an overlap function is performed during sudden screen switching, flashing occurs due to overlapping of images, and there is a problem that it cannot be applied to compression of a digital video signal. In order to solve this problem, the present invention performs a fade out function for a predetermined time for the previous frame and a predetermined time for the next frame when a sudden screen change occurs in the fade out / in mode. The present invention is designed to perform a fade-in function. When the screen changeover is detected, the present invention performs a fade out / in function instead of performing an overlap function. Therefore, the image can be prevented from bursting due to a sudden screen change. By increasing the correlation, the compression ratio in the compression of the digital video signal can be improved.

Description

Digital TV Screen Switcher

1 is a block diagram of a conventional fade out device.

2 is a waveform diagram of a multiplication coefficient.

3 is a characteristic curve diagram of the overflower 102.

4 is a timing diagram of FIG.

5 is an exemplary diagram of a fade out screen.

6 is a block diagram of a screen switching device of the present invention.

7 is a configuration diagram of a screen switching determination circuit in FIG.

8 is a configuration diagram of a multiplication coefficient generation circuit in FIG.

9 is a waveform diagram for fade out / in processing.

10 is a timing diagram of FIG.

* Explanation of symbols for main parts of the drawings

201: path switching unit 202: delay unit

203: Screen change detection unit 204: Multiplier

205: digital to analog converter 206: remote control

207; Microcomputer 211: Adder

212: vector size calculation circuit 213: screen switching determination circuit

214: multiplication coefficient generation circuit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to screen switching of a digital TV, and more particularly, to a screen switching device of a digital TV that can prevent a screen bleeding by performing a fade out / in function during sudden screen switching.

FIG. 1 is a block diagram of a conventional fade-out circuit, as shown therein. In the normal mode, the input digital video signal Vi is passed as it is, and in the fade-out mode, the fade-out video signal VF passes through the video signal Vi. Adder 101 for adding and outputting, an over-plug 102 for limiting the output level of the adder 101, and a digital-to-analog converter for converting the digital output signal of the over-plug 102 into an analog signal. 103, a frame memory 104 delaying one frame of the video signal output from the overflow 102 by one frame, and the frame memory 104 according to the normal / fade out signal (N / F). ) Leads / light signals (R / ), A memory control unit 107 for outputting a signal, a remote control transmitter 105 for transmitting a selection key signal of a viewer, a multiplication coefficient α corresponding to the output signal of the remote control transmitter 105, and a normal / fade out signal ( / F) to multiply the multiplication coefficient α of the remote control receiver 106 by the frame video signal in the frame memory 104 to multiply the fade-out video signal _VF . The multiplier 106 outputs to the adder 101.

Referring to the operation of the prior art as follows.

When the digital image signal Vi is input to the adder 101 as the image data F1, F2, F3, ... F3 in units of frames as shown in FIG. 4A, the viewer selects a fade out mode on the remote controller. If the normal mode is not set, the remote control receiver 106 may generate a normal signal as shown in FIG. ) Is activated at a low potential, so that the memory controller 107 causes the read signal R to be inactive at low potential as shown in FIG. 4 (d) and write signal as shown in FIG. Will be activated at low potential.

In this case, as shown in FIG. 4E, the frame memory 104 continuously writes the video signal of the current frame output from the overflow 102 without reading the video signal of the previous frame. .

Accordingly, the fade-out video signal VF of the multiplier 108 is not input to the adder 101, so that the image data F1-F3 in the unit of image frame is applied to the adder 101 as shown in FIG. It passes through as it is and is transmitted to the overflow 102.

The overflow 102 increases the level of the signal V _B in proportion to the input signal V _A as shown in FIG. 3, and then increases the output level when the input signal V _A reaches the predetermined level V ₁ . The output will be at a certain level without the need.

This is to prevent the circuit loop from oscillating by excessive output.

Therefore, when the digital video signal output from the overflow 102 is converted into an analog signal by the digital / analog converter 103 and output, the cathode ray tube displays a single screen according to the input video signal Vi.

On the other hand, when the viewer selects the fade out mode key on the key matrix of the remote control and transmits the signal according to the remote control transmitter 105, the remote control receiver 106 receives the moment when the transmission signal of the remote control transmitter 105 is input (for example, At the point of time F4, as shown in FIG. 4 (b), the normal signal ( Inactive at high potential, while fade-out signal F is active at high potential.

Accordingly, the memory control unit 107 causes the write signal (as shown in FIG. ) Is inactive at a high potential and outputs, whereas the read signal R is active at a high potential as shown in FIG. 4 (d), and outputs the frame signal 104 to the image signal F3 of the last frame of the normal mode. After writing, the previous frame image signal F3 currently stored as shown in FIG.

At this time, the multiplier 108 multiplies the video signal F3 of the previous frame input from the frame memory 104 by the multiplication coefficient signal α0-α4 as shown in FIG. As shown in FIG. 4 (f), the output signal is output as a fade-out video signal V _F.

As a result, the adder 101 fades out the video signals VF = α0 · F3, α1 · F3, α2 · F3 from the multiplier 108 to the frame image signals F4, F5, F6, ... currently input. When the frame image signal is output as shown in FIG. 4 (g), the overflow 102 and the digital / analog converter 103 are sequentially transmitted to the cathode ray tube.

Therefore, in the first screen, the previous frame video signals α0 and F3 overlapping with the current frame video signal F4 are displayed the same, but as shown in FIG. 2, the multiplication coefficient α is one frame (1 / 30sec). By gradually falling from α0 → α1 → α2 → ---, the screen of the previous frame overlapped as shown in FIG. 5 becomes thinner gradually and disappears from the screen as soon as the multiplication coefficient α becomes “0”.

The above operation is a case where the user presses the fade out mode key once on the remote controller. When the key is pressed continuously, the fade out screen is displayed continuously, and the holding time of the multiplication coefficients α0, α1, α2, and-is maintained. By adjusting, you can change the fade out rate.

However, in the related art, since the overlapping function of the image is performed when the screen is changed suddenly, there is a problem that the image is blurred due to the overlap.

In addition, the prior art is not applicable to the compression of a digital video signal, but merely adds a TV function.

In order to solve the conventional problem, the present invention suddenly performs a fade-out function for a predetermined time for a previous frame and a fade-in function for a predetermined time for a next frame in the case of a sudden screen change. It is an object of the present invention to provide a digital TV screen switching device that can prevent the blurring of an image generated during screen switching and improve the compression ratio when compressing a digital video signal by increasing the correlation between adjacent frames. .

The present invention is a path switching means for switching the output path of the digital input video signal (Vi) according to the fade out / in processing to achieve the above object, and outputting in the path switching means in the case of setting the fade out / in processing Delay means for delaying a predetermined digital video signal for a predetermined time; and screen switching for determining a multiplication coefficient α according to whether the screen is switched or not by estimating the motion of the i-th frame and the (i-1) -th frame of the delay means detecting means, the display switching detection multiplication means for means for outputting a video signal (V _FI), which is multiplied by the multiplication factor (α) to the output of the delay means and the output signal (V _FI) or the path switching of the multiplication means Digital / analog conversion means for analog-converting the video signal Vi input through the means, remote control means for selecting functions such as fade out / in processing, and the number of the remote controllers. If the transmission signal is the signal corresponding to the setting of the fade-out / in processing mode, and a control means for outputting a control signal (Sctl) to couple to said path switching means to the delay means.

The screen change detection means comprises: an adder for detecting the i-th frame Fi and the (i-1) th frame Fi-1 by the delay means and obtaining the difference F _i -F _i-1 ; A vector magnitude calculating circuit that calculates the magnitude of the motion vector based on the calculated difference value (Fi-Fi-1), and if the magnitude of the motion vector of the vector magnitude calculating circuit is larger than the reference value, it is determined that the screen is switched and a high signal is outputted. A screen switching determination circuit that outputs a low signal when it is determined that it is not a screen switching, and a signal whose fading out / in waveform is output as a multiplication coefficient α when the output of the screen switching determination circuit is high and “l” when it is low. Is constituted by a multiplication coefficient generating circuit that outputs a multiplication coefficient α.

Hereinafter, the present invention will be described in detail with reference to the drawings.

6 is a block diagram of the present invention, as shown therein, a path switching unit 201 for switching the output path of the digital input video signal Vi according to whether the fade out / in processing is set, and the fade out / in processing. A delay unit 202 for delaying the digital video signal Vi output from the path switching unit 201 for a predetermined time by setting the mode, the i-th frame and the (i-1) -th frame of the delay unit 202; Outputting the multiplication coefficient α of the screen switching detection unit 203 and the multiplication coefficient α of the screen switching detection unit 203 to estimate the multiplication coefficient α by estimating whether the screen is switched by estimating the motion of the screen. A digital / analog converter for analog-converting the multiplier 204 multiplied by (V _F ) and the output signal V _FI of the multiplier 204 or the video signal Vi output from the path switching unit 201 ( 205, remote controller 206 for selecting keys for setting desired functions, and If the transmission signal of the mocon 206 is a signal according to the fade out / in processing mode selection, the path switching unit 201 is composed of a microcomputer 207 which outputs a control signal Sctl so as to be connected to the delay unit 202. do.

The screen change detector 203 adds the difference value F _i -F _i-1 obtained by the delay unit 202 to the i-th frame Fi and the (i-1) th frame Fi-1. And the vector magnitude calculating circuit 212 for calculating the difference value Fi-Fi-1 of the adder 211 as the magnitude of the motion vector, and whether the magnitude of the motion vector of the vector magnitude calculating circuit 212 is larger than the reference value. If the output of the screen switching determination circuit 213 is high and the output of the screen switching determination circuit 213 is judged to be the screen switching, and the output is a high signal. The multiplication coefficient generating circuit 214 outputs data of the waveform of / and outputs a signal of "l" if it is low.

Referring to the operation and effect of the present invention configured as described above are as follows.

The path switching unit 201 may select whether to output the digital video signal Vi without performing a fade out / in process or perform a fade out / in process according to the control signal Scl of the microcomputer 207. have.

That is, when the digital image data Vi in the frame unit is input to the path switching unit 201, the microcomputer 207 does not set the fade out / in processing mode with the remote controller 206. The operation of the path switching unit 201 is controlled to input the digital image data Vi to 205.

At this time, since there is no input of the digital video signal Vi to the delay unit 202, there is no video signal output from the multiplier 204.

Accordingly, the digital / analog converter 205 converts the digital video signal Vi, which has passed through the path switch 201, into an analog signal and outputs the analog signal to the cathode ray tube to display a single signal according to the digital video signal Vi on the screen. The image is displayed.

On the other hand, when the user sets the fade out / in processing mode with the remote controller 206 when the digital image data Vi in the frame unit is input to the path switching unit 201, the micro signal that has received the transmission signal of the remote controller 206 is used. The computer 207 controls the operation of the path switching unit 201 such that the digital image data Vi is input to the delay unit 202.

Accordingly, the delay unit 202 sequentially delays the digital video signal Vi passing through the path switching unit 201 through (2n + 1) frame delays and outputs the result to the multiplier 204.

At this time, the screen change detection unit 203 detects the i-th frame Fi and the (i-1) -th frame Fi-1 of the delay unit 202 to determine whether to change the screen, and adds the motion. When 211 detects the difference F _i -F _{i + 1} between the i th and (i + 1) th frame F _i (F _{i + 1} ), the vector magnitude calculating circuit 212 causes the difference value ( F _i -F _{i + 1} ) is calculated as the magnitude of the motion vector for the digital image signal Vi, and the screen switching determining circuit 213 as shown in FIG. 7 compares whether the magnitude of the motion vector is larger than the reference value.

Accordingly, when the magnitude of the motion vector is smaller than the reference value, the screen change determining circuit 213 determines that the screen is not changed and outputs a low signal to the multiplication coefficient generating circuit 214 as shown in FIG.

Therefore, since the multiplication coefficient generating circuit 214 outputs a multiplication coefficient α having "l", the multiplier 204 outputs the delay signal V _F of the delay unit 202 to the digital / analog converter 205. Therefore, the monitor displays a single image with a predetermined time delay.

On the contrary, when the magnitude of the motion vector is larger than the reference value, the screen switching determination circuit 213 determines that the screen is switched and outputs a high signal to the multiplication coefficient generation circuit 214.

At this time, the multiplication coefficient generating circuit 214 outputs fade out / in data such as the waveform of FIG. 9 to the multiplier 204 with the multiplication coefficient α.

Therefore, since the multiplier 204 multiplies the delay signal V _F of the delay unit 202 by the multiplication coefficient α and outputs it to the digital / analog converter 205, the image of the previous frame is gradually darkened on the screen of the monitor. After losing, the video of the current frame is gradually lightened and displayed.

The above operation will be described with reference to FIGS. 9 and 10, for example, when the frame delay is "9".

The timing diagram of FIG. 10 illustrates a case in which a screen change occurs abruptly in the fifth frame F5 of the digital image signal Vi delayed by the delay unit 202. When a high signal is output by screen switching determination, the multiplication coefficient generation circuit 214 fades out the previous four frames based on the '5' th frame F5, as shown in FIG. 10 (b). And multiplication coefficient? Of the waveform as shown in FIG. 9 is outputted so as to fade out each of the next four frames.

At this time, in order to perform fade out and fade in processing based on the frame F5, whether the screen is switched is calculated during the period of the '0' th frame F0 and '6' during the period of the '1' th frame F1. Since the operation of calculating whether to change the screen is sequentially performed at the 'th frame F6, the screen change detection time is five previous frame periods.

In general, when the frame delay is (2n + 1), whether or not the screen is switched in (n + 1) previous frames is calculated.

Here, the multiplication coefficient α for fade out / in processing by screen switching is “1 → 3/4 → 2/4 → 1/4 → 0 → 1/4 → 2/4 → 3/4 → 1”. It is calculated in order and output to the multiplier 204.

Accordingly, when the output V _FI of the multiplier 204 is converted into an analog signal by the digital / analog converter 205 and output to the monitor, the four previous frames F1 to F4 based on the frame F5 in which the screen change occurs. ) Is gradually darkened and disappears from the reference frame F5, and the next four frames F6 to F9 gradually lighten to display an image.

As described in detail above, when the screen change occurs, the present invention performs a fade out / in function instead of an overlap function, thereby preventing bleeding of the image due to sudden screen change and increasing correlation between adjacent frames. As a result, the compression rate may be improved when the digital video signal is compressed.

Claims (5)

Path switching means for switching the output path of the digital input video signal Vi by the control signal Sctl depending on whether the fade out / in mode is set, and outputting from the path switching means by setting the fade out / in mode. A delay means for delaying the digital video signal Vi for a predetermined time, and a multiplication coefficient α as the screen transition is determined by detecting motions of the i-th frame and the (i-1) -th frame of the delay means. A screen switching detection means for determining a multiplier, a multiplication means for multiplying the multiplication coefficient? Of the screen switching detection means by the output of the delay means, and an image inputted to the output signal VFI of the multiplication means or the path switching means. Digital / analog conversion means for analog-converting the signal Vi, and control means for controlling the path switching means in accordance with a remote control signal. Digital TV screen switching device. The method of claim 1, wherein the path switching means outputs the digital input video signal Vi to the digital / analog converting means when the fade out / in mode is not set, and to the delay means when the fade out / in mode is set. Digital TV screen switching device, characterized in that configured as a switch. The digital TV screen switching device according to claim 1, wherein the delay means is configured by connecting (2n + 1) frame delay units in series. The adder according to claim 1, wherein the screen change detection means detects the first frame Fi and the (i-1) th frame Fi-1 from the delay means and obtains the difference F _i -F _i-1 . And a vector magnitude calculating circuit for calculating the difference value (Fi-Fi-1) of the adder as the magnitude of the motion vector, and a screen switching for judging whether or not to switch the screen by comparing the motion vector magnitude and the reference value of the vector magnitude calculating circuit. A discrimination circuit and a multiplication coefficient generating circuit for outputting a multiplication coefficient α when judging occurrence of screen switching and outputting data of "l" when judging that no screen switching occurs. Digital TV's screen switching device. The digital screen switching circuit of claim 4, wherein the screen switching determination circuit determines that screen switching occurs when the vector size of the vector size calculating circuit is larger than a predetermined reference value, and that no screen switching occurs when the screen switching determination circuit is smaller. Device.