KR100200824B1 - Fading speed control circuit - Google Patents

Abstract

In the video fade speed control circuit according to the present invention, the user can easily grasp the speed and degree of the fade by controlling the speed of the video fade using a microcomputer and displaying the fade speed and the fade progress on the screen using the OSD function. There is this.

Description

Video Fade Speed Control Circuit

1 is a circuit diagram showing a conventional fade in / fade out circuit.

2 is a circuit diagram according to an embodiment of an image fade speed control circuit according to the present invention.

3A to 3D are waveform diagrams showing an example of a fade speed mode that is changed by the second switch among the components of the key input section in FIG.

* Explanation of symbols for main parts of the drawings

10: key input unit 12: micom

14: signal processor 16: OSD

18: screen

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fade speed control circuit of a video signal in a video signal processing apparatus. In particular, the present invention relates to a video fade speed control circuit for controlling a speed of a fade by using a microcomputer and displaying a fade speed and a degree of fade on a screen. .

In general, video signal processing apparatuses include television receivers, video cassette recorders, and camcorders. Among them, a camcorder adds a fade-in / fade-out circuit that gradually disappears or appears gradually in order to increase image effects when the scene changes. Herein, the fade in is a case where the image information gradually appears and the fade out is a case where the image information gradually disappears. Since the operation mode is set by the user's direct control, such a fade in / out function is generally provided with a mode selection switch on the outside of the camcorder.

1 is an example applied to a camcorder as a conventional image fade in / fade out circuit.

Referring to FIG. 1, when the fade switch (not shown) connected to the base terminal of the PNP transistor Q1 is turned on, the fade signal gradually increases through an integrator composed of a resistor R3 and a capacitor C1. do. When this fade switch is turned from on to off, the fade signal gradually decreases.

An integrator consisting of resistor R3 and capacitor C1 causes the fade signal to gradually increase or decrease.

The encoder 1 is to perform a fade function in the camcorder, and is made according to the level of a voltage applied to the fade terminal of the encoder 1. That is, fade occurs when the level of the voltage applied to the fade terminal falls within 2.0 to 2.9 V. When the voltage is 2.9 V, white fade or black fade occurs depending on the selection of the fade mode.

However, in the above-described conventional fade in / fade out circuit, the speed of the fade in / fade out is fixed in hardware, and a full fade in or fade out occurs 3 to 4 seconds after the fade switch is turned on. Therefore, it is difficult to determine the progress of the fade, there is a problem that can not adjust the fade speed.

Accordingly, an object of the present invention is to control the speed of the fade by using a microcomputer to solve the above problems and to display the fade speed and fade progress on the screen using the On Screen Display (hereinafter referred to as OSD) function The present invention provides a video fade speed control circuit for making a user easily grasp by clay.

In order to achieve the above object, the image fade speed control circuit according to the present invention

A signal processor configured to process a signal to generate a composite video signal from an input luminance signal and a color signal;

Key input section for inputting a video fade mode and a fade speed selection key:

A microcomputer for varying a voltage level applied to the signal processor according to a fade mode and a fade speed selected by the key input unit;

It characterized in that it comprises an on-screen display for indicating on the screen the fade mode, the fade progress rate, the fade speed controlled by the micom.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention.

2 is a block diagram according to an embodiment of an image fade speed control circuit according to the present invention.

The block diagram shown in FIG. 2 includes a signal processing unit 14 for signal processing to generate a composite video signal from the inputted luminance myth and color signals, and a key input unit for inputting a key for selecting an image fade mode and a fade speed. (10), the microcomputer 12 for varying the voltage level applied to the signal processor 14 according to the fade mode and the fade speed selected by the key input unit 10, the fade mode controlled by the microcomputer 12, It consists of an on-screen display 16 for indicating the fade progression and fade speed on the screen 18.

3A and 3B are waveform diagrams showing an example of a fade speed mode that is changed by the second switch SW2 among the components of the key input unit 10 in FIG. 2, wherein the mode corresponding to the maximum speed is speed 3; This is an example. 3a is a waveform corresponding to speed 0, 3b is speed 1, 3c is speed 2, and 3d is speed 3. FIG.

The operation of the present invention will now be described with reference to the accompanying drawings.

With reference to FIG. 2, the key input unit 10 includes a first switch SW1 (not shown) that is a fade in / fade toggle switch and a second switch SW2 (not shown) that is a fade speed control switch. Is made of.

Here, the first switch SW1 determines whether the fade mode is set to fade in or fade out, and simultaneously controls the microcomputer 12 to perform the operation of the selected fade mode. That is, whenever the first switch SW1 is pressed, the microcomputer 12 controls to repeat the operation of fade-in → fade-out → fade-in.

The second switch SW2 changes the fade speed mode each time it is pressed. That is, each time the second switch SW2 is pressed, the fade speed in the microcomputer 12 changes from speed 0 to speed 1 to speed 2 to ... For example, when the speed 3 is maximum, the state of FIG. 3 is repeated with reference to FIGS. 3A to 3D.

The signal processor 14 is used to generate an image signal using the input R-Y and B-Y color difference signals. When there is a fade signal, the signal processor 14 adjusts the brightness signal level to adjust the brightness of the image signal.

The microcomputer 12 selects a fade mode and a fade speed from the rising edges of the first and second switches of the key input unit 10. When the fade in is selected, the microcomputer 12 outputs to the digital / analog converter built in the microcomputer 12. Is increased by time zone, and if fade out is selected, the output to digital / analog converter is decreased by time zone to adjust the level of the luminance signal.

The speed is also adjusted by varying the interval between the output change times to the digital / analog converter according to the selected fade speed.

Then, the fade in / out, fade progress rate, and fade speed are displayed on the screen 18 through the OSD 16. FIG.

As described above, the video fade speed control method and circuit according to the present invention controls the speed of the video fade by using a microcomputer and displays the fade speed and fade progress on the screen by using the OSD function. There is an advantage that can be easily identified.

Claims (3)

A signal processor configured to process a signal to generate a composite video signal from an inputted luminance myth and color signal; A key input unit for inputting a key for selecting an image fade mode and a fade speed; When the image fade mode selected by the key input unit is a fade in, the output to the built-in digital / analog converter is increased by time zone, and when the fade out is selected, the output to the digital / analog converter is reduced by time zone and the selected fade is selected. A fade progress output unit controlling a level of a luminance signal according to a mode; A fade speed adjusting unit adjusting the speed by varying an interval between output change times to the digital / analog converter according to the fade speed selected by the key input unit; And an on-screen display for displaying on a screen a fade mode, a fade progress rate, and a fade speed controlled by the fade progress output unit and the fade speed control unit. The image fade speed control circuit of claim 1, wherein the key input unit comprises a first switch which is a fade in / fade out toggle switch and a second switch which is a fade speed control switch. The image fade speed control circuit of claim 2, wherein a fade mode and a fade speed are selected at rising edges of the first switch and the second switch.