GB2262409A

GB2262409A - Video camera fade control.

Info

Publication number: GB2262409A
Application number: GB9225679A
Authority: GB
Inventors: Woon-Hee Na
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 1991-12-09
Filing date: 1992-12-09
Publication date: 1993-06-16
Also published as: DE4241308A1; KR940010173B1; KR930015724A; GB9225679D0; JPH0670231A

Abstract

The apparatus generates a blanking area of blue colour having a triangular shape in each corner of the video image for fading-in or fading-out a video image obtained from video camera 1. Four coordinate determiners 70 - 76 are provided to calculate the coordinates of the transition between the video image and the blanking area which are connected to four area generators 80 - 86. These control blue screen generator 9 to produce the blue blanking area as required. The effect is progressive, the blanking area increasing in size for fade-out, and decreasing for fade-in, controlled by switches 5 and 6 respectively. <IMAGE>

Description

VIDEO CAMERA FADE CONTROL The present invention relates to video signal processing systems for video cameras.

In a typical video camera, when photographing an object, there are fade-in (to become bright gradually from a black level) and fade-out (to become dark gradually from a white level) functions. However, these fade-in and fade-out functions of the video camera are performed usually only between white and black levels. Such a technique is disclosed in Japanese Utility Model Publication No. 2-130169, for example. Thus, the fade-in and fade-out functions may be monotonous.

Preferred embodiments of the present invention aim to provide an apparatus for controlling fade-in and fade-out functions capable of variously diversifying by the use of a blue screen of a triangular shape.

According to one aspect of the present invention, there is provided an apparatus for controlling fade-in and fade-out functions of a video camera, comprising: a video signal processor for processing a video signal photographed in said camera and recording said video signal via a video tape recorder; a synchronizing signal separator connected to receive said video signal and to detect vertical and horizontal synchronizing signals therefrom; a fade-in switch connected to said synchronizing signal separator, for selecting a key signal for a fade-in function; a fade-out switch connected to said synchronizing signal separator, for selecting a key signal for a fade-out function; a microprocessor connected to said synchronizing signal separator, for generating a control signal and a coordinate signal in response to a number of pulses of said horizontal synchronizing signal;; first to fourth coordinate determiners connected to said microprocessor, for varying coordinates from respective corners of a display screen in response to said coordinate signal; first to fourth area generators connected to said first to fourth coordinate determiners, respectively, each for generating a respective area of a triangular shape; and a blue screen generator connected to said first to fourth area generators, for generating a blue screen corresponding to each of said areas.

Preferably, said blue screen is gradually increased in triangular areas of the same size from respective corners of a display screen when the fade-out function is performed, to erase progressively the video signal of an object.

Preferably, said blue screen is gradually decreased in triangular areas of the same size towards respective corners of a display screen when the fade in function is performed, to display progressively the video signal of an object.

According to another aspect of the present invention, there is provided an apparatus for controlling fade-in and/or fade-out in a video camera, the apparatus comprising means for receiving a video image signal to be displayed, means for generating a blanking signal of a predetermined pattern, and means for progressively replacing one of said signals with the other so as to fade into or out of said image signal.

Preferably, said predetermined pattern comprises a solid colour other than black, white or grey.

An apparatus as above may further comprise any one or more of the features disclosed in the accompanying specification, claims, abstract and/or drawings, in any combination.

The invention extends to a video camera provided with an apparatus according to any of the preceding aspects of the invention.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which: Figure 1 is a block diagram of one example of an apparatus for controlling fade-in and fade-out functions of a video camera according to the present invention; Figure 2 is a diagram showing a television screen of NTSC system having 525 scanning lines and a 15,734 Khz horizontal synchronizing frequency; Figure 3 is a flow chart illustrating fade-in and fade-out functions of the apparatus of Figure 1; and Figures 4A to 4F are diagrams showing examples of a television screen when fade-in and fade-out functions are performed.

Referring to Figure 1, a video signal for an object photographed by a camera 1 is a composite video signal including a synchronizing signal. The composite video signal is applied to a video signal processor 2 and to a synchronizing signal separator 3. The video signal processor 2 records the video signal generated from the camera 1 via a video tape recorder (not shown). The synchronizing signal separator 3 extracts a vertical synchronizing signal V-sync and a horizontal synchronizing signal H-sync from the video signal generated from the camera 1 and supplies the vertical and horizontal synchronizing signals to a microprocessor 4. The microprocessor 4 checks whether or not the vertical and horizontal synchronizing signals are applied and the number of pulses of the vertical and horizontal synchronizing signals being received.Moreover, the microprocessor 4 generates control signals for controlling the video signal processor 2 and the camera 1.

As is well known in the art, since the camera 1 and the video signal processor 2 are controlled by the control signal generated from the microprocessor 4, if the camera 1 photographs an object and provides the video signal to the video signal processor 2, the video signal processor 2 controls the video signal of the object to be recorded on the video tape recorder.

If a user depresses a fade-in switch 5, the microprocessor 4 senses a signal applied to a first port A and operates a fade-in function. Similarly, if a fade-out switch 6 is selected, the microprocessor 4 operates a fade-out function by sensing a signal applied to a second port B. For carrying out the fade-in and fade-out functions, the microprocessor 4 counts the number of pulses of the horizontal synchronizing signal produced from the synchronizing signal separator 3. In response to the number of counted pulses, the microprocessor 4 generates an output signal (x,y) to first to fourth coordinate determiners 70, 72, 74 and 76.

As shown in Figure 2, the first to fourth coordinate determiners 70 to 76 determine the position of coordinates which are obtained by dividing a 15,734 KHz horizontal synchronizing frequency of an abscissa and 525 scanning lines of an ordinate by 100, respectively. The first coordinate determiner 70 produces a control signal for setting a coordinate A(4x,21y) from a coordinate (0,0). Similarly, the second, third and fourth coordinate determiners 72, 74 and 76 generate control signals for setting coordinates B(4x,525-21y), C(100-4x, 525-21y) and D(100-4x,21y) from coordinates (0,525), (100,525) and (100,0), respectively. In this case, variables x and y are the same positive number. Hence, whenever the number of pulses of the horizontal synchronizing signal are incremented by 4, the microprocessor 4 increases the variables x and y of the coordinate (x,y) by 1. Consequently, whenever the microprocessor 4 generates an increased output signal, the first to fourth coordinate determiners 70 to 76 generate coordinate determining control signals such that a respective area of triangular shape is increased toward a central point P of the display screen. Further, whenever the microprocessor 4 produces a decreased output signal, the first to fourth coordinate determiners 70 to 76 generate the coordinate determining control signals such that each respective area of triangular shape is decremented from the central point P toward the respective corner of the screen.

The coordinate determining control signals generated from the first to fourth coordinate determiners 70 to 76 are supplied to first to four area generators 80, 82, 84 and 86. The first to fourth area generators 80 to 86 generate the above-mentioned areas 250, 252, 254 and 256 of triangular shape. The outputs of the first to fourth area generators 80 to 86 are applied to a blue screen generator 9. The blue screen generator 9 supplies a blue chrominance signal corresponding to the area of the triangular shape generated from the first to fourth area generators 80 to 86 to the video signal processor 2 under the control of the microprocessor 4. At this time, the video signal processor 2 mutes the video signals of each of the areas 250 to 256 of triangular shape.For example, if the output signal (x,y) of the microprocessor 4 is increased from (0,0) to (8,8), the areas 250 to 256 of triangular shape and blue screen are increased from the respective corners of the television screen (or other display screen). However, if the output signal (x,y) is decreased from (8,8) to (0,0), the areas 250 to 256 of triangular shape are decreased towards the respective corners of the television screen.

That is, each blue screen area of triangular shape is incremented or decremented by the same amount.

Referring to Figure 3, in order to process the fade-in and fade-out functions, there are provided a mode checking process for checking whether or not a fade-in or fade-out mode is selected, a fade-in process for reducing the areas of triangular shape towards the corners of the screen when the fadein mode is selected, and a fade-out process for increasing the areas of triangular shape towards the central point of the screen when the fade-out mode is selected.

An example of operation of the apparatus of Figure 1 will now be described with reference to Figures 1 to 4F.

Referring again to Figure 1, the video signal of an object photographed in the camera 1 is applied to the video signal processor 2 and recorded via a video tape recorder by a control signal generated from the microprocessor 4.

The vertical and horizontal synchronizing signals included in the video signal are detected in the synchronizing signal separator 3 and applied to the microprocessor 4. If the fade-in or fade-out switch 5 or 6 is not selected, the microprocessor 4 generates control signals of logic "low" state through terminals C and D. Then the blue screen generator 9 does not produce a blue screen and the video signal photographed in the camera 1 is recorded via the video tape recorder.

If a user depresses the fade-out switch 6, the fade-out function is performed. That is, the microprocessor 4 senses this in step 101 and checks whether or not a horizontal synchronizing signal is applied in step 102. If the horizontal synchronizing signal is applied, the microprocessor 4 counts the number of pulses of the horizontal synchronizing signal in step 103. In step 104, the number of pulses of the horizontal synchronizing signal is checked to see if it is 4. If the number of pulses of the horizontal synchronizing signal is 4, the microprocessor 4 supplies, in step 105, an output signal (1,1) to the first to fourth coordinate determiners 70 to 76. The first to fourth coordinate determiners 70 to 76 respectively generate coordinates (4,21), (4,504), (96, 504) and (96,21), and these values are applied to the first to fourth area generators 80 to 86.The first to fourth area generators 80 to 86 generate triangular area signals and supply the signals to the blue screen generator 9.

Then the blue screen generator 9 produces a blue screen corresponding to the areas of the triangular area signals of the first to fourth area generators 80 to 86 under the control of the microprocessor 4. The blue screen of triangular shape is provided to the video signal processor 2 and the video signal processor 2 increases the blue screen area by the same amount from each corner of the television screen by the control signal generated at terminal D of the microprocessor 4, to mute the video signal photographed in the camera 1.

In step 107, the microprocessor 4 checks whether or not the horizontal synchronizing signal exists. If there is the horizontal synchronizing signal, a count value n of the microprocessor 4 is incremented by 1 in step 108. As a result, the area of the triangular shape shown in Figure 2 is gradually increased. These steps are repeated until the count value n is 25.

Meanwhile, the output signal (x, y) is gradually increased, and the blue screen formed by the first to fourth coordinate determiners 70 to 76 becomes bigger and bigger. If the count value n of microprocessor is 25, the television screen is totally filled with the blue screen. In other words, the television screen mutes all video signal photographed in the camera 1.

When photographing an object, if a user does not depress the fade-out switch 6, the video signal of. the object is displayed on the television screen as shown in Figure 4A. If the count value n is 12, the object is partially cut off by the blue screen as indicated in Figure 4B. The greater the count value n, the larger the blue screen becomes, as shown in Figures 4C to 4E.

Moreover, when the count value n is 25, the television screen is filled with the blue screen as shown in Figure 4F.

In step 101, if the fade-out switch 6 is not selected, the microprocessor 4 checks, in step 110, whether or not the fade-in switch 5 is depressed. If the fade-in switch 5 is not selected, the video signal photographed in the camera 1 is normally recorded via the video tape recorder. If the fade-in switch 5 is depressed, the microprocessor 4 checks, in step 111, whether or not the horizontal synchronizing signal is applied. If the horizontal synchronizing signal is applied, the microprocessor 4 generates the output signal (25,25) in step 112. The output signal (25,25) is applied to the first to fourth coordinate determiners 70 to 76 to determine coordinates and the first to fourth area generators 80 to 86 produce the respective areas of triangular shape. The areas of triangular shape are provided to the blue screen generator 9 and the television screen is filled with the blue screen. In this case, the microprocessor 4 generates the control signals through the terminals C and D for controlling the blue screen generator 9 and the video signal processor 2.

Moreover, if (100-4n) horizontal synchronizing signals are applied, the microprocessor 4 produces the output signal (24,24) in step 114. By repeating the loop formed by steps 114 to 118, the blue screen is gradually decreased and the object appears. If the count value n is 25, the object to be photographed is displayed on the entire screen. Consequently, when photographing an object, if a user depresses the fade-in switch, the blue screen shown in Figure 4F is displayed as first on the television screen and gradually the blue screen is decreased to reveal finally the full screen, as indicated in Figure 4A.

As described above, when the fade-out switch 6 is selected, the television screen displays the video signal as shown in Figure 4A. Thereafter, the video signal gradually disappears and the blue screen is displayed. On the other hand, if the fade-in switch 5 is selected, the television screen gradually displays the video signal in Figure 4A from the initial blue screen in Figure 4F.

The illustrated apparatus provides fade-in and fade-out functions using a blue screen by forming areas of triangular shape. Thus, the enhanced fadein and fade-out functions can be obtained.

While preferred embodiments of the present invention have been particularly shown and described, it will be understood by those skilled in the art that foregoing and other changes in form and details may be made without departing from the spirit and scope of the present invention.

The invention may be applied to systems other than NTSC systems such as, for example, the PAL and SECAM systems used in Europe and elsewhere.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMS:

1. An apparatus for controlling fade-in and fade-out functions of a video camera, comprising: a video signal processor for processing a video signal photographed in said camera and recording said video signal via a video tape recorder; a synchronizing signal separator connected to receive said video signal and to detect vertical and horizontal synchronizing signals therefrom; a fade-in switch connected to said synchronizing signal separator, for selecting a key signal for a fade-in function; a fade-out switch connected to said synchronizing signal separator, for selecting a key signal for a fade-out function; a microprocessor connected to said synchronizing signal separator, for generating a control signal and a coordinate signal in response to a number of pulses of said horizontal synchronizing signal;; first to fourth coordinate determiners connected to said microprocessor, for varying coordinates from respective corners of a display screen in response to said coordinate signal; first to fourth area generators connected to said first to fourth coordinate determiners, respectively, each for generating a respective area of a triangular shape; and a blue screen generator connected to said first to fourth area generators, for generating a blue screen corresponding to each of said areas.

2. An apparatus for controlling fade-in and fade-out functions of a video camera as claimed in claim 1, wherein said blue screen is gradually increased in triangular areas of the same size from respective corners of a display screen when the fade-out function is performed, to erase progressively the video signal of an object.

3. An apparatus for controlling fade-in and fade-out functions of a video camera as claimed in claim 1, wherein said blue screen is gradually decreased in triangular areas of the same size towards respective corners of a display screen when the fade-in function is performed, to display progressively the video signal of an object.

4. An apparatus for controlling fade-in and/or fade-out in a video camera, the apparatus comprising means for receiving a video image signal to be displayed, means for generating a blanking signal of a predetermined pattern, and means for progressively replacing one of said signals with the other so as to fade into or out of said image signal.

5. An apparatus according to claim 4, wherein said predetermined pattern comprises a solid colour other than black, white or grey.

6. An apparatus according to claim 4 or 5, further comprising any one or more of the features disclosed in the accompanying specification, claims, abstract and/or drawings, in any combination.

7. An apparatus for controlling fade-in and/or fade-out in a video camera, the apparatus being substantially as hereinbefore described with reference to the accompanying drawings.

8. A video camera provided with an apparatus according to any of the preceding claims.