JPH02280472A - Video camera - Google Patents

Abstract

PURPOSE:To form a superimpose picture without using troublesome constitution by providing a storage means storing a video signal, extracting selectively an area of a specific color of a picture represented by a video signal and synthesizing the stored picture and other picture during being picked up. CONSTITUTION:This camera is provided with a synchronization control means 14 outputting a video signal from an image pickup means 12 and reading a video signal stored from a storage means 20, a 1st selection means 28 outputting selectively the video signal outputted from the image pickup means 12 and the video signal read from the storage means 20 to an output means, and a color detection means 22 detecting it when a signal representing a specific color is included in the video signal obtained from one of the image pickup means 12 and the storage means 20 and controlling the 1st selection means 28 in response to the result of detection. When the detection means 22 detects the signal of the specific color, the video signal obtained at that time from one of the image pickup means 12 and the storage means 20 is replaced into the other video signal and then outputted to apply synthesis of the picture. Thus, the video camera capable of synthesizing the picture with high operability is obtained in this way.

Description

TECHNICAL FIELD The present invention relates to image signal synthesis equipment, and more particularly to a video camera that synthesizes a plurality of images using a chromakey signal.

In recent years, with the spread of video cameras and video tape recorders, there has been a demand for diversification of methods for photographing and recording subjects. For example, people and scenery that have been photographed separately are superimposed, and characters such as a title and date are combined and recorded in one image.

In the prior art, such images are synthesized using a method in which, for example, two video cameras simultaneously capture separate images and the two are synthesized using a chroma key. When combining video signals output from two video cameras into a single image according to chromakey, both cameras need to operate in precise synchronization. Therefore, we genlocked the two video cameras using a synchronization signal generator using a phase-locked loop.
The conventional method was to combine the video signals from both cameras synchronously and use a specific color signal included in the video signal from one camera as a chroma key. In this system,
For example, one video camera may be used to record a person against a background of a certain color, while the other camera may be used to record another scene. By using the background color as a chroma key, extracting the signal of the person and adding it to the background part of the landscape image, it is possible to synthesize both images. As described above, in the conventional method, two video cameras had to be used and synchronized adjustment between them was required, and the device was therefore bulky and lacked maneuverability.

Also, for example, JP-A-54-1131229, JP-A-54-1131229, JP-A-54-1131229
-142092゜59-19490 and 83-9
No. 0285 discloses an image synthesis device that synthesizes images using chromakey. All of these conventional image synthesis devices utilize chroma key signals to obtain special effects such as reduction and color change. A compact image synthesis device that is easy to operate has not yet been realized.

OBJECTS It is an object of the present invention to overcome the drawbacks of the prior art and to provide a video camera with high operability that can perform image composition.

DISCLOSURE OF THE INVENTION According to the present invention, a video camera having an imaging means for capturing an image of a field and outputting a video signal representing the field, and an output means for outputting a video signal stores the video signal. driving the storage means, the imaging means, and the storage means in synchronization;
Synchronous control means for outputting a video signal from the imaging means and reading the stored video signal from the storage means, and selectively outputting the video signal output from the imaging means and the video signal read from the storage means to the output means. A first selecting means for outputting, detecting when a signal representing a specific color is included in the video signal obtained from one of the imaging means and the storage means, and depending on the result of this detection, and a color detection means for controlling the selection means.When the one-color detection means detects a signal of a specific color, it controls the first selection means and outputs the image signal obtained at that time from one of the imaging means and the storage means. , the video signal obtained from the other of the imaging means and the storage means is replaced and outputted from the output means, thereby synthesizing the image.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described in detail with reference to FIG. FIG. 1 shows a block configuration of an embodiment of a video camera according to the present invention. This video camera is a photographing device with a chroma key function that photographs a scene with an image sensor 12, combines two images according to a chroma key designation, and outputs the composite image from an output 44. This basically includes a synchronization signal generation circuit 14, a timing generation circuit 16, a process amplifier circuit 18, a memory 20, a color comparison circuit 22, an operation mode control circuit 24, and an encoder 26. In this embodiment, each of these components is housed in a single housing to construct an easy-to-handle video camera.

A lens 1o is arranged on the incident optical axis of the image sensor 12,
Light from the subject is incident on the image sensor 12 through the lens 10. As the image sensor 12, a solid-state image sensor, such as a COD, is advantageously applied, and a video signal corresponding to incident light is outputted at an output of 6 degrees.

The output 60 of the image sensor 12 is connected to a process amplification circuit 18, which clips the video signal below a specified level, removes noise and distortion, corrects the gradation, and performs a signal specific to the image sensor 12. This circuit forms a luminance signal Y and color difference signals R-Y and B-Y from the color signals of the pixel array. These outputs 66 of process amplifier circuit 18 are connected to encoder 28 through switch 28 , to color comparison circuit 22 through switch 30 , and directly to memory 20 .

The encoder 26 converts the luminance signal Y and color difference signals R-Y, B-Y from the process amplifier circuit 18 into, for example, NTS
This is a signal processing circuit that converts into a C format composite color video signal and outputs it to the video output terminal 44. Of course, the video output terminal 44 may be a PAL or SECAM format instead of NTSC, for example, a video monitor,
An image output device such as an electronic viewfinder and/or video recorder is connected.

The color comparison circuit 22 receives a color selection signal from the operation mode control circuit 24 to be described later, and compares this with the color difference signals R-Y and B-Y from the process amplifier circuit 18 to generate a color selection signal. This circuit outputs a chromakey signal from its output 84 when a video signal of a specific color portion designated by is input.

The output 64 of the color comparison circuit 22 is connected to the drive circuit of the switch 28. The switch 28 selectively takes one of two connection states in response to the chroma key signal obtained from the output 84 of the color comparison circuit 22, and connects the process amplifier circuit 1.
This is a selection circuit that selectively connects the input 86 from 8 or the input 68 from memory 2o to encoder 26.

The memory 20 is a temporary storage circuit that converts the video signal output from the process amplifier circuit 18 into digital data and stores it, and has a storage capacity that can store, for example, a video signal for one field or frame, that is, one frame. Includes RAM with Memory 20 also. It has an output 68 that converts the accumulated video signal data into a corresponding analog signal and outputs it, and this output 68 is connected to the encoder 26 via the other terminal of the switch 28 as shown. Reading and writing of memory 20 is controlled from operating mode control circuit 24 through its control ratio cuff 6.

Among the outputs 68 of the memory 20, the color difference signals R-Y and B-
Y is also connected to the input of the color comparison circuit 22 via the switch 30. The switch 30 is connected to the operation mode control circuit 2.
In response to the operation mode signal supplied from the output cuff 0 of No. 4, one of the two connection states is selectively taken, and the input 66 from the process amplifier circuit 18 or the input 68 from the memory 20 is selectively compared in color. This is a selection circuit connected to the circuit 22.

The operation mode control circuit 24 is a control circuit that controls the chroma key operation and title insertion operation of this device, and the chroma key operation switch 3 is used to manually set various operation conditions.
6, a color selection switch 38 and a chroma key/title changeover switch 40. The control circuit 24 controls the memory 20 according to the conditions set by these key switches.
writing/reading, chromakey output of color comparison circuit 22,
and controls the operation of switch 30.

The chromakey activation switch 36 is a manual switch that instructs the device to perform image synthesis.
The color selection switch 3 is a key switch for specifying a specific color to be used as a chroma key signal, and in this embodiment, three operating positions are used to selectively specify one of three colors, for example, three primary colors. This device can also selectively combine two images using chroma keying and insert a full-color title into the image. The chroma key/title changeover switch 40 selects these two functions.

Incidentally, drive signals for the image pickup device 12 and the process amplifier circuit 18 are provided from the timing generation circuit 16 through signal lines 72 and 74, respectively. The timing generation circuit 18 is a circuit that generates a lock signal necessary for driving the image pickup device 12 and the process amplifier circuit 18 in response to the synchronization signal generated by the synchronization signal generation circuit 14. The synchronization signal generation circuit 14 generates drive signals necessary for scanning video signals such as horizontal and vertical synchronization signals and color subcarriers from a reference clock generated by a crystal oscillator 32, for example, and transmits them to a timing generation circuit 16 and an encoder. 26 and memory 20. Further, the clock for the memory 20 is supplied from a crystal oscillator 32 via a buffer amplifier 34.

Next, an image synthesis operation using chroma key will be explained. The operator first turns off the chroma key switch 36,
The chroma key/title switch 40 selects chroma key. Note that the color selection switch 38 may be placed in any position.The operation mode control circuit 24
The color comparison circuit 22 is controlled by the control line 62 on the condition that the
Deactivate. This causes the color comparison circuit 22 to set the switch 28 to the state shown by its control output 64,
Therefore, the output 6B of the process amplifier circuit 18 is connected to the input of the encoder 26.

The operator then photographs an image to be used as a background, for example image 46 shown in FIG. 2A. When a photographing instruction is input to the present apparatus, the operation mode control circuit 24 controls the synchronization signal generation circuit 16 and the timing generation circuit 16 in response to the instruction, and drives the image sensor 12 and the process amplification circuit 18. The object is imaged by the image sensor 12 through the lens 10, and read out to the process amplifier circuit 18 as a video signal representing the object.

The process amplifier circuit 18 removes noise and distortion and converts it into a luminance signal Y and color difference signals BY and RY.

The video signal from the output 86 of the process amplifier circuit 18 is input to the encoder 26 via the switch 28, where it is converted into a standard format video signal and is converted to the video signal at the video Yamao terminal 4.
Output from 4. Therefore, the image 4B of the object scene can be visually recognized on the video monitor.

At this time, the operating mode control circuit 24 sends a write signal to the memory 20 via the control line 76. As a result, the video signal of the output 66 of the process amplifier circuit 18 is also input to the memory 20, and is stored therein as one field of still images in the form of digital data.

Next, the operator photographs the person 48 against a background of a back screen 50 of a specific color, for example blue, as shown in FIG. 2B. At this time, blue, which is the same color as the back screen 50, is specified as the chroma key using the color selection switch 38, and the chroma key switch 38 is turned on.

The operation mode control circuit 24 energizes the color comparison circuit 22 on the condition that the chroma key switch 36 is turned on.

As a result, the connection state of the switch 28 is changed to the Iromura circuit 22.
be under the control of The switch 30 also selects the illustrated connection position, ie, the output 66 of the process amplifier circuit 1, and connects it to the color comparison circuit 22. Operating mode control circuit 24 also provides a read signal to memory 20 via control line 78. In synchronization with this, the memory 20 reads its stored contents, that is, video signal data representing the background image 4B, and outputs this as an analog signal from its output 88 by rask scanning. Operation mode control circuit 24
Also provides a signal specifying blue in this example to the color comparison circuit 22 through the control line B2.

When the image sensor 12 and the process amplifier circuit 18 are driven in the same manner as described above, the image sensor 12 images the object field 52 including the back screen 50, and the video signal representing this image is sent from the process amplifier circuit 18 to the switch 30. It is then input to the color comparison circuit 22. When the color comparison circuit 22 receives a signal corresponding to the blue color of the back screen 50, it outputs a chromakey signal to its output 64. In response, switch 28 connects the output 68 of memory 20 to the input of encoder 28 . During other periods, the output 86 from the process amplifier circuit 18 is connected to the encoder 26. That is, during the period when the image signal output from the image sensor 12 is scanned corresponding to the person 48, the one-color comparison circuit 22 connects the switch 28 to the lower side in the figure.

At this time, the memory 20 reads the video signal data representing the background image 48 and outputs it from the output 68 by rask scanning, as described above. Therefore, the read output 88 from the memory 20 is input to the encoder 26 only during the period when the chromakey signal 78 is occurring, and during the remaining period,
The output 66 from the process amplifier circuit 1 is sent to the encoder 28
is input. Therefore, the video signal input to the encoder 26 includes the video signal of the background 48 in the portion corresponding to the back screen 50 of one image 52, and the video signal of the person 48 in the other portions. Thus the second
A video signal representing the resulting composite image 54 shown in FIG. In this way, the video signal output from the video output terminal 44 represents a so-called composite image in which the person 48 is superimposed on the background image 46.

In the video camera of this embodiment, when title insertion is specified with the chroma key/title changeover switch 40, the memory 2
0 can also be used as a full-color title memory.

In such an application, for example, a title image is photographed in the same manner as the background 46 described above, and video signal data of the title image is stored in the memory 20. next,
When title insertion is specified with the chroma key/title changeover switch 40, the operation mode control circuit 24 outputs the control line 70.
The switch 30 is set to the opposite connection state as shown, that is, so that the readout output B8 of the memory 20 is taken into the color comparison circuit 22. Further, the control of the switch 28 is placed under the color comparison circuit 22.

Therefore, when another subject is photographed in the same way as the above-mentioned photograph of the person 48, the one-color comparison circuit generates a chromakey signal 64 using a specific color included in the readout output 88 from the memory 20 as a key, and responds accordingly. to control the switching of switch 2. Therefore, the video signal input to the encoder 28 represents an image obtained by inserting the title read out from the memory 20 into the video signal from the image sensor 12 and combining it.

Note that the output 66 of the process amplifier circuit 18 is directly input to the encoder 28, and the encoded video signal is sent to the memory 20.
It is also possible to perform image synthesis using a similar chroma key signal. Such an embodiment is shown in FIG. In this embodiment, the output 80 of encoder 26 is connected through switch 28a to video output terminal 44 and directly to the write input of memory 20. Output 68 of memory 20 is connected to switch 28a and decoder 82. The decoder 82 converts the video signal encoded by the encoder 26 into a luminance signal Y and a color difference signal R-Y.
, B-Y, and its output 84 is connected to the input of the color comparison circuit 22 via the switch 30. As can be seen from this configuration, in this example,
Encoded video signal data is stored in the memory 20, and other operations are basically the same as those of the embodiments described above.

Effects The video camera according to the present invention includes a storage means for storing a video signal, and is capable of selectively extracting a specific color area of an image represented by the video signal and combining the stored image with another image being shot. As a result, a superimposed image can be formed without requiring a complicated configuration such as genlocking two video cameras as in the conventional method. As a result, a video camera with a chromakey function is realized.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a video camera according to the present invention, and FIGS. 2A, 2B, and 2C are explanatory diagrams for explaining an example of image synthesis in the embodiment shown in FIG. 1. . FIG. 3 is a block diagram of another embodiment of a video camera to which the present invention is applied. 10°12°14°18°18°20°22°24. 26゜'' ■ 1 Momme 10'T% (7゜11゜, lens image sensor, synchronization signal generation circuit, timing generation circuit, process amplifier circuit, memory, color comparison circuit, operation mode control circuit, encoder. 44゜ video output terminal

Claims (1)

[Scope of Claims] 1. A video camera having an imaging means for capturing an image of a field and outputting a video signal representing the scene, and an output means for outputting a video signal, the camera comprising: storage means for storing signals; and synchronization control for driving the imaging means and the storage means in synchronization, causing the imaging means to output the video signal, and reading the stored video signal from the storage means. means; first selection means for selectively outputting a video signal output from the imaging means and a video signal read from the storage means to the output means; and one of the imaging means and the storage means. a color detection means for detecting when a signal representing a specific color is included in the obtained video signal and controlling the first selection means according to the result of this detection, the color detection means comprising: When the signal of the specific color is detected, the first selection means is controlled to replace the video signal obtained at that time from one of the imaging means and the storage means with the video signal obtained from the other of the imaging means and the storage means. A video camera characterized in that images are synthesized by outputting from the output means. 2. The camera according to claim 1, wherein the camera includes a second selector that selects either the video signal output from the image pickup means or the video signal read out from the storage means and inputs the selected video signal to the color detection means. A video camera characterized in that it includes selection means.