JPH04266270A - Video signal synthesis system - Google Patents

Abstract

PURPOSE:To synthesize a video signal from other external picture processing unit onto a video signal of a picture section in terms of analog signals and to attain compatibility with other model at a comparatively lower cost. CONSTITUTION:The video signal synthesis system in which a video signal of its own equipment and a video signal of other external equipment are synthesized is provided with a video signal level variable means 5 varying a level of a video signal, an analog video signal adder means 8, and a synchronization means 10 synchronizing the external video signal with its own video signal. Then its own video signal is synchronized with the external video signal by the synchronization means 10 and the level of the external video signal is adjusted by the video signal level variable means 5 and the result is added to its own video signal by the analog video signal adder means 8 to synthesize them.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal synthesis system, and more particularly to a video signal synthesis system between different image processing apparatuses.

0002

2. Description of the Related Art In recent years, with the practical application of image compression technology, image devices capable of displaying photographic-level images have become widespread. Therefore, if it is possible to synthesize images with other image devices such as character devices, graphics devices, or other image devices, it will be possible to provide a wide variety of screen compositing services, and the functions of the image processing device It greatly contributes to expansion.

Conventionally, external input devices for image processing apparatuses have been general consumer video equipment such as video cameras and professional video equipment. Therefore, the amount of images that could be captured was limited.

[0004] Furthermore, the compositing process with an external video input device is
For example, as shown in Figure 3, analog/digital (A/D
) Conversion units 100, 101, memories 102, 103, synthesis memory 104, digital/analog (D/A) conversion unit 105, display unit 106, etc. 100, the signal is once converted into a digital signal and stored in the memory 102, and the video analog signal from another device is also converted to a digital signal by the A/D converter 101.
The digital signal is converted into a digital signal and stored in the memory 103.

[0005]Then, the respective video digital signals held in these memories 102 and 103 are synthesized in a synthesis memory 104, converted back to an analog signal in a D/A conversion section 105, and displayed on a display section 106. The video signal is displayed.

[0006]

As described above, in the process of compositing with an external video input device, the video is once stored in the built-in video memories 102 and 103, and then composited in the digital domain. Therefore, a memory for synthesis is required, which increases the cost.

Moreover, as is clear from FIG. 3, since the video analog signal is once digitized and then analogized again, quantization distortion occurs and accuracy deteriorates.

Therefore, an object of the present invention is to provide a video signal synthesis method that eliminates the need for a memory for synthesis and improves quantization distortion by synthesizing video signals input from other image processing devices as analog signals. It is to provide.

[0009]

[Means for Solving the Problems] In order to achieve the above object, the present invention has an input section 1, a CPU 2,
image section 3, D/A conversion section 4, video signal level variable section 5,
Analog switch sections 6, 7, analog video signal addition and amplification section 8, driver 9, PLL (Phase-Locked
A loop section 10, a display section 20, etc. are provided. The input section 1 is provided with an A/D conversion section 11, a PLL section 12, and the like.

A video signal transmitted from an external video device such as a TV camera is input to the input section 1, and this is converted into a digital signal by the A/D conversion section 11, and the synchronization signal is sent to the PLL section 12. A synchronization signal (horizontal synchronization, vertical synchronization) is obtained and transmitted to the image section 3. As a result, the self-use video signal is held in the frame memory within the image unit 3.

Further, a video signal from another image processing device such as a personal computer is input to a video signal level variable section 5, and its synchronization signal is input to a PLL section 10.

The video signal level variable unit 5 adjusts the video signal from another image processing device so that the dynamic range of the input video signal is the same as that of its own video signal. If the signal is too bright, adjust it to the same brightness as your own video signal. Conversely, if it is too dark, adjust the brightness in the same way.

Furthermore, the PLL unit 10 adjusts its own synchronization signal to match the input synchronization signal of another image processing device.

[0014]

[Operation] A video signal transmitted from another image processing device such as a personal computer is transmitted to the video signal level variable section 5, and its dynamic range is changed to the same dynamic range as the own video signal. When the signal is too bright or too dark, the brightness is adjusted to balance with the own.

Furthermore, the synchronization signal transmitted from another image processing device is input to the PLL section 10, and the synchronization signal of the PLL section 10 is made to match the synchronization signal transmitted from the outside.

Then, when the image section 3 turns on the analog switch sections 6 and 7 in response to an instruction from the CPU 2, the video signal output from the frame memory of the image section 3 becomes D/D.
The A converter 4 converts the signal into an analog signal, the analog video signal summing and amplifying section 8 combines the signal with a video signal transmitted from another image processing device, and displays the signal on the display section 20 via the driver 9 .

[0017]

[Embodiment] An embodiment of the present invention will be explained based on FIGS. 1 and 2.

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a detailed diagram of the main part thereof.

In FIG. 1, reference numeral 1 denotes an input section, into which a video signal and a synchronization signal are input from an external video device such as a TV camera, and the video signal is converted into a digital signal by an A/D conversion section 11. Further, the synchronization signal is input to the PLL section 12, and control in synchronization with this is performed in the image section 3.

Reference numeral 2 denotes a CPU, which comprehensively controls the entire image processing apparatus.

Reference numeral 3 denotes an image section, which outputs switching control signals for the analog switch sections 6 and 7 based on settings from the CPU 1, and has a memory for holding video signals from its own external video equipment. .

Reference numeral 5 denotes a video signal level variable section, which matches the reference level when adding analog signals. For example, a video signal from an external video device for personal use has 0 to 255 gradations like a natural image, and a video signal from another image processing device with 0 to 15 gradations like a computer is simply added in analog form. However, the addition is not accurate. Therefore, 128, the middle of 256 gradations, and 8, the middle of 16 gradations, match, and it is necessary to adjust the upper and lower gradations accordingly so that they are balanced. Since the gradation can be determined by the input signal, this can be done accordingly. Furthermore, when the input from another image processing device is too bright or too dark, it can be adjusted by making the appropriate level variable.

Reference numerals 6 and 7 are analog switch sections, respectively, and depending on the switching signal output from the image section 3, only the analog switch section 6 is turned on, only the analog switch section 7 is on, both are on, and both are off. controlled. When displaying a video signal from another image processing device in combination with its own video signal, both analog switch units 6 and 7 are turned on. If you want to display only one of them, turn on the one you want to display.

The analog video signal addition and amplification section 8 is for adding the analog signals transmitted from the analog switch sections 6 and 7, and as shown in FIG.
0, resistors R1 to R5, etc., and this summing operational amplifier 30 is used, for example, with a non-inverting input, and can be configured with one operational amplifier by selecting one that has addition, amplification, and drive capabilities. can.

Reference numeral 10 denotes a PLL unit which receives a synchronization signal (
The horizontal synchronization signal) is compared in phase with the horizontal synchronization signal of its own image processing device, and its own horizontal synchronization signal is synchronized with that from the outside. This allows the two to be synchronized.

As shown in FIG. 2, the input signal from another image processing device is actually input to the interface 21, and the video signal is impedance matched in the Z matching section 22 and input to the video signal level variable section 5, where the level is adjusted. will be held.

[0027] At this time, since it is determined in advance how the level settings should be set according to the input other image processing apparatuses, for example, other image processing apparatuses are classified into about four types of level adjustments. At this time, depending on the information for setting the video signal level, the CPU 2 outputs a 2-bit adjustment control signal automatically or by keyboard input, and selects and controls an appropriate one.

The video signal whose level has been adjusted in this way is clamped by the clamp section 23 and transmitted to the analog switch section 6 via the buffer 24. The video signal output from the image section 3 is converted into an analog signal by the D/A converter 4, clamped by the clamp section 25, and transmitted to the analog switch section 7 via the buffer 26. The analog video signal addition and amplification section 8 synthesizes the video signals, and outputs the synthesized video signals to the display section 20 via the driver 9 for display.

As described above, in the present invention, the analog signals are not simply added to each other, but the video signal level from another external image processing device is varied and added, and the switching section displays the combined output. In addition, it is possible to output and display the video of the external image processing device and the video of the main image section independently. By changing the PLL circuit in accordance with the display frequency of the external image processing device, it becomes possible to easily connect other models.

[0030]

[Effects of the Invention] According to the present invention, external video signals can be synthesized in analog form without converting them into digital signals, which not only eliminates the need for a conversion circuit but also eliminates the presence of quantization errors. can. Moreover, it can be combined with various external image processing devices.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a detailed diagram of the main part of the present invention.

FIG. 3 is a conventional example of video signal synthesis.

[Explanation of symbols] 1 Input section 2 CPU 3 Image section 4 Digital/analog conversion section 5 Video signal level variable section 6, 7 Analog switch section 8 Analog video signal addition amplification section 9 Driver 10 Phase lock loop section

Claims (2)

[Claims] Claim 1: Video signal level variable means (5) for varying the level of the video signal in a video signal synthesis method that combines the video signal of the own device and the video signal of another external device.
, an analog video signal adding means (8), and a synchronizing means (10) for synchronizing the external video signal and the own video signal, and the self-video signal is added to the external video signal with the synchronizing means (10).
10), the level of the external video signal is adjusted by the video signal level variable means (5), and this and the own video signal are added by the analog video signal addition means (8) to synthesize the video signal. A video signal synthesis method characterized by: 2. The analog video signal adding means (8)
2. A video signal according to claim 1, further comprising a switching means (6) for switching a video signal from the outside and a switching means (7) for switching a video signal from the device itself, on each input side of the video signal. Synthesis method.