JPH05103260A - Video signal synthesizer - Google Patents

Abstract

PURPOSE:To successively attain a picture synthesis by synchronizing the video signal of one arbitrary system of the plural video systems with the other video signal. CONSTITUTION:An input signal respectively supplied from a video input terminal 11 and a synchronizing input terminal 12 is transmitted through a synchronizing separator circuit 13 to a scan frequency measuring and judging circuit 14. An output signal from the circuit 14 is transmitted to an MPU 15, and a picture memory controller 18 is controlled by the MPU 15 by a control signal for setting the writing capacity of the input video signal so that the data writing area of a picture memory 20 can be set. The picture memory controller 18 reads out the data from the picture memory 20 synchronously with a reading clock in the system of the input video signal, and the output video signal obtained by synthesizing the input video signal with the other video signal by a synthesizing circuit 25 is outputted from a video output terminal 26.

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 for automatically converting a video signal of any one of a plurality of video signal systems into a video signal based on other image information and synthesizing the video signal. It relates to the device.

[0002]

2. Description of the Related Art Currently, television receivers and monitors for displaying video signals are based on the current broadcasting system, NTSC,
PAL, SECAM, so-called clear vision, high-definition, etc. operate at different scan frequencies to display images. Further, recently, in order to use a computer image displayed on a monitor for a computer, which is different from the current broadcasting system, for broadcasting, the scan frequency is often converted and used.

In general, a switcher used for screen synthesizing performs screen synthesizing of video signals having the same scan frequency. Here, the above-mentioned television receiver or monitor can be relatively easily realized as a multi-scan type that is displayed according to a plurality of scan frequencies, and various types of input video signals are displayed on one monitor. A monitor is also made. However, a video signal synthesizing device for synthesizing video signals between different systems requires a process such as so-called line interpolation, which complicates the circuit configuration.

[0004]

In the above video signal synthesizing apparatus, when the number of scanning lines for each method is different, processing such as line interpolation is required for each method.
That is, the number of scanning lines is increased / decreased to perform an interpolation operation corresponding to a desired number of scanning lines, and a process such as calculation according to an interlaced / non-interlaced method is required. Becomes complicated. As a result, the video signal synthesizing apparatus becomes very expensive. Further, the video signal synthesizing apparatus can only deal with synthesizing the video signals for performing conversion between preset methods.

In view of the above-mentioned circumstances, the present invention has a simple structure to automatically associate a video signal of any one of a plurality of input systems with a video signal based on other image information. It is an object of the present invention to provide a video signal synthesizing device that enables easy screen synthesis.

[0006]

A video signal synthesizing apparatus according to the present invention synthesizes a video signal of any one of a plurality of video signal systems with a video signal based on other image information and outputs it. A video signal synthesizing apparatus, comprising: a scan frequency measuring means for measuring a scan frequency of the input video signal; an image memory in which the other image information is written; and an image memory in the image memory based on data from the scan frequency measuring means. Writing capacity setting means for setting the capacity of the image information writing area, and writing / writing the image information to / from the writing area set in the image memory according to the set value of the writing capacity setting means. By having an image memory control means for controlling reading and an image synthesizing means for synthesizing an output video signal from the image memory and the input video signal, the above-mentioned problems can be solved. It is decided.

[0007]

The video signal synthesizing apparatus according to the present invention measures the scan frequency, which is the image information of the input video signal,
Based on the image information of the input video signal, another video signal is converted using an image memory and combined with the input video signal and output.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a video signal synthesizing apparatus according to the present invention will be described with reference to the drawings.

The video signal synthesizing apparatus of the present invention will be described with reference to the schematic circuit configuration shown in FIG. The input video signal and the input sync signal supplied to the video input terminal 11 and the sync input terminal 12 of the video signal synthesizer shown in FIG. 1 include a video signal and a sync signal of any one of various video signal systems. Is being supplied. The input video signal is supplied to the synthesizing circuit 23, which will be described later, and also to the sync separation circuit 13. The input sync signal is supplied to the sync separation circuit 13 and is output as an output sync signal via the output terminal 27.

Here, the input video signal is sent to the sync separation circuit 13 for separating the sync signal from the input video signal when there is no input sync signal supplied from the input terminal 12. .. In this way, the sync separation circuit 13 separates the horizontal sync signal H and the vertical sync signal V and supplies them to the scan frequency measuring and discriminating circuit 14, which is the scan frequency measuring means.

The scan frequency measuring and discriminating circuit 14
Measures the scan frequency in order to detect the system of the input video signal (in particular, the number of scanning lines defined in the system). The scan frequency is a horizontal frequency and a vertical frequency (f _H , f _V ). The circuit also determines whether the input video signal is interlaced scanning or non-interlaced scanning. The scan frequency measuring and discriminating circuit 14 operates under the control of the MPU 15 described later. This scan frequency measurement and discrimination circuit 1
The signal measured and discriminated in 4 is sent to the MPU 15.

The MPU 15 is a writing capacity setting means for setting the capacity of the image information writing area in the image memory 20 in which other image information is written based on the data from the scan frequency measuring and discriminating circuit 14. In other words,
The MPU 15 sets the number of scanning lines, for example, according to the system of the input video signal. Also, this MP
The U 15 controls input / output of a serial input / output interface (hereinafter abbreviated as SIO) 17. SI above
O17 is connected to the tablet 16 for specifying the position. The MPU 15 also calculates information such as which address on the image memory the designated position sent from the tablet 16 is, and supplies it to the image memory controller 18 and the prescaler 24. The detected number of scanning lines is used for this address calculation.

The image memory controller 18 is an image memory control means for controlling the writing / reading of the image information in the writing area set in the image memory 20. This image memory controller 18 is
According to the control signal from the PU 15, the memory amount of the image memory 20 is variably set and secured by a necessary scanning line segment.

The image memory 20 has a maximum capacity as a frame memory among various video signal systems. As described above, the use area of the image memory 20 is set according to the number of scanning lines of the input video signal method, and the image information of the other method is written in this area. The image memory controller 18 is also a component of a so-called phase locked loop (PLL) 19.

The PLL circuit 19 comprises a loop including the phase comparator 21, the low pass filter (LPF) 22, the voltage controlled oscillator (VCO) 23, the prescaler 24 and the image memory controller 18. The image memory controller 18 has an internal horizontal synchronizing signal (Int.
HD) is supplied to a phase comparator 21 in a so-called phase locked loop (PLL) 19. Further, the phase comparator 21 takes in the horizontal sync signal H from the sync separation circuit 13 as an external horizontal sync signal. Phase comparator 2
1 sends both phases to the voltage controlled oscillator (VCO) 23 via the LPF 22. The voltage controlled oscillator 23
Sends a high frequency to the prescaler 24 which is a frequency divider. The prescaler 24 divides the high frequency signal supplied according to the control signal from the MPU 15 and supplies it to the image memory controller 18 as a clock CK.

In this way, the PLL 19 is connected to the MPU.
Image memory controller 1 according to a control signal from 15.
The clock supplied to 8 is variably controlled.

The image memory controller 18 reads the other image information written in the image memory 20 at the scan frequency of the system of the input video signal so as to achieve the synchronization required for the synthesis with the input video signal. I am taking it. In this way, the other image information is sent to the synthesizing circuit 25 as a video signal of the same system (that is, the same synchronization relationship) as the input video signal.

The synthesizing circuit 25 includes the image memory 20.
Is a video synthesizing means for synthesizing the output video signal from the input video signal from the input video terminal 11. In this way, the synthesizing circuit 25 synthesizes and replaces both the input video signal and other image information in synchronization with the image information of the system of the input video signal, and outputs the output video signal synthesized at the output terminal 26. Is output.

With this configuration, the output video signal synthesized through the output terminal 26 can easily correspond to the scan frequency of the input video signal at any scan frequency selected by the tablet 16. Like Moreover, this video signal synthesizer
Since the scan frequency set in 6 is not limited to the conventional combination of the video signals of only the preset method, it can be continuously set arbitrarily. Further, the conventional complex and expensive video signal synthesizer can be realized with a simple configuration, and each scan frequency of another video signal with respect to the input video signal can be automatically made to correspond to the scan frequency of the input video signal. it can.

Here, in the conventional video signal synthesizing apparatus, for example, a frame memory corresponding to one fixed system is prepared and converted into an image corresponding to each scan frequency of the input video signal by line interpolation processing or the like. Therefore, the circuit configuration was complicated.

However, in this embodiment, in order to form an image corresponding to each scan frequency of the input video signal, the capacity of the image memory is secured in accordance with the number of scanning lines of the system of the input video signal, and the input video is input from the image memory. Other image information is converted into the input video signal system by reading at the same scan frequency as the signal system. As described above, the conversion of the image information does not require a processing circuit such as line interpolation which has been conventionally used. Therefore, the video signal synthesizing device does not require a complicated circuit configuration and can simplify the circuit.

Actually, as mentioned above, NTSC, P
It is possible to easily combine the so-called clear vision (hereinafter abbreviated as EDTV) of high definition and various computer signals by system conversion without being limited to the system conversion of AL and SECAM. By this video composition, the video signal composition apparatus can display the generated figure, character, etc. without distortion. In addition,
The video signal synthesizing apparatus of the present invention is not limited to the so-called IDTV system and the EDTV system, and in principle, it can be applied to so-called high-definition high-definition.

[0023]

As is apparent from the above description, according to the video signal synthesizing apparatus of the present invention, the scan frequency measuring means for measuring the scan frequency of the input video signal and the other image information are written. An image memory, a write capacity setting means for setting the capacity of an image information writing area in the image memory based on data from the scan frequency measuring means, and the image according to the set value of the write capacity setting means. Image memory control means for controlling writing / reading of the image information to / from a writing area set in the memory;
By having a video synthesizing means for synthesizing the output video signal from the image memory and the input video signal,
With a simple configuration, a video signal of any one of a plurality of video signal systems can be combined with a video signal based on other image information and output.

Further, the video signal synthesizing apparatus can automatically and variably perform another video signal having a synchronous relationship with the input video signal.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of an embodiment of a video signal synthesizing apparatus according to the present invention.

[Explanation of symbols]

11: Video input terminal 12: Synchronous input terminal 13: Synchronous separation circuit 14 ··········· Scan frequency measurement and discrimination circuit 15 ····· MPU 16 ····· Tablet 18 ··· Image memory controller 19 PLL circuit 20 Image memory 25・ ・ ・ ・ Composite circuit 26 ・ ・ ・ ・ ・ ・ ・ Video output terminal 27 ・ ・ ・ ・ ・ ・ ・ Synchronous output terminal

Claims (1)

[Claims] 1. A video signal synthesizing device for synthesizing and outputting a video signal based on another image information to a video signal of any one of a plurality of video signal systems, the scan of the input video signal. Scan frequency measuring means for measuring the frequency, image memory in which the other image information is written, and write capacity for setting the capacity of the image information writing area in the image memory based on the data from the scan frequency measuring means. Setting means, image memory control means for controlling writing / reading of the image information to / from the writing area set in the image memory according to the setting value of the writing capacity setting means, A video signal synthesizing apparatus comprising: a video synthesizing means for synthesizing an output video signal and the input video signal.