Television – Format – Including additional information
Reexamination Certificate
1998-09-24
2001-01-09
Flynn, Nathan (Department: 2711)
Television
Format
Including additional information
C348S441000
Reexamination Certificate
active
06172710
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a frame converter which continuously outputs a plurality of image signals in a synchronized state while switching the respective asynchronous image signals.
A device called a video switcher which switches image signals from a plurality of cameras and the like and outputs the signals as one image signal is known. In switching such image signals, the input image signals from the cameras are often asynchronous with each other. The disturbance of synchronous signals in the output image signals is inconvenient.
In this case, all the input image signals are synchronized in advance by using a camera having a TBC (Time Base Corrector) function. Otherwise, asynchronous-isochronous conversion must be performed for each input by using a frame converting device having a frame memory. A camera having the TBC function is expensive, and therefore it is difficult to use the camera in a low-price system.
Further, in the frame converting device, the number of frame memories is the same as that of input image signals. While a image signal is stored into one of the frame memories, reading from another frame memory is performed. In the frame converting device having this construction, the number of frame memories must be the same as that of input image signals. This increases the price of the device.
SUMMARY OF THE INVENTION
The present invention has been made to solve the above-described problems, and has its object to realize a frame converter which continuously outputs a plurality of image signals in a synchronized state while switching the respective asynchronous image signals by using fewer frame memories than the number of the input image signals.
Accordingly, the present invention as a means of solving the problems is as follows.
The invention recited in claim
1
is a frame converter comprising: a plurality of signal input means respectively for receiving a plurality of image signals; identification signal supply means for supplying identification signals to discriminate the respective image signals to non-image areas of the image signals from said plurality of signal input means; a plurality of storage means for storing the image signals from said plurality of signal input means, respectively in frame units; and signal output means for alternately reading the image signals stored in said plurality of storage means and outputting the read signals.
The frame converter time-divisionally stores and reads respective plural image signals with respect to the plurality of storage means fewer than the input image signals while switching the signal input means and the signal output means at a predetermined timing, thus continuously outputs the image signals in a synchronized state while switching the asynchronous image signals. Further, as the apparatus stores the respective image signals, with identification signals, into the storage means, the respective image signals can be easily managed.
The invention recited in claim
2
is the frame converter according to the above-described invention (1), further comprising control means for switching said signal input means and said signal output means.
The invention recited in claim
3
is the frame converter according to the above-described invention (1) or (2), wherein said storage means store image signals at any timing within a period of continues frames.
The invention recited in claim
4
is the frame converter according to any one of the above-described inventions (1) to (3), wherein said storage means have independently operative input port and output port, and output an output image signal which is treated in storing operation.
REFERENCES:
patent: 4109276 (1978-08-01), Kopkins, Jr. et al.
patent: 5150212 (1992-09-01), Han
patent: 5341492 (1994-08-01), Sakata
patent: 5526050 (1996-06-01), King et al.
patent: 5661527 (1997-08-01), Ferguson
patent: 5739864 (1998-04-01), Copeland
Flynn Nathan
Thorne Gregroy L.
U.S. Philips Corporation
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