Computer graphics processing and selective visual display system – Display driving control circuitry – Display power source
Reexamination Certificate
1998-07-07
2002-11-19
Saras, Steven (Department: 2775)
Computer graphics processing and selective visual display system
Display driving control circuitry
Display power source
C345S003400
Reexamination Certificate
active
06483502
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to an image reproducing apparatus, projector, image reproducing system, and information storing medium, and particularly relates to an image reproducing apparatus, projector, image reproducing system, and information storing medium wherein input analog image signals are sampled according to display pixels and reproduced.
2. Description of Related Art
There are known image reproducing apparatuses in which input analog image signals are sampled according to display pixels and reproduced. Examples of such image display apparatuses include projectors using liquid crystal shutters (liquid crystal light valves), liquid crystal displays, plasma displays, and the like.
In order to use such an image reproducing apparatus and to sample and reproduce analog image signals supplied for, e.g., a computer, the input analog image data is subjected to sampling for each pixel of the liquid crystal shutter, liquid crystal display, or plasma display which is being used. How the parameters for sampling of the analog image signals are set at the time of the sampling processing is a crucial factor for good image reproduction.
The reason is that the sampling parameters slightly differ one from another depending on the type of computer supplying the image signals, or the computer manufacturer, even regarding analog image signals belonging to a group called VGA which represents a resolution of 640 by 480 pixels, for example.
For example, a sampling clock is used for sampling in order to create digital data according to each pixel, and when one horizontal scanning period corresponds to an output cycle of 800 pixels, the clock frequency is set such that 800 pulses are output during the one horizontal scanning period. In the event that the frequency of the sampling clock is different, problems arise in which there is a discrepancy between the sampling timing necessary for good image reproduction and the actual sampling timing.
Accordingly, it is important to perform auto-determination of the display mode in an accurate manner based on the input analog image signals, and to perform sampling processing of the signals using optimal sampling parameters.
In order to conduct this automatic determination, conventional apparatuses have employed a system in which tables are prepared beforehand for each display mode for identifying the display mode from the following three types of data: horizontal scanning data (one horizontal scanning period), vertical scanning data (how many vertical scanning lines are scanned per output cycle of vertical synchronous signal), and synchronous signal polarity data (the polarity of horizontal and vertical synchronous signals). Further, the three types of data from the input analog image signals, i.e., the horizontal scanning data, vertical scanning data, and polarity are checked against the aforementioned table, thus identifying the display mode in the event that all three items completely match the criteria.
However, rapid technological advances are being made nowadays, and the resolution of the image signals output from the computer is not limited to the aforementioned VGA. Rather, there are several types such as SVGA (800 by 600 pixels), XGA (1024 by 768), etc., and further, such a plurality of resolutions of analog image signals are often selectively output from the same computer. There are many types of analog image signals of each resolution in which the horizontal or vertical scanning data closely resembles that of analog image signals of another resolution, and moreover, there are many cases in which, for example, the horizontal scanning data is almost the same between VGA analog image signals output from a computer from a Company A and SVGA analog image signals output from a computer from a Company B.
Accordingly, it is difficult to accurately determine the great variety of display modes using the aforementioned known display mode determination means. There are instances in which, for example, a display mode which originally belongs to VGA is incorrectly determined to be a display mode belonging to SVGA, which is entirely different.
Further, the conventional determination method searches a display mode in which the analog image signal's horizontal scanning data, vertical scanning data, and polarity data completely match from the determination table. For example, if the horizontal scanning data or vertical scanning data slightly differ from the data in the determination table, the process becomes permanently trapped in the display mode determination loop process, in which cases the reproduced image is not displayed at all.
In the event that such a condition occurs, the user can deal with the problem by setting the sampling parameters according to the type of computer being used or the display mode. However, users not familiar with the equipment tend to determine the problem as being a malfunction of the display reproducing apparatus, necessitating effective countermeasures.
SUMMARY OF THE INVENTION
The present invention has been made in light of such needs, and accordingly, it is an object of the present invention to provide an image reproducing apparatus, projector, image reproducing system, and information storing medium wherein optimal sampling parameters are automatically set according to input analog image signals, enabling image reproduction in a sure manner.
In order to achieve the above objects, the image reproducing apparatus according to the present invention is an image reproducing apparatus which samples and reproduces input analog image signals in accordance with display pixels. The image reproducing apparatus comprises: automatic determination means for automatically determining a display mode from the analog image signals; and image data generating means. Sampling parameters for sampling and reproducing analog image signals in accordance with display pixels are set for each display mode, and the image data generating means samples the analog image signals in accordance with display pixels, based on the sampling parameters corresponding with the determined display mode. The automatic determination means comprises: storing means for storing determination data which has been formed by weighting and grouping each display mode using the horizontal scanning data of the analog image signals, the vertical scanning data of the analog image signals, and polarity data of the synchronous signals; determination condition detecting means for detecting the input horizontal scanning data and vertical scanning data of the input analog image signals, and polarity data of the synchronous signals; and determination means for determining the display mode of the analog image signals input from the grouped determination data, using at least one of the detected horizontal scanning data and vertical scanning data of the analog image signals, and synchronous signals.
Also, the information storing medium according to the present invention is an information storing medium for an image reproducing apparatus which samples and reproduces input analog image signals in accordance with display pixels, the information storing medium comprises: information for automatically determining a display mode from the analog image signals; and information for sampling and generating image data. Sampling parameters for sampling and reproducing input analog image signals in accordance with display pixels are set for each display mode, and the input analog image signals are scanned and image data is reproduced in accordance with display pixels, based on the sampling parameters corresponding with the determined display mode. The information for automatically determining comprises: information for determining data which has been formed by weighting and grouping each display mode using the horizontal scanning data of the analog image signals, the vertical scanning data of the analog image signals, and polarity data of the synchronous signals; information for detecting the input horizontal scanning data and vertical scanning
Awad Amr
Oliff & Berridg,e PLC
Saras Steven
Seiko Epson Corporation
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