Computer graphics processing and selective visual display system – Computer graphics processing – Attributes
Reexamination Certificate
1999-04-28
2003-05-06
Bella, Matthew C. (Department: 2676)
Computer graphics processing and selective visual display system
Computer graphics processing
Attributes
C345S619000, C345S694000
Reexamination Certificate
active
06559855
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a method for transferring image information.
2. Prior Art
Following techniques have been employed: to equip both of a main body of a computer and a display device with a storage device storing image information, to communicate between them if image information stored in the storage device in the main body of the computer is updated by the main body of the computer and to limit data transferred from the main body of the computer to an updated portion, and to refresh displayed content on the display device with image information stored in the storage device in the display device. For instance, U.S. Pat. No. 5,726,677 discloses that VRAM of the main body of the computer is connected to RAM in an X driver of an LCD module via a special bus and if data of the VRAM is updated, the updated portion is transferred via the special bus. This patent does not disclose any detailed method for transferring the data from the VRAM to the RAM in the X driver of the LCD module.
Japanese Unexamined Patent Application No. Hei 8-179740 discloses that the image generation side thins out and transmits graded data from the frame memory according to a predetermined rule and the image display side stores part of graded data which comprises a preceding image frame based on the rule to complement the transmitted graded data with the stored graded data. For instance, on the image generation side, if high order bit data of the graded data of the preceding image frame is identical, a signal representing the identity and low order bit data are transferred, and if it is not identical, a signal representing the non-identity and high order bit data are transferred. Meanwhile, on the image display side, high order bit data of the preceding image frame is stored, and the graded data is complemented by transmitted low order bit data and stored high order bit data if the signal representing the identity is received, and the graded data is complemented by transmitted high order bit data plus preset constant data as low order bit data if the signal representing the non-identity is received.
Another technique to transfer image information divided into several frames has been employed. Japanese Unexamined Patent Application No. Hei 4-86190 discloses that source data for display is thinned out at every predetermined number n and read out and then transferred. For instance, it is disclosed that every one of n lines are transferred and the transmission speed is 1
.
Furthermore, Japanese Unexamined Patent Application No. Hei 6-22303 discloses that a frame is divided into a plurality of subframe areas and only divided single frame area is transmitted for each frame with thinning out. This allows a plurality of subframes to reproduce the original single frame, to decrease the load on the display side by transferring only changed portions (differences) between frames as well as significantly reducing transmission capacity. In addition, transmission volume is further reduced by using a compression. However, the transmitting and receiving sides must execute more complicated processing.
Meanwhile, there exists a technology called gradation emulation. It does not represent a plurality of gradation levels in a single frame but represents them over a plurality of frames, often using a dither pattern. For instance, U.S. Pat. No. 5,712,651 discloses that it comprises 16 dither matrixes corresponding to 16 levels of gradation. In addition, in order to prevent flickers on the display screen, a dither matrix is provided for each frame. At gradation level
1
, 16 dither patterns corresponding to the frames 1 to 16 are provided, one dot of which lights up. In this patent, dither matrixes are used for gradation emulation and not for updating image information stored in the display.
Also, with regard to a ferrodielectric liquid crystal display, there exists a technology to check, when partial writing to a display memory occurs, the number of displayed lines whose display data was changed by the partial writing and to write partially to the ferrodielectric liquid crystal display only if the number of changed lines is equal to or less than a predetermined number (for instance, U.S. Pat. No. 5,629,717/Japanese Patent Publication No. 2617345). This technology is a specific technology to ferrodielectric liquid crystal displays.
Furthermore, also with regard to ferrodielectric liquid crystal displays, there exists a technology comprising a flag memory which represents whether or not each line was rewritten and a flag counter which calculates the number of flags of the flag memory on the full screen, wherein the full screen is refreshed if the number of the flags is up to one, and partial rewriting is performed if it is between two and four, and the full screen is refreshed if it is equal to or more than five (for instance, Japanese Unexamined Patent Publication No. Hei 5-241528). This patent also describes that some lines may not be refreshed if a partial rewriting mode continues, in which case the threshold is to be changed. This technology is also specific to ferrodielectric liquid crystal displays.
As seen in the above background arts, there is none in which a dither matrix is used for updating images stored in a display device in transferring image information between the main body of a computer and the display device. In addition, it is not mentioned that, also in transferring image information between the main body of a computer and the display device, the image information stored in the main body of a computer is divided into a plurality of blocks, the number of pixels whose data is changed or rewritten is counted for each block, and the image information in blocks exceeding a predetermined number is transferred to the display device block by block.
Thus, an object of the present invention is to enable transfer of image information of high resolution via a transmission line with limited width by using a simple mechanism.
In addition, another object of the present invention is to enable more natural display of image information transferred via a transmission line with limited band width by using a simple mechanism.
In addition, still another object of the present invention is to reduce power consumption and unnecessary radiation by lowering transmission rate of image information.
SUMMARY OF THE INVENTION
The present invention is to be handled as follows. If first image information which is stored in a first apparatus and comprises a plurality of pixels is transferred to a second apparatus in order to update second image information stored in the second apparatus, following steps are performed: defining a plurality of blocks in the first image information, wherein each block has a size of a predetermined dither matrix; and transferring each pixel information in each block to the second apparatus in order of a value of a corresponding element of the dither matrix. By transferring in order of a value of a corresponding element in the dither matrix, it becomes possible to transfer image information of high resolution even if the transmission line has low band width and to update and display image information in a natural form in the second apparatus. Moreover, it is also possible to put each pixel an order of transfer before transferring and to transfer them in that order thereafter.
The second aspect of the present invention is as follows. That is, if image information which is stored in a first apparatus and comprises a plurality of pixels is transferred to a second apparatus, wherein the pixels are divided into blocks, and each block has a size of a predetermined dither matrix, following steps are performed: determining, in order of a value of a corresponding element in the dither matrix, whether each pixel in each block of the image information should be transferred to the second apparatus; and transferring information of the pixels which are determined to be transferred in the order to the second apparatus. In this way, it is possible to avoid information tran
Kawase Kei
Moriyama Takao
Nakamura Fusashi
Bella Matthew C.
Jordan, Esq. Kevin M.
Monestime Mackly
Scully Scott Murphy & Presser
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