JPH11126045A - Display controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To display an image on a display unit in which one pixel is divided into plural scanning lines. SOLUTION: Multilevel image data displayable on a display unit 14 are stored in a frame memory. A control part 4 reads out the number of scanning lines dividing one line from the display unit 14 and rewrite control part 10 changes scanning addresses of the display unit 14 in accordance with the number into addresses of lines of the frame memory to read out lines corresponding to the addresses of the scanning lines. In a gradation control part 11, lines are converted into scanning lines according to what number-th scanning line a scanning line under consideration is in among the lines to output them to the display unit 14 and an image is displayed on the unit 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a display system, and more particularly to a display control device for performing display based on raster image data.

[0002]

2. Description of the Related Art In recent years, graphics cards for display in computers have been increasing in resolution, multicolor display, and variety. As an example, the number of display colors is 1670
All colors are available in all colors, and the display size is 640 × 480, 800 × 600, 1024 × 76 for horizontal display dots and vertical line dots.
8, 1280 × 1024 and 1600 × 1280, and the resolution is getting higher.

On the other hand, when a video signal is received and displayed on a flat panel display such as a liquid crystal display panel, pixels are divided in order to achieve a sufficient display capability with respect to the number of display colors of the video data received by the panel. A method of increasing the gradation (display color) by the size of the divided area has been performed.

In general, the segment side (information line side) is divided in order to prevent the scanning duty and the frame rate from decreasing, but the common side (scanning line side) may be divided in order to increase the number of display colors. .

[0005]

However, the above-described conventional method has caused the following problems. (1) In order to display the same image on a display having a different common-side division number (including a case where the division is not performed), the number of lines of image data to be sent must be changed for each display. (2) When pixels are divided on the common side (scanning line side), the common side scanning address line data is different from the line address of the frame memory storing one frame of image data, and the scanning address can be used in common. Absent.

SUMMARY OF THE INVENTION The present invention has been made in view of the above conventional example, and has as its object to provide a display control device capable of transmitting appropriate image data to a display for display according to the number of common divisions of the display. And

[0007]

In order to achieve the above object, the present invention has the following arrangement. That is, a display control device that divides one line of image data into a plurality of scanning lines and displays an image on a display that expresses gradation,
According to the target scanning line address and the number of divided scanning lines, the target line of the image data is converted into output data corresponding to the divided scanning line, and the output data is displayed as data to be displayed on the target scanning line. Output to the container.

[0008]

FIG. 1 is a block diagram of a display system according to an embodiment of the present invention. Hereinafter, embodiments of the present invention will be described with reference to the drawings. <Configuration of Display System> First, the function of each unit in FIG. 1 will be described. The host 1 supplies video data to the display. Mainly, personal computers, workstations, and televisions. The input conversion unit 2 is a host 1
A / D conversion is performed when the input signal is an analog video signal, and the video signal is parallelized according to the speed of the video signal transfer signal. A demultiplexer function that can be transferred to a host, a control signal that informs the user when the demultiplexer is used, and a detection function that detects that the host 1 is an interlace signal (every other line), such as a television. , And control signals for informing the odd and even fields. In the case of digital signals, if the signals are multiplexed in time and the number of transfer lines is reduced, a decoder that restores the time-multiplexed data and a sampling clock for the multiplexed data are used. A PLL to be reproduced is included.

Further, analog video signals, digital video signals, television signals (NTSC, PAL, SEC)
AM), the control unit 4 receives a selection signal for selecting which video signal to display from the host by the inter-host communication unit 3 or the hub control unit 17. Then, the data is transferred from the control unit 4 to the input conversion unit 2. The input video signal is switched based on this signal.

[0010] The inter-host communication section 3 provides information in input video data from the host, such as identification of interlace or non-interlace, gamma correction data, brightness, contrast, screen position information, display mode (display dot line number). ), And receives the identification of the input video signal described above. The control unit 4 performs system control of the present system, and can perform arithmetic processing and input / output data transfer by a microprocessor. Digital halftone section 5
Performs dither processing on the transferred video data. The dither table rewriting control unit 6 rewrites the multi-value dither table and the dither threshold value table in the dither halftone processing unit 5. The frame memory control unit 7 sequentially stores the dither halftone data in the frame memory, simultaneously outputs the dither halftone data of one frame before from the frame memory, and outputs the desired line unit data according to the instruction of the rewrite control unit 10. Controls reading from the frame memory. The frame memory 8 stores a frame to be displayed. The motion detector 9 compares the dither halftone data of the previous frame with the currently output dither halftone processing data,
Detect movement. The rewrite control unit 10 includes the motion detection unit 9
The rewriting is controlled on a line-by-line basis based on the data of (1) and the rewriting speed information from the display unit. Gradation control unit 1
Reference numeral 1 denotes gradation data of a pixel when the pixel of the display unit is divided into at least two when the common side (vertical side) display physical dot line is different from the display dot and line data on the input video side. To process. The line output control unit 12 adds a scan address indicating a position to be displayed on the display unit, and transfers the display unit. The drive control unit 13 controls the drive of the display unit 14. The display unit 14 includes a segment and common driver IC circuit, a panel, a backlight, a backlight inverter, and the like. In the display unit 14, data indicating the number of display colors of the display device is described in the ROM, and can be transferred to the control unit 4 by serial transfer. The trimmer 15 is used when the user controls image quality, screen position, and the like.

The power supply unit 16 supplies power to the display system and peripheral devices connected to the display system. The hub control unit 17 supplies display data and the like from the host 1 to the display system and peripheral devices connected to the display system. The hub control unit 17 is compatible with a USB (Universal Serial Bus) whose specifications are being studied recently, or an IE which is a standard.
It is capable of receiving an EE1394 data stream, and includes a switch circuit for connecting data to the display unit and connected peripheral devices, an accord circuit for each data, an interface with an external control unit, and the like. The video data selector 18 selects the data of the display or the peripheral device received by the hub control unit 17 and stores the data in the frame memory 8. <Operation of Display Control Unit> In the configuration of FIG. 1, a portion excluding the host 1 and the display unit 14 will be referred to as a display control unit. Next, an operation procedure of the display control unit will be described.

First, the display system sends display unit data including data on the number of display colors and data on the number of common divisions to the control unit 4 from a ROM inside the display unit 14 when the power is turned on. Then, from the control unit 4 to the dither table rewrite control unit 6 and the gradation control unit 11
Transfer the necessary data. Or, the control unit 4
May be transferred, or a value set by the user with the user trimmer 15 may be transferred.

The dither table rewriting control unit 6 selects a dither threshold value necessary for the number of display colors required for input from a table prepared in advance, or calculates the table by an arithmetic unit, so that the digital halftone processing 5 is executed. Rewrite the dither threshold table and the multi-value dither table inside. The number of input bits may be determined in advance, or the inter-host communication unit 3 may receive and determine the information from the host. Alternatively, the display mode is calculated from the horizontal synchronization signal in the input conversion unit 2, and
The input bit may be used. Rewriting of the dither table is performed when the display unit changes or when the display mode changes when the host changes, even when the power is not turned on.

When the rewriting of the dither table is completed,
First, the video signal output from the host 1 is converted and selected by the input conversion unit 2 into video data suitable for the next processing unit. For example, if the input video signal is a CRT analog signal, A / D conversion is performed. Or
For differential digital signals, TTL level or CMO
Convert to S level. Here, if the transfer frequency to be sent to the next stage is high, for example, if it exceeds 100 MHz, the video signal is demultiplexed to double the video data path width, and the transfer clock (pixel clock signal) is reduced to half.

If the input video signal is an interlaced signal like a television signal, it outputs a determination signal and a determination signal for odd and even fields. One of these digitized video signals is selected based on information obtained by the inter-host communication unit 3 or the hub control unit 17 and input to the digital halftone processing unit 5 to perform dither halftone processing.

The video signal subjected to the dither halftone processing is controlled by the frame memory control 7 and stored in the frame memory 8 for at least one frame. Then, unless an input is prohibited by the control of the rewrite control unit 10, the data in the frame memory is updated in frame units.

On the other hand, the video data subjected to the dither halftone processing in the dither halftone processing 5 is sent to the motion detecting section 9. In synchronism with the video data, dither halftone-processed video data located at the same coordinates at least one frame before is input from the frame memory 8 to the motion detection unit 9.

The motion detector 9 compares the levels of the two input data in pixel units, and if the different amounts exceed a certain threshold th, the result is detected in units of horizontal lines or in units of regions. Save as part.
The stored data is sequentially transferred to the rewrite control unit 10, and the portion determined to have moved is output from the frame memory 8 to the gradation control unit 11. If no motion is detected, the image data is output from the frame memory 8 to the gradation control unit 11 by multi-interlace in order to perform refresh drawing for refreshing the entire screen. Refresh is performed by multi-interlace or random interlace to prevent flicker. In the case of a display device without flicker, non-interlace may be used.

The dither halftone data output from the frame memory 8 is sent to the gradation control unit 11. Here, video signal conversion suitable for the information on the number of common divisions of the display unit 14 received from the control unit 4 is performed, and the data is sent to the line output control unit 12. And the line output controller 1
At 2, the scan address information is added and transferred to the display unit 14. The scanning address information is data of a line specified by the rewrite control unit 10 for the frame memory 8.

On the other hand, the line output control unit 12 sends the write timing of the display to the drive control unit 13. The drive control unit 13 transfers the drive waveform data to the driver IC circuit in the display unit 14 in accordance with the timing. The display unit 14 draws video data on a line specified by a scan address based on the transferred video data, drive waveform data, and scan address data. <Operation of the Gradation Control Unit 11> Next, the operation of the gradation control unit 11 will be described.

First, FIG. 2 shows an example of the configuration of a display device in which the common side is divided into two. In this example, the common side and the segment side are both divided into two, and one pixel is represented by four cells 0 to 3 having different sizes, thereby enabling display of 16 gradations. That is, of the bits representing one pixel, the most significant bit corresponds to cell 3, the second bit corresponds to cell 2, the third bit corresponds to cell 1, and the least significant bit corresponds to cell 0. I have.

When the common side is divided into two or more,
This is basically the same except that the number of outputs of the common driver IC in each line is increased. The segment side (information line side) is also divided into two parts.
The same holds true for three or more divisions. Also, in this example, for simplicity of explanation, single-color 4-bit image data is used to compose one pixel.
If B is one set and one pixel, it can be applied to a color display.

FIG. 3 shows a block diagram for generating the gradation data for the display shown in FIG. 2 and its peripheral portion. FIG. 3 is a diagram showing a configuration which is a part of FIG. 1 and is necessary for outputting the frame data stored in the frame memory 8.

First, the scanning address signal indicating the address of the scanning line for rewriting the display, which is determined by the rewriting control unit 10, is converted into the frame memory address to which the pixel data of that address is input, and the scanning address conversion 103. Is converted. In FIG. 2, 1 of the image data
Since the line is divided into two scanning lines of the display, the address of the line of the frame memory is reduced by halving the scanning address, that is, by shifting one bit to the lower side of the scanning address. can get. For example, if the scanning address is “1”, the line address in the image data is “0”, so “0” is output as the frame address. The obtained frame memory address is given to the frame memory control unit 7, and desired line data is output from the frame memory 8 according to the value of the frame address. At the same time, the scanning address signal is sent to the gradation control unit 11.

When the number of pixel divisions on the common side is n, the determination unit 101 determines that m = log 2 n (a logarithm having a base of 2; m
Outputs an m-bit output obtained by truncation after the decimal point. That is, it is determined which scan line the current scan address corresponds to when the image data is divided into scan lines. For example, in FIG. 2, since the division is performed in two, the gradation control unit 11 may determine whether the scanning address is an even number or an odd number based on the value of the least significant bit and output it. In the case of four divisions, 0 to 3 are sequentially output as the scanning address advances.

The data input from the frame memory 8 is converted by the data conversion unit 102 according to the output result of the judgment unit 101. In this example, if the scanning address is an even number, the upper 2 bits of the input image data are extracted as output image data (determination section output 0), and if the scanning address is odd, the lower 2 bits of the input image data are output (determination section output 1). Take it out as image data. In this conversion data, only upper bits (or only lower bits) of each pixel are packed and output image data is obtained.

That is, in this example, one transfer of output image data is performed by transferring two cells (segment direction). When no data conversion is performed, one cell is used. The image data conversion pattern can be freely changed by rewriting the table from the control unit 4 by using a look-up table in the data conversion unit 102. Thus, the image data is converted according to the scanning address data.

In the case of a display device that is not divided by common, the information is sent from the control unit 4 to the scanning address conversion unit 103 and the selector 104 in the gradation control unit 11. The scanning address conversion unit 103 outputs the frame address as it is without performing the scanning address conversion. The selector 104 switches the image data stored in the frame memory 8 to output image data as it is.

As described above, according to the display control unit of the present embodiment, the common division number of the display unit is fetched, the frame address is designated from the scanning address according to the number, and the read image data is converted into the division number. By performing conversion and outputting in accordance with the above, an image can be normally displayed using the same image data, no matter how common the display units are divided. In addition, since appropriate gradation image data can be transferred to various types of display units having different numbers of common-side divisions, a common display control unit can be used for display units that are produced in small quantities and various types. Cost merit comes out.

[0030]

[Other Embodiments] Even if the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus (for example, a copying machine) Machine, facsimile machine, etc.).

Another object of the present invention is to provide a storage medium storing a program code of software for realizing the functions of the above-described embodiments to a system or apparatus, and to provide a computer (or CPU) of the system or apparatus.
Or MPU) reads and executes the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) Performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instructions of the program code, The case where the CPU of the function expansion board or the function expansion unit performs part or all of the actual processing, and the function of the above-described embodiment is realized by the processing.

[0036]

As described above, according to the present invention,
Appropriate gradation image data can be displayed even on a display divided into common.

[0037]

[Brief description of the drawings]

FIG. 1 is a block diagram of a display system.

FIG. 2 is a diagram illustrating an example of common division of a display.

FIG. 3 is a partial block diagram of a display control unit.

Claims (9)

[Claims] 1. A display control device for dividing a line of image data into a plurality of scanning lines and displaying an image on a display device for expressing gradation, comprising: a scanning line address of interest and a number of divided scanning lines. A display control apparatus for converting a target line of image data into output data corresponding to a divided scanning line, and outputting the output data to the display as data to be displayed on the target scanning line. . 2. The display control device according to claim 1, wherein the image data is grayscale image data that can be displayed by the display. 3. The display according to claim 1, wherein one pixel is further divided along a scanning line direction, and data output to the display is data obtained by dividing one pixel along a scanning line direction. The display control device according to claim 1, wherein: 4. The display device further comprises an input unit for inputting the number of scanning lines into which one line of image data is divided in the display, wherein the image data is converted into output data according to the input number. The display control device according to claim 1. 5. The image display device according to claim 1, further comprising a storage unit configured to store the number of scanning lines into which one line of the image data is divided in the display device, wherein the image data is converted into output data according to the stored number. The display control device according to claim 1. 6. The display control device according to claim 4, wherein the input unit reads a number stored in the display. 7. Input means for inputting image data, conversion means for converting the input image data into gradation image data which can be displayed on the display, and storage means for storing the converted gradation image data The display control device according to claim 1, further comprising: 8. The scanning line address of interest is converted into a corresponding line address of the image data stored in the storage means, and the data of the line address is used as a line of interest to output data corresponding to the scanning line of interest. The display control device according to claim 7, wherein conversion is performed. 9. The display device has a display cell corresponding to each bit of data indicating one pixel of image data, and extracts a bit corresponding to a cell on a target scan line from data of the target line. 2. The display control device according to claim 1, wherein the display control device converts the data into output data corresponding to the divided scanning lines.