JPH09305102A - Method of displaying image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend a time for writing image data by shortening a time for reading out image data from a frame buffer composed of DRAM. SOLUTION: An image processor 71 stores a map and a GUI image in a frame buffer composed of DRAM and also divides the frame buffer 74 storing the GUI image 101 into many blocks consisting of m by n picture elements, and stores the data in transparent/opaque block storage part 82, which indicates whether or not an opaque color part of the GUI image exists in each block. In the case of reading out, the image processor 71 refers to the stored data and determines whether the opaque color part of the GUT image exists in the block to which the image to be read belongs, and if it does not exists, the processor reads out only the map image, but if it exists, the processor reads out each map image and GUI image from the map frame buffer and GUI frame buffer respectively and displays the map and the GUI image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display method for displaying a graphic user interface (GUI) image together with a map image, and more particularly to an image display method in which a map frame buffer and a GUI frame buffer are composed of DRAM.

[0002]

2. Description of the Related Art A navigation device that guides a vehicle so that a driver can easily reach a desired destination detects a vehicle position and reads map data around the vehicle position from a CD-ROM. And drawing a map image on a display screen and a vehicle position mark on a predetermined location on the map image. Then, as the current position changes due to the movement of the vehicle, scroll the map,
The map information around the vehicle position is always visible at a glance. Also, a GUI image having various menu items, scale levels, GPS marks, etc. is displayed in an overlapping manner on the map image. The menu items include various menu items such as a map display switching menu and a guide route setting menu to a destination.

FIG. 5 is an explanatory diagram of image display control in the navigation device. 23 is a VR for storing a map image
A map frame buffer having an AM structure, which stores a map image (for example, a 3 × 3 screen map image) of an area larger than the area displayed on the display screen so that the map can be scrolled as the vehicle moves. To be done. 24 is 1
A GUI frame buffer that stores GUI images for screens, CM is a vehicle position mark, GM is a GPS mark, SCL is a scale level image, and MNA is a menu item image. Reference numeral 29 denotes a color monitor for displaying a GUI image on a map around the vehicle position in an overlapping manner. According to the position of the vehicle, the map information for the surrounding 3 × 3 screens is read from a CD-ROM (not shown), a map image is generated by using the map information and stored in the map frame buffer 23. , Generates a GUI image based on predetermined GUI data, and stores it in the GUI frame buffer 24. In this state, the window W for cutting out the map image from the map frame buffer 23
The position of D is controlled according to the vehicle position, and the window WD
The map image for one screen shown by is the frame buffer for map 1
At the same time, the GUI image is read from the GUI frame buffer 24, and the GUI image is superimposed on the map image and drawn on the color monitor 29.

FIG. 6 is a block diagram of the navigation system. 11 is a CD-ROM for storing map information, and 12 is a C-ROM.
D-ROM driver, 13 is a self-contained navigation sensor,
It has a relative azimuth sensor (angle sensor) such as a vibration gyro that detects a vehicle rotation angle and a distance sensor that generates one pulse for each predetermined traveling distance. Reference numeral 14 is a GPS receiver, 15 is a multi-beam antenna, and 16 is a remote controller. On the remote control, move the cursor, vehicle position mark, etc. in 8 directions relative to the map, move the menu selection bar up / down / left / right to select the desired menu item, and set the focus position. There is a joystick key that is pressed when performing a menu or selecting a menu, an expansion key that is operated when displaying a detailed map, a reduction key that is operated when displaying a wide area map, and a vehicle position. A navigation key for displaying a map to be displayed together with vehicle position marks, a memory key operated when storing a desired point, a power key, and the like are provided.

Reference numeral 17 denotes a peripheral interface unit, and 18 denotes a processing unit (CPU), which controls the entire navigation device, calculates the vehicle position, corrects the vehicle position by the projection method or the map matching method, and guides the route to the destination. Setting control, guidance control along the guide route, map enlargement / reduction control, and readout control of map data around the vehicle position. Reference numeral 19 denotes a program memory (ROM) that stores programs for executing the above various controls,
Reference numeral 20 is a data memory (RAM) for reading other map data, set guide route, traveling route, map information and the like read from the CD-ROM, and 21 is a bus line.

Reference numeral 22 is an image processor, 23 is a VRAM-structured map frame buffer for storing map images, and 24 is a map frame buffer.
Is a GUI frame buffer having a VRAM configuration for storing GUI images. The image processor 22 is a CD-R
Based on the map information read from the OM, a bitmapped map image around the vehicle position is generated and stored in the map frame buffer 23, or a predetermined GUI image is generated and stored in the GUI frame buffer 24. Or
The position of the window WD is controlled to control the reading of the map image and the reading of the GUI image in the window. The map frame buffer 23 sequentially outputs the map image in the window pixel by pixel in synchronization with the raster scan of the color monitor 3. Similarly to the map frame buffer, the GUI frame buffer 24 sequentially outputs the GUI image pixel by pixel in synchronization with the raster scan. The image data of 1 pixel is an 8-bit palette NO. So, you can specify 2 ⁸ colors.

Reference numeral 25 is a timing signal generator, which includes a horizontal synchronizing signal HS, a vertical synchronizing signal VS, and a pixel clock DTC.
And various timing signals are generated. Pixel clock DT
C is a clock signal whose period required for scanning between adjacent pixels is one cycle. A color palette control unit 26 checks whether the GUI image data corresponding to the pixel position (H, V) (H is a horizontal position, V is a vertical position) output from the GUI frame buffer 24 indicates a transparent color. However, if the color is transparent, the frame buffer for map 2
The map image data output from No. 3 is output, and when it is non-transparent, the GUI image data is output. Reference numeral 27 is a color palette. Corresponding to R, G, B
Values (R, G, B data) are stored. Map frame buffer 23 and GUI frame buffer 24
The image data of each pixel in the pallet NO. The R, G, B data of each pixel can be obtained by referring to the color palette 27. 28 is NTS for the R, G, B data output from the color palette 27.
NTSC to convert to color signal of C system color monitor
The encoder (DA converter) 29 is an NTSC color monitor.

With the above structure, the GUI image can be displayed on the color monitor 29 by being superimposed on the map image around the vehicle position, and the window position (map cutout range) is controlled according to the movement of the vehicle to scroll the map. Can be displayed. In this case, the map frame buffer 23 and G
Since the UI frame buffer 24 has a VRAM configuration, while writing the map image and the GUI image in each frame buffer, the map image and the GUI image stored in each frame buffer can be read asynchronously with the writing. .

FIG. 7 is a schematic configuration diagram of the VRAM, which is DR
A memory cell (frame buffer) 51 having an AM structure and a serial access memory unit (SAM unit) 52 are provided. The image data generated by the image processor 22 can be stored in the memory cell 51 via the random port RP pixel by pixel. Also, from the memory cell 51 to the SAM
Image data for one horizontal line can be transferred to the unit 52 at a time, and image data can be read from the SAM unit 52 pixel by pixel via the serial port SP. Therefore, when the horizontal synchronizing signal is generated, the image data for one predetermined horizontal line is transferred from the memory cell 51 to the SAM unit 5.
2 to the pixel clock DT from the SAM unit 52.
Synchronize with C and send image data pixel by pixel to serial port S
An image generated by the image processor 22 can be written to the memory cell 51 via the random port RP in parallel with such reading. From the above,
When the VRAM is used as the map frame buffer 23 and the GUI frame buffer 24, there is an advantage that images can be written in and read from these frame buffers in parallel. However, since the VRAM is expensive, recently, instead of the VRAM, the frame buffer is configured by the DRAM.

FIG. 8 is a block diagram of the periphery of the frame buffer when the frame buffer is composed of DRAM.
Is a DRAM, 32 is a map frame buffer configured in a partial area of the DRAM, 33 is a GUI frame buffer configured in a partial area of the DRAM, and 34 is a map for a plurality of pixels read from the map frame buffer 32. A map FIFO buffer that stores an image and outputs one pixel at a time in synchronization with the pixel clock DTC, and 35 is a GUI
G for plural pixels read from the frame buffer 33 for
This is a GUI FIFO buffer that stores a UI image and outputs it pixel by pixel in synchronization with a pixel clock DTC.

Unlike VRAM, DRAM 31 has only one data access port. For this reason, writing cannot be performed during reading, writing is performed after reading is completed, and when reading is necessary, writing is interrupted and reading is performed. Data bus DBS
Is 32 bits, the image processor 22 can read out image data of 4 pixels (1 pixel data is 8 bits) at a time and store it in the FIFO buffer. Therefore, the map frame buffer 32 and the GUI frame buffer 33
Image data of 4 pixels is read from each
The FI is written in the FO buffers 34 and 35 and
Image data for four pixels is output from the FO buffers 34 and 35 in synchronization with the pixel clock DTC. Then, every time the output of the image data of 4 pixels is completed, the image data of the next 4 pixels is transferred from the frame buffers 32 and 33 to the FIF.
The pixel clock DT is written in the O buffers 34 and 35.
The control of outputting each pixel in synchronization with C is repeated.
The image processor 22 generates an image and writes the generated image in these frame buffers while the image data is not being read from the frame buffers 32 and 33. Actually, from the frame buffer to the pixel clock DT
Image data can be read with a clock faster than C, and image data for n pixels, for example, 8 pixels can be read out by the FIFO.
It is written in the buffers 34 and 35. Then, every time the image data for 8 pixels is output from each of the FIFO buffers 34, 35 in synchronization with the pixel clock, the image data for the next 8 pixels is written from the frame buffers 32, 33 to the FIFO buffers 34, 35. Be done. Image processor 22
Generates an image and writes the generated image in these frame buffers while the image data is not being read from the frame buffers 32 and 33.

[0012]

A frame buffer having a DRAM structure has an advantage of being less expensive than a frame buffer having a VRAM structure. However, the frame buffer having the DRAM structure needs to frequently read out the image data, and further, the map frame buffer 32 and the GUI frame buffer 3 are required.
The image data must be read from both of the three, and during this period, a new image cannot be generated and written in the frame buffer, resulting in a reduction in the processing capability of the image processor.
Further, when the vehicle is traveling at high speed, it is necessary to rewrite the map image in the map frame buffer 34 in a short time, but the writing time is insufficient and high-speed rewriting cannot be performed, and the map scrolling is performed. There is a problem that the display cannot be performed smoothly.

Therefore, an object of the present invention is to provide an image display method capable of shortening the time for reading image data from the frame buffer and lengthening the time for writing image data in the frame buffer. Another object of the present invention is to provide an image display method capable of rewriting a map image at high speed even with a frame buffer having a DRAM structure.

[0014]

According to the present invention, there is provided a DRA for storing a map image and a GUI image, respectively.
An M configuration frame buffer, a means for dividing the frame buffer for storing the GUI image into a large number of blocks of m × n pixels, and information indicating whether or not a non-transparent color portion of the GUI image exists in each block. Storage means for storing,
When the image is read, a means for determining whether or not the non-transparent color portion of the GUI image exists in the block to which the pixel to be read exists from the stored information, and if it does not exist, only the map image is read out. Map image and G
This is achieved by means of reading the UI image and controlling the display of the map and the GUI image. ... Claim 1

Further, according to the present invention, when the image data of a plurality of pixels is read from the frame buffer with one access, the GUI is assigned to the block to which the plurality of pixels belong.
Means for determining whether or not a non-transparent color portion of the image exists,
When it does not exist, only the map image of a plurality of pixels is read out, and when it exists, a map image and a GUI image of a plurality of pixels are read out, and the map and the GUI image are displayed. ... Claim 2

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

(A) Outline of the present invention FIG. 1 is a schematic explanatory view of the present invention, in which 101 is a GUI image, CM is a vehicle position mark, GM is a GPS mark, and SC.
L is a scale level image, and MNA is a menu item image. 71 is an image processor, 74 is a DRAM-configured GU
A frame buffer for I, a FIFO buffer for GUI 76, and a transparent / non-transparent block storage unit 82.

The GUI image 101 is mostly transparent. The GUI image data of the transparent portion is read from the GUI frame buffer 74 one by one, and the GUI FIFO buffer 76 is read.
You don't have to remember it. Therefore, a frame buffer 74 of M × N (for example, 240 × 320) pixels for storing GUI images
Is divided into a large number (= 6 × 8) of blocks B _{01 to} B ₄₈ each including m × n (for example, 40 × 40) pixels, and the image processor 71 determines whether or not a non-transparent portion of the GUI image exists in each block. Then, the transparent / non-transparent block data is stored in the transparent / non-transparent block storage unit 82. In the GUI image 101 of FIG. 1, the shaded blocks are transparent blocks and the others are non-transparent blocks. The transparent block is “0” and the non-transparent block is “1”.
2 is stored.

GU from the GUI frame buffer 74
At the time of reading the I image, the image processor 71 refers to the transparent / non-transparent block data to determine whether or not the non-transparent color portion of the GUI image exists in the block to which the pixel to be read out of the image belongs. Only the map image is read from the map frame buffer to the map FIFO buffer, and if it exists, both the map image and the GUI image are read into the map and GUI FIFO buffers to display the map and the GUI image. By doing so, it is not necessary to read the GUI image from the frame buffer in the transparent block, the image reading time can be shortened, and the image writing time to the frame buffer can be increased accordingly. Thereby, DRAM
Even with the frame buffer having the configuration, the map image can be rewritten at high speed and the map can be scrolled smoothly.

(B) Configuration FIG. 2 is a configuration diagram of a display system in a navigation device embodying the image display method of the present invention. Reference numeral 71 is an image processor, 72 is a DRAM, 73 is a map frame buffer formed by a partial area of the DRAM, 74 is a GUI frame buffer formed by a partial area of the DRAM, and 75 is a plurality of frames read from the map frame buffer 73. A map FIFO buffer that stores a map image of pixels and outputs pixel by pixel in synchronization with the pixel clock DTC. Reference numeral 76 stores a GUI image of a plurality of pixels read from the GUI frame buffer 74 and also uses a pixel clock DTC. This is a GUI FIFO buffer that outputs one pixel in synchronization.

The image processor 71 uses a map image and a G image.
UI image generation, 7 to each frame buffer of these images
Control writing / reading of 3,74. Unlike VRAM, DRAM 72 has only one data access port. Therefore, the image processor 71 interrupts the writing during the reading, writes the image after the reading is completed, and interrupts the writing when the reading becomes necessary and reads the image. Since the image data of 1 pixel is composed of 8 bits and the data bus DBS is 32 bits, the image processor 71 reads out the image data of 4 pixels at a time and outputs the data to the predetermined FIFO buffer 75,
Write to 76. Actually, the image processor 71 can read the image data from the frame buffers 75 and 76 at a clock faster than the pixel clock DTC, and write the image data for n pixels, for example, 8 pixels to the FIFO buffers 75 and 76. Then, every time the image data for 8 pixels is output from each FIFO buffer 75.76 in synchronization with the pixel clock, the image processor 71 outputs the image data for the next 8 pixels from the frame buffers 73 and 74 to the FI.
Write to the FO buffers 75 and 76.

Reference numeral 77 is a timing signal generator, which is a horizontal synchronizing signal HS, a vertical synchronizing signal VS, and a pixel clock DTC.
And various timing signals are generated. Reference numeral 78 denotes a color palette control unit that checks whether the GUI image data corresponding to the pixel position (H, V) output from the GUI FIFO buffer 76 indicates a transparent color. The map data output from the FIFO buffer 75 for output is output, and if it is non-transparent, the GUI image data is output. Reference numeral 79 is a color palette. Values (R, G, B data) of R, G, B are stored in correspondence with (0 to 225). The image data of each pixel in the map frame buffer 73 and the GUI frame buffer 74 is displayed in palette no. The R, G, B data of each pixel can be obtained by referring to the color palette 79. Reference numeral 80 designates the R, G, B data output from the color palette 79 as NTSC.
An NTSC encoder (DA converter) 81 for converting a color signal of a system color monitor is a NTSC system color monitor.

Reference numeral 82 denotes a transparent / non-transparent block storage section, which is an m × n frame buffer 74 of M × N (for example 240 × 320) pixels for storing GUI images as shown in FIG.
A large number (= 6 × 8) of block B consisting of (for example, 40 × 40) pixels
₀₁ when divided into .about.B _48, is configured to store the transparent / non-transparent block data indicating whether the non-transparent portion of the GUI image in each block is present. Reference numeral 83 is a bus line to which the main CPU, ROM, RAM, peripheral interface, etc. of the navigation device are connected.

(C) Transparent / Nontransparent Block Data Creation Processing FIG. 3 is a flowchart of transparent / nontransparent block data creation processing by the image processor 71. At the initial stage, the contents of the transparent / non-transparent block storage unit 82 are cleared to "0". When the image processor 71 generates a GUI image,
The GUI image is displayed for each pixel in the GUI frame buffer 74.
(Steps 201 and 202). Next, it is checked whether the image data of each pixel indicates a transparent color or a non-transparent color (step 203). If the image data is a non-transparent color, the block in which the pixel is located is obtained, and the transparency corresponding to the block is determined. / Write non-transparent (= "1") to the corresponding position of the non-transparent block storage device 82 (step 204).

After that, or when the pixel data is transparent in step 203, it is checked whether the GUI image generation processing is completed (step 205). If not completed, the processing from step 201 onward is repeated. As described above, the transparent / non-transparent block data is stored in the transparent / non-transparent block storage device 82. In the above, the transparent / non-transparent block data is created while writing the GUI image in the frame buffer, but the transparent / non-transparent block data can be created after writing the GUI image in the frame buffer 74.

(D) Image data read and display processing FIG. 4 is a processing flow of the present invention for reading image data from the frame buffers 73 and 74. Image processor 7
1 monitors whether it is the timing to read the image data (step 301). If it is not the timing to read the image, the generation of the map image or the GUI image and the writing processing to the frame buffers 73 and 74, and other processing are executed. (Step 302).

On the other hand, at the image reading timing, the image processor 71 reads the map image (for four pixels) from the map frame buffer 73 and outputs it to the map FIFO.
The data is stored in the buffer 75 (step 303). Then
Whether or not the block to which the four pixels to be read belong is a transparent block is checked by referring to the transparent / non-transparent block data (step 304). For non-transparent blocks,
The GUI image data for four pixels is read from the GUI frame buffer 74 and stored in the GUI FIFO buffer 76 (step 305). In the case of a transparent block, GUI image data is not read from the GUI frame buffer 74. After that, the process returns to step 301 and the subsequent processes are repeated. The image processor 71 has a pixel clock D
Frame buffer 75, 76 with a clock faster than TC
Since the image data can be read out more, the processing from step 303 onward is repeated for the next four pixels,
8 pixel map image data, GUI image data (GUI
The image data may not be read out, or only 4 pixels or all 8 pixels may be read out).
It is stored in the O buffer 76.

Thereafter, each F is synchronized with the pixel clock DTC.
Image data is read from the IFO buffers 75 and 76 pixel by pixel and input to the color palette control unit 78.
The color palette control unit 78 checks whether the GUI image data input from the GUI FIFO buffer 76 is a transparent color, and if it is a transparent color, outputs the map image data output from the map FIFO buffer 75, If it is non-transparent, GUI image data is output. The color palette 79 obtains R, G, B data corresponding to the input image data (palette number), and the NTSC encoder 8
0, the NTSC encoder converts the R, G, B data into a color signal of NTSC system, and the color monitor 8
Display the image in 1. When the image display of all pixels (= 8 pixels) stored in the FIFO buffers 75 and 76 is completed,
The image read timing comes. When the image reading timing comes, the image processor 71 interrupts the image generation and the writing process to the frame buffer, and performs the process from step 303 onward to read the next image data of 8 pixels from the frame buffer.

(E) Modification Although the case where the image processor is provided has been described above, the function of the image processor may be provided to the main processing unit (CPU) of the navigation device. In the above description, the GUI image is displayed over the map image, but the GUI image may be displayed so as to stand out from the map image by adding the R, G, B data of the map image and the GUI image. it can. The case where the GUI frame buffer is divided into blocks of 40 × 40 pixels has been described above, but the present invention is not limited to this size.
Number of pixels that can be read from the frame buffer at one time (= 4
It is also possible to configure one block with pixels). As described above, the present invention has been described with reference to the examples. However, the present invention can be variously modified according to the gist of the present invention described in the claims.
The present invention does not exclude these.

[0029]

As described above, according to the present invention, a map image and a GU
Each of the I images is stored in the frame buffer of the DRAM structure, and the frame buffer storing the GUI image is divided into a large number of blocks of m × n pixels, and whether or not the non-transparent color portion of the GUI image exists in each block. (GU
Information indicating the transparency / non-transparency of the I image is stored in the memory,
When the image is read, whether or not the non-transparent color portion of the GUI image exists (transparent / non-transparent) in the block to which the pixel to be read belongs is obtained from the stored information, and if it does not exist (in the case of a transparent block), the map Read only the image,
If it exists (in the case of a non-transparent block), the map image and the GUI image are read out to control the display of the map and the GUI image.
No need to read images from the frame buffer,
The image reading time can be shortened, and the image writing time to the frame buffer can be increased accordingly. As a result, even if the frame buffer has a DRAM configuration,
The map image can be rewritten at high speed and the map can be scrolled smoothly.

Further, according to the present invention, when the image data of a plurality of pixels is read by one access, if the block to which the plurality of pixels belong is a transparent block, only the map image of a plurality of pixels is read, and the non-transparent block is read. In this case, since the map image and the GUI image of a plurality of pixels are read out to control the display of the map and the GUI image, it is not necessary to read out the GUI image from the frame buffer in the transparent block, and the image reading time can be shortened. ,
The image writing time to the frame buffer can be increased by that amount, which allows the map image to be rewritten at high speed even in the frame buffer having the DRAM structure, and the map scrolling can be smoothly performed. it can.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of the present invention.

FIG. 2 is a configuration diagram of a display system of the present invention.

FIG. 3 is a transparent / non-transparent block data creation processing flow.

FIG. 4 is a flow chart of image data read processing.

FIG. 5 is an explanatory diagram of image display control in the navigation device.

FIG. 6 is a configuration diagram of a navigation device.

FIG. 7 is a configuration diagram of a VRAM.

FIG. 8 is a conventional configuration diagram around a frame buffer when the frame buffer is a DRAM.

[Explanation of symbols]

 101..GUI image 71..Image processor 74..DRAM frame GUI frame buffer 76..GUI FIFO buffer 82..Transparent / non-transparent block storage unit

Claims (2)

[Claims] 1. An image display method for displaying a graphic user interface (GUI) image together with a map image, wherein the map image and the GUI image are respectively stored in a frame buffer having a DRAM structure and a frame buffer for storing the GUI image is m × n. The image is divided into a large number of blocks, and information indicating whether or not a non-transparent color portion of the GUI image exists in each block is stored. When the image is read, the GUI image is non-transparent in the block to which the read target pixel belongs. Whether or not a color portion exists is obtained from the stored information, and when it does not exist, only the map image is read out, and when it exists, the map image and the GUI image are read out to control the display of the map and the GUI image. Characteristic image display method. 2. When the image data of a plurality of pixels is read from the frame buffer with one access, whether or not the non-transparent color portion of the GUI image exists in the block to which the plurality of pixels belong is determined from the stored information and does not exist. 2. The image display according to claim 1, wherein only a map image of a plurality of pixels is read out in the case of being present, and a map image and a GUI image of a plurality of pixels are respectively read out when they are present to control the display of the map and the GUI image. Method.