JP2008305030A - Composite image generation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite image generation device capable of reducing the amount of access data of a video memory. <P>SOLUTION: In a switch-layer transmitting color information area 12, α value conversion data indicating determined results is memorized after determining from an α value as for whether or not a pixel has a transmitting color for each pixel on a switch-layer (step S4). Then, when reading switch-layer pixel data, the pixel data only for non-transmitting color which is not the transmitting color or half-transmitting color is read out by referring to the α value conversion data associated with each pixel (step S7), and the pixel data for the transmitting color is skipped in reading. Further, a composite image is generated by superimposing the switch-layer pixel data on navigation-layer pixel data for the non-transmitting color which is not the transmitting color or the half-transmitting color only. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a composite image generation apparatus suitable for generating an image in which a plurality of screen layers and the like are superimposed.

Conventionally, a display control apparatus that displays a plurality of screens in an overlapping manner has been proposed (see, for example, Patent Document 1). In the display control device described in Patent Document 1, when the display data color read from the foreground plane plane memory is transparent color data, the display data color read from the background plane plane memory is selected by the selector as composite display data. indicate.
Japanese Patent Laid-Open No. 9-90934

  Originally, the transparent color data is data that does not need to be read from the plane memory as display data because it does not need to be actually displayed. However, in the display control device described above, since reading from the plane memory is performed due to the necessity of combining transparent and non-transparent screens, the reading of the extra data becomes a load on the memory bus, which may lead to a decrease in system performance. .

  Further, when the display of the lower layer is hidden by the display of the upper layer, it is possible to reduce the load on the video memory by preventing the data of the hidden portion from being read from the video memory as in the above display control device. However, in a navigation image that is often composed of a lower layer map image and an upper layer switch image, such as a navigation device, most of the switch image is occupied by a transparent color. There are few portions that do not need to be read in the image, and the load on the video memory cannot be effectively reduced.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a composite image generating apparatus capable of reducing the amount of access data in a video memory.

The composite image generation apparatus according to claim 1, which is made to achieve the above object,
A composite image in which layers of a plurality of layers are superimposed,
Pixel data storage means for storing pixel data for each layer;
For each upper layer pixel, transparent color determination means for determining whether the pixel is a transparent color or not,
Transmission color information storage means for storing the transmission color information determined by the transmission color determination means in association with each pixel;
A data reading unit that refers to the information on the transmission color stored in the transmission color information storage unit and reads out pixel data of a pixel that is not a transmission color from the pixel data storage unit among the pixels of the upper layer;
A composite image is generated by superimposing the upper layer pixel data and the lower layer pixel data, which are not transparent colors, read by the data reading unit.

  Thereby, the data reading means does not read out the pixel data of the pixel which is the transparent color from the pixel data storage means among the pixels of the upper layer, and only the pixel data of the pixel which is not the transparent color is stored in the pixel data storage means. Therefore, the amount of access data stored in the pixel data storage means can be reduced. As a result, the hindrance to arithmetic processing and drawing processing in the composite image generating apparatus is reduced.

  According to the composite image generating apparatus of the second aspect, when the pixel data of the lower layer stored in the pixel data storage means is changed, the pixel data of the pixel which is not the transparent color is read out.

  When the pixel data of the lower layer is changed, the pixel data storage means frequently reads and writes the pixel data of the lower layer, which increases the processing load of data reading and writing. Therefore, when the pixel data of the lower layer is changed, only the pixel data of the pixel that is not a transparent color is read, thereby reducing the processing load due to the reading of the pixel data of the upper layer and generating a composite image The processing load on the entire apparatus is reduced.

  The composite image generation apparatus according to claim 3, wherein the composite image generation apparatus generates a navigation image in which pixel data of two layers having a graphic image as an upper layer and a map image as a lower layer are superimposed as a composite image. To do.

  The navigation image is configured by superimposing a graphic image that is an upper layer on a map image that is a lower layer, and most of the upper layer occupies a transparent color, and the user of the navigation device The image does not change until a graphic such as a switch is operated. Therefore, in the image display device that displays the navigation image, the access data amount of the upper layer pixel data can be more effectively reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, an example will be described in which the composite image generation device of the present invention is applied to a navigation device that displays a map around the current location or provides route guidance while displaying a route reaching the destination on the map. .

  FIG. 1 shows the overall configuration of an image ECU 100 that constitutes the navigation device. The image ECU 100 is mainly configured as a microcomputer, and includes a video memory 10, a display data reading circuit 20, a transmission color information writing circuit 30, a switch layer data buffer 40, a navigation layer data buffer 50, a screen synthesis circuit 60, CPU 70 etc. are provided.

  The video memory 10 includes a switch layer pixel data area 11 that stores pixel data (switch layer pixel data) of the switch layer screen shown in FIG. 2, a switch layer transmission color information area 12 that stores switch layer transmission color information described below, and 2 is divided into three memory areas of a navigation layer pixel data area 13 for storing pixel data (navigation layer pixel data) of the navigation layer screen shown in FIG.

  As shown in FIG. 2, the switch layer pixel data is data for displaying a graphic image such as an operation switch of the navigation device. Most of the switch layer is occupied by a transparent color, and a graphic portion such as an operation switch has a non-transparent color or a semi-transparent color. The navigation layer pixel data is data for displaying a map image.

  The image ECU 100 generates a navigation image as a composite image by performing a screen composition process in which two layers having a switch layer as an upper layer and a navigation layer as a lower layer are overlapped, and outputs the navigation image to a display device or the like. . FIG. 2 shows an image of the RGB output image.

  The display data read circuit 20 executes data read control for reading switch layer pixel data and navigation layer pixel data from the video memory 10. Further, the display data reading circuit 20 determines the color (transparent color / non-transparent color / translucent color) of each pixel of the switch layer.

  FIG. 3 shows the data structure of the switch layer pixel data. For each pixel, an α value (8 bits), an R value (8 bits), and a G value (8 bits) indicating transparent color / non-transparent color / translucent color are shown. ), And B value (8 bits). The α value is assigned 0x00 for a transparent color and 0xff for a non-transparent color. In the case of a semi-transparent color, 0x01 to 0xfe are assigned according to the transmittance.

  In the display data reading circuit 20, if the α value is 0x00, the pixel is determined to be a transparent color, and if it is 0x01 to 0xff, the pixel is a non-transparent color or a semi-transparent color that is not a transparent color. Is determined.

  In the transmission color information writing circuit 30, the transmission color determination result determined by the display data reading circuit 20 is converted into 1-bit α value conversion data (“0” for transmission color, non-transmission color that is not transmission color, or semi-transmission color) If it is, “1”) is stored in the switch layer transmission color information area 12. At this time, as shown in FIGS. 4A and 4B, each switch layer pixel is stored (written) in association with each pixel (corresponding to the pixel position). Thereby, the α value (8 bits) of one pixel is converted into 1-bit α value conversion data, and this α value conversion data is stored in the switch layer transmission color information area 12 as switch layer transmission color information.

  As described above, when the α value conversion data is stored in the switch layer transmission color information area 12, the display data reading circuit 20 refers to the α value conversion data for each pixel of the switch layer when reading the switch layer pixel data. , Only pixel data of α value conversion data ≠ 0 (non-transparent color that is not transparent color or semi-transparent color = 1) is read.

  The switch layer data buffer 40 temporarily stores the switch layer pixel data read by the display data read circuit 20, and the navigation layer data buffer 50 temporarily stores the navigation layer pixel data read by the display data read circuit 20. To do. As shown in FIG. 2, the screen compositing circuit 60 performs screen compositing processing in which two layers having the switch layer as an upper layer and the navigation layer as a lower layer are overlapped. An RGB output image generated by this image composition processing is output.

  Next, display data reading processing by the image ECU 100 will be described with reference to the flowchart shown in FIG. In step S1 shown in FIG. 5, the switch layer is drawn. When the drawing is completed, the pixel data of the switch layer in the first frame is read in step S2.

  In step S3, the α value for each pixel of the switch layer is extracted, and the color (transparent color / non-transparent color / semi-transparent color) of the pixel is determined. Then, from the determination result, the α value is converted into 1-bit α value conversion data (“0” for a transparent color, “1” for a non-transparent color that is not a transparent color, or a semi-transparent color). In step S4, the α value conversion data is written back (stored) in the switch layer transmission color information area 12.

  Steps S5 to S7 are processes for the second and subsequent frames. First, in step S5, the α value conversion data written back in step S4 is read. In step S6, whether the α value conversion data is “1” (that is, the determination target pixel in the switch layer of the second frame is Whether it is a non-transparent color that is not a transparent color or a semi-transparent color).

  If an affirmative determination is made in step S5 (determined to be a non-transparent color or a semi-transparent color), the process proceeds to step S6. If a negative determination is made in step S5 (determined to be a transparent color), The switch layer pixel data of the pixel is not read from the switch layer pixel data area 11 (i.e., skipped), and the process proceeds to step S8.

  In step S 7, the switch layer pixel data of the pixel determined to have the α value conversion data “1” is read from the switch layer pixel data area 11. In step S8, it is determined whether reading or skipping of switch layer pixel data for one frame has been completed.

  If an affirmative determination is made in step S8, the process proceeds to step S9. If a negative determination is made, reading or skipping of switch layer pixel data for one frame has not been completed, so the process proceeds to step S5. Returning, the pixel to be determined is sequentially changed according to the arrangement order of the pixels of the switch layer, and the above-described processing is repeated.

  When the reading or skipping of the switch layer pixel data for one frame is completed, it is determined in step S9 whether or not the switch layer pixel data stored in the switch layer pixel data area 11 has been updated. . If it has been updated, the process returns to step S1 to repeat the above-described process. On the other hand, if not updated, the process returns to step S5, and the above-described process is repeated.

  In the navigation image, most of the graphic images that are upper layers occupy a transparent color, and until the navigation device user operates a graphic such as an operation switch, the pixel data of the switch layer does not exist. There is no change. Accordingly, since it is often determined that the update has not been performed in step S9, in the image display device that displays the navigation image, the access data amount of the upper layer pixel data can be more effectively reduced. Can do.

  As described above, in the image ECU 100 according to the present embodiment, for each pixel of the switch layer, it is determined from the α value whether the pixel is a transmission color or a transmission color, and the determination result indicates α The value conversion data is stored in the switch layer transmission color information area 12. Thereafter, when the switch layer pixel data is read out, only the non-transparent color or semi-transparent color pixel data that is not the transparent color is read with reference to the α value conversion data associated with each pixel, and the transparent color Some pixel data is skipped. Then, a composite image is generated by superimposing the switch layer pixel data and the navigation layer pixel data of only the non-transparent color that is not the transparent color or the semi-transparent color.

  Accordingly, pixel data of a pixel that is a transparent color among the pixels of the switch layer is not read from the switch layer pixel data area 11 of the video memory 10 (i.e., skipped), and is a non-transparent color that is not a transparent color, or Since only the pixel data of the translucent color pixel is read out, the access data amount of the video memory 10 can be reduced. As a result, the hindrance to arithmetic processing and drawing processing in the composite image generating apparatus is reduced.

  For example, if the switch layer is 30% transparent color and the switch layer has not been updated for 10 frames (usually displayed at a rate of 60 frames per second), the video memory 10 of the switch layer can be obtained using this image ECU 100. The amount of access data is 1536 KByte (first frame) + 48 KByte (write back) + 9 x (48 KByte + 1536 Kbyte x 0.3) (2 to 10 frames) = 6163.2 Kbytes. 1 frame to 10 frames) = 15360KByte. Therefore, the access amount to the video memory 10 can be greatly reduced.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  For example, in a navigation image, when a map image as a lower layer is scroll-displayed, navigation layer pixel data is frequently read and written in the video memory 10, and the processing load of data reading and writing increases. Therefore, when the navigation layer pixel data is changed, the display data reading process described above is executed so that only the non-transparent color or translucent color switch layer pixel data is read. The processing load due to the reading of the switch layer pixel data can be reduced, and the processing load on the entire image ECU 100 is reduced.

2 is a block diagram illustrating an overall configuration of an image ECU 100. FIG. It is an image figure of the RGB output data which synthesize | combined those switch layer screens, a navigation layer screen, and those screens. It is a figure which shows the data structure of switch layer pixel data. (A) is a diagram showing a memory arrangement of switch layer pixel data, and (b) is a diagram showing a memory arrangement of switch layer transmission color information data. 5 is a flowchart for explaining display data reading processing by the image ECU 100.

Explanation of symbols

10 video memory 11 switch layer pixel data area 12 switch layer transmission color information area 13 navigation layer pixel data area 20 display data read circuit 30 transmission color information write circuit 40 switch layer data buffer 50 navigation layer data buffer 60 screen composition circuit 70 CPU
100 Image ECU

Claims (3)

A composite image generation apparatus that generates a composite image in which a plurality of layers are superimposed,
Pixel data storage means for storing pixel data for each layer;
For each upper layer pixel, transparent color determination means for determining whether the pixel is a transparent color or not,
Transmission color information storage means for storing the transmission color information determined by the transmission color determination means in association with each pixel;
Data reading means for referring to information on the transparent color stored in the transparent color information storage means, and reading out pixel data of pixels that are not transparent color from the pixel data storage means among the pixels of the upper layer,
A composite image generation apparatus that generates a composite image obtained by superimposing pixel data of an upper layer that is not a transparent color and pixel data of a lower layer read by the data reading unit.   2. The composite image generation according to claim 1, wherein the data reading unit reads pixel data of a pixel that is not a transparent color when the pixel data of the lower layer stored in the pixel data storage unit is changed. apparatus.   The composite image generation device generates a navigation image in which pixel data of two layers of layers having a graphic image as an upper layer and a map image as a lower layer are superimposed as the composite image. Or the synthetic image production | generation apparatus of 2 description.

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