Image display system scrolling image at high speed using data compression

• US 7,034,839 B2
• Filed: 05/14/2003
• Issued: 04/25/2006
• Est. Priority Date: 07/15/2002
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Morishita, Yoji
• Primary Examiner(s): Chauhan, Ulka J.
• Application Number:
  US10/437,071
• Publication Number:
  US 20040008183A1
• Time in Patent Office: 1,077 Days
• Field of Search: 345/503, 345/520, 345/522, 345/530, 345/531, 345/536, 345/555, 382/113, 382/232, 382/254, 701 23- 25, 701/28, 701/200, 701/212, 715/784, 340/995.1, 340/995.14, 340/995.15, 340/995.18
• US Class Current: 345/555
• CPC Class Codes: G01C 21/367 Details, e.g. road map scale, orientation, zooming, illumination, level of detail, scrolling of road map or positioning of current position marker
• CPC Class Codes: G09G 2340/02 Handling of images in compressed format, e.g. JPEG, MPEG
• CPC Class Codes: G09G 5/024 using colour registers, e.g. to control background, foreground, surface filling G09G5/06 takes precedence
• CPC Class Codes: G09G 5/346 for systems having a bit-mapped display memory
• CPC Class Codes: H04N 19/132 Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
• CPC Class Codes: H04N 19/17 the unit being an image region, e.g. an object
• CPC Class Codes: H04N 19/186 the unit being a colour or a chrominance component
• CPC Class Codes: H04N 19/426 using memory downsizing methods
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder

Abstract

When a user pushes a scroll-direction key, an ECU obtains, from a memory, a division map corresponding to a division located in a direction designated by the scroll-direction key. The ECU then outputs the division map to a display controller. The display controller compresses the division map to store in a VRAM. At scrolling a displayed image, the display controller expands the compressed division map. It then outputs, to an image signal generator, only a necessary portion of the expanded division map. Thereby, the displayed image can be scrolled at high speed and easily recognizable for the user.

Claims

1. An image display system comprising:

first storing means for storing image data;

commanding means for commanding a start of scrolling a displayed image on a display;

compressing means for retrieving a given portion of the image data from the first storing means when the start of scrolling the displayed image is commanded by the commanding means, and then compressing the given portion of the image data to generate compressed data, wherein the given portion of the image data includes the image data that is to be displayed at scrolling;

second storing means for storing the compressed data;

expanding means for expanding the compressed data stored in the second storing means to generate expanded data; and

image displaying means for displaying, by using the expanded data, the displayed image at scrolling,

wherein the second storing means further stores the given portion of the image data that is not compressed by the compressing means, and

wherein the compressing means retrieves the given portion of the image data that is not compressed from the second storing means and then compresses the given portion of the image data when the start of scrolling the displayed image is commanded by the commanding means.

2. An image display system comprising:

first storing means for storing image data;

commanding means for commanding a start of scrolling a displayed image on a display;

compressing means for retrieving a given portion of the image data from the first storing means when the start of scrolling the displayed image is commanded by the commanding means, and then compressing the given portion of the image data to generate compressed data, wherein the given portion of the image data includes the image data that is to be displayed at scrolling;

second storing means for storing the compressed data;

expanding means for expanding the compressed data stored in the second storing means to generate expanded data;

image displaying means for displaying, by using the expanded data, the displayed image at scrolling; and

direction designating means for designating a direction of scrolling,

wherein the compressing means compresses the given portion of the image data including the image data that is to be displayed when the displayed image is scrolled towards the direction designated by the direction designating means.

3. An image display system comprising:

first storing means for storing image data;

commanding means for commanding a start of scrolling a displayed image on a display;

compressing means for retrieving a given portion of the image data from the first storing means when the start of scrolling the displayed image is commanded by the commanding means, and then compressing the given portion of the image data to generate compressed data, wherein the given portion of the image data includes the image data that is to be displayed at scrolling;

second storing means for storing the compressed data;

expanding means for expanding the compressed data stored in the second storing means to generate expanded data;

image displaying means for displaying, by using the expanded data, the displayed image at scrolling; and

measuring means for measuring a data amount of the compressed data generated by the compressing means,

wherein the compressing means is capable of switching a plurality of compressing methods that have respective compression rates to generate the compressed data,

wherein the compressing means compresses certain image data to generate first compressed data by using a first compressing method, and

wherein, when a data amount of the first compressed data that is measured by the measuring means is more than a predetermined data amount, the compressing means compresses the certain image data by using a second compressing method to generate second compressed data, wherein the second compressed data is smaller than the first compressed data.

4. An image display system comprising:

first storing means for storing image data;

commanding means for commanding a start of scrolling a displayed image on a display;

compressing means for retrieving a given portion of the image data from the first storing means when the start of scrolling the displayed image is commanded by the commanding means, and then compressing the given portion of the image data to generate compressed data, wherein the given portion of the image data includes the image data that is to be displayed at scrolling;

second storing means for storing the compressed data;

expanding means for expanding the compressed data stored in the second storing means to generate expanded data;

image displaying means for displaying, by using the expanded data, the displayed image at scrolling,

wherein the compressing means includes biasing means for biasing distribution of color information included in the image data, and

wherein the compressing means nonreversibly compresses the given portion of the image data through biasing the distribution of the color information included in the given portion of the image data by the biasing means.

5. An image display system comprising

first storing means for storing image data;

commanding means for commanding a start of scrolling a displayed image on a display;

compressing means for retrieving a given portion of the image data from the first storing means when the start of scrolling the displayed image is commanded by the commanding means, and then compressing the given portion of the image data to generate compressed data, wherein the given portion of the image data includes the image data that is to be displayed at scrolling;

second storing means for storing the compressed data;

expanding means for expanding the compressed data stored in the second storing means to generate expanded data;

image displaying means for displaying, by using the expanded data, the displayed image at scrolling,

wherein the image data includes pieces of color information, each of the pieces of the color information being included in pixel information that is possessed by each of a plurality of pixels,

wherein the compressing means compresses the given portion of the image data nonreversibly by substituting another piece of the color information for a certain piece of the color information of a certain pixel included in the image data,

wherein the substituted another piece of the color information is included in one of pixels adjoining the certain pixel, and

wherein the substituted another piece of the color information is most frequently included in the pixels adjoining the certain pixel.

7. An image display system comprising:

first storing means for storing image data;

commanding means for commanding a start of scrolling a displayed image on a display;

compressing means for retrieving a given portion of the image data from the first storing means when the start of scrolling the displayed image is commanded by the commanding means, and then compressing the given portion of the image data to generate compressed data, wherein the given portion of the image data includes the image data that is to be displayed at scrolling;

second storing means for storing the compressed data;

expanding means for expanding the compressed data stored in the second staring means to generate expanded data;

image displaying means for displaying, by using the expanded data, the displayed image at scrolling,

wherein the image data includes pieces of color information, each of the pieces of the color information being included in pixel information that is possessed by each of a plurality of pixels,

wherein the compressing means compresses the given portion of the image data nonreversibly by substituting another piece of the color information for a certain piece of the color information of a certain pixel included in the image data,

prohibiting means for setting prohibited color information that is prohibited from being replaced with the substituted another piece of the color information,

wherein, when the certain piece of the color information is the prohibited color information, the compressing means compresses the given portion of the image data without substituting another piece of the color information for the certain piece of the color information of the certain pixel included in the image data.

6. An image display system according to claim 7, further comprising:

first storing means for storing image data;

commanding means for commanding a start of scrolling a displayed image on a display;

compressing means for retrieving a given portion of the image data from the first storing means when the start of scrolling the displayed image is commanded by the commanding means, and then compressing the given portion of the image data to generate compressed data, wherein the given portion of the image data includes the image data that is to be displayed at scrolling;

second storing means for storing the compressed data;

expanding means for expanding the compressed data stored in the second storing means to generate expanded data;

image displaying means for displaying, by using the expanded data, the displayed image at scrolling,

wherein the image data include pieces of color information, each of the pieces of the color information being included in pixel information that is possessed by each of a plurality of pixels,

wherein the compressing means compresses the given portion of the image data nonreversibly by substituting another piece of the color information for a certain piece of the color information of a certain pixel included in the image data,

color information setting means for setting the color information of any one of the pixels,

wherein the substituted another piece of the color information is set by the color information setting means, and

wherein the color information set by the color information setting means is color information of a background of the displayed image.

8. An image display system comprising:

first storing means for storing image data;

commanding means for commanding a start of scrolling a displayed image on a display;

compressing means for retrieving a given portion of the image data from the first storing means when the start of scrolling the displayed image is commanded by the commanding means, and then compressing the given portion of the image data to generate compressed data, wherein the given portion of the image data includes the image data that is to be displayed at scrolling;

second storing means for storing the compressed data;

expanding means for expanding the compressed data stored in the second storing means to generate expanded data;

image displaying means for displaying, by using the expanded data, the displayed image at scrolling,

wherein the image data include pieces of color information, each of the pieces of the color information being included in pixel information that is possessed by each of a plurality of pixels,

wherein the compressing means compresses the given portion of the image data nonreversibly by substituting another piece of the color information for a certain piece of the color information of a certain pixel included in the image data, and

wherein the substituted another piece of the color information is included in one of pixels adjoining the certain pixel.

9. An image display system comprising:

first storing means for storing image data;

commanding means for commanding a start of scrolling a displayed image on a display;

compressing means for retrieving a given protion of the image data from the first storing means when the start of scrolling the displayed image is commanded by the commanding means, and then compressing the given protion of the image data to generate compressed data, wherein the given portion of the image data includes the image data that is to be displayed at scrolling;

second storing means for storing the compressed data;

expanding means for expanding the compressed data stored in the second storing means to generate expanded data;

image displaying means for displaying, by using the expanded data, the displayed image at scrolling,

wherein the image data includes pieces of color information, each of the pieces of the color information being included in pixel information that is possessed by each of a plurality of pixels,

wherein the compressing means compresses the given portion of the image data nonreversibly by substituting another piece of the color information for a certain piece of the color information of a certain pixel included in the image data, and

color information setting means for setting the color information of any one of the pixels,

wherein the substituted another piece of the color information is set by the color information setting means.