Image data refreshing method and display system using the same

1. An image data refreshing method used in an image data display device, the method comprising:

(a) defining a refreshing center of a display area according to a visual focus of a present frame displayed on the display area;

(b) dividing the display area into at least a first sub-display area and a second sub-display area according to the refreshing center, wherein the refreshing center is located within the first sub-display area which is surrounded by the second sub-display area;

(c) setting the refreshing rate of image data of the first sub-display area and that of the second sub-display area respectively; and

(d) refreshing the image data of the first sub-display area and that of the second sub-display area respectively;

wherein the image data of the first sub-display area and that of the second sub-display area are transmitted respectively from an image data source device to the image data display device according to the refreshing rate of the image data of the first sub-display area and that of the second sub-display area respectively; and wherein the refreshing rate of the image data of the second sub-display area is lower than the refreshing rate of the image data of the first sub-display area; and the image data source device sends fewer amount of data bits for the second sub-display area by skipping at least a portion of the image data of the second sub-display area in at least one frame.

2. The image data refreshing method according to claim 1 , wherein the shapes of the first sub-display area and the second sub-display area are a rectangle or a rectangular ring respectively.

3. The image data refreshing method according to claim 1 , wherein the refreshing center is substantially located at a cursor of a mouse, wherein the closer to the refreshing center the sub-display is, the higher the refreshing rate of image data of the sub-display area will be.

4. A projector, comprising:

a controlling unit for setting a refreshing center of a display area according to a visual focus of a present frame displayed on the display area and dividing the display area into at least a first sub-display area and a second sub-display area according to the refreshing center, wherein the refreshing center is located within the first sub-display area which is surrounded by the second sub-display area;

a memory unit for storing image data of the first sub-display area and that of the second sub-display area;

a transmission module for providing an image data update request signal to an image data source device and receiving the image data; and

a projection unit for displaying the image data of the first sub-display area and that of the second sub-display area;

wherein when the image data source device receives the image data update request signal, the image data of the first sub-display area and that of the second sub-display area are transmitted according to the refreshing rate of the image data of the first sub-display area and that of the second sub-display area respectively from the image data source device; and wherein the refreshing rate of the image data of the second sub-display area is lower than the refreshing rate of the image data of the first sub-display area; and the image data source device sends fewer amount of data bits for the second sub-display area by skipping at least a portion of the image data of the second sub-display area in at least one frame.

5. The projector according to claim 4 , wherein the controlling unit is further used for setting the refreshing rate of image data of the first sub-display area and that of the second sub-display area.

6. The projector according to claim 4 , wherein the image data of the first sub-display area is a differential image data generated from comparing the image data of the first sub-display area of the present frame with a to-be-updated image data of the first sub-display area, and the image data of the second sub-display area is another differential image data generated from comparing the image data of the second sub-display area of the present frame with a to-be-updated image data of the second sub-display area.

7. The projector according to claim 4 , wherein the shapes of the first sub-display area and the second sub-display area are a rectangle or a rectangular ring.

8. The projector according to claim 4 , wherein the visual focus is substantially located at a cursor of a mouse.

9. The projector according to claim 4 , wherein the closer to the refreshing center the sub-display area is, the higher the refreshing rate of image data of the sub-display area will be.

10. An image data displaying system for displaying image data, comprising:

an image data displaying device, comprising:

a controlling unit for setting a refreshing center of a display area according to a visual focus of a present frame displayed on the display area and dividing the display area into at least a first sub-display area and a second sub-display area according to the refreshing center, wherein the refreshing center is located within the first sub-display area which is surrounded by the second sub-display area, and the controlling unit is further used for setting the refreshing rate of image data of the first sub-display area and that of the second sub-display area and provide an image data update request signal;

a memory unit for storing the image data of the first sub-display area and that of the second sub-display area;

a transmission module for providing the image data update request signal to an image data source device and receiving the image data from the image data source device; and

a projection unit for displaying the image data of the first sub-display area and that of the second sub-display area; and

the image data source device, comprising:

a processing unit for receiving the image data update request signal and transmitting the image data according to the image data update request signal;

wherein when the image data source device receives the image data update request signal, the image data of the first sub-display area and that of the second sub-display area are transmitted according to the refreshing rate of the image data of the first sub-display area and that of the second sub-display area respectively from the image data source device; and wherein the refreshing rate of the image data of the second sub-display area is lower than the refreshing rate of the image data of the first sub-display area; and the image data source device sends fewer amount of data bits for the second sub-display area by skipping at least a portion of the image data of the second sub-display area in at least one frame.

11. The displaying system according to claim 10 , wherein the shape of the first sub-display area and that of the second sub-display area are a rectangle or a rectangular ring.

12. The displaying system according to claim 10 , wherein the visual focus is substantially located at a cursor of a mouse.

13. The displaying system according to claim 10 , wherein the closer to the refreshing center the sub-display area is, the higher the refreshing rate of image data will be.

14. The displaying system according to claim 10 , wherein the image data source device further comprises

a frame capturing unit for capturing the image data of the present frame; and

a frame detecting unit for comparing the image data of the frame currently displayed with a to-be-updated image data so as to generate a differential image data;

wherein when the image data source device receives the image data update request signal, the differential image data of the first sub-display area and that of the second sub-display area are transmitted according to the refreshing rate of the image data of the first sub-display area and that of the second sub-display area respectively from the image data source device.

15. The displaying system according to claim 14 , wherein the frame detecting unit further stores a frame updating rule which records the transmission sequence of the differential image data of the first sub-display area and that of the second sub-display area; and

a compressing/encoding unit for compressing/encoding the differential image data.