Display device and method for adjusting gray-level of image frame depending on environment illumination

• US 8,963,901 B2
• Filed: 08/08/2011
• Issued: 02/24/2015
• Est. Priority Date: 04/20/2011
• Status: Active Grant

• Current Assignee: Wistron Corporation
• Original Assignee: Wistron Corporation
• Inventors: Chang, Yao-Tsung
• Primary Examiner(s): Pham, Long D
• Application Number:
  US13/204,880
• Publication Number:
  US 20120268436A1
• Time in Patent Office: 1,296 Days
• Field of Search: 345/207
• US Class Current: 345/207
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/34 by control of light from an independent source
• CPC Class Codes: G09G 3/344 based on particles moving in a fluid or in a gas, e.g. electrophoretic devices electrophoretic devices per se G02F1/167
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A display apparatus and method for adjusting the gray level depending on environment illumination is used to adjust the average-gray-level of an image frame with a plurality of pixels. The display device includes a display-panel, an optical-sensor, a controller, and an adjusting module. The display-panel displays the image frame with the plurality of pixels. The optical-sensor is used to obtain the environment illumination. The controller is used to drive the display-panel to display the image frame. The adjusting module is used to adjust gray-levels of the pixels according to the environment illumination. When the environment illumination is too high, the adjusting module raises the gray-level of partial or all pixels; and when the environment illumination is too low, the adjusting module reduces the gray-level of partial or all pixels; so that visual effect of the display device is enhanced.

Claims

1. A display device for adjusting a gray-level of a image frame depending on environment illumination, comprising:

a reflecting ambient light display-panel, for displaying an image frame with a plurality of pixels, and each pixel of the reflecting ambient light display-panel reflects an ambient light according to a gray-level thereof;

an optical-sensor, for obtaining the environment illumination, wherein the optical-sensor and the reflecting ambient light display-panel are located on the same side surface of the display device;

a controller, for driving the display-panel to display the image frame; and

an adjusting module, for adjusting gray-levels of at least partial pixels in the image frame according to the environment illumination;

wherein a reference illumination range is designated to the adjusting module, and the adjusting module determines whether the obtained environment illumination is within the reference illumination range;

wherein when the environment illumination is higher than the reference illumination range, the adjusting module raises the gray-levels of at least partial pixels in the image frame according to the environment illumination;

wherein when the environment illumination is lower than the reference illumination range, the adjusting module reduces the gray-levels of at least partial pixels in the image frame according to the environment illumination; and

wherein a gray-level median interval is further designated to the adjusting module;

when the environment illumination is higher than the reference illumination range and an average gray-level of the image frame is lower than or higher than the gray-level median interval, the adjusting module performs an image inverse process on the image frame.

2. The display device as claimed in claim 1, wherein the adjusting module is an independent electronic component, electrically connected to the controller.

3. The display device as claimed in claim 1, further comprising a memory module, electrically connected to the controller, wherein the adjusting module is a program code, stored in the memory module, and loaded and executed by the controller.

4. The display device as claimed in claim 1, wherein the adjusting module is an independent electronic component, electrically connected to the controller.

5. The display device as claimed in claim 1, wherein when the environment illumination is lower than the reference illumination range and an average gray-level of the image frame is higher than the gray-level median interval, the adjusting module performs the image inverse process on the image frame.

6. The display device as claimed in claim 1, wherein the controller marks the partial image frame with the text data before the adjustment of the gray-level is performed on the image frame, and the adjusting module then performs the adjustment of gray-level on the partial image frame.

7. A method for adjusting a gray-level of a image frame depending on environment illumination, for adjusting the gray-level of at least partial image frame in the image frame, wherein the partial image frame comprises a plurality of pixels and each pixel reflects an ambient light according to the gray-level thereof, the method comprising the steps of:

obtaining the environment illumination;

designating a reference illumination range;

determining whether the environment illumination is higher than or lower than the reference illumination range; and

if the environment illumination is higher than the reference illumination range, raising gray-levels of at least partial pixels in the partial image frame according to the environment illumination, and displaying the adjusted image frame;

if the environment illumination is lower than the reference illumination range, reducing gray-levels of the at least partial pixels in the partial image frame according to the environment illumination, and displaying the adjusted image frame;

if the environment illumination is neither not higher than or lower than the reference illumination range, obtaining the environment illumination again instead of adjusting the gray-level of the image frame;

wherein raising the gray-levels of the at least partial pixels in the partial image frame comprises;

determining a first gray-level according to the environment illumination;

determining a gray-level added value required when the lowest gray-level is adjusted to the first gray-level in the partial image frame;

adding the gray-level added value to the gray-level of each pixel in the partial image frame;

determining whether the highest gray-level in the adjusted image frame is higher than an upper limit of a gray-level variation range of the image frame;

if the highest gray-level in the adjusted image frame is not higher than the gray-level variation range of the image frame, generating the adjusted image frame according to an adjustment result; and

if the highest gray-level in the adjusted image frame is higher than the upper limit of the gray-level variation range of the image frame, adjusting the highest gray-level to the upper limit of the gray-level variation range, so as to reduce the gray-level variation range;

performing linear adjustment on the gray-level of each pixel in the image frame, so as to map each gray-level to the reduced gray-level variation range; and

obtaining the adjusted gray-level of each pixel, so as to generate the adjusted image frame.

8. The method as claimed in claim 7, wherein before determining the first gray-level according to the environment illumination, the method comprises:

determining whether an average gray-level of the partial image frame is lower than a gray-level median interval;

if the average gray-level of the partial image frame is lower than the gray-level median interval, performing an image inverse process on the partial image frame, so as to generate the adjusted image frame.

9. The method as claimed in claim 7, wherein reducing the average gray-level of the image frame comprises:

determining a second gray-level according to the environment illumination;

determining a gray-level reduced value required when the highest gray-level is adjusted to the second gray-level in the partial image frame;

subtracting the gray-level reduced value to the gray-level of each pixel in the partial image frame;

determining whether the lowest gray-level in the adjusted image frame is lower than a lower limit of a gray-level variation range of the image frame;

if the lowest gray-level in the adjusted image frame is not lower than the gray-level variation range of the image frame, generating the adjusted image frame according to an adjustment result; and

if the lowest gray-level in the adjusted image frame is lower than the lower limit of the gray-level variation range of the image frame, adjusting the lowest gray-level in the adjusted image frame to the lower limit of the gray-level variation range to reduce the gray-level variation range;

performing linear adjustment on the gray-level of each pixel in the image frame, so as to map each gray-level to the reduced gray-level variation range; and

obtaining the adjusted gray-level of each pixel, so as to generate the adjusted image frame.

10. The method as claimed in claim 9, wherein before determining the second gray-level according to the environment illumination, the method further comprises:

determining whether the average gray-level of the partial image frame is higher than a gray-level median interval;

if the average gray-level of the partial image frame is higher than the gray-level median interval, performing an image inverse process on the partial image frame, so as to generate the adjusted image frame.

11. The method as claimed in claim 7, wherein when the display content of the image frame is text data, adjusting the gray-levels of all pixels in the image frame according to the environment illumination.

12. The method as claimed in claim 7, wherein when the display content of the image frame is text data and graphs, adjusting the gray-levels of partial pixels corresponding to the text data in the image frame.

13. A display device for adjusting a gray-level of a image frame depending on environment illumination, comprising:

a reflecting ambient light display-panel, for displaying an image frame with a plurality of pixels, and each pixel of the reflecting ambient light display-panel reflects an ambient light according to a gray-level thereof;

an optical-sensor, for obtaining the environment illumination;

a controller, for driving the display-panel to display the image frame; and

an adjusting module, for adjusting gray-levels of at least partial pixels in the image frame according to the environment illumination;

wherein a reference illumination range is designated to the adjusting module, and the adjusting module determines whether the obtained environment illumination is within the reference illumination range;

wherein when the environment illumination is higher than the reference illumination range, the adjusting module raises the gray-levels of at least partial pixels in the image frame according to the environment illumination, so that the brightness of a reflected light generated after the ambient light is reflected is reduced;

wherein when the environment illumination is lower than the reference illumination range, the adjusting module reduces the gray-levels of at least partial pixels in the image frame according to the environment illumination, so that the brightness of the reflected light is high; and

wherein a gray-level median interval is further designated to the adjusting module;

when the environment illumination is lower than the reference illumination range and an average gray-level of the image frame is higher than the gray-level median interval, the adjusting module performs an image inverse process on the image frame.

14. A method for adjusting a gray-level of a image frame depending on environment illumination, for adjusting the gray-level of at least partial image frame in the image frame, wherein the partial image frame comprises a plurality of pixels and each pixel reflects an ambient light according to the gray-level thereof, the method comprising the steps of:

obtaining the environment illumination;

designating a reference illumination range;

determining whether the environment illumination is higher than or lower than the reference illumination range; and

if the environment illumination is higher than the reference illumination range, raising gray-levels of at least partial pixels in the partial image frame according to the environment illumination so that the brightness of a reflected light generated after the ambient light is reflected is reduced, and displaying the adjusted image frame;

if the environment illumination is lower than the reference illumination range, reducing gray-levels of the at least partial pixels in the partial image frame according to the environment illumination so that the brightness of the reflected light is high, and displaying the adjusted image frame;

if the environment illumination is neither not higher than or lower than the reference illumination range, obtaining the environment illumination again instead of adjusting the gray-level of the image frame;

wherein reducing the average gray-level of the image frame comprises;

determining a second gray-level according to the environment illumination;

determining a gray-level reduced value required when the highest gray-level is adjusted to the second gray-level in the partial image frame;

subtracting the gray-level reduced value to the gray-level of each pixel in the partial image frame;

determining whether the lowest gray-level in the adjusted image frame is lower than a lower limit of a gray-level variation range of the image frame;

if the lowest gray-level in the adjusted image frame is not lower than the gray-level variation range of the image frame, generating the adjusted image frame according to an adjustment result; and

if the lowest gray-level in the adjusted image frame is lower than the lower limit of the gray-level variation range of the image frame, adjusting the lowest gray-level in the adjusted image frame to the lower limit of the gray-level variation range to reduce the gray-level variation range;

performing linear adjustment on the gray-level of each pixel in the image frame, so as to map each gray-level to the reduced gray-level variation range; and

obtaining the adjusted gray-level of each pixel, so as to generate the adjusted image frame.