Refresh rate dependent adaptive dithering for a variable refresh rate display

Patent metadata

Field	Value
Publication number	US-9837030-B2
Application number	US-201514712821-A
Country	US
Kind code	B2
Filing date	May 14, 2015
Priority date	May 22, 2014
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

A method, computer program product, and system for selectively disabling temporal dithering is disclosed. The method includes the steps of configuring a display device to refresh utilizing a dynamic refresh rate to display images and selectively disabling temporal dithering of the images based on the dynamic refresh rate. Selectively disabling temporal dithering may comprise determining a dynamic refresh rate associated with a current frame of image data and disabling temporal dithering for the current frame of image data when the dynamic refresh rate is less than a first threshold value, or enabling temporal dithering for the current frame of image data when the dynamic refresh rate is greater than or equal to a second threshold value.

First claim

What is claimed is:

1. A method, comprising:
configuring a display device utilizing a dynamic refresh rate, the display device configured to operate synchronously with a processing unit configured to generate image data for presentation on the display device; and
selectively disabling temporal dithering based on the dynamic refresh rate,
wherein each frame of image data includes a plurality of pixels, each pixel encoding a color value having a plurality of components, and
wherein truncated bits for each component of the color values encoded by the plurality of pixels are discarded when temporal dithering is disabled.

2. The method of claim 1 , wherein the display device is one of a liquid crystal display (LCD), a light emitting diode (LED) display, an organic light emitting diode (OLED) display, and an active-matrix OLED (AMOLED) display.

3. The method of claim 2 , wherein the display device refreshes a plurality of pixel elements in the display device in response to receiving a frame of image data via a video interface.

4. The method of claim 1 , wherein selectively disabling temporal dithering based on the dynamic refresh rate comprises:
determining the dynamic refresh rate associated with a current frame of image data; and
disabling temporal dithering for the current frame of image data when the dynamic refresh rate is less than a first threshold value, or
enabling temporal dithering for the current frame of image data when the dynamic refresh rate is greater than or equal to a second threshold value.

5. The method of claim 4 , wherein the first threshold value is equal to the second threshold value.

6. The method of claim 4 , wherein the first threshold value is less than the second threshold value by an offset value to implement a hysteresis in selectively disabling the temporal dithering.

7. The method of claim 6 , wherein the first threshold value is approximately 50 Hz, the second threshold value is approximately 60 Hz, and the offset value is 10 Hz.

8. The method of claim 4 , wherein the first threshold value and the second threshold value are specified by a user.

9. The method of claim 4 , wherein determining the dynamic refresh rate associated with the current frame of image data comprises calculating a delay time by subtracting a time associated with a previous frame of image data from a time associated with the current frame of image data, wherein the current frame of image data is presented on the display device immediately subsequent to the previous frame of image data.

10. The method of claim 4 , wherein determining the dynamic refresh rate associated with the current frame of image data comprises calculating an average delay time associated with N frames of image data by dividing a difference between a time associated with an N th frame of image data in the plurality of frames of image data from a time associated with the current frame of image data in the plurality of frames of image data with N, wherein the current frame of image data is presented on the display device N−1 frames after the N th frame of image data.

11. The method of claim 4 , wherein the processing unit comprises a graphics processing unit (GPU) configured to:
determine the dynamic refresh rate associated with the current frame of image data; and
enable or disable the temporal dithering based on the dynamic refresh rate.

12. The method of claim 4 , wherein a scaling unit included in the display device is configured to:
receive the current frame of image data via a video interface;
scale the current frame of image data to match a native resolution of the display device;
determine the dynamic refresh rate associated with the current frame of image data; and
enable or disable the temporal dithering based on the dynamic refresh rate.

13. The method of claim 4 , wherein a timing controller included in the display device is configured to:
receive the current frame of image data;
determine the dynamic refresh rate associated with the current frame of image data;
enable or disable the temporal dithering based on the dynamic refresh rate; and
control row drivers and column drivers to present the current frame of image data on a screen of the display device.

14. The method of claim 1 , wherein truncated bits for each component of the color values encoded by the plurality of pixels are utilized to select a dither pattern to apply to the image data when temporal dithering is enabled.

15. A non-transitory computer-readable storage medium storing instructions that, when executed by a processor, cause the processor to perform steps comprising:
configuring a display device utilizing a dynamic refresh rate, the display device configured to operate synchronously with a processing unit configured to generate image data for presentation on the display device; and
selectively disabling temporal dithering of the images based on the dynamic refresh rate,
wherein each frame of image data includes a plurality of pixels, each pixel encoding a color value having a plurality of components, and
wherein truncated bits for each component of the color values encoded by the plurality of pixels are discarded when temporal dithering is disabled.

16. The non-transitory computer-readable storage medium of claim 15 , wherein selectively disabling temporal dithering based on the dynamic refresh rate comprises:
determining the dynamic refresh rate associated with a current frame of image data; and
disabling temporal dithering for the current frame of image data when the dynamic refresh rate is less than a first threshold value, or
enabling temporal dithering for the current frame of image data when the dynamic refresh rate is greater than or equal to a second threshold value.

17. The non-transitory computer-readable storage medium of claim 16 , wherein determining the dynamic refresh rate associated with the current frame of image data comprises calculating a delay time by subtracting a time associated with a previous frame of image data from a time associated with the current frame of image data, wherein the current frame of image data is presented on the display device immediately subsequent to the previous frame of image data.

18. The non-transitory computer-readable storage medium of claim 15 , wherein truncated bits for each component of the color values encoded by the plurality of pixels are utilized to select a dither pattern to apply to the image data when temporal dithering is enabled.

19. A system, comprising:
a display device that utilizes a dynamic refresh rate; and
a processing unit configured to generate image data for presentation on the display device, wherein the display device is configured to operate synchronously with the processing unit,
wherein temporal dithering of the images is selectively disabled based on the dynamic refresh rate,
wherein each frame of image data includes a plurality of pixels, each pixel encoding a color value having a plurality of components,
wherein truncated bits for each component of the color values encoded by the plurality of pixels are discarded when temporal dithering is disabled.

20. The system of claim 19 , wherein selectively disabling temporal dithering based on the dynamic refresh rate comprises:
determining the dynamic refresh rate associated with a current frame of image data; and
disabling temporal dithering for the current frame of image data when the dynamic refresh rate is less than a first threshold value, or
enabling temporal dithering for the current frame of ima

Assignees

• Nvidia Corp

Inventors

• Verbeure Tom

Classifications

• G09G3/2003

  Display of colours (specific for liquid crystal displays G09G3/3607) · CPC title

• G09G2340/0435

  Change or adaptation of the frame rate of the video stream · CPC title

• G09G2360/08

  Power processing, i.e. workload management for processors involved in display operations, such as CPUs or GPUs · CPC title

• G09G2330/021

  Power management, e.g. power saving · CPC title

• G09G5/001

  Arbitration of resources in a display system, e.g. control of access to frame buffer by video controller and/or main processor · CPC title