REFRESH RATE DEPENDENT ADAPTIVE DITHERING FOR A VARIABLE REFRESH RATE DISPLAY

• US 20150339994A1
• Filed: 05/14/2015
• Published: 11/26/2015
• Est. Priority Date: 05/22/2014
• Status: Active Grant

• Current Assignee: NVIDIA Corporation
• Original Assignee: NVIDIA Corporation
• Inventors: Verbeure, Tom
• Granted Patent: US 9,837,030 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/14 Digital output to display device ; Cooperation and interconnection of the display device with other functional units
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2340/0435 Change or adaptation of the frame rate of the video stream
• CPC Class Codes: G09G 2360/08 Power processing, i.e. workload management for processors involved in display operations, such as CPUs or GPUs
• CPC Class Codes: G09G 2370/022 Centralised management of display operation, e.g. in a server instead of locally
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/2044 using dithering
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general
• CPC Class Codes: G09G 3/3618 with automatic refresh of the display panel using sense/write circuits
• CPC Class Codes: G09G 5/001 Arbitration of resources in a display system, e.g. control of access to frame buffer by video controller and/or main processor
• CPC Class Codes: G09G 5/363 Graphics controllers
• CPC Class Codes: G09G 5/399 using two or more bit-mapped memories, the operations of which are switched in time, e.g. ping-pong buffers

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.

Claims

1. A method, comprising:

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.

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 pixels in response to receiving a frame of image data via a video interface.

4. The method of claim 1, wherein selectively disabling temporal dithering of the images 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 a graphics processing unit (GPU) is 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 images on a screen of the display device.

14. 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 to refresh utilizing a dynamic refresh rate to display images; and

selectively disabling temporal dithering of the images based on the dynamic refresh rate.

15. The non-transitory computer-readable storage medium of claim 14, wherein selectively disabling temporal dithering of the images 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.

16. The non-transitory computer-readable storage medium of claim 15, 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.

17. A system, comprising:

a display device configured to refresh utilizing a dynamic refresh rate to display images, wherein temporal dithering of the images is selectively disabled based on the dynamic refresh rate.

18. The system of claim 17, wherein selectively disabling temporal dithering of the images 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.

19. The system of claim 18, wherein the display device includes a scaling unit that 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.

20. The system of claim 18, further comprising a graphics processing unit 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.