Devices and methods for reducing artefacts in display devices by the use of overdrive

• US 9,280,943 B2
• Filed: 02/13/2009
• Issued: 03/08/2016
• Est. Priority Date: 02/13/2009
• Status: Active Grant

• Current Assignee: Barco NV
• Original Assignee: Barco NV
• Inventors: Kimpe, Tom, Marchessoux, Cdric
• Primary Examiner(s): Patel, Kumar
• Assistant Examiner(s): Said, Mansour M
• Application Number:
  US12/371,028
• Publication Number:
  US 20100207960A1
• Time in Patent Office: 2,580 Days
• Field of Search: 345 87-100, 345/204, 345207-208, 345210-214, 345698-699, 345/690
• US Class Current: 1/1
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2340/16 Determination of a pixel data signal depending on the signal applied in the previous frame
• CPC Class Codes: G09G 2360/18 Use of a frame buffer in a display terminal, inclusive of the display panel
• CPC Class Codes: G09G 3/2044 using dithering
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

The invention relates to a method for reducing imaging artifacts during a frame-changeover from a current frame to a following frame displayed by a display device comprising a plurality of pixels, wherein the artifacts are reduced by overdriving at least one control signal for controlling the pixel intensity of the related pixel during the frame-changeover, wherein the overdrive is carried out in dependence of the magnitude of an intensity step between a designated start intensity value of the pixel within the current frame and a designated target intensity value of the pixel within the following frame.

Claims

1. A method for controlling imaging artefacts during a frame-changeover from a current frame to a following frame displayed by a display device comprising a plurality of pixels, said method comprising the step:

reducing the artefacts by overdriving at least one control signal for controlling the pixel intensity of the related pixel during a frame-changeover,

wherein overdriving comprises the steps of;

determining a relative overdrive value for the current frame in dependence of a magnitude of an intensity step between a designated start intensity value of the pixel within the current frame and a designated target intensity value of the pixel within a following frame, wherein the magnitude of the overdrive is based on a set of predetermined overdrive magnitudes, said predetermined overdrive magnitudes being stored in a first memory,

weighting the magnitude of the overdrive by a predetermined overdrive weighting factor or predetermined overdrive weighting function, said predetermined weighting factor or predetermined overdrive weighting function being based on a human visual perception system, wherein the predetermined overdrive weighting factor or overdrive weighting function is stored in a second memory,

determining an overdrive value in dependence of a magnitude of an intensity step between a currently reached intensity value of the pixel within the current frame and the designated target intensity value of the pixel within the following frame, and

determining an overdrive intensity value of the control signal in dependence of the predetermined target intensity value, the overdrive value, and the relative overdrive value,

wherein the overdrive for the following frame is carried out in dependence of a prediction of the actual pixel intensity value reached at the beginning of the following frame.

2. The method according to claim 1, wherein the method comprises the further step of determining an image noise characteristic from a set of frames, the set comprising at least the current frame and a following frame, wherein the overdriving is based upon the determined image noise characteristic.

3. The method according to claim 1, wherein the magnitude of the overdrive is based on the type of image content being displayed or the application for which the display system is being used.

4. The method according to claim 1, wherein the magnitude of the overdrive is adapted by a predetermined overdrive weighting factor or predetermined overdrive weighting function, such that the color consistency of the display system is improved.

5. The method according to claim 1, wherein the magnitude of the overdrive for at least one type or color of sub pixel is adjusted in accordance with a transition speed of at least one other type or color of sub pixel.

6. The method according to claim 1, wherein the display device is a liquid crystal display device.

7. The method according to claim 1, wherein the artefacts are reduced by overdriving each individual control signal for controlling the intensity of each related pixel during the frame-changeover.

8. The method according to claim 1, further comprising the step of selecting the degree of overdrive, wherein during small intensity steps of the pixel, the pixel is not overdriven, and wherein during large intensity steps of the pixel, the pixel will be fully overdriven.

9. The method according to claim 1, wherein the overdriving occurs if and only if a given condition on the intensity step is met.

10. A display device having means of reducing imaging artefacts during a frame-changeover from a current frame to a following frame displayed by a display device comprising a plurality of pixels, the display device comprising:

a controller configured to reduce the artefacts by overdriving at least one control signal for controlling the pixel intensity of the related pixel during a frame-changeover, and

the controller is configured to determine a relative overdrive value for the current frame in dependence of a magnitude of an intensity step between a designated start intensity value of the pixel within the current frame and a designated target intensity value of the pixel within a following frame,

wherein the controller is configured to determine the magnitude of the overdrive based on a set of predetermined overdrive magnitudes,

wherein the magnitude of the overdrive is weighted by a predetermined overdrive weighting factor or predetermined overdrive weighting function, said predetermined weighting factor or predetermined overdrive weighting function being based on a human visual perception system,

wherein the controller is also configured to determine an overdrive value in dependence of a magnitude of an intensity step between a currently reached intensity value of the pixel within the current frame and the designated target intensity value of the pixel within the following frame and to determine an overdrive intensity value of the control signal in dependence of the predetermined target intensity value, the overdrive value, and the relative overdrive value,

wherein the controller further comprises a first memory to store the set of predetermined overdrive magnitudes and a second memory to store the predetermined overdrive weighting factor or overdrive weighting function, wherein the overdrive for the following frame is carried out in dependence of a prediction of the actual pixel intensity value reached at the beginning of the following frame.

11. The display device according to claim 10, further comprising a calculator configured to determine an image noise characteristic from a set of frames, the set comprising at least the current frame and a following frame, wherein the overdriving is based upon the determined image noise characteristic.

12. The display device according to claim 10, wherein the display device is a liquid crystal display device.

13. The display device according to claim 10, wherein the artefacts are reduced by overdriving each individual control signal for controlling the intensity of each related pixel during the frame-changeover.

14. A controller for a display device that reduces imaging artefacts during a frame-changeover from a current frame to a following frame displayed by a display device comprising a plurality of pixels, the controller being configured to:

reduce the artefacts by overdriving at least one control signal for controlling the pixel intensity of the related pixel during a frame-changeover, and

determine a relative overdrive value for the current frame in dependence of a magnitude of an intensity step between a designated start intensity value of the pixel within the current frame and a designated target intensity value of the pixel within a following frame, and to determine the magnitude of the overdrive based on a set of predetermined overdrive magnitudes,

wherein the magnitude of the overdrive is weighted by a predetermined overdrive weighting factor or predetermined overdrive weighting function, said predetermined weighting factor or predetermined overdrive weighting function being based on a human visual perception system,

wherein the controller is also configured to determine an overdrive value in dependence of a magnitude of an intensity step between a currently reached intensity value of the pixel within the current frame and the designated target intensity value of the pixel within the following frame and to determine an overdrive intensity value of the control signal in dependence of the predetermined target intensity value, the overdrive value, and the relative overdrive value,

wherein the controller comprises a first memory to store the set of predetermined overdrive magnitudes and a second memory to store the predetermined overdrive weighting factor or overdrive weighting function, wherein the overdrive for the following frame is carried out in dependence of a prediction of the actual pixel intensity value reached at the beginning of the following frame.

15. The controller according to claim 14, further comprising a calculator configured to determine an image noise characteristic from a set of frames, the set comprising at least the current frame and a following frame, wherein the overdriving is based upon the determined image noise characteristic.

16. The controller according to claim 14, wherein the display device is a liquid crystal display device.

17. The controller according to claim 14, wherein controller is configured to reduce the artefacts by overdriving each individual control signal that controls the intensity of each related pixel during the frame-changeover.

18. A non-transitory machine readable medium storing a computer program product for controlling a display device having means of reducing imaging artefacts during a frame-changeover from a current frame to a following frame displayed by a display device comprising a plurality of pixels, the computer program product comprising code segments which when executed by a processing engine is configured to:

reduce the artefacts by overdriving at least one control signal for controlling the pixel intensity of the related pixel during a frame-changeover, and

determine a relative overdrive value for the current frame in dependence of a magnitude of an intensity step between a designated start intensity value of the pixel within the current frame and a designated target intensity value of the pixel within a following frame, and to determine the magnitude of the overdrive based on a set of predetermined overdrive magnitudes,

wherein the magnitude of the overdrive is weighted by a predetermined overdrive weighting factor or predetermined overdrive weighting function, said predetermined weighting factor or predetermined overdrive weighting function being based on a human visual perception system, wherein the controller is also configured to determine an overdrive value in dependence of a magnitude of an intensity step between a currently reached intensity value of the pixel within the current frame and the designated target intensity value of the pixel within the following frame and to determine an overdrive intensity value of the control signal in dependence of the predetermined target intensity value, the overdrive value, and the relative overdrive value, wherein the predetermined overdrive magnitudes are stored in a first memory and the predetermined overdrive weighting factor or overdrive weighting function is stored in a second memory, and wherein the overdrive for the following frame is carried out in dependence of a prediction of the actual pixel intensity value reached at the beginning of the following frame.

19. The non-transitory machine readable medium according to claim 18, wherein the computer program product comprising the code segments further comprise, when executed on a processing engine:

determine an image noise characteristic from a set of frames, the set comprising at least the current frame and a following frame, wherein the overdriving is based upon the determined image noise characteristic.