Flicker band automated detection system and method

• US 8,768,160 B2
• Filed: 12/30/2009
• Issued: 07/01/2014
• Est. Priority Date: 02/10/2006
• Status: Active Grant

• Current Assignee: NVIDIA Corporation
• Original Assignee: NVIDIA Corporation
• Inventors: Lin, Shang Hung, He, Hu, Tjandrasuwita, Ignatius B.
• Primary Examiner(s): Perkey, W B
• Application Number:
  US12/649,888
• Publication Number:
  US 20100103310A1
• Time in Patent Office: 1,644 Days
• Field of Search: 396/213, 396/234, 396/246, 348/226.1, 348/366
• US Class Current: 396/234
• CPC Class Codes: H04N 23/70 Circuitry for compensating brightness variation in the scene
• CPC Class Codes: H04N 23/745 Detection of flicker frequency or suppression of flicker wherein the flicker is caused by illumination, e.g. due to fluorescent tube illumination or pulsed LED illumination

Abstract

A flicker band automated detection system and method are presented. In one embodiment an incidental motion mitigation exposure setting method includes receiving image input information; performing a motion mitigating flicker band automatic detection process; and implementing exposure settings based upon results of the motion mitigating flicker band automatic detection process. The auto flicker band detection process includes performing a motion mitigating process on an illumination intensity indication. Content impacts on an the motion mitigated illumination intensity indication are minimized. The motion mitigated illumination intensity indication is binarized. A correlation of the motion mitigated illumination intensity and a reference illumination intensity frequency is established.

Claims

1. A motion mitigating flicker band automatic detection process comprising

performing a motion mitigating process on an illumination intensity indication;

minimizing content impacts on an said motion mitigated illumination intensity indication;

and

finding a correlation of said motion mitigated illumination intensity and a reference illumination intensity frequency.

2. A motion mitigating flicker band automatic detection process of claim 1 wherein said motion mitigation process includes:

performing image sub-sampling; and

averaging illumination intensity values from a plurality of pixel rows of said resulting sub-sampled image.

3. A motion mitigating flicker band automatic detection process of claim 1 wherein a number of down sampled pixel rows is maintained above a minimum that is greater than a video frame rate.

4. A motion mitigating flicker band automatic detection process of claim 1 wherein minimizing content impacts on said illumination intensity indication includes subtracting illumination intensity values of a first frame from illumination intensity values of a second frame.

5. A motion mitigating flicker band automatic detection process of claim 1 wherein a correlation score is utilized to establish the correlation of the motion mitigated illumination intensity to a reference illumination intensity frequency.

6. A motion mitigating flicker band automatic detection process of claim 5 wherein said correlation score is assigned based upon the following manipulation:

7. A motion mitigating flicker band automatic detection process of claim 5 wherein said reference frequency is selected to correspond with a power source frequency.

8. A motion mitigating flicker band automatic detection process of claim 2 further comprising selecting reliable down-sampled pixels for said averaging.

9. A motion mitigating flicker band automatic detection process of claim 8 wherein said reliable down-sampled pixels include pixels associated with smooth well lit surface.

10. A motion mitigating flicker band automatic detection process of claim 1 further comprising binarizing said motion mitigated illumination intensity indication in which said binarizing includes comparing each entry value in a subtraction buffer with a moving average value and if a row in the subtraction buffer as a value larger than the mean the values change to one, otherwise the values change to negative one;

and wherein minimizing content impacts on said illumination intensity indication includes subtracting illumination intensity values of a first frame from illumination intensity values of a second frame.

11. A motion mitigating flicker band automatic detection system comprising

means for performing a motion mitigating process on an illumination intensity indication;

means for minimizing content impacts on an said motion mitigated illumination intensity indication;

means for binarizing said motion mitigated illumination intensity indication; and

means for finding a correlation of said motion mitigated illumination intensity and a reference illumination intensity frequency.

12. A motion mitigating flicker band automatic detection system of claim 11 wherein said motion mitigation process is performed by:

means for performing image sub-sampling; and

means for averaging illumination intensity values from a plurality of pixel rows of said resulting sub-sampled image.

13. A motion mitigating flicker band automatic detection system of claim 11 wherein a number of down sampled pixel rows is maintained above a minimum that is greater than a video frame rate.

14. A motion mitigating flicker band automatic detection system of claim 11 wherein said means for minimizing content impacts on said illumination intensity indication includes means for subtracting illumination intensity values of a first frame from illumination intensity values of a second frame.

15. A motion mitigating flicker band automatic detection system of claim 11 wherein a correlation score is utilized to establish the correlation of the motion mitigated illumination intensity to a reference illumination intensity frequency.

16. A motion mitigating flicker band automatic detection system of claim 15 wherein said correlation score is assigned based upon the following manipulation:

17. A motion mitigating flicker band automatic detection system of claim 15 wherein said reference frequency is selected to correspond with a power source frequency.

18. A motion mitigating flicker band automatic detection system of claim 11 further comprising means for selecting reliable down-sampled pixels for said averaging.

19. A motion mitigating flicker band automatic detection system of claim 18 wherein said reliable down-sampled pixels include pixels associated with smooth well lit surface.

20. A motion mitigating flicker band automatic detection system of claim 11 wherein means for binarizing said illumination intensity indication includes means for comparing each entry value in a subtraction buffer with a moving average value and if a row in the subtraction buffer as a value larger than the mean the values change to one, otherwise the values change to negative one.