Defective pixel detection

Patent metadata

Field	Value
Publication number	US-12244979-B2
Application number	US-202217983905-A
Country	US
Kind code	B2
Filing date	Nov 9, 2022
Priority date	Jul 28, 2022
Publication date	Mar 4, 2025
Grant date	Mar 4, 2025

Abstract

Various embodiments disclosed herein relate to defective pixel detection and correction, and more specifically to using threshold functions based on color channels to compare pixel values to threshold values. A method is provided herein that comprises identifying a color channel of an image pixel in a frame and identifying a threshold function based at least on the color channel. The method further comprises applying the threshold function to one or more nearest-neighbor values to obtain a threshold value and determining whether a corresponding sensor pixel is defective based at least on a comparison of the image pixel to the threshold value.

First claim

What is claimed is:

1. A method, comprising:
identifying a color channel of an image pixel in a frame;
identifying a threshold function based on the color channel;
identifying one or more nearest-neighboring image pixels with respect to the image pixels, in which the nearest-neighboring image pixels are of the color channel of the image pixel;
applying the threshold function to the one or more nearest-neighbor image pixel values to obtain a threshold value; and
determining whether a corresponding sensor pixel is defective based on a comparison of the image pixel to the threshold value
wherein the identifying of the threshold function further includes identifying an offset pattern of the one or more nearest-neighboring image pixels specific to a subset of color channels to which the image pixel and the one or more nearest-neighboring pixels belong.

2. The method of claim 1 , further comprising storing a value of the image pixel and a subset of the one or more nearest-neighbor values based on the offset pattern.

3. The method of claim 1 , wherein the one or more nearest-neighbor values comprise an average value of the one or more nearest-neighbor image pixels.

4. The method of claim 1 , wherein the color channel is one among a red color channel, a blue color channel, a green color channel, and an infrared color channel.

5. The method of claim 1 , further comprising correcting the image pixel in the frame.

6. A pixel processing subsystem, comprising:
a processing device; and
device memory operatively coupled to the processing device and system memory, wherein the device memory provides the pixel processing subsystem with pixel data from the system memory;
wherein the processing device is configured to:
identify a color channel of an image pixel in a frame;
identify a threshold function based on the color channel;
identifying nearest-neighboring image pixels with respect to the image pixels, in which the nearest-neighboring image pixels are of the color channel of the image pixel;
apply the threshold function to one or more nearest-neighbor values to obtain a threshold value; and
determine whether a corresponding sensorpixel is defective based on a comparison of the image pixel to the threshold value;
wherein the identifying of the threshold function further includes identifying an offset pattern of the nearest-neighboring image pixels specific to a subset of color channels to which the image pixel and the nearest-neighboring pixels belong.

7. The pixel processing subsystem of claim 6 , further comprising determining a representative value of the nearest-neighbor image pixels, wherein the applying of the threshold function includes applying the threshold function to the representative value.

8. The pixel processing subsystem of claim 6 , wherein the processing device is further configured to store a value of the image pixel and a subset of the nearest-neighbor values based on the offset pattern.

9. The pixel processing subsystem of claim 6 , wherein the processing device is further configured to, in response to determining that the corresponding sensor pixel is defective, store defective pixel data corresponding to the defective sensor pixel and produce defective pixel metrics indicative of a number of defective sensor pixels based on the defective pixel data.

10. The pixel processing subsystem of claim 6 , wherein the color channel is one among a red color channel, a blue color channel, a green color channel, and an infrared color channel.

11. The pixel processing subsystem of claim 6 , wherein the processing device is further configured to correct the image pixel in the frame.

12. The pixel processing subsystem of claim 7 , wherein the representative value is an average value.

13. A system, comprising:
a defective pixel detection component configured to:
identify a color channel of an image pixel in a frame;
identify a threshold function based on the color channel;
identify nearest-neighboring image pixels with respect to the image pixel, in which the nearest-neighboring image pixels are of the color channel of the image pixel;
apply the threshold function to nearest-neighbor values to obtain a threshold value; and
determine whether a corresponding sensor pixel is defective based on a comparison of the image pixel to the threshold value,
wherein the identifying of the threshold function further includes identifying an offset pattern of the nearest-neighboring image pixels specific to a subset of color channels to which the image pixel and the nearest-neighboring pixels belong; and

a pixel corrector component configured to correct the image pixel.

14. The system of claim 13 , further comprising determining an average value of nearest-neighbor image pixel values, wherein the threshold function is applied to the average value.

15. The system of claim 13 , wherein the defective pixel detection component is further configured to store a value of the image pixel and a subset of the nearest-neighbor values based on the offset pattern.

16. The pixel processing unit of claim 13 , wherein the defective pixel detection component is further configured to, in response to determining that the corresponding sensor pixel is defective, store defective pixel data corresponding to the defective sensor pixel and produce defective pixel metrics indicative of a number of defective sensor pixels based on the defective pixel data.

17. The system of claim 13 , wherein the color channel is one among a red color channel, a blue color channel, a green color channel, and an infrared color channel.

Assignees

• Texas Instruments Inc

Inventors

• Ren Jing-Fei
• Garud Hrushikesh
• Allu Rajasekhar
• Hua Gang
• Nandan Niraj
• Mangla Mayank
• Mody Mihir Narendra

Classifications

• G06T7/0002

  Inspection of images, e.g. flaw detection · CPC title

• G06T2207/10024

  Color image · CPC title

• G06T2207/30168

  Image quality inspection · CPC title

• G06T7/90

  Determination of colour characteristics · CPC title

• H04N25/131

  including elements passing infrared wavelengths · CPC title