Blooming artifact elimination in high dynamic range imaging

Patent metadata

Field	Value
Publication number	US-12375829-B2
Application number	US-202318500361-A
Country	US
Kind code	B2
Filing date	Nov 2, 2023
Priority date	Nov 2, 2023
Publication date	Jul 29, 2025
Grant date	Jul 29, 2025

Abstract

Image sensors, imaging systems, and methods for eliminating blooming artifacts in high dynamic range imaging. The image sensor includes a pixel array and a controller. The controller is configured to detect that a first pixel signal is at or below a barrier value. The first pixel signal is generated during a first exposure. The controller is also configured to compare neighboring pixel signals to the barrier value. The controller is further configured to determine a first image value for the center pixel based on a second pixel signal when at least one of the neighboring pixel signals is above the barrier value. The second pixel signal is generated during a second exposure that is shorter than the first exposure. The controller is also configured to set the first image value to the first pixel signal when each of the neighboring pixel signals is at or below the barrier value.

First claim

What is claimed is:

1. An image sensor, comprising:
a pixel array including a plurality of image sensor pixels; and
a controller configured to:
for one or more of the plurality of image sensor pixels:
detect that a first pixel signal is at or below a barrier value, the first pixel signal generated by a pixel of the plurality of image sensor pixels during a first exposure duration, the pixel being a center pixel,
compare a plurality of neighboring pixel signals to the barrier value, the plurality of neighboring pixel signals generated during the first exposure duration, and
determine a first image value for the center pixel based on a second pixel signal when at least one of the plurality of neighboring pixel signals is above the barrier value, the second pixel signal generated by the center pixel during a second exposure duration that is shorter than the first exposure duration.

2. The image sensor of claim 1 , wherein, to determine the first image value based on the second pixel signal, the controller is further configured to set the first image value to a product of the second pixel signal and an exposure ratio between the second exposure duration and the first exposure duration.

3. The image sensor of claim 1 , wherein the controller is further configured to:
compare the first pixel signal to a noise threshold value that is less than the barrier value, and
set the first image value to the first pixel signal when the first pixel signal is below the noise threshold value.

4. The image sensor of claim 1 , wherein the controller is further configured to set the first image value to the first pixel signal when each of the plurality of neighboring pixel signals is at or below the barrier level.

5. The image sensor of claim 1 , wherein the plurality of neighboring pixel signals is generated by image sensor pixels that are positioned adjacent to the center pixel on a row or a column of the pixel array.

6. The image sensor of claim 1 , wherein the plurality of neighboring pixel signals is generated by image sensor pixels that are positioned diagonally-adjacent to the center pixel.

7. The image sensor of claim 1 , wherein the controller is further configured to generate a high dynamic range image based on the first image value for each of the one or more of the plurality of image sensor pixels.

8. The image sensor of claim 1 , wherein the controller is further configured to read out the first pixel signal, the second pixel signal, and the plurality of neighboring pixel signals.

9. An imaging system, comprising:
a lens system;
an image sensor in operational relationship with the lens system and comprising a pixel array including a plurality of image sensor pixels; and
an imaging controller configured to:
for one or more of the plurality of image sensor pixels:
detect that a first pixel signal is at or below a barrier value, the first pixel signal generated by a center pixel during a first exposure,
compare a plurality of neighboring pixel signals to the barrier value, the plurality of neighboring pixel signals generated during the first exposure,
determine a first image value for the center pixel based on a second pixel signal when at least one of the plurality of neighboring pixel signals is above the barrier value, the second pixel signal generated by the center pixel during a second exposure that is less than the first exposure, and
set the first image value to the first pixel signal when each of the plurality of neighboring pixel signals is at or below the barrier value.

10. The imaging system of claim 9 , wherein, to determine the first image value based on the second pixel signal, the imaging controller is further configured to set the first image value to a product of the second pixel signal and an exposure ratio between the second exposure and the first exposure.

11. The imaging system of claim 9 , wherein the imaging controller is further configured to:
compare the first pixel signal to a noise threshold value that is less than the barrier value, and
set the first image value to the first pixel signal when the first pixel signal is below the noise threshold value.

12. The imaging system of claim 9 , wherein the plurality of neighboring pixel signals are generated by two of the plurality of image sensor pixels that are positioned next to the center pixel on a row or a column of the pixel array.

13. The imaging system of claim 9 , wherein the plurality of neighboring pixel signals are generated by four of the plurality of image sensor pixels that are positioned diagonally-adjacent to the center pixel.

14. The imaging system of claim 9 , wherein the plurality of neighboring pixel signals are generated by eight of the plurality of image sensor pixels that are positioned around the center pixel.

15. The imaging system of claim 9 , wherein the imaging controller is further configured to generate a high dynamic range image based on the first image value for each of the one or more of the plurality of image sensor pixels.

16. The imaging system of claim 9 , wherein the imaging controller is further configured to receive the first pixel signal, the second pixel signal, and the plurality of neighboring pixel signals from the image sensor.

17. A method for eliminating blooming artifacts in high dynamic range imaging, the method comprising:
for one or more of a plurality of image sensor pixels included in a pixel array:
detecting that a first pixel signal is at or below a barrier value, the first pixel signal generated by a center pixel during a first exposure duration;
comparing a plurality of neighboring pixel signals to the barrier value, the plurality of neighboring pixel signals generated during the first exposure duration;
determining a first image value for the center pixel based on a second pixel signal when at least one of the plurality of neighboring pixel signals is above the barrier value, the second pixel signal generated by the center pixel during a second exposure duration that is shorter than the first exposure duration; and
setting the first image value to the first pixel signal when each of the plurality of neighboring pixel signals is at or below the barrier value.

18. The method of claim 17 , wherein determining the first image value based on the second pixel signal further includes setting the first image value to a product of the second pixel signal and an exposure ratio between the second exposure duration and the first exposure duration.

19. The method of claim 17 , further comprising:
comparing the first pixel signal to a noise threshold value that is less than the barrier value; and
setting the first image value to the first pixel signal when the first pixel signal is below the noise threshold value.

20. The method of claim 17 , wherein the method further comprises generating a high dynamic range image based on the first image value for each of the one or more of the plurality of image sensor pixels.

Assignees

• Semiconductor Components Ind Llc

Inventors

• Skorka Orit
• Vanhoff Barry
• Ispasoiu Radu
• Anderson Grady
• Huggett Anthony Richard

Classifications

• H04N25/589 Primary

  with different integration times, e.g. short and long exposures · CPC title

• H04N23/71 Primary

  Circuitry for evaluating the brightness variation · CPC title

• H04N23/73

  by influencing the exposure time · CPC title

• H04N25/59

  by controlling the amount of charge storable in the pixel, e.g. modification of the charge conversion ratio of the floating node capacitance · CPC title

• H04N25/78

  Readout circuits for addressed sensors, e.g. output amplifiers or A/D converters · CPC title