Image Sensor Having Pixels with Different Integration Periods

• US 20150163422A1
• Filed: 12/05/2013
• Published: 06/11/2015
• Est. Priority Date: 12/05/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Fan, Xiaofeng, Lee, Chiajen, Malone, Michael R., Sharma, Anup K.
• Granted Patent: US 9,596,420 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04N 25/533 by using differing integration times for different sensor regions
• CPC Class Codes: H04N 25/583 with different integration times

Abstract

An image sensor includes pixels that accumulate charge during a first integration period and pixels that accumulate charge during shorter second integration periods when an image is captured. The pixels having the shorter second integration period accumulate charge at two or more different times during the first integration period. Charge is read out of the pixels associated with the first integration period at the end of the first integration period, while charge is read out of the pixels having the second integration period at the end of each second integration period.

Claims

1. An imaging system, comprising:

an image sensor having a plurality of pixels, wherein a first portion of the pixels accumulate charge for a first integration period and a second portion of the pixels accumulate charge for a shorter second integration period, wherein the second portion of the pixels having the shorter second integration period accumulate charge two or more times during the first integration period.

2. The imaging system as in claim 1, further comprising readout circuitry operatively connected to the plurality of pixels.

3. The imaging system as in claim 2, further comprising a processor operatively connected to the readout circuitry, wherein the processor is adapted to enable the readout circuitry to read charge out of the second portion of the pixels at two or more different times.

4. The imaging system as in claim 3, wherein the processor is adapted to enable the readout circuitry to read charge out of the first portion of the pixels at the end of the first integration period.

5. The imaging system as in claim 3, wherein the processor is adapted to adjust which pixels are associated with the first and second integration periods.

6. The imaging system as in claim 3, wherein the processor is adapted to determine an amount of time for each second integration period.

7. A method for capturing an image, the method comprising:

beginning a first integration period for a first portion of pixels in an image sensor;

beginning a second integration period for a second portion of pixels in the image sensor, wherein the second integration period is shorter than the first integration period;

reading out charge from the second portion of the pixels during the first integration period at the end of the second integration period;

beginning another second integration period for the second portion of the pixels; and

reading out charge from the first and second portions of the pixels at the end of the first integration period.

8. The method as in claim 7, further comprising combining the charge read out at the end of the first integration period with the charge read out at the end of the earlier second integration period to produce a final image.

9. The method as in claim 7, wherein each second integration period is substantially an equal amount of time.

10. The method as in claim 7, wherein an amount of time in one second integration period differs from an amount of time in another second integration period.

11. The method as in claim 7, further comprising changing which pixels are associated with the first and second integration periods.

12. A method for capturing an image, the method comprising:

beginning a first integration period for a first plurality of pixels in an image sensor;

during the first integration period, beginning a plurality of second integration periods for a second plurality of pixels in the image sensor, wherein the second integration period is shorter than the first integration period and each second integration period begins at a distinct time within the first integration period; and

at the end of each second integration period, reading out charge from the second plurality of pixels.

13. The method as in claim 12, further comprising at the end of the first integration period, reading out charge from the first plurality of pixels.

14. The method as in claim 13, further comprising combining the charge read out at the end of the first integration period with the charge read out at the end of each second integration period to produce a final image.

15. The method as in claim 12, wherein each second integration period is substantially an equal amount of time.

16. The method as in claim 12, wherein an amount of time in one second integration period differs from an amount of time in another second integration period.

17. The method as in claim 12, further comprising prior to beginning the plurality of second integration periods, determining timing for the plurality of second integration periods.

18. The method as in claim 17, wherein determining timing for the plurality of second integration periods comprises:

capturing one or more test images; and

analyzing at least one test image to determining timing for the plurality of second integration periods.

19. The method as in claim 18, further comprising:

capturing N images, where N is an integer equal to or greater than one;

determining whether the timing for the plurality of second integration periods is to change after the N images have been captured; and

when the timing changes, changing the timing for at least one second integration period in the plurality of second integration periods.

20. The method as in claim 12, further comprising changing which pixels are associated with the first and second integration periods.