Methods for capturing and reading out images from an image sensor

• US 8,194,165 B2
• Filed: 09/30/2009
• Issued: 06/05/2012
• Est. Priority Date: 09/30/2009
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: TRUESENSE Imaging, Inc. (ON Semiconductor Corporation)
• Inventors: Border, John N., Compton, John T., Nichols, David N.
• Primary Examiner(s): SELBY, GEVELL V
• Application Number:
  US12/570,027
• Publication Number:
  US 20110075010A1
• Time in Patent Office: 979 Days
• Field of Search: 348/275, 348/311, 348/317, 348/362
• US Class Current: 348/317
• CPC Class Codes: H04N 25/134 based on three different wavelength filter elements
• CPC Class Codes: H04N 25/46 by combining or binning pixels
• CPC Class Codes: H04N 25/583 with different integration times
• CPC Class Codes: H04N 25/589 with different integration times, e.g. short and long exposures
• CPC Class Codes: H04N 25/70 SSIS architectures; Circuits associated therewith
• CPC Class Codes: H04N 25/73 using interline transfer [IT]

Abstract

Multiple images are captured where the exposure times for some of the images overlap and the images are spatially overlapped. Charge packets are transferred from one or more portions of pixels after particular integration periods, thereby enabling the portion or portions of pixels to begin another integration period while one or more other portions of pixels continue to integrate charge. Charge packets may be binned during readout of the images from the image sensor. Comparison of two or more images having different lengths of overlapping or non-overlapping exposure periods provides motion information. The multiple images can then be aligned to compensate for motion between the images and assembled into a combined image with an improved signal to noise ratio and reduced motion blur.

Claims

1. A method for capturing images with an image sensor that includes a plurality of pixels each including a photosensitive area, a plurality of vertical charge coupled devices (VCCDs) each comprising a plurality of charge storage elements and positioned adjacent to respective columns of pixels, and transfer mechanisms for transferring charge packets from the photosensitive areas to respective charge storage elements, the method comprising:

beginning light integration for all of the pixels, wherein the photosensitive areas accumulate charge packets;

transferring charge packets from a first portion of pixels to respective charge storage elements in the VCCDs at a first time, wherein the charge packets from the first portion of pixels have a first integration period;

ending light integration for all of the pixels;

shifting the charge packets one or more charge storage elements in each VCCD;

transferring charge packets from the same first portion of pixels to respective charge storage elements in the VCCDs at a second time, wherein the second time is subsequent to the first time and the charge packets from the first portion of pixels have a second integration period that is different from the first integration period;

reading out the charge packets from the VCCDs;

transferring charge packets from a second portion of pixels to respective charge storage elements in the VCCDs, wherein the charge packets from the second portion of pixels have a third integration period that is substantially equal to the sum of the first and second integration periods; and

reading out the charge packets from the VCCDs.

2. The method of claim 1, further comprising resetting the photosensitive areas in the image sensor.

3. The method of claim 1, wherein shifting the charge packets one or more charge storage elements in each VCCD comprises shifting the charge packets one shift element in each VCCD.

4. The method of claim 1, wherein beginning light integration for all of the pixels comprises opening a mechanical shutter.

5. The method of claim 4, wherein ending light integration for all of the pixels comprises closing the mechanical shutter.

6. The method of claim 1, wherein transferring charge packets from the first portion of pixels to respective charge storage elements in the VCCDs at the first time comprises transferring charge packets from odd numbered lines of pixels to respective charge storage elements in the VCCDs at the first time, wherein the charge packets from the odd numbered lines of pixels have the first integration period.

7. The method of claim 6, wherein transferring charge packets from the second portion of pixels to respective charge storage elements in the VCCDs at the third time comprises transferring charge packets from even numbered lines of pixels to respective charge storage elements in the VCCDs at the third time, wherein the charge packets from the even numbered lines of pixels have the third integration period that is substantially equal to the sum of the first and second integration periods.

8. The method of claim 1, wherein the first portion of pixels comprises single non-adjacent lines of pixels and the second portion of pixels comprises single non-adjacent lines of pixels.

9. The method of claim 1, wherein the first portion of pixels comprises multiple adjacent lines of pixels and the second portion of pixels comprises multiple adjacent lines of pixels.

10. The method of claim 9, wherein the first and second portions of pixels alternate with respect to each other.

11. The method of claim 1, wherein the charge storage elements to which the charge packets from the first portion of pixels are transferred are different from the charge storage elements to which the charge packets from the second portion of pixels are transferred.

12. The method of claim 1, wherein each charge storage element in the VCCDs is associated with only a single pixel.

13. The method of claim 1, wherein beginning light integration for all of the pixels comprises performing an electronic shutter operation.

14. The method of claim 1, wherein each pixel comprises a color filter element associated therewith.