Methods for capturing and reading out images from an image sensor
View Patent ↗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.
1. A method for producing multiple 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;
binning charge packets in the VCCDs by shifting a portion of the charge packets one or more charge storage elements in each VCCD;
transferring charge packets from the first portion of pixels to respective charge storage elements in the VCCDs at a second time, wherein the charge packets from the first portion of pixels have a second 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 at a third time, wherein the charge packets from the second portion of pixels have a third integration period that is different from 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 binning charge packets in the VCCDs by shifting a portion of the charge packets one or more charge storage elements in each VCCD comprises binning charge packets of the same color and having the same integration period in the VCCDs by shifting a portion of the charge packets one or more charge storage elements in each VCCD.
7. The method of claim 6 , wherein transferring charge packets from the first portion of pixels to respective charge storage elements in the VCCDs at a second time comprises binning charge packets of the same color and having different integration periods by transferring charge packets from the first portion of pixels to respective charge storage elements in the VCCDs at a second time, wherein the charge packets from the first portion of pixels have a second integration period.
8. The method of claim 1 , wherein the first and second portions of pixels comprise single lines of pixels.
9. The method of claim 1 , wherein the first and second portions of pixels comprise multiple lines of pixels.
10. The method of claim 9 , wherein the multiple lines of pixels comprise multiple adjacent lines of pixels, and wherein the first and second portions of pixels alternate with respect to each other.