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 first charge packets from all of the pixels to respective charge storage elements in the VCCDs at a first time, wherein the first charge packets from the pixels have a first integration period;
binning the first charge packets in the VCCDs by shifting a portion of the first charge packets one or more charge storage elements in each VCCD to generate binned charge packets occupying a first group of charge storage elements;
ending light integration for all of the pixels;
transferring second charge packets from a first portion of pixels to a second group of charge storage elements in the VCCDs at a second time, wherein the second time is subsequent to the first time and the second charge packets from the first portion of pixels have a second integration period that is different from the first integration period;
reading out the binned charge packets and the second charge packets from the VCCDs together;
transferring third charge packets from remaining pixels to respective charge storage elements in the VCCDs; and
reading out the third 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 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 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 two different colors in the VCCDs by shifting a portion of the charge packets one or more charge storage elements in each VCCD.
8. The method of claim 1 , wherein the first 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.
10. The method of claim 1 , wherein each charge storage element in the VCCDs is associated with only a single pixel.
11. The method of claim 1 , wherein the third charge packets have a third integration time different from the second integration time.