摘要 |
In accordance with the invention, a region of interest (ROI) acquired by a frame transfer CCD is read out as quickly as if the imaging area of the CCD were no larger than the ROI. The imaging area of the CCD outside of the ROI is masked, preventing light from contaminating the rest of the imaging area. After a suitable exposure time the image pixels of the ROI are shifted into the storage region of the frame transfer CCD. Once the ROI is under the mask in the storage region, the next exposure may begin, and so too does the image readout. Now the CCD shifts exactly the number of rows in the ROI into the serial register one at a time and digitizes the number of pixels in each row. This process results in a series of valid ROIs separated by a series of spacer regions pipelining down the storage region of the CCD. As an example, using a standard frame transfer mode of operation, a commercially available frame transfer camera (IPentaMAX) can achieve 83 FPS on a 50x50 ROI. In accordance with this invention, a 50x50 ROI can be read out at 877 FPS
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