Anti-saturation read method of overflow-resistant function-free frame transfer CCD

Abstract

The invention relates to an anti-saturation read method of an overflow-resistant function-free frame transfer CCD. The method comprises following steps of controlling the clock of a storage area to transfer downwards for one line, controlling the clock of an imaging area to rapidly transfer upwards for a plurality of lines, transferring the exposure charge of the imaging area to the surface line; controlling a horizontal read register and a read circuit to read a line, and keeping the electric level of the clock of the imaging area at default electric level, thus preventing strong interferences on the output analog signals of the CCD; and repeatedly executing the former two steps until finishing reading the whole frame of image. The exposure charge of the imaging area is transferred to the surface line intermittently while the image is continuously transferred downwards and horizontally read; the overflow charge after saturation is absorbed by an anti-blooming structure at the upper side of the line; the exposure charge of the imaging area is transferred and cleared timely; and the phenomenon of polluting the read image, resulting from massive pixel saturation and charge overflow and diffusion is avoided.

Description

technical field [0001] The invention belongs to the technical field of photoelectric detection, and in particular relates to an anti-saturation readout method of a frame transfer CCD without an anti-overflow function. Background technique [0002] Using methods such as "frame transfer-charge dumping / readout reset" multiple times in a row can achieve a shorter exposure time than the frame readout time on the frame transfer CCD, or even zero exposure time, so that more intense optical signals can be detected . The short exposure time is followed by a fast frame transfer and a long frame readout process. During frame readout, the imaging area clock is placed at a default level, that is, in the state of exposing and collecting charges. But for the application of strong light and short exposure time, the charge collected at this stage will be excessive and useless. Under strong light, the imaging area will soon be saturated with pixels. If the CCD does not have an anti-overfl...

AI Technical Summary

Problems solved by technology

[0003] The technical problem solved by the present invention is to overcome the deficiencies of the existing methods. Through the special design of the driving sequence, the timely cleaning of useless exposure charges in the imaging area during the frame readout period is realized on the frame transfer CCD, and the charge overflow and pollution after the pixel is saturated are avoided. Occurrence of readout image phenomenon provides an anti-saturation readout method for frame transfer CCD without anti-overflow function

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