Image Sensor and Its Imaging Method Based on Time Delay Integration (tdi)

Abstract

An image sensor based on time delay integration (TDI) and its imaging method are disclosed. Wherein, the image sensor based on time delay integration TDI includes: a multi-stage line array, including a plurality of single-stage line arrays arranged along the scanning direction of the image sensor, wherein each single-stage line array includes multiple lines arranged along the line array direction pixels; wherein, each single-stage linear array enters the counting mode in response to the first control signal, and enters the transfer mode in response to the second control signal, wherein, in the counting mode, each single-stage linear array enters the incident The optical signal to the pixel is counted and the count value is obtained, and in the transfer mode, each level of single-level line array stops counting, except for the last level of single-level line array, other levels of single-level line array will be The current count value obtained is output to the next-stage single-stage line array, and the current count value obtained by the last-stage single-stage line array is output.

Description

technical field [0001] The present disclosure relates to a time delay integration (Time delay integration, TDI) based image sensor and its imaging method, in particular to an image sensor and a corresponding imaging method using a single photon avalanche diode (SPAD, single photon avalanchediode) to realize time delay integration . Background technique [0002] Time-delay integration is an imaging method to improve image signal-to-noise ratio in high-speed scanning imaging mode, which is usually used in CCD (charge coupled device) technology, that is, TDI-CCD image sensor. figure 1 A schematic diagram of a TDI image sensor used for imaging is shown. In the line scan system, the increasing direction of the TDI image sensor series is the camera scanning direction, multiple exposure imaging of the same scene through different levels of line arrays can prolong the equivalent integration time of imaging, which is conducive to improving the signal-to-noise ratio . There is a po...

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Problems solved by technology

[0003] However, the TDI-CCD image sensor has some disadvantages such as high manufacturing cost and high operating voltage. The industry recently proposed a TDI image sensor based on CMOS technology.

TDI-CMOS technology is compatible with CMOS technology, and the cost is low, but its transfer method is generally to perform analog domain accumulation or digital domain accumulation after the row and column are read out, which is easy to introduce noise and requires complex control timing

Generally speaking, there is a certain gap between TDI-CMOS image sensor noise level and image quality and TDI-CCD

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