Image sensor based on time delay integration (TDI) and imaging method thereof

Abstract

The present invention discloses an image sensor based on time delay integration (TDI) and an imaging method thereof. The image sensor based on time delay integration TDI comprises a multi-stage lineararray which comprises a plurality of single-stage linear arrays arranged in the scanning direction of the image sensor, and each single-stage linear array comprises a plurality of pixels arranged inthe linear array direction; each stage of single-stage linear array enters a counting mode in response to a first control signal to enter a transfer mode in response to the second control signal, wherein in the counting mode, each stage of single-stage linear array counts the optical signals incident on the pixels and obtains a count value; and in the transfer mode, each stage of single-stage linear array stops counting, except the last stage of single-stage linear array, the other stages of single-stage linear arrays output the obtained current counting value to the next stage of single-stagelinear array, and the last stage of single-stage linear array outputs the obtained current counting value.

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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