CN-122027911-A - Reading circuit for infrared and low-light image fusion and working time sequence and imaging system thereof

CN122027911ACN 122027911 ACN122027911 ACN 122027911ACN-122027911-A

Abstract

The invention discloses a reading circuit for infrared and low-light-level image fusion and a working time sequence and an imaging system thereof, belonging to the technical field of infrared and low-light-level imaging. The readout circuit comprises a pixel array unit circuit, a column-level sample-hold processing circuit, an output buffer, a bias generating circuit and a digital controller. The readout circuit designs a readout circuit for infrared and low-light-level image fusion by adopting two input stage mixed structures of direct injection and a capacitive transimpedance amplifier, realizes that infrared and low-light-level image signals can be respectively integrated and respectively read out by adopting the same set of light paths, the same type of sensors (such as indium gallium arsenic, colloid quantum dots and the like) and the same readout circuit, ensures the performance of a readout circuit chip for infrared and low-light-level image fusion, simultaneously ensures the accurate alignment of infrared and low-light-level images and the performance of real-time signal acquisition, and ensures the multifunctional and miniaturized integration of an infrared and low-light-level image fusion imaging system.

Inventors

LI YU
HONG JIANTANG

Assignees

昆明钍晶科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260213

Claims (10)

1. The reading circuit for fusing infrared and micro-light images is characterized by comprising a pixel array unit circuit, a column-level sampling-holding processing circuit, an output buffer, a bias generating circuit and a digital controller, Wherein, the The pixel array unit circuit is used for receiving detection signals generated by the infrared and micro-light dual-signal focal plane array and transmitting integrated signals generated by the pixel array unit circuit to the column-level sample-hold processing circuit in parallel through a column-level bus; the column-level sample-hold processing circuit is used for sampling-holding the integrated signal; The output buffer is used for transmitting the sampling signal to an output port; The digital controller is used for providing a required digital control signal and communicating with a system to which the readout circuit belongs so as to control the readout circuit; The bias generating circuit is used for providing bias voltages of the pixel array unit circuit, the column-level sample-hold processing circuit and the output buffer amplifier.
2. The infrared and low-light level image fusion readout circuit according to claim 1, wherein, The pixel level unit circuit in the pixel array unit circuit comprises a direct injection input stage circuit and a capacitive transimpedance amplifier input stage circuit, wherein the direct injection input stage circuit is used for integrating infrared photoelectric signals generated by the infrared and low-light dual-signal focal plane array unit and outputting infrared integrated signals, and the capacitive transimpedance amplifier input stage circuit is used for integrating low-light photoelectric signals generated by the infrared and low-light dual-signal focal plane array unit and outputting low-light integrated signals.
3. The infrared and low-light level image fusion readout circuit according to claim 2, wherein, The direct injection input stage circuit comprises a second switch tube, a fourth switch tube, a first integration capacitor, a sixth switch tube, an eighth switch tube and a second integration capacitor, and a tenth switch tube used as an infrared integrated voltage signal readout switch, wherein the eighth switch tube is used for selecting integration and then readout or integration and simultaneous readout functions, Wherein, the The first electrode of the second switching tube is connected with the negative electrode of the infrared and low-light dual-signal focal plane array, the second electrode of the second switching tube is used for being connected with a first integral control signal, the third electrode of the second switching tube is connected with the first electrode of the eighth switching tube, the first electrode of the fourth switching tube and one electrode of the first integral capacitor, and the other electrode of the first integral capacitor is grounded; The second electrode of the eighth switching tube is used for accessing an integral and simultaneously reading a signal or integrating and then reading the signal, the third electrode of the eighth switching tube is connected with the first electrode of the tenth switching tube, the first electrode of the sixth switching tube and one electrode of the second integral capacitor, and the other electrode of the second integral capacitor is grounded; the second electrode of the fourth switching tube is used for being connected with a first reset pulse signal, the second electrode of the sixth switching tube is used for being connected with a second reset pulse signal, and the third electrode of the fourth switching tube and the third electrode of the sixth switching tube are both used for being connected with a reset level.
4. The infrared and low-light level image fusion readout circuit according to claim 3, wherein, The capacitive transimpedance amplifier input stage circuit comprises a first switching tube, a third switching tube, an operational amplifier, a third integrating capacitor and a fifth switching tube used as a low-light-level integrated voltage signal readout switch, Wherein, the The first electrode of the first switching tube is connected with the negative electrode of the infrared and low-light dual-signal focal plane array, the second electrode of the first switching tube is used for being connected with a second integral control signal, the third electrode of the first switching tube is connected with the first electrode of the third switching tube, the first end of the operational amplifier and one electrode of the third integral capacitor, and the second end of the operational amplifier is used for being connected with an in-phase input level; the third end of the operational amplifier, the other electrode of the third integrating capacitor and the third electrode of the third switching tube are all connected with the first electrode of the fifth switching tube, and the second electrode of the fifth switching tube is used for being connected with a second read signal; The third electrode of the fifth switching tube and the third electrode of the tenth switching tube are connected with a source follower, The operational amplifier is used for amplifying signals obtained by detection of the infrared and low-light dual-signal focal plane array.
5. The readout circuit for infrared and micro-light image fusion according to claim 4, further comprising a source follower for transmitting the infrared integrated signal or the micro-light integrated signal, The source follower comprises a seventh switching tube and a ninth switching tube, Wherein, the The second electrode of the ninth switching tube is connected with the third electrode of the fifth switching tube and the third electrode of the tenth switching tube, the first electrode of the ninth switching tube is grounded, and the third electrode of the ninth switching tube is connected with the third electrode of the seventh switching tube and is used as an output end of the source follower; The first electrode of the seventh switching tube is used for being connected with an analog voltage, and the second electrode of the seventh switching tube is used for being connected with an active load input level.
6. The infrared and low-light level image fusion readout circuit according to claim 5, wherein, The first switching tube to the tenth switching tube are field effect transistors; The first electrode of the field effect transistor is a source electrode, the second electrode is a grid electrode, and the third electrode is a drain electrode; the first end of the operational amplifier is an inverting input end, the second end of the operational amplifier is a non-inverting input end, and the third end of the operational amplifier is an output end.
7. The infrared and low-light level image fusion readout circuit according to claim 5, wherein, The field effect transistor is a metal-oxide-semiconductor transistor.
8. The infrared and low-light level image fusion readout circuit according to claim 7, wherein, The field effect transistor is an N-type metal-oxide-semiconductor transistor.
9. An operation timing sequence of the readout circuit for infrared and micro-light image fusion, which is used for controlling the operation timing sequence of the readout circuit for infrared and micro-light image fusion according to any one of claims 6 to 8, and sequentially comprises: At a first moment, a first integration control signal is input, wherein the first integration control signal is set to be high level, a second integration control signal is set to be low level, a third reset pulse signal is set to be low level, and the integration of the N frame of infrared information of a target is started, at the moment, a second field effect transistor serving as a direct injection tube is closed, N is a positive integer, and a first readout signal is set to be low level; At a second moment, the fourth field effect transistor and the sixth field effect transistor are turned off simultaneously, at the moment, the first reset pulse signal and the second reset pulse signal are set to be low level, the first reset pulse signal and the second reset pulse signal are directly injected into an input stage circuit to start N frame integration on target infrared information, and infrared light currents generated by infrared and low-light double-signal focal plane arrays are integrated on the first integration capacitor and the second integration capacitor simultaneously; At a third moment, after photocurrent integration is completed, the second field effect transistor is turned off, at the moment, the first integration control signal is set to be low level, the tenth field effect transistor is turned on from the previous turn-off, the first readout signal is set to be high level, the infrared integration signals held on the first integration capacitor and the second integration capacitor are read out through the ninth field effect transistor in the source follower and then are transmitted to the corresponding column-level sample-hold processing circuit, a first sample-hold signal is obtained, the first sample-hold signal is transmitted to an output port, after the reading out is completed, the tenth field effect transistor is turned off, and thus, the reading out of the infrared signal of the Nth frame is completed; at a fourth moment, the second integration control signal is input, wherein the second integration control signal is set to be high level, the first integration control signal is set to be low level, the integration of the frame N glimmer information of the target is started, the first field effect transistor is closed, the third reset pulse signal is set to be high level, and the third field effect transistor is closed at the same time, so that the third integration capacitor is reset to the in-phase input level of the operational amplifier; At a fifth moment, the third field effect transistor is turned off, a third reset pulse signal is set to be at a low level at the moment, the integration of the shimmer signal of the Nth frame is started, and the shimmer photocurrent generated by the infrared and shimmer double-signal focal plane array is integrated on the third integration capacitor; At a sixth moment, after the photocurrent integration is completed, the first field effect transistor is turned off, at the moment, the second integration control signal is set to be at a low level, the fifth field effect transistor is turned on, at the moment, the second readout signal is set to be at a high level, the micro-light integration signal held on the third integration capacitor is read out through the ninth field effect transistor and then transmitted to a corresponding column-level sample-hold processing circuit, so as to obtain a second sample-hold signal, and the second sample-hold signal is transmitted to the output port; at the seventh moment, the readout is completed, the fifth field effect transistor is turned off, and thus the reading of the shimmer signal of the nth frame is completed.
10. An imaging system comprising the readout circuit for infrared and low-light image fusion according to any one of claims 1 to 8.

Description

Reading circuit for infrared and low-light image fusion and working time sequence and imaging system thereof Technical Field The invention belongs to the technical field of infrared and low-light imaging, and particularly relates to a readout circuit for infrared and low-light image fusion and a working time sequence and an imaging system thereof. Background Infrared thermal imaging can display the target profile by differences in thermal radiation of the object. The infrared image is an image generated by heat radiation of the object, so that the infrared detector can passively acquire target information in a scene, well display the thermal characteristics of a hidden target, and have little influence by illumination conditions and bad weather. However, due to the limitation of infrared thermal imaging mechanism, the thermal contrast of the infrared image is low, the spatial correlation is weak, the reflecting capability of target details and textures is poor, and therefore the infrared imaging effect does not accord with the visual habit of human eyes. In contrast, low-light imaging belongs to the visible light category, and particularly under low illumination, the target information is richer than that of an infrared image, so that the contour and texture information of rich targets and environments can be better provided, and the scene is more real and vivid. However, the micro-light imaging effect is limited by the environment and the distance, the imaging noise is very large when the weather is bad, and the target is easy to lose under the condition that the chromaticity difference between the target and the background is small. Therefore, the infrared thermal imaging technology, like a "thermal perspective lamp", can lock the target by capturing the thermal radiation of the object in a complex environment such as darkness, smoke, etc. The micro-light imaging is similar to a high-definition 'detail magnifying glass', and fine features of a target can be accurately captured by virtue of the resolution of sub-pixel levels. Therefore, the infrared and low-light images are subjected to depth fusion, so that an all-weather and all-dimensional accurate tracking system can be formed, the accuracy and reliability of detection and tracking are greatly improved, the technology has wide development prospect, and more comprehensive and clearer image information can be provided in the fields of military, security, medical treatment, environmental protection and the like. In the technical field of infrared and low-light-level image fusion, a traditional imaging system generally relies on a dual-light path, namely an infrared detector and/or a low-light-level detector for imaging, and then data fusion is achieved through later data processing. The method not only increases the complexity and cost of an imaging system, but also brings great challenges to the functions of real-time acquisition, storage, processing and the like of the multi-sensor video images. With the progress of photoelectric materials, focal plane detectors capable of responding to both short-wave infrared signals and low-light signals, such as an InGaAs short-wave infrared detector, generally has a response wave band of 800nm-2600nm, and a response wave band of 700nm-2000nm. Typically, the response band of the photodetector is 700nm-1000nm, and the response band of the short-wave infrared detector is 1000nm-3000nm. Therefore, the response wave bands of the InGaAs infrared detector and the colloid quantum dot infrared detector cover most of the shortwave wave bands and most of the low-light wave bands ‌. This makes it possible to detect both short-wave information and low-light information of the target by using the same type of focal plane detector. In order to overcome the problems of the conventional infrared and low-light-level image multi-optical-path fusion system, the response wave bands of the existing infrared/low-light-level detectors are fully utilized, and a readout circuit and an imaging system for infrared and low-light-level image fusion, which have high integration level, low cost and high system operation efficiency, are needed. The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art. Disclosure of Invention The invention aims to solve the problems and provide a readout circuit for infrared and low-light-level image fusion, and an operating time sequence and an imaging system thereof. The first aspect of the invention provides a readout circuit for infrared and micro-light image fusion, which comprises a pixel array unit circuit, a column-level sample-hold processing circuit, an output buffer, a bias generating circuit and a digital controller, Wherein, the The pixel array unit circuit