阅读说明：本技术 一种基于通光量自适应调控的成像探测装置及其控制方法 (Imaging detection device based on adaptive control of light flux and control method thereof ) 是由 李正周 于 2019-11-29 设计创作，主要内容包括：本发明公开了一种基于通光量自适应调控的成像探测装置,包括光电探测器及设置在光电探测器前端的通光量自适应调控窗口,光电探测器的输出端与通光量自适应调控窗口的反馈信号输入端电连接,通光量自适应调控窗口用于基于光电探测器获取的成像图像的灰度分布对通光量自适应调控窗口各个位置的通光量进行自适应调控。本发明还公开了上述成像探测装置对应的控制方法。本发明可以在探测器前端对光强进行自适应/自动调控,避免探测器饱和与受光不均匀问题,扩大目标探测的动态范围,并使整个探测器的受光量更加均匀,提高在低对比度、高亮度背景条件下的探测能力。另外,还可以避免频繁的人工调光操作,使探测过程更加自动便捷,提高工作效率。(The invention discloses an imaging detection device based on adaptive control of light flux, which comprises a photoelectric detector and a light flux adaptive control window arranged at the front end of the photoelectric detector, wherein the output end of the photoelectric detector is electrically connected with the feedback signal input end of the light flux adaptive control window, and the light flux adaptive control window is used for adaptively controlling the light flux of each position of the light flux adaptive control window based on the gray scale distribution of an imaging image acquired by the photoelectric detector. The invention also discloses a control method corresponding to the imaging detection device. The invention can self-adaptively/automatically regulate and control the light intensity at the front end of the detector, avoid the problems of saturation and nonuniform light receiving of the detector, expand the dynamic range of target detection, make the light receiving quantity of the whole detector more uniform and improve the detection capability under the background conditions of low contrast and high brightness. In addition, frequent manual dimming operation can be avoided, the detection process is more automatic and convenient, and the working efficiency is improved.)

1. An imaging detection device based on the adaptive control of the light flux is characterized by comprising a photoelectric detector and a light flux adaptive control window arranged at the front end of the photoelectric detector, wherein the output end of the photoelectric detector is electrically connected with the feedback signal input end of the light flux adaptive control window, and the light flux adaptive control window is used for adaptively controlling the light flux of each position of the light flux adaptive control window based on the gray scale distribution of an imaging image acquired by the photoelectric detector.

2. The imaging detection device based on adaptive control of the amount of light passing according to claim 1, wherein the adaptive control window of the amount of light passing comprises a liquid crystal spatial light modulator and two orthogonally arranged polarizers, the two orthogonally arranged polarizers are respectively arranged at two sides of the liquid crystal spatial light modulator, a feedback signal input end of the liquid crystal spatial light modulator is connected with an output end of the photoelectric detector as an input end of the adaptive control window of the amount of light passing, and the imaging light beam enters the liquid crystal spatial light modulator through one polarizer and then enters the photoelectric detector through the other polarizer.

3. The imaging detection device based on adaptive control of the amount of light passing according to claim 2, wherein the liquid crystal spatial light modulator comprises a plurality of independent units arranged in an array, and the liquid crystal spatial light modulator can apply a voltage corresponding to the gray distribution of the imaging image obtained by the photodetector to each independent unit, so that the light intensity of the light passing through each independent unit is changed, and the adaptive control of the amount of light passing is realized.

4. A control method of an imaging detection device based on the adaptive control of the light flux is characterized in that the method is used for controlling the imaging detection device based on the adaptive control of the light flux, the imaging detection device based on the adaptive control of the light flux comprises a photoelectric detector and a light flux adaptive control window arranged at the front end of the photoelectric detector, the output end of the photoelectric detector is electrically connected with the feedback signal input end of the light flux adaptive control window, and the method comprises the following steps:

s1, acquiring an imaging image by the photoelectric detector, and executing the step S2;

s2, converting the imaging image into gray scale distribution information, sending the gray scale distribution information to a light flux amount adaptive control window, and executing the step S3;

s3, the self-adaptive light-flux control window adjusts the self-light-flux based on the gray-scale distribution information, so that the imaging light beam is emitted to the photoelectric detector, and the step S1 is executed until the detection process is finished.

5. The method according to claim 4, wherein the adaptive control window comprises a liquid crystal spatial light modulator and two orthogonally arranged polarizers, the two orthogonally arranged polarizers are respectively arranged on two sides of the liquid crystal spatial light modulator, a feedback signal input end of the liquid crystal spatial light modulator is connected with an output end of the photodetector as an input end of the adaptive control window, and the imaging light beam enters the liquid crystal spatial light modulator through one polarizer and then enters the photodetector through the other polarizer.

6. The method for controlling an imaging detection apparatus based on adaptive control of the amount of light flux according to claim 5, wherein the liquid crystal spatial light modulator includes a plurality of independent units arranged in an array, and in step S3, the liquid crystal spatial light modulator applies a voltage corresponding to the gray scale distribution of the imaging image obtained by the photodetector to each of the independent units, thereby changing the intensity of light transmitted by each of the independent units to realize adaptive control of the amount of light flux.

7. The method for controlling an imaging detection apparatus based on adaptive control of the amount of light flux according to claim 6, wherein the method for calculating the corresponding voltage of each individual unit comprises:

(1) counting the gray distribution of the image, calculating an image segmentation threshold value by using an Otsu method between maximum classes, and carrying out binarization processing on the image;

(2) filtering stray noise of the image after binarization processing by adopting a binary morphological filter, counting a connected region by utilizing a binary image connected region marking method based on line segment scanning, and judging and separating a local saturated region;

(3) local saturated imaging is carried out on the photoelectric detector, and voltage is applied to pixels of the liquid crystal spatial light modulator, so that the gray level of an image in a saturated area of the processed photoelectric detector is consistent with the gray level of an image in a non-saturated area, and the uniform background of the image of the whole photoelectric detector is ensured;

(4) and imaging the overall saturation of the photoelectric detector, and applying the same voltage to the whole pixel of the liquid crystal spatial light modulator to keep the quantized median of the gray scale of the whole image of the processed photoelectric detector.

8. The control method of imaging detection device based on adaptive control of luminous flux according to claim 7, characterized in that the method of judging and separating the local saturation region is that when there is only one and only one connected region of the binarized image, it is judged that the detector is imaged locally saturated, and the connected region is a local saturation region; otherwise, judging that the imaging of the detector is saturated or normal according to whether the image gray scale distribution is concentrated in a high-brightness range.

9. The method as claimed in claim 7, wherein the voltage applied to the liquid crystal spatial light modulator is calculated by calculating the corresponding voltage of each individual cell by calculating the light transmittance, and the functional relationship β (U) between the voltage applied to the liquid crystal spatial light modulator and the light transmittance is obtained by a test calibration method.

Technical Field

The invention belongs to the field of photoelectric detection, and particularly relates to an imaging detection device based on adaptive control of light flux amount and a control method thereof.

Background

With the rapid development of aerospace technology, people explore space more and more frequently, and a large number of space targets including normally-operated satellites and various space debris float in outer space, which poses serious threats to normally-operated spacecrafts and satellites. The space target monitoring mainly utilizes a telescope to carry out real-time observation, tracking and early warning on the space target, and effective detection of the target is the premise and guarantee of the space target monitoring. Due to the long observation distance, the target usually occupies dozens of pixels or even a few pixels on the imaging system, and is very weak. Meanwhile, the image has a large amount of noise interference, and the target signal-to-noise ratio is extremely low. Furthermore, during the day, due to the presence of a strong daylighting background, especially near the sun, the weak signal of the target is completely drowned in the daylighting background radiation. Therefore, daytime detection has always been a challenge.

Because the optical system cannot be absolutely ideal, the light receiving quantity of all positions of the target surface of the detector is often uneven, and the pan bottom effect of bright middle and dark edge of the image is easily caused. If located near a strong object such as the sun, the detector is easily saturated and a trapezoidal image with light near the sun and dark far from the sun may appear. Meanwhile, the detection system often has a lot of stray light and dirty points, which causes irregular brightness fluctuation of the image. These phenomena have great influence on the detection in the daytime, and it can be said that the problems of detector saturation and uneven light reception are one of the biggest obstacles to improving the detection capability in the daytime.

In order to improve daytime detectability, optical filtering techniques and digital image processing techniques are mainly used at present. The filtering technology is to perform narrow-band or polarization filtering on the natural light background by using a filter device such as a filter or a polarizing plate, thereby reducing the amount of light passing through the natural light background while maintaining the target energy. The technology can effectively weaken the background intensity and improve the target contrast, but cannot completely avoid the saturation of the detector and also cannot solve the problem of uneven light receiving of the detector. The digital image processing includes image filtering technology, image background prediction and subtraction technology, image multi-frame accumulation technology and the like. Although the image processing technologies can greatly improve the detection capability and solve the problem of uneven light reception to a certain extent, the method also has an inherent defect that the acquired image is always subjected to post-processing, the final result is limited by the information received by the front-end detector, and the digital image processing has a certain limit on the improvement of the detection capability if the detector is saturated. Moreover, since the image information contains the influence components of the optical system, the sun, and the stray light, the problem of light receiving unevenness cannot be completely overcome.

In summary, the invention discloses an imaging detection device based on adaptive control of light flux amount and a control method thereof, which can solve the problems of detector saturation and nonuniform light receiving in photoelectric detection under a strong background condition.

Disclosure of Invention

Aiming at the defects of the prior art, the problems to be solved by the invention are as follows: the saturation and the nonuniform light receiving of a detector in photoelectric detection under the strong background condition are avoided.

The invention adopts the following technical scheme:

an imaging detection device based on the adaptive control of the light flux comprises a photoelectric detector and a light flux adaptive control window arranged at the front end of the photoelectric detector, wherein the output end of the photoelectric detector is electrically connected with the feedback signal input end of the light flux adaptive control window, and the light flux adaptive control window is used for adaptively controlling the light flux of each position of the light flux adaptive control window based on the gray scale distribution of an imaging image acquired by the photoelectric detector.

Preferably, the light flux adaptive control window comprises a liquid crystal spatial light modulator and two orthogonally arranged polarizing plates, the two orthogonally arranged polarizing plates are respectively arranged on two sides of the liquid crystal spatial light modulator, a feedback signal input end of the liquid crystal spatial light modulator is used as an input end of the light flux adaptive control window and is connected with an output end of the photoelectric detector, and an imaging light beam enters the liquid crystal spatial light modulator through one polarizing plate and then enters the photoelectric detector through the other polarizing plate.

Preferably, the liquid crystal spatial light modulator includes a plurality of independent units arranged in an array, and the liquid crystal spatial light modulator may apply a voltage corresponding to a gray scale distribution of an imaging image acquired by the photodetector to each of the independent units, so as to change a light intensity of light transmitted by each of the independent units, thereby implementing adaptive control of a light transmission amount.

A control method of an imaging detection device based on the adaptive control of the luminous flux is used for controlling the imaging detection device based on the adaptive control of the luminous flux, the imaging detection device based on the adaptive control of the luminous flux comprises a photoelectric detector and a luminous flux adaptive control window arranged at the front end of the photoelectric detector, the output end of the photoelectric detector is electrically connected with the feedback signal input end of the luminous flux adaptive control window, and the method comprises the following steps:

s1, acquiring an imaging image by the photoelectric detector, and executing the step S2;

s2, converting the imaging image into gray scale distribution information, sending the gray scale distribution information to a light flux amount adaptive control window, and executing the step S3;

s3, the self-adaptive light-flux control window adjusts the self-light-flux based on the gray-scale distribution information, so that the imaging light beam is emitted to the photoelectric detector, and the step S1 is executed until the detection process is finished.

Preferably, the light flux adaptive control window comprises a liquid crystal spatial light modulator and two orthogonally arranged polarizing plates, the two orthogonally arranged polarizing plates are respectively arranged on two sides of the liquid crystal spatial light modulator, a feedback signal input end of the liquid crystal spatial light modulator is used as an input end of the light flux adaptive control window and is connected with an output end of the photoelectric detector, and an imaging light beam enters the liquid crystal spatial light modulator through one polarizing plate and then enters the photoelectric detector through the other polarizing plate.

Preferably, the liquid crystal spatial light modulator includes a plurality of independent units arranged in an array, and in step S3, the liquid crystal spatial light modulator applies a voltage corresponding to the gray scale distribution of the imaging image obtained by the photodetector to each independent unit, so as to change the light intensity of the light transmitted by each independent unit, thereby implementing adaptive control of the amount of transmitted light.

Preferably, the method of calculating the corresponding voltage of each individual cell comprises:

(1) counting the gray distribution of the image, calculating an image segmentation threshold value by using an Otsu method between maximum classes, and carrying out binarization processing on the image;

(2) filtering stray noise of the image after binarization processing by adopting a binary morphological filter, counting a connected region by utilizing a binary image connected region marking method based on line segment scanning, and judging and separating a local saturated region;

(3) local saturated imaging is carried out on the photoelectric detector, and voltage is applied to pixels of the liquid crystal spatial light modulator, so that the gray level of an image in a saturated area of the processed photoelectric detector is consistent with the gray level of an image in a non-saturated area, and the uniform background of the image of the whole photoelectric detector is ensured;

(4) and imaging the overall saturation of the photoelectric detector, and applying the same voltage to the whole pixel of the liquid crystal spatial light modulator to keep the quantized median of the gray scale of the whole image of the processed photoelectric detector.

Preferably, the method for judging and separating the local saturated regions is that when there is only one connected region of the binary image, the connected region is judged to be the local saturated region of the detector image; otherwise, judging that the imaging of the detector is saturated or normal according to whether the image gray scale distribution is concentrated in a high-brightness range.

Preferably, the voltage value applied to the liquid crystal spatial light modulator is calculated by light transmittance, so as to calculate the corresponding voltage of each independent cell, and the functional relation β (U) between the voltage value applied to the liquid crystal spatial light modulator and the light transmittance is obtained by a test calibration mode in advance.

In summary, the present invention discloses an imaging detection apparatus based on adaptive control of a light flux amount, which includes a photodetector and a light flux amount adaptive control window disposed at a front end of the photodetector, wherein an output end of the photodetector is electrically connected to a feedback signal input end of the light flux amount adaptive control window, and the light flux amount adaptive control window is configured to adaptively control the light flux amount at each position of the light flux amount adaptive control window based on a gray scale distribution of an imaging image acquired by the photodetector. The invention also discloses a control method corresponding to the imaging detection device. The invention can self-adaptively/automatically regulate and control the light intensity at the front end of the detector, avoid the problems of saturation and nonuniform light receiving of the detector, expand the dynamic range of target detection, make the light receiving quantity of the whole detector more uniform and improve the detection capability under the background conditions of low contrast and high brightness. In addition, frequent manual dimming operation can be avoided, the detection process is more automatic and convenient, and the working efficiency is improved.

Drawings

For purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made in detail to the present invention as illustrated in the accompanying drawings, in which:

FIG. 1 is a schematic structural diagram of an imaging detection device based on adaptive control of luminous flux according to the present disclosure;

FIG. 2 is a schematic diagram of the writing light, reading light and output light definitions of a liquid crystal spatial light modulator pixel;

FIG. 3 is a schematic diagram of the principle of the electro-optic effect of liquid crystal without an applied electric field;

FIG. 4 is a schematic diagram of the principle of the electro-optic effect of liquid crystals after an electric field is applied;

FIG. 5 is a partial saturation image of a photodetector before modulation;

FIG. 6 is a local saturation region extracted from an image;

fig. 7 shows the result of fig. 5 after the adaptive window is turned on.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

The invention discloses an imaging detection device based on adaptive control of light flux, which comprises a photoelectric detector and a light flux adaptive control window arranged at the front end of the photoelectric detector, wherein the output end of the photoelectric detector is electrically connected with the feedback signal input end of the light flux adaptive control window, and the light flux adaptive control window is used for adaptively controlling the light flux of each position of the light flux adaptive control window based on the gray scale distribution of an imaging image acquired by the photoelectric detector.

The invention can self-adaptively/automatically regulate and control the light intensity at the front end of the detector, avoid the problems of saturation and nonuniform light receiving of the detector, expand the dynamic range of target detection, make the light receiving quantity of the whole detector more uniform and improve the detection capability under the background conditions of low contrast and high brightness. In addition, frequent manual dimming operation can be avoided, the detection process is more automatic and convenient, and the working efficiency is improved.