Online axis calibration device and method for composite detection system

Abstract

The invention discloses an online axis calibration device and method for a composite detection system, and belongs to the field of photoelectric detection.The online axis calibration device comprises the composite detection system and an axis alignment system.The composite detection system comprises a laser, an infrared detector, a laser moving reflector and the like; the two infrared detection shafts are respectively used for emitting laser beams, performing infrared imaging on laser bright spots and adjusting the optical axis deviation value of a laser emitting shaft and an infrared detection shaft; the alignment system comprises a collimator and a target, the emitted laser beam is focused on the target through the collimator to generate heat radiation, and the heat radiation is imaged into a laser bright spot in an infrared detector; the distance between the laser bright spot and the center of the infrared view field is the optical axis deviation value of the laser emission axis and the infrared detection axis, and closed-loop alignment of the laser movable reflector is achieved. The device has the laser axis and infrared axis angle deviation detection and alignment capability of a composite detection system, has the advantages of being online, passive, reliable, suitable for various carrier environments and the like, and is beneficial to improving the capability of an active and passive composite detection system.

Description

Technical Field

[0001] The invention belongs to the field of photoelectric detection, and in particular to an online axis calibration device and method for a composite detection system. Background Art

[0002] Infrared detection is a passive detection method with good concealment. It can obtain the azimuth and angle of distant targets through search and tracking, but it cannot directly obtain the distance information of the target. Laser detection can achieve high-precision distance and speed measurement of the target, making up for the defects of infrared detection. Therefore, the composite detection technology of infrared passive imaging and laser active ranging can make full use of the advantages of two single-mode optical detection to obtain rich target information such as angle, azimuth and distance of the target.

[0003] When the active and passive composite detection system is working, it uses the infrared passive detection system to perform large field of view imaging, obtain the two-dimensional positioning information of the target, and then drive the high-precision servo mechanism to perform laser pointing and ranging, so as to realize multiple information detection of the target. From the working mode of the active and passive composite detection system, it can be seen that the high-precision alignment of the laser axis and the infrared axis is a necessary condition for realizing laser detection. The axis error will cause the laser to be unable to point to the target to achieve ranging. At present, the alignment process of the infrared and laser axes of the composite detection system is generally completed in the optical adjustment stage, and the optical axis is not detected and corrected in the later system work. However, the infrared and laser in the composite detection system are basically two independent optical systems. Due to the large environmental differences in different regions, altitudes, carriers and other application scenarios, the detection optical axis will move slightly, resulting in alignment deviation between the infrared and laser axes, affecting the detection capability of the system, and even causing the mission to fail. Therefore, in order to improve the reliability and environmental adaptability of the active and passive composite detection system, the system needs to have the function of online optical axis deviation detection and correction. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides an online axis calibration device and method for a composite detection system, which can detect and correct the deviation of the system's infrared and laser optical axes at different times and locations, achieve high-precision alignment of the system's optical axes, and effectively improve the detection capability of the active and passive composite detection system in different scenarios.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] An online shaft alignment device for a composite detection system comprises a composite detection system and a shaft alignment system, wherein:

[0007] The composite detection system includes a laser and an infrared detector, which are respectively used to emit a laser beam and perform infrared imaging on the laser bright spot;

[0008] The axis alignment system includes a collimator and a target. The emitted laser beam is focused on the target through the collimator, so that a corresponding position on the target generates thermal radiation and is imaged as a laser bright spot in the infrared detector.

[0009] The distance between the laser bright spot and the center of the infrared field of view is the optical axis deviation between the laser emission axis and the infrared detection axis of the composite detection system. The optical axis deviation is adjusted to achieve closed-loop alignment of the laser emission axis and the infrared detection axis of the composite detection system.

[0010] Furthermore, the composite detection system includes any one of total reflection type, catadioptric type and transmission type.

[0011] Furthermore, the composite detection system also includes a laser dynamic reflector, and the laser beam emitted by the laser enters the axis alignment system through the laser dynamic reflector, and the optical axis deviation is adjusted by adjusting the laser dynamic reflector.

[0012] Furthermore, the optical axis deviation ,in,( , ) is the pixel coordinate of the center of the infrared field of view, ( , ) is the pixel coordinate of the laser spot.

[0013] Furthermore, the active-passive composite detection system is composed of a main reflector, a spectroscope, an infrared detector, a laser dynamic reflector, a laser focusing mirror, a laser detector, a laser, a signal processing component, etc. When the composite detection system works normally, it detects the target through the infrared system, controls the servo to stably track the target, and then emits a laser for ranging. The main reflector is mounted on the servo system. When the axis is aligned, the main reflector is controlled by the servo to turn to the axis alignment system, so that the target of the axis alignment system is imaged in the field of view of the infrared detector; the infrared detector images the target of the axis alignment system and the laser spots gathered on the target; the signal processing component processes the image collected by the infrared detector in real time to obtain the optical axis deviation of the infrared and laser; the spectroscope reflects the laser and transmits the infrared light, and is used to separate the infrared and laser; the laser dynamic reflector is located in the laser emission and receiving optical path, and can quickly and accurately adjust the laser axis angle, which is the actuator for adjusting the axis in the axis alignment method; the laser is used to emit a laser beam whose parameters such as power and divergence angle meet the requirements.

[0014] The axis alignment system includes a collimator and a target, which are installed inside the composite detection system, wherein the collimator consists of a primary mirror and a secondary mirror, focuses the laser beam entering the aperture onto the target at the focal plane, and collimates the infrared light emitted by the laser spot to the composite detection system; wherein the target is a thin slice of special material, which is placed on the focal plane of the collimator, and the laser is focused on the target to generate heat and form an image on the infrared detector of the composite detection system, thereby detecting the pointing deviation between the laser axis and the infrared axis. In order to make the imaging contrast of the laser spot good, it is necessary to select a target with suitable materials and parameters.

[0015] Furthermore, based on the mechanism of heat radiation generated by laser focusing on the target through a collimator, the pointing position of the laser axis can be directly observed and detected on the infrared image collected by the infrared detector. The distance between the laser bright spot and the center of the infrared field of view in the infrared image is the pointing deviation between the laser axis and the infrared axis of the composite detection system. The control system feeds back the pointing deviation between the laser and infrared to the laser dynamic reflector in the composite detection system, and the laser dynamic reflector adjusts the pointing of the laser axis, and the closed loop realizes the alignment of the laser axis and the infrared axis of the active and passive composite detection system.

[0016] Furthermore, the shaft alignment system is installed on the composite detection system, and the shaft alignment process can be executed online in different working environments and working hours.

[0017] Furthermore, the target located on the focal plane of the axis alignment system is a disc made of special material, so that the laser spot focused on the target can be clearly imaged in the infrared field of view.

[0018] Furthermore, the alignment system is passive, and during alignment, the main reflector turns toward the alignment system so that the target of the alignment system is imaged in the field of view of the infrared detector, and the center of the infrared field of view represents the infrared axis direction of the composite detection system.

[0019] On the other hand, the present invention provides an online axis calibration method for a composite detection system, comprising the following steps:

[0020] Step 1: Build a composite detection system, in which the laser is used to emit a laser beam and the infrared detector is used to perform infrared imaging of the received laser bright spot;

[0021] Step 2: Building an axis alignment system, the axis alignment system includes a collimator and a target, the emitted laser beam is focused on the target through the collimator, so that the corresponding position on the target generates thermal radiation and is imaged as a laser bright spot in the infrared detector;

[0022] Step three, calculate the optical axis deviation. The distance Δ between the laser bright spot and the center of the infrared field of view is the optical axis deviation between the laser emission axis and the infrared detection axis of the composite detection system. Adjust the optical axis deviation to achieve closed-loop alignment of the laser emission axis and the infrared detection axis of the composite detection system.

[0023] In a third aspect, the present invention provides an electronic device, comprising: one or more processors; a memory for storing one or more programs; wherein, when the one or more programs are executed by the one or more processors, the one or more processors implement the aforementioned online axis calibration method for a composite detection system.

[0024] In a fourth aspect, the present invention provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, enables the processor to implement the aforementioned online axis calibration method for a composite detection system.

[0025] The beneficial effects of the present invention are:

[0026] (1) The present invention realizes the online optical axis alignment of the active and passive composite detection system. When the composite detection system works normally, the present invention can complete the detection and alignment of the infrared and laser optical axes at any place and time.

[0027] (2) The present invention has the functions of optical axis deviation detection and correction, which can not only detect the deviation of the infrared and laser optical axes of the composite detection system online, but also perform optical axis alignment in real time.

[0028] (3) The present invention realizes high-precision alignment of the infrared and laser optical axes of the composite detection system. The present invention is a closed-loop axis alignment method that uses the mechanism that the laser is focused on the target to generate heat and generate thermal radiation to detect the laser axis position. By optimizing the target material and the optimization algorithm, the system's detection accuracy of the laser spot position in the infrared image is improved. With the combination of a high-precision moving mirror, real-time detection and closed-loop axis adjustment, sub-pixel optical axis alignment accuracy can be achieved.

[0029] (4) The present invention has high environmental adaptability and is applicable to different regions and carriers. The detection and correction of the optical axis deviation of the active and passive composite detection system is not affected by ambient temperature and vibration.

[0030] (5) The method and structure of the present invention are simple and reliable, and are generally applicable to most active and passive composite detection systems. The axis alignment system adopted by the present invention is passive, has a stable structure, and has simple axis alignment steps. It can be applicable to most active and passive composite detection systems by simply changing the parameters and installation position of the axis alignment system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is one of the optical structure schematic diagrams of an online axis calibration device of a composite detection system of the present invention;

[0032] Figure 2 This is a second schematic diagram of the optical structure of an online axis calibration device of a composite detection system of the present invention;

[0033] Figure 3It is a schematic diagram of the deviation between the laser bright spot on the target and the center of the infrared field of view in the infrared image during the online axis calibration method of the present invention.

[0034] Reference numerals:

[0035] 1-active and passive composite detection system; 2-infrared detector; 3-infrared focusing mirror; 4-beam splitter; 5-primary reflector; 6-laser; 7-hole reflector; 8-laser detector; 9-laser focusing mirror; 10-laser dynamic reflector; 11-axis alignment system; 12-collimator; 13-target; 14-infrared field of view center; 15-laser bright spot; 16-laser reflector; 17-laser beam expander; 18-first receiving collimator; 19-second receiving collimator, 20-refractive off-axis composite detection system. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0037] like Figure 1As shown, an online axis calibration device of a composite detection system of the present invention includes an active and passive composite detection system 1 and an axis alignment system 11, wherein the active and passive composite detection system 1 is composed of an infrared detector 2, an infrared focusing mirror 3, a spectroscope 4, a main reflector 5, a laser 6, a hole-digging reflector 7, a laser detector 8, a laser focusing mirror 9 and a laser dynamic reflector 10, wherein the infrared detector 2 is used to image the detection target, the infrared focusing mirror 3 converges the infrared radiation detected by the system onto the focal plane of the infrared detector 2, the spectroscope 4 reflects near-infrared lasers and transmits medium and long-wave infrared light, and the laser dynamic reflector 10 is located in the laser detection optical path and is used to adjust the direction of the laser detection axis. The axis alignment system 11 is composed of a collimator 12 and a target 13. When the active and passive composite detection system 1 is aligned with the line optical axis, the servo is controlled to turn the main reflector 5 toward the axis alignment system 11, and the angle of the main reflector 5 is adjusted so that the target 13 of the axis alignment system 11 is imaged near the infrared field of view center 14 of the infrared detector 2. The field of view center of the infrared detector 2 is the infrared detection optical axis direction of the active and passive composite detection system 1; the laser 6 is turned on, and the laser beam passes through the small hole of the hole-digging reflector 7 and is reflected by the laser dynamic reflector 10 to the beam splitter 4, and then is reflected by the beam splitter 4 and the main reflector 5 respectively and enters the axis alignment system 11, and is focused by the collimator 12 to the target 1 3, the laser spot position on the target 13 generates heat and generates thermal radiation, which is collimated by the collimator 12 and then returns to the main reflector 5, and then passes through the beam splitter 4 after being reflected, and then is focused by the infrared focusing mirror 3 and converged on the focal plane of the infrared detector 2, and is imaged in the field of view of the infrared detector 2. In the field of view of the infrared detector 2, the distance between the laser bright spot 15 and the infrared field center 14 is the angle deviation between the infrared optical axis and the laser optical axis in the active-passive composite detection system 1. The laser emission axis angle is adjusted by controlling the laser dynamic reflector 10 to eliminate the angle deviation between the infrared and laser optical axes, and the axis alignment is completed.

[0038] Furthermore, the reflected laser light also reaches the laser focusing mirror 9 and the laser detector 8 via the beam splitter 4 , the laser dynamic reflector 10 , and the hole-punched reflector 7 , and the intensity of the laser light emitted by the laser 6 can be further measured.

[0039] like Figure 2 As shown in FIG. 1 , another preferred embodiment of the present invention, the online axis calibration device of the composite detection system includes a refractive off-axis composite detection system 20 and an axis alignment system 11. The off-axis composite detection system 21 is composed of an infrared detector 2, an infrared focusing mirror 3, a beam splitter 4, a laser detector 8, a laser focusing mirror 9, a first receiving collimator 18, a second receiving collimator 19, a laser 6, a laser beam expander 17, a laser dynamic reflector 10 and a laser reflector 16. The axis alignment system 11 is composed of a collimator 12 and a target 13. Figure 1When the refractive off-axis composite detection system 20 is aligned with the line optical axis, the refractive off-axis composite detection system 20 is turned to the axis alignment system 11, so that the target 13 of the axis alignment system 11 is imaged near the infrared field of view center 14 of the infrared detector 2. The infrared field of view center 14 of the infrared detector 2 is the infrared detection optical axis direction of the refractive off-axis composite detection system 20; turn on the laser 6, the laser beam is expanded by the laser beam expander 17, and then reflected by the laser dynamic reflector 10 to the laser reflector 16, and then enters the axis alignment system 11 after being reflected again, and is focused by the collimator 12 to the target 13. The laser beam on the target 13 The light spot generates heat to generate infrared thermal radiation, which is collimated by the parallel light tube 12 and then transmitted through the first receiving collimator 18 and the second receiving collimator 19 to reach the spectroscope 4, and then transmitted to the infrared focusing mirror 3. After focusing, it converges on the focal plane of the infrared detector 2 and is imaged in the field of view of the infrared detector 2. In the field of view of the infrared detector 2, the distance between the laser bright spot 15 and the infrared field of view center 14 is the angular deviation between the infrared optical axis and the laser optical axis in the composite detection system 20. The angular deviation between the infrared and laser optical axes is eliminated by controlling the laser dynamic reflector 10 to adjust the laser emission axis angle, thereby completing the axis alignment.

[0040] Similarly, the laser light partially reflected by the laser reflecting mirror 16 reaches the laser focusing mirror 9 and the laser detector 8 along the optical path, and the intensity of the laser light emitted by the laser 6 can be further measured.

[0041] Preferably, the target 13 is a circular sheet of a special material, such as Figure 3 As shown, during alignment, the laser beam emitted by the laser 6 enters the alignment system 11, is focused on the target 13 to generate heat and is imaged on the infrared detector 2. The distance Δ between the infrared field center 14 of the infrared detector 2 and the laser bright spot 15 represents the angular deviation of the optical axis between the laser emission axis and the infrared detection axis of the composite detection system.

[0042] On the other hand, the present invention provides an online axis calibration method for a composite detection system. Figure 1 For example, the following steps are included:

[0043] Step 1: Start the axis alignment process, the composite detection system turns to the axis alignment system 11, so that the target 13 of the axis alignment system 11 is imaged on the infrared detector 2, and the infrared field of view center 14 of the composite detection system is determined to correspond to the position of the target 13;

[0044] The axis alignment system 11 is installed at a specific position of the composite detection system in the online axis calibration device of the composite detection system. During the online axis alignment, the main reflector 5 is servo-controlled to turn to the axis alignment system 11, and the target 13 of the axis alignment system 11 is imaged near the infrared field of view center 14 of the infrared detector 2. The imaged infrared field of view center 14 is the infrared optical axis of the composite detection system, and the corresponding pixel coordinates are ( , ). During the axis alignment process, the servo position is fixed to keep the azimuth and pitch angle of the main reflector 5 unchanged.

[0045] Step 2: Detect the pointing deviation between the infrared axis of the composite detection system and the laser emission axis;

[0046] The composite detection system has already aligned the infrared and laser axes during the optical assembly stage. The optical axis deviation caused by the influence of the external environment on the composite detection system in the later stage is relatively small. The online optical axis alignment method proposed in the present invention corrects the dynamic optical axis deviation in the later use of the system. Turn on the laser 6, and the laser beam passes through the hole-digging reflector 7, the laser dynamic reflector 10, the beam splitter 4 and the main reflector 5 in sequence, and then enters the aperture of the axis alignment system 11. After being converged by the parallel light tube 12, the laser beam is focused into a small spot with high energy density on the target 13. Due to the high energy density of the laser spot, the corresponding position on the target 13 generates heat and generates infrared thermal radiation. The infrared thermal radiation is detected by the composite detection system and imaged as a laser bright spot 15 in the infrared detector 2. The pixel position coordinates of the laser bright spot 15 are obtained by performing image processing on the image formed by the infrared detector 2 ( , ), the distance Δ between the laser bright spot 15 and the infrared field center 14 in the infrared image is the optical axis deviation between the laser emission axis and the infrared detection axis of the composite detection system. The angular deviation of the optical axis can be calculated according to the system parameters.

[0047] ,

[0048] Step 3: Adjust the laser axis angle by using the laser moving reflector 10 to achieve online alignment between the infrared axis and the laser axis;

[0049] When the deviation between the infrared axis and the laser axis of the composite detection system Δ>0, Δ is substituted into the equivalent formula of the laser dynamic reflector 10 to obtain the angle change that the laser dynamic reflector 10 should adjust, and the laser dynamic reflector 10 adjusts the direction of the laser axis according to the angle change. Since the equivalent formula of the laser dynamic reflector 10 is affected by environmental factors such as temperature and has errors, it is impossible to accurately align the axis by performing the above steps once.

[0050] Therefore, the detection of the deviation Δ between the infrared axis and the laser axis of the composite detection system in step 2 and the adjustment process of the laser axis through the laser dynamic reflector 10 in step 3 are repeated until the laser bright spot 15 in the infrared image of the infrared detector 2 coincides with the infrared field center 14 (Δ=0), completing the closed-loop alignment of the infrared axis and the laser axis of the composite detection system. Fix the angle of the laser dynamic reflector 10, turn the main reflector 5 to the detection direction, and the composite detection system can start to work normally.

[0051] The invention proposes a composite detection system online axis calibration method and device, which is not only suitable for Figure 1 The catadioptric optical system shown and Figure 2 The invention is not only applicable to the off-axis refractive composite detection system, but also to the reflective and transmissive optical systems. The alignment method of the invention can be effectively used online when the composite detection system is in different working environments. It can not only measure the pointing deviation of the infrared and laser optical axes of the composite detection system, but also adjust the direction of the laser optical axis in a closed loop according to the measurement results, so as to achieve high-precision alignment of the infrared and laser optical axes, and improve the detection capability and environmental adaptability of the active and passive composite detection system.

[0052] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An online axis calibration device for a composite detection system, characterized in that: It includes a composite detection system and an axis alignment system, among which: The composite detection system includes a laser and an infrared detector, which are respectively used to emit a laser beam and perform infrared imaging on the laser bright spot; The axis alignment system includes a collimator and a target. The emitted laser beam is focused on the target through the collimator, so that a corresponding position on the target generates thermal radiation and is imaged as a laser bright spot in the infrared detector. The distance between the laser bright spot and the center of the infrared field of view is the optical axis deviation between the laser emission axis and the infrared detection axis of the composite detection system. The optical axis deviation is adjusted to achieve closed-loop alignment of the laser emission axis and the infrared detection axis of the composite detection system.

2. The online axis calibration device of a composite detection system according to claim 1, characterized in that: The composite detection system includes any one of total reflection type, catadioptric type and transmission type.

3. The online axis calibration device of a composite detection system according to claim 1, characterized in that: The composite detection system also includes a laser dynamic reflector. The laser beam emitted by the laser enters the axis alignment system through the laser dynamic reflector, and the optical axis deviation is adjusted by adjusting the laser dynamic reflector.

4. The online axis calibration device of a composite detection system according to claim 1, characterized in that: The optical axis deviation ,in,( , ) is the pixel coordinate of the center of the infrared field of view, ( , ) is the pixel coordinate of the laser spot.

5. The online axis calibration device of a composite detection system according to claim 2, characterized in that: When the composite detection system is an active-passive composite detection system, the laser is turned on, and the laser beam passes through the small hole of the hole-digging reflector and is reflected by the laser dynamic reflector to the beam splitter, and then is reflected by the beam splitter and the main reflector in turn and enters the collimator to be focused on the target. The laser point position on the target generates heat to generate thermal radiation, which is collimated by the collimator and then returns to the main reflector and the beam splitter. After being focused by the infrared focusing mirror, it converges on the focal plane of the infrared detector and is imaged in the field of view of the infrared detector to form a laser bright spot.

6. The online axis calibration device of a composite detection system according to claim 2, characterized in that: When the composite detection system is a refractive off-axis composite detection system, the laser is turned on, and the laser beam is expanded by a beam expander and reflected by a laser dynamic reflector to a laser reflector. After being reflected again, it enters a collimator and is focused on a target. The laser point on the target generates heat to generate infrared thermal radiation. The thermal radiation is collimated by a collimator and sequentially transmitted through a first receiving collimator and a second receiving collimator to reach a beam splitter, and then transmitted to an infrared focusing mirror. After being focused, it converges on a focal plane of an infrared detector and is imaged in the field of view of an infrared detector to form a laser bright spot.

7. The online axis calibration device of a composite detection system according to claim 4, characterized in that: The control system feeds back the optical axis deviation to the laser dynamic reflector in the composite detection system, and the laser dynamic reflector adjusts the direction of the laser axis to achieve alignment of the laser axis and the infrared axis of the composite detection system.

8. A composite detection system online axis calibration method, characterized in that: The steps include: Step 1: Build a composite detection system, in which the laser is used to emit a laser beam and the infrared detector is used to perform infrared imaging of the received laser bright spot; Step 2: Building an axis alignment system, the axis alignment system includes a collimator and a target, the emitted laser beam is focused on the target through the collimator, so that the corresponding position on the target generates thermal radiation and is imaged as a laser bright spot in the infrared detector; Step three, calculate the optical axis deviation. The distance Δ between the laser bright spot and the center of the infrared field of view is the optical axis deviation between the laser emission axis and the infrared detection axis of the composite detection system. Adjust the optical axis deviation to achieve closed-loop alignment of the laser emission axis and the infrared detection axis of the composite detection system.

9. An electronic device, characterized in that: include: one or more processors; A memory for storing one or more programs; When one or more programs are executed by the one or more processors, the one or more processors implement the online axis calibration method for a composite detection system as described in claim 8.

10. A computer-readable storage medium, characterized in that: Executable instructions are stored thereon, and when the instructions are executed by the processor, the processor can implement the online axis calibration method of a composite detection system as described in claim 8.

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