Five-prism-based screen target screen face perpendicularity calibration device and calibration method thereof

Abstract

The application relates to a five-prism-based screen target screen surface perpendicularity calibration device and a calibration method thereof, and relates to the technical field of photoelectric measurement. In order to solve the problems of complex calibration operation, high device cost and difficulty in ensuring the accuracy and uniformity of screen target measurement data in the existing screen target screen surface perpendicularity calibration method, the device comprises a standard five-prism, mechanical clamping, a screen target, a base and an adjustable flat collimating light source. The screen target comprises an optical lens, a laser coarse adjustment indication frame, a support frame, a precision translation table, a rotating table, a slit diaphragm, a linear array photoelectric detector, a rotating shaft and a screen target box body. The application can perform whole machine testing without disassembling the screen target components, is convenient for product reinspection in any environment, simplifies the calibration steps compared with the traditional screen target calibration method, and significantly improves the calibration accuracy. The calibration method is simple in steps, guarantees the accuracy and uniformity of value transmission, effectively shortens the calibration time, and improves the measurement accuracy and efficiency of the screen target.

Description

Technical Field

[0001] This invention relates to the field of photoelectric measurement technology, specifically to a pentaprism-based celestial target celestial surface verticality calibration device and calibration method thereof. Background Technology

[0002] The canopy target is a key piece of equipment in China's weapons testing field. Its basic principle is that when a projectile passes through the canopy target's field of view, it blocks some of the light, causing a change in the light flux entering the target. This change is then converted into a projectile's "passage signal" by photoelectric conversion devices and signal processing circuits. The calibration of the canopy target is a powerful guarantee of the accuracy and reliability of its parameters and measured data, and is an indispensable and crucial part of range testing.

[0003] In the 2017 national standard specification for dome targets, the dome surface verticality calibration method is divided into the following two types based on the position of the dome objective lens optical axis:

[0004] (1) When the optical axis of the astrophotography objective is horizontal, remove the photoelectric conversion component of the astrophotography target, place the astrophotography target 3m to 4m away from the white wall and adjust it to be horizontal; observe the clear slit image formed on the wall by illuminating the slit; adjust the pitch of the astrophotography target and visually measure that the optical axis of the astrophotography objective is perpendicular to the wall; draw a plumb line on the wall and make it pass through the point where the optical axis of the astrophotography objective is perpendicular to the wall; calculate the perpendicularity error between the astrophotography surface and the horizontal plane by observing, positioning and accurately measuring the size of the slit image in the astrophotography.

[0005] (2) When the optical axis of the celestial objective is vertical, draw a line segment MN on the ceiling at a height of 3m to 4m above the lens; remove the celestial target panel and photoelectric conversion component, with the slit facing upward and aligned with the direction of MN; align the vertical reticle of the theodolite telescope with point M and aim at the slit; by translating and rotating the celestial target, make the vertical reticle bisect the image of the slit on the theodolite telescope reticle; adjust the celestial objective to face upward, illuminate the slit, and form a clear slit image on the ceiling; calculate the verticality error between the celestial surface and the horizontal plane by measuring the distance from the line MN to the two edges of the slit image and the distance from the celestial objective to the ceiling.

[0006] This method uses wall-mounted auxiliary lines to observe, locate, and measure the size of the slit image in the canopy, thereby calculating the verticality error between the canopy surface and the horizontal plane. However, it suffers from significant human measurement errors and requires repeated disassembly and reassembly of the canopy target components, making the operation process complex and difficult to ensure the accuracy and consistency of the canopy target measurement data.

[0007] The verticality calibration of the dome target can also be achieved by taking a light curtain strip (usually rectangular) parallel to the reference plane at a certain point on the dome surface (a certain distance h from the lens), and detecting the deviation between this light curtain strip and the reference position. This deviation, combined with the parameter h, can make the light curtain of the dome target visible, and calculate the parallelism or verticality between the two planes to be measured. The position detection mechanism mainly consists of a light source, a base, an optical lens, and a pinhole. The diameter of the light source can be adjusted according to actual needs. The position of the position detection mechanism is fixed by a gantry frame. The dome target is placed on the operating table, and the plane of the operating table is adjusted to be parallel to the horizontal plane. The dome target is leveled in the working state. The dome target is moved on the operating table in the direction perpendicular to the reference plane, so that the field of view or the dome surface of the dome target passes through the two position detection mechanisms. The movement distance of the two position detection mechanisms on the dome target at the two positions where there is a signal and there is no signal is recorded respectively. This is used to calculate and determine the positional relationship between the light curtain strip and the reference line, and realize the calibration of the verticality of the dome surface to the horizontal plane. This calibration method requires a specific gantry frame, which takes up a lot of space, is inconvenient to move, and has a complex calibration process with high costs. Summary of the Invention

[0008] To address the problems of complex calibration operations, high device costs, and difficulty in ensuring accurate and consistent measurement data of the canopy target in current canopy target verticality calibration methods, this invention proposes a canopy target verticality calibration device and calibration method based on a pentaprism.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] The pentaprism-based sky target sky surface verticality calibration device includes a standard pentaprism, mechanical clamping, sky target, base and adjustable leveling and collimating light source. The sky target includes an optical lens, laser coarse adjustment indicator frame, support frame, precision translation stage, rotary stage, slit aperture, linear array photodetector, rotation axis and sky target box.

[0011] The rotary table is fixed on the base, and its center is coaxial with the center of the field of view of the sky target, controlling the sky target to rotate around the z-axis; the precision translation stage is located above the rotary table, controlling the sky target to translate along the y-axis; the support frame is fixed in the translation track of the precision translation stage and can move along the translation guide rail; the sky target box is fixed on the support frame through the rotation shafts on both sides, controlling the sky target box to perform pitch operation;

[0012] A standard pentaprism is fixed directly above the optical lens by a mechanical clamp, and the standard pentaprism can be rotated precisely around the x-axis by the mechanical clamp;

[0013] The upper surface of the celestial target box is engraved with a laser coarse adjustment indicator frame. The laser coarse adjustment indicator frame is located directly above the slit aperture, and its long side is parallel to the slit direction of the slit aperture, so that the laser coarse adjustment indicator frame is parallel to the celestial and passes through the center position of the optical lens.

[0014] The optical lens meets the testing range of the celestial target and can image objects that are relatively close. The linear array photodetector is placed at the image plane of the optical lens, and the slit aperture is close to the detection surface of the linear array photodetector. When the laser sweeps through the optical lens, it can generate an imaging signal on the linear array photodetector.

[0015] The adjustable collimating light source uses a theodolite or a bubble level in conjunction with a self-collimating collimator to obtain a horizontal laser beam.

[0016] A method for calibrating the verticality of the canopy surface of a pentaprism-based canopy target is characterized by the following steps:

[0017] Step 1: Place the target to be calibrated on the ground and place the bubble level in the center of the upper surface of the target housing, ensuring that it is stable and will not slide or rotate. Adjust the precision translation stage, rotation stage, support frame and rotation axis by observing the bubble level to make the upper surface of the target level.

[0018] Step 2: Place the autocollimating collimator on the central axis of the field of view of the celestial target, place the bubble level on the upper surface of the autocollimating collimator, and adjust the laser to be horizontal by observing the bubble level;

[0019] Step 3: Fix the standard pentaprism on the mechanical clamp and adjust the height of the autocollimating collimator so that the horizontal beam emitted by the autocollimating collimator illuminates the main section of the standard pentaprism. Based on the optical principle of the standard pentaprism, the horizontal laser is deflected by 90° from the original incident direction after being reflected twice in the standard pentaprism and then vertically illuminates the upper surface of the sky-canopy target box.

[0020] Step 4: Rotate the standard pentaprism strictly around the x-axis to perform laser scanning, observe the laser scanning trajectory, and fine-tune the height of the autocollimating collimator so that the laser scanning trajectory coincides with the laser coarse adjustment indicator frame.

[0021] Step 5: Adjust and reduce the sweeping angle of the standard pentaprism so that the straight sweeping trajectory of the emitted light on the upper surface of the celestial target box does not exceed the edge of the optical lens frame. The shadow area A is the beam surface that can be detected by the linear array photodetector 3-7. At the same time, observe the output signal of the linear array photodetector 3-7.

[0022] Step 6: Adjust the slit aperture and the linear array photodetector. When the linear array photodetector detects a continuous and uninterrupted light signal, it is determined that the laser sweep trajectory coincides with the slit aperture, thus completing the calibration of the verticality of the canopy surface of the canopy target.

[0023] The trajectory length of the laser scanning is greater than the length of the slit aperture, and the size of the linear photodetector located below the slit aperture is greater than the size of the slit aperture, ensuring that the light flux of the linear photodetector reaches its maximum value.

[0024] The beneficial effects of this invention are as follows:

[0025] 1. This invention does not require disassembling the sky dome target components, allowing for whole-machine testing and facilitating product re-inspection in any environment. Compared to traditional sky dome target calibration methods, it simplifies the calibration steps and significantly improves calibration accuracy.

[0026] 2. The adjustable collimating light source, standard pentaprism, bubble level, and other components in the canopy target verticality calibration device of the present invention are already mature and widely used in the market, which effectively reduces the cost of high-precision calibration of the canopy target.

[0027] 3. The calibration method described in this invention has simple steps and realizes the visualization and electronicization of the testing process through photoelectric conversion, avoiding human measurement errors, ensuring the accuracy and uniformity of value transmission, effectively shortening the calibration time, and improving the measurement accuracy and efficiency of the celestial target. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a calibration device for the verticality of a canopy surface of a pentaprism-based canopy target according to the present invention.

[0029] Figure 2 This is a top view of the canopy target described in this invention;

[0030] Figure 3 This is a schematic diagram of the laser scanning state of the pentaprism of the present invention. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings.

[0032] like Figure 1 As shown, the pentaprism-based dome target verticality calibration device includes a standard pentaprism 1, a mechanical clamp 2, a dome target 3, a base 4, and an adjustable collimating light source 5. The dome target 3 includes an optical lens 3-1, a laser coarse adjustment indicator frame 3-2, a support frame 3-3, a precision translation stage 3-4, a rotating stage 3-5, a slit aperture 3-6, a linear array photodetector 3-7, a rotating shaft 3-8, and a dome target housing 3-9.

[0033] The rotating platform 3-5 is fixed on the base 4, and its center is coaxial with the center of the field of view of the sky target, controlling the sky target to rotate around the z-axis; the precision translation platform 3-4 is located above the rotating platform 3-5, controlling the sky target to translate along the y-axis; the support frame 3-3 is fixed in the translation track of the precision translation platform 3-4 and can move along the translation guide rail; the sky target box 3-9 is fixed on the support frame 3-3 through the rotating shafts 3-8 on both sides, and the sky target box 3-9 can be tilted.

[0034] The standard pentaprism 1 is fixed directly above the optical lens 3-1 by the mechanical clamp 2, and the standard pentaprism 1 can be rotated strictly around the x-axis by the mechanical clamp 2.

[0035] See Figure 2 The upper surface of the canopy target box 3-9 is engraved with a laser coarse adjustment indicator frame 3-2. The laser coarse adjustment indicator frame 3-2 is located directly above the slit aperture 3-6, and its long side is parallel to the slit direction of the slit aperture 3-6, so that the laser coarse adjustment indicator frame 3-2 is parallel to the canopy and passes through the center position of the optical lens 3-1.

[0036] The optical lens 3-1 can image objects that are relatively close while meeting the testing range of the celestial target. The slit aperture 3-6 is close to the detection surface of the linear array photodetector 3-7. The linear array photodetector 3-7 is placed at the image plane of the optical lens 3-1. When the laser sweeps through the optical lens 3-1, it can generate an imaging signal on the linear array photodetector 3-7.

[0037] The adjustable collimating light source 5 uses a theodolite or a bubble level in conjunction with a self-collimating collimator to obtain a horizontal laser beam.

[0038] The present invention provides a method for calibrating the verticality of the canopy surface of a pentaprism-based canopy target, comprising the following steps:

[0039] Step 1: Place the target 3 to be calibrated on the ground and place the bubble level in the center of the upper surface of the target housing 3-9, ensuring that it is stable and will not slide or rotate. Adjust the precision translation stage 3-4, the rotation stage 3-5, the support frame 3-3 and the rotation axis 3-8 by observing the bubble level, so that the upper surface of the target is at a horizontal position.

[0040] Step 2: Place the autocollimating collimator on the central axis of the field of view of the celestial target 3, place the bubble level on the upper surface of the autocollimating collimator, and adjust the laser to be horizontal by observing the bubble level;

[0041] Step 3: Fix the standard pentaprism 1 onto the mechanical clamp 2, and adjust the height of the autocollimating collimator so that the horizontal beam emitted from the autocollimating collimator illuminates the principal section of the standard pentaprism 1. (See also...) Figure 3 Based on the optical principle of a standard pentaprism, the horizontal laser is reflected twice within the standard pentaprism 1 and deflected by 90° from the original incident direction, then vertically irradiates the upper surface of the canopy target box 3-9.

[0042] Step 4: Rotate the standard pentaprism 1 strictly around the x-axis to perform laser scanning, observe the laser scanning trajectory, and fine-tune the height of the autocollimating collimator so that the laser scanning trajectory coincides with the laser coarse adjustment indicator 3-2.

[0043] Step 5: Adjust and reduce the sweeping angle of the standard pentaprism 1 so that the linear sweeping trajectory of the emitted light on the upper surface of the celestial target box 3-9 does not exceed the edge of the optical lens 3-1 frame. (See [link]) Figure 3 The shaded area A is the beam surface that can be detected by the linear photodetector 3-7, and the output signal of the linear photodetector 3-7 is observed at the same time.

[0044] Step 6: Adjust the slit aperture 3-6 and the linear array photodetector 3-7. When the linear array photodetector 3-7 detects a continuous and uninterrupted light signal, it is determined that the laser sweep trajectory coincides with the slit aperture 3-6, thus completing the calibration of the celestial target.

[0045] To ensure that the light flux of the linear array photodetector 3-7 reaches its maximum value, the trajectory length of the laser sweep must be greater than the length of the slit aperture 3-6, and the size of the linear array photodetector 3-7 located below the slit aperture 3-6 must be greater than the size of the slit aperture 3-6.

[0046] The above description is only a preferred 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 within the scope of protection of the present invention.

Claims

1. A pentaprism-based device for calibrating the verticality of a canopy surface in a canopy target, characterized in that, It includes a standard pentaprism (1), mechanical clamping (2), a dome target (3), a base (4), and an adjustable collimating light source (5). The dome target (3) includes an optical lens (3-1), a laser coarse adjustment indicator frame (3-2), a support frame (3-3), a precision translation stage (3-4), a rotating stage (3-5), a slit aperture (3-6), a linear array photodetector (3-7), a rotating axis (3-8), and a dome target housing (3-9). The rotating platform (3-5) is fixed on the base (4), and its center is coaxial with the center of the field of view of the celestial target, controlling the celestial target to rotate. The axis rotates; the precision translation stage (3-4) is located above the rotary stage (3-5), controlling the celestial target along the axis. Axis translation; the support frame (3-3) is fixed in the translation track of the precision translation stage (3-4) and can move along the translation guide rail; the dome target box (3-9) is fixed on the support frame (3-3) through the rotating shafts (3-8) on both sides, and can be tilted; The standard pentaprism (1) is fixed directly above the optical lens (3-1) by a mechanical clamp (2). The standard pentaprism (1) can be rotated by the mechanical clamp (2). The axis rotates; The upper surface of the celestial target box (3-9) is engraved with a laser coarse adjustment indicator frame (3-2). The laser coarse adjustment indicator frame (3-2) is located directly above the slit aperture (3-6), and its long side is parallel to the slit direction of the slit aperture (3-6), so that the laser coarse adjustment indicator frame (3-2) is parallel to the celestial and passes through the center position of the optical lens (3-1). The optical lens (3-1) can image objects that are close to the target while meeting the testing range of the sky screen. The slit aperture (3-6) is close to the detection surface of the linear array photodetector (3-7). The linear array photodetector (3-7) is placed at the image plane of the optical lens (3-1). When the laser sweeps through the optical lens (3-1), it can generate an imaging signal on the linear array photodetector (3-7).

2. The pentaprism-based celestial target celestial surface verticality calibration device according to claim 1, characterized in that, The adjustable collimating light source (5) uses a theodolite or a bubble level in conjunction with a self-collimating collimator to obtain a horizontal laser beam.

3. The method for calibrating the verticality of the canopy surface of a canopy target based on a pentaprism as described in claim 2, characterized in that, Includes the following steps: Step 1: Place the target to be calibrated (3) on the ground and place the bubble level in the center of the upper surface of the target box (3-9) to ensure that it is stable and will not slide or rotate. Adjust the precision translation stage (3-4), the rotation stage (3-5), the support frame (3-3) and the rotation axis (3-8) by observing the bubble level to make the upper surface of the target level. Step 2: Place the autocollimating collimator on the central axis of the field of view of the celestial target (3), place the bubble level on the upper surface of the autocollimating collimator, and adjust the laser to be horizontal by observing the bubble level; Step 3: Fix the standard pentaprism (1) on the mechanical clamp (2), adjust the height of the autocollimating collimator so that the horizontal beam emitted by the autocollimating collimator illuminates the main section of the standard pentaprism (1); based on the optical principle of the standard pentaprism, the horizontal laser is deflected by 90° from the original incident direction after being reflected twice in the standard pentaprism (1), and is vertically illuminated on the upper surface of the canopy target box (3-9); Step 4, make the standard pentaprism (1) strictly rotate The axis is rotated to perform laser scanning. The laser scanning trajectory is observed, and the height of the self-collimating collimator is finely adjusted so that the laser scanning trajectory coincides with the laser coarse adjustment indicator frame (3-2). Step 5: Adjust and reduce the sweeping angle of the standard pentaprism (1) so that the linear sweeping trajectory of the emitted light on the upper surface of the sky target box (3-9) does not exceed the edge of the lens frame of the optical lens (3-1). The laser sweeping trajectory plane is the beam surface that can be detected by the linear array photodetector (3-7). At the same time, observe the output signal of the linear array photodetector (3-7). Step 6: Adjust the slit aperture (3-6) and the linear array photodetector (3-7). When the linear array photodetector (3-7) detects a continuous and uninterrupted light signal, it is determined that the laser sweep trajectory coincides with the slit aperture (3-6), thus completing the calibration of the sky screen target.

4. The method for calibrating the verticality of the canopy surface of a canopy target based on a pentaprism as described in claim 3, characterized in that, The length of the laser scanning trajectory is greater than the length of the slit aperture (3-6), and the size of the linear array photodetector (3-7) located below the slit aperture (3-6) is greater than the size of the slit aperture (3-6), ensuring that the light flux of the linear array photodetector (3-7) reaches its maximum value.

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