Optical axis consistency measuring method for receiving optical axis of laser range finder

Abstract

The invention discloses an optical axis consistency measuring method for a receiving optical axis of a laser range finder, which belongs to the field of calculation and comprises the following steps of: imaging an object in a laser receiving window through a beam splitter prism by using a short-wave infrared phase unit, closing a laser source, and imaging a visual aiming optical axis by using the short-wave infrared phase unit. The pixel difference between the center of the laser receiving optical axis and the center of the visual aiming optical axis is calculated, the optical axis deviation is calculated according to parameters such as the focal length of the lens and the pixel size, and the technical problem of measuring the optical axis deviation is solved. Errors caused by disassembly and the trouble of re-correction are avoided, the measurement process is simple and visual, tedious steps in measurement are reduced, optical axis consistency measurement can be rapidly completed, the measurement and correction speed is remarkably increased, and the use performance and stability of the laser range finder are improved.

Description

Technical Field

[0001] The invention belongs to the field of computing, and in particular relates to a method for measuring the optical axis consistency of a receiving optical axis of a laser rangefinder. Background Art

[0002] Modern complex optoelectronic devices integrate multiple optoelectronic sensors, such as television, infrared imaging, laser ranging, etc. Since these devices usually contain multiple optical systems, the optical axis consistency calibration between them becomes an important and complex issue, especially for laser ranging systems. The optical axis consistency of the laser rangefinder directly affects its performance, especially the maximum range.

[0003] The traditional method of measuring optical axis consistency has significant disadvantages:

[0004] 1. It is not possible to directly measure the deviation of the laser receiving optical axis, especially without disassembling the equipment.

[0005] 2. The calibration process is cumbersome and imprecise. For example, when removing devices such as avalanche tubes and narrow-band filters, new installation errors may be introduced, affecting the consistency of the optical axis.

[0006] 3. Insufficient calibration accuracy and lack of effective and quantitative measurement methods lead to unstable or unreliable test results. Summary of the invention

[0007] The purpose of the present invention is to provide a method for measuring the optical axis consistency of a receiving optical axis of a laser rangefinder, thereby solving the technical problem of measuring the optical axis deviation.

[0008] To achieve the above object, the present invention adopts the following technical solution:

[0009] A method for measuring the optical axis consistency of a receiving optical axis of a laser rangefinder comprises the following steps:

[0010] Step 1: Place the laser rangefinder to be tested on the stage assembly, and adjust the stage so that the laser receiving window is aligned with the light output / light input port of the measuring device;

[0011] Step 2: Select the preset laser power for the laser rangefinder to be tested and emit the laser, and the laser passes through the beam splitter prism group to evenly illuminate the laser receiving window;

[0012] Step 3: Use the short-wave infrared camera group to image the object in the laser receiving window through the beam splitter prism group, and adjust the postures of the short-wave infrared camera group, the laser rangefinder to be tested, and the beam splitter prism group to obtain a clear image of the laser receiving pinhole aperture of the laser rangefinder to be tested;

[0013] Step 4: The short-wave infrared camera group transmits the captured image of the laser receiving pinhole aperture to the image processing module, and the image processing module saves the image. The center of the laser receiving pinhole aperture in the image represents the laser receiving optical axis;

[0014] Step 5: Turn off the laser source, and use the short-wave infrared camera group to image the visual aiming scale in the laser receiving window to obtain a scale image; the scale center of the scale image represents the visual aiming optical axis; if there is no visual aiming scale, introduce the image of the collimator into the optical hinge group, and then transfer the image to the short-wave infrared camera group; the short-wave infrared camera group sends the visual aiming optical axis image to the image processing module;

[0015] Step 6: The image processing module calculates the pixel difference between the center of the laser receiving optical axis and the center of the visual aiming optical axis, calculates the optical axis deviation according to the lens focal length and the pixel size, and outputs the calculation result of the optical axis deviation;

[0016] Step 7: Replace the corresponding optical components according to different laser bands to adapt to different models of laser rangefinders being tested.

[0017] Preferably, the beam splitter prism assembly comprises a beam splitter prism, a beam splitter prism base and a light shield. The beam splitter prism is placed on the beam splitter prism base and is equipped with a light shield for preventing stray light. The beam splitter prism base is used to fine-tune the posture of the beam splitter prism.

[0018] Preferably, the laser rangefinder to be tested includes a laser head, a laser collimator, a laser adjustable power supply and a laser head holder, wherein the laser adjustable power supply is used to adjust the laser output power; the laser collimator is used to ensure that the light output by the laser head is parallel light; the laser head holder is used to fine-tune the attitude of the laser head, that is, to fine-tune the output laser direction; the laser head is used to emit laser;

[0019] Preferably, the short-wave infrared camera group comprises a short-wave infrared camera, a short-wave infrared lens, a camera base, a narrow-band color filter and a camera power supply; the short-wave infrared camera is placed on the camera base; the short-wave infrared lens is used for focusing; the narrow-band color filter is used for filtering images; and the camera base is used for fine-tuning the posture of the short-wave infrared camera;

[0020] Preferably, the image processing module is a host computer or a tablet computer.

[0021] Preferably, when executing step 6, the calculation formula for calculating the optical axis deviation according to the lens focal length and the pixel size is as follows:

[0022]

[0023] Among them, lP is the deviation, n is the number of pixels that deviate from the center of the laser receiving optical axis and the center of the visual aiming optical axis, d is the pixel size, and fa is the focal length of the short-wave infrared lens.

[0024] The optical axis consistency measurement method of the receiving optical axis of a laser rangefinder described in the present invention solves the technical problem of measuring the optical axis deviation. The present invention can provide high-precision optical axis consistency measurement through image measurement and optical axis deviation calculation. There is no need to disassemble the laser rangefinder, thus avoiding the error caused by disassembly and the trouble of re-calibration. The measurement process is simple and intuitive, reducing the cumbersome steps in the measurement, and can quickly complete the optical axis consistency measurement, significantly improving the measurement and correction speed, and improving the performance and stability of the laser rangefinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0026] like Figure 1 The method for measuring the optical axis consistency of a receiving optical axis of a laser rangefinder shown in the figure comprises the following steps:

[0027] Step 1: Place the laser rangefinder to be tested on the stage assembly, and adjust the stage so that the laser receiving window is aligned with the light output / light input port of the measuring device;

[0028] The laser rangefinder to be tested includes a laser head, a laser collimator, a laser adjustable power supply and a laser head holder. The laser adjustable power supply is used to adjust the laser output power; the laser collimator is used to ensure that the light output by the laser head is parallel light; the laser head holder is used to fine-tune the laser head posture, that is, fine-tune the output laser direction; the laser head is used to emit laser.

[0029] Step 2: Select the preset laser power for the laser rangefinder to be tested and emit the laser, and the laser passes through the beam splitter prism group to evenly illuminate the laser receiving window;

[0030] The beam splitter prism assembly comprises a beam splitter prism, a beam splitter prism base and a light shield. The beam splitter prism is placed on the beam splitter prism base and is equipped with a light shield for preventing stray light. The beam splitter prism base is used for fine-tuning the posture of the beam splitter prism.

[0031] Step 3: Use the short-wave infrared camera group to image the object in the laser receiving window through the beam splitter prism group, and adjust the postures of the short-wave infrared camera group, the laser rangefinder to be tested, and the beam splitter prism group to obtain a clear image of the laser receiving pinhole aperture of the laser rangefinder to be tested;

[0032] The short-wave infrared camera group comprises a short-wave infrared camera, a short-wave infrared lens, a camera base, a narrow-band color filter and a camera power supply; the short-wave infrared camera is placed on the camera base; the short-wave infrared lens is used for focusing; the narrow-band color filter is used for filtering images; and the camera base is used for fine-tuning the posture of the short-wave infrared camera.

[0033] Step 4: The short-wave infrared camera group transmits the captured image of the laser receiving pinhole aperture to the image processing module, and the image processing module saves the image. The center of the laser receiving pinhole aperture in the image represents the laser receiving optical axis;

[0034] The image processing module is a host computer or a tablet computer.

[0035] Step 5: Turn off the laser source, and use the short-wave infrared camera group to image the visual aiming scale in the laser receiving window to obtain a scale image; the scale center of the scale image represents the visual aiming optical axis; if there is no visual aiming scale, introduce the image of the collimator into the optical hinge group, and then transfer the image to the short-wave infrared camera group; the short-wave infrared camera group sends the visual aiming optical axis image to the image processing module;

[0036] In this embodiment, the optical hinge group is placed in front of the beam splitter group. When necessary, the image of the collimator or other optical division can be introduced into the optical hinge group and transferred to the short-wave infrared camera group with almost no deviation. If there is only a laser emission optical axis and no visual aiming optical axis, a visual aiming mirror can be added. First, the laser emission optical axis and the visual aiming optical axis can be aligned by using other devices through the imaging spots of the laser on the photographic paper, and then the image can be introduced.

[0037] Step 6: The image processing module calculates the pixel difference between the center of the laser receiving optical axis and the center of the visual aiming optical axis, calculates the optical axis deviation according to the lens focal length and the pixel size, and outputs the calculation result of the optical axis deviation;

[0038] When executing step 6, the calculation formula for calculating the optical axis deviation based on the lens focal length and pixel size is as follows:

[0039]

[0040] Among them, lP is the deviation, n is the number of pixels that deviate from the center of the laser receiving optical axis and the center of the visual aiming optical axis, d is the pixel size, and fa is the focal length of the short-wave infrared lens.

[0041] Step 7: Replace the corresponding optical components according to different laser bands to adapt to different models of laser rangefinders being tested.

[0042] For laser rangefinders with different laser bands, such as 1.06m laser rangefinder and 1.54m laser, the beam splitter, laser, collimator, narrow-band filter and other monomers of different bands can be replaced for adaptation.

[0043] In this embodiment, the beam splitter prism group, laser light source group, short-wave infrared camera group and optical hinge group are all placed on the same flat plate, and their optical paths need to be basically adjusted and aligned. When in use, they need to be used together with a stage group, a collimator group, etc.

[0044] The present invention provides a simple, intuitive and accurate measuring device and method without destroying the laser rangefinder body, and realizes the rapid measurement and high-precision interpretation of the optical axis consistency of the laser rangefinder receiving optical axis.

[0045] The following is an example of a specific application scenario of this embodiment:

[0046] Step S1: Installation and positioning of laser rangefinder: Place the laser rangefinder to be tested on the stage assembly, adjust the stage position and posture, and ensure that the laser receiving window of the rangefinder is basically aligned with the light output / light input of the device. This alignment ensures the precise alignment of the laser irradiation direction and the laser receiving window to avoid measurement errors.

[0047] The stage adjustment accuracy ensures that the laser beam can accurately illuminate the laser receiving window. Through precise alignment, the accuracy of the subsequent measurement is guaranteed, ensuring that there is no deviation between the laser and the laser receiving window.

[0048] Step S2: Laser emission and optical path adjustment: Select the appropriate laser power and emit the laser through the laser source group. The laser evenly illuminates the inside of the laser receiving window through the beam splitter prism to ensure that the laser spot size is uniform and covers the entire receiving area. The laser head holder, beam splitter prism base and stage can be adjusted to further optimize the beam irradiation angle and range.

[0049] The laser is evenly distributed through the beam splitter prism to ensure uniform light intensity distribution in the irradiated area, so as to obtain a clear and stable spot image in the subsequent imaging process. The angle and position of each component are adjusted to ensure that the laser accurately irradiates the receiving window.

[0050] Step S3: short-wave infrared camera imaging: using a short-wave infrared camera assembly, the laser receiving aperture diaphragm in the laser receiving window is imaged with the aid of a beam splitter prism. The short-wave infrared camera base, the beam splitter prism base, and the laser head holder can be adjusted to ensure that the laser receiving aperture diaphragm is located at the center of the camera image.

[0051] The image of the laser receiving window is transmitted to the short-wave infrared camera through the beam splitter prism to ensure that the laser receiving aperture diaphragm appears clearly in the center of the camera image. The quality and clarity of the image directly affect the subsequent measurement accuracy of the optical axis deviation.

[0052] Step S4: Camera focus and image optimization: Adjust the short-wave infrared camera lens for precise focus to ensure that the image of the laser receiving pinhole aperture is clearly visible. The center of the aperture in the image will represent the receiving optical axis of the laser rangefinder.

[0053] Focusing is to improve the image clarity and ensure that the center position of the laser receiving pinhole aperture is accurately obtained in the image. A clear image is essential for the subsequent accurate calculation of the optical axis deviation.

[0054] Step S5: Save the laser receiving optical axis image: Save the focused image, where the center of the laser receiving pinhole aperture in the image is the position of the laser receiving optical axis.

[0055] Step S6: Turn off the laser power and visual optical graticule imaging: Turn off the laser power, remove the narrow-band filter, and use the short-wave infrared camera group to image the visual optical graticule in the laser receiving window. If necessary, a visible light source (such as a flashlight) can be used for auxiliary lighting to ensure the clarity of the image.

[0056] The imaging of the visual optical graticule can help us determine the position of the visual aiming optical axis. By combining visible light illumination with infrared camera imaging, a clear and accurate optical axis image is ensured.

[0057] Step S7: Introduce the visual aiming optical axis image: If there is no ready-made visual optical graticule in the laser receiving window, a visual aiming graticule at another position can be introduced through an optical hinge and transferred to the short-wave infrared camera group. If the laser emission optical axis is inconsistent with the visual aiming optical axis, the visual sight can be adjusted to align the two, and then the visual aiming graticule can be introduced for measurement.

[0058] The step of introducing and transferring the visual aiming optical axis image ensures the accurate alignment of the optical axis. Through this step, a clear visual aiming optical axis image can be obtained, which is convenient for comparison and calculation with the laser receiving optical axis image.

[0059] Step S8: Save the visual aiming optical axis image: save the image containing the visual aiming optical axis, and the center of the aiming scale in the image is the position of the visual aiming optical axis.

[0060] Step S9: The pixel difference between the two optical axis centers is calculated by the measurement software, and the optical axis deviation can be calculated according to the lens focal length parameters, pixel size, etc. The calculation formula is as follows:

[0061]

[0062] Among them, lP is the deviation, n is the number of pixels that deviate from the center of the laser receiving optical axis and the center of the visual aiming optical axis, d is the pixel size, and fa is the focal length of the short-wave infrared lens.

[0063] Through the precise pixel difference calculation formula, the deviation between the laser receiving optical axis and the visual aiming optical axis can be quantified, ensuring the accuracy of optical axis consistency measurement.

[0064] Step S10: Outputting the optical axis deviation.

[0065] The optical axis consistency measurement method of the receiving optical axis of a laser rangefinder described in the present invention solves the technical problem of measuring the optical axis deviation. The present invention can provide high-precision optical axis consistency measurement through image measurement and optical axis deviation calculation. There is no need to disassemble the laser rangefinder, thus avoiding the error caused by disassembly and the trouble of re-calibration. The measurement process is simple and intuitive, reducing the cumbersome steps in the measurement, and can quickly complete the optical axis consistency measurement, significantly improving the measurement and correction speed, and improving the performance and stability of the laser rangefinder.

Claims

1. A method for measuring the optical axis consistency of a laser rangefinder receiving optical axis, characterized in that: The steps include: Step 1: Place the laser rangefinder to be tested on the stage assembly, and adjust the stage so that the laser receiving window is aligned with the light output / light input port of the measuring device; Step 2: Select the preset laser power for the laser rangefinder to be tested and emit the laser, and the laser passes through the beam splitter prism group to evenly illuminate the laser receiving window; Step 3: Use the short-wave infrared camera group to image the object in the laser receiving window through the beam splitter prism group, and adjust the postures of the short-wave infrared camera group, the laser rangefinder to be tested, and the beam splitter prism group to obtain a clear image of the laser receiving pinhole aperture of the laser rangefinder to be tested; Step 4: The short-wave infrared camera group transmits the captured image of the laser receiving pinhole aperture to the image processing module, and the image processing module saves the image. The center of the laser receiving pinhole aperture in the image represents the laser receiving optical axis; Step 5: Turn off the laser source, and use the short-wave infrared camera group to image the visual aiming scale in the laser receiving window to obtain a scale image; the scale center of the scale image represents the visual aiming optical axis; if there is no visual aiming scale, introduce the image of the collimator into the optical hinge group, and then transfer the image to the short-wave infrared camera group; the short-wave infrared camera group sends the visual aiming optical axis image to the image processing module; Step 6: The image processing module calculates the pixel difference between the center of the laser receiving optical axis and the center of the visual aiming optical axis, calculates the optical axis deviation according to the lens focal length and the pixel size, and outputs the calculation result of the optical axis deviation; Step 7: Replace the corresponding optical components according to different laser bands to adapt to different models of laser rangefinders being tested.

2. The method for measuring the optical axis consistency of the receiving optical axis of a laser rangefinder according to claim 1, characterized in that: The beam splitter prism assembly comprises a beam splitter prism, a beam splitter prism base and a light shield. The beam splitter prism is placed on the beam splitter prism base and is equipped with a light shield for preventing stray light. The beam splitter prism base is used to fine-tune the posture of the beam splitter prism to ensure accurate guidance of the light path.

3. The method for measuring the optical axis consistency of a laser rangefinder receiving optical axis according to claim 1, characterized in that: The laser rangefinder to be tested includes a laser head, a laser collimator, a laser adjustable power supply and a laser head holder. The laser adjustable power supply is used to adjust the laser output power; the laser collimator is used to ensure that the light output by the laser head is parallel light; the laser head holder is used to fine-tune the laser head posture, that is, fine-tune the output laser direction; the laser head is used to emit laser.

4. The method for measuring the optical axis consistency of a laser rangefinder receiving optical axis according to claim 1, characterized in that: The short-wave infrared camera group comprises a short-wave infrared camera, a short-wave infrared lens, a camera base, a narrow-band color filter and a camera power supply; the short-wave infrared camera is placed on the camera base; the short-wave infrared lens is used for focusing; the narrow-band color filter is used for filtering images; and the camera base is used for fine-tuning the posture of the short-wave infrared camera.

5. The method for measuring the optical axis consistency of the receiving optical axis of a laser rangefinder according to claim 1, characterized in that: The image processing module is a host computer or a tablet computer.

6. The method for measuring the optical axis consistency of the receiving optical axis of a laser rangefinder according to claim 1, characterized in that: When executing step 6, the calculation formula for calculating the optical axis deviation based on the lens focal length and pixel size is as follows: Among them, lP is the deviation, n is the number of pixels that deviate from the center of the laser receiving optical axis and the center of the visual aiming optical axis, d is the pixel size, and fa is the focal length of the short-wave infrared lens.

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