Optical axis calibration device based on reference light

Abstract

The utility model discloses a kind of optical axis calibration devices based on reference light, belong to optical measurement technical field.It includes: adjustable fast mirror module, including the electric adjustable component for adjusting the light direction of measured and the fast mirror connected with it;Reference light module, including reference light generator and the light splitter for adjusting the direction of reference light;Splitting module, including light splitting component, adjustable filter component and mirror component;Measuring module, including camera, the detector for detecting the position of light beam on camera target surface and the data processor for obtaining the offset of light beam on camera target surface, the data processor makes electric adjustable component according to offset adjustment fast mirror's yaw, to control the closed loop of measured light to same offset position.The utility model can correct the optical axis offset phenomenon that optical axis camera occurs, and the optical path design of this calibration device is simple, easy to realize, and it is convenient, fast to adjust and calibrate, and it is less to complete the required components of adjustment and calibration, low in cost.

Description

Technical Field

[0001] This utility model relates to the field of optical calibration technology, specifically to an optical axis calibration device based on reference light. Background Technology

[0002] After a period of operation, or in environments with excessively high temperatures, cameras are prone to optical axis drift, leading to decreased image quality or uneven image sharpness. By monitoring the optical axis offset and adjusting the incident angle of the measured light accordingly, optical axis calibration can be achieved, improving the image quality of the measured light on the camera's target surface.

[0003] In the prior art, patent CN117492219A discloses a device and method for optimizing beam combining quality in a pump detection system based on a single camera, comprising: a beam directivity adjustment module, including an electrically adjustable component for adjusting the directivity of the light being modulated and a beam combining component for combining the light being modulated and a reference light; a first beam splitting component for dividing the beam combining optical path into a first optical path and a second optical path; a beam directivity measurement module including a detachable filter component, a second beam splitting component, an optical path delay component, a rotatable fan blade, a beam compression component, and a camera; the second optical path, after entering the second beam splitting component, is divided into a first beam splitting beam and a second beam splitting beam with equal energy, the second beam splitting beam being delayed by the optical path delay component and then traveling parallel to the first beam splitting beam, the fan blade rotating so that the first beam splitting beam and the second beam splitting beam hit the camera at different times after passing through the beam compression component; and a control unit connected to the electrically adjustable component and the camera.

[0004] To improve the beam combining quality of pump and probe beams in pump measurements, the aforementioned patent uses one beam as a reference beam, quantitatively monitors the deviation between the other beam and the reference beam, and adjusts the directivity of the modulated beam based on the position of the reference beam to ensure it aligns with the reference beam. While this patent uses a reference beam for beam combining calibration, it suffers from drawbacks such as complex optical path design, numerous required calibration components, and inconvenient adjustment. Utility Model Content

[0005] This invention aims to solve the problem of complex optical path design in existing beam calibration devices. It proposes an optical axis calibration device based on a reference light. This device can correct the optical axis offset phenomenon caused by temperature rise in the optical axis camera. The device also has the advantages of simple and easy-to-implement optical path design, convenient and fast adjustment.

[0006] To achieve the above-mentioned objectives, the technical solution of this utility model is as follows:

[0007] An optical axis calibration device based on a reference light, comprising:

[0008] Adjustable fast-reflecting mirror module, including an electrically adjustable component for adjusting the directionality of the light being measured and a fast-reflecting mirror connected thereto;

[0009] The reference light module includes a reference light generator and a beam splitter for adjusting the directivity of the reference light;

[0010] The beam splitting module includes a beam splitter assembly, an adjustable filter assembly, and a mirror assembly. The beam splitter assembly is used to split light from a beam splitter or fast-reflecting mirror into two beams with different propagation paths. The adjustable filter assembly is respectively set on the propagation paths of the two beams, and can be switched to achieve three levels: complete cutoff of the beams, allowing only the measured light to pass through, and allowing only the reference light to pass through. The mirror assembly is used to adjust the directivity of the beams after passing through the adjustable filter assembly, so that after passing through the beam splitter assembly and the mirror assembly, they hit the camera target surface.

[0011] The measurement module includes a camera, a detector for detecting the position of a light beam on the camera target surface, and a data processor for acquiring the offset of a reference light on the camera target surface. The data processor is connected to an electrically adjustable component, which adjusts the sway of the fast-reflecting mirror according to the offset.

[0012] Preferably, the beam splitting component is a second folding mirror that is partially transparent and partially reflective to both the reference light and the light being measured. The second folding mirror splits the light being measured or the reference light into a first beam on the beam transmission path and a second beam on the beam reflection path.

[0013] Preferably, the filtering assembly includes a filter A disposed on the beam transmission path and a filter B disposed on the beam reflection path.

[0014] Preferably, the reflector assembly includes a first total reflection mirror disposed on the beam transmission path and a second total reflection mirror disposed on the beam reflection path; the first total reflection mirror and the second total reflection mirror are reflectors that reflect the measured light and the reference light from one side.

[0015] Preferably, the reflecting surfaces of the first and second total reflection mirrors are deflected at a certain angle from the incident direction of the light after the light is filtered by the light assembly. This deflection angle ensures that the incident light does not return to the emitter along the original light path.

[0016] Preferably, the beam incident front end of the second folding mirror is further provided with a first folding mirror for changing the transmission direction of the measured light and the reference light, and the first folding mirror and the second folding mirror are arranged in parallel and spaced apart.

[0017] Preferably, the fast reflector, beam splitter, and first folding mirror are on the same horizontal plane, and the beam splitter is a reflector that is fully transparent to the light being measured and partially transparent and partially reflective to the reference light.

[0018] Preferably, the frames of the fast-reflecting mirror, beam splitter, second folding mirror, first total reflection mirror, and second total reflection mirror are made of Invar steel.

[0019] The working principle of this calibration device is as follows:

[0020] In the first stage: the fast-reflecting mirror is adjusted to zero, and a second reference light is emitted towards the beam splitter. After being reflected by the beam splitter, the second reference light enters the beam splitting module and is split into two beams with different propagation paths (light reflection path and light refraction path). The adjustable filter component on the light transmission path is controlled to the full cut-off position to cut off the first beam. The adjustable filter component on the light reflection path is controlled to the position that only allows the reference light to pass through, so that the second beam passes through the adjustable filter component and hits the mirror assembly. At this time, by adjusting the mirror assembly, the second beam passes through the beam splitting assembly and the mirror group, forming a light spot on one side of the center line of the camera target surface.

[0021] The second reference beam is turned off, and the first reference beam is emitted towards the fast-reflecting mirror. After being reflected by the fast-reflecting mirror, the first reference beam passes through the beam splitter and then enters the beam splitting module, splitting into two beams with different propagation paths. The adjustable filter component on the light reflection path is controlled to the full cutoff position to cut off the second beam splitting. The adjustable filter component on the light transmission path is controlled to the position that only allows the reference beam to pass through, so that the first beam splitting passes through the adjustable filter component and hits the mirror assembly. At this time, by adjusting the mirror assembly, the first beam splitting passes through the beam splitting assembly and the mirror group and hits the other side of the center line of the camera target surface, forming a second light spot.

[0022] In the second stage: turn off the first reference light, emit the light to be measured into the fast mirror, switch the adjustable filter component on the light transmission path to the setting that only allows the light to be measured to pass through, and then adjust the fast mirror to close the loop to the position of the second spot formed by the first reference light on the camera target surface.

[0023] In the third stage: Before use, turn on the second reference light. If the optical axis of the second reference light is offset, the measurement module measures the amount of optical axis offset and feeds the offset back to the electrically adjustable component to control the fast-reflecting mirror to make the measured light close the loop to the offset position.

[0024] In summary, this utility model has the following advantages:

[0025] This invention's calibration device measures the offset of a reference light, causing the measured light to close the loop to the offset position. This calibrates the optical axis misalignment phenomenon of an optical axis camera, thereby improving environmental adaptability. The calibration device features a simple and easy-to-implement optical path design, convenient and fast calibration, requires few components, and is low in cost. Attached Figure Description

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments, wherein:

[0027] Figure 1 This is a schematic diagram of the optical path of the calibration device;

[0028] Figure 2 This is a schematic diagram showing the results of the first stage of calibration using this calibration device;

[0029] Figure 3 This is a schematic diagram showing the results of the second stage of calibration using this calibration device;

[0030] Figure 4 This is a schematic diagram showing the results of the third stage of calibration using this calibration device.

[0031] In the picture:

[0032] 1. Quick-reflecting mirror, 2. Beam splitter, 3. First folding mirror, 4. Second folding mirror, 5. Filter A, 6. Filter B, 7. First total reflection mirror, 8. Second total reflection mirror, 9. Optical axis camera, 10. Data processor, 11. Crosshair reference line, 12. Spot 1, 13. Spot 2, 14. Target area A, 15. Target area B. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0035] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0036] Example 1

[0037] This embodiment provides an optical axis calibration device based on a reference light, see, for example... Figure 1The optical path diagram shown indicates that the calibration device includes an adjustable fast mirror module, a reference light module, a beam splitter module, and a measurement module.

[0038] The adjustable fast-reflecting mirror module includes an electrically adjustable component for adjusting the directionality of the measured light and a fast-reflecting mirror 1 connected thereto. Based on the electrically adjustable component, the fast-reflecting mirror 1 has two-dimensional oscillation around its major and minor axes, as well as a closed-loop function for off-target measurement. The fast-reflecting mirror 1 can perform total internal reflection of the measured light, and the reflection angle of the measured light can be adjusted by rotation.

[0039] The reference light module includes a reference light generator and a beam splitter 2 for adjusting the directivity of the reference light. The beam splitter 2 is a reflector that is fully transparent to the light being measured and partially transparent and partially reflective to the reference light.

[0040] The beam splitting module includes a beam splitter assembly, an adjustable filter assembly, and a mirror assembly. The beam splitter assembly is used to split light from a beam splitter or fast-reflecting mirror into two beams with different propagation paths. The adjustable filter assembly is set on the propagation paths of the two beams and can be switched to achieve three levels: complete cutoff of the beams, allowing only the measured light to pass through, and allowing only the reference light to pass through. The mirror assembly is used to adjust the directivity of the beams after passing through the adjustable filter assembly, so that after passing through the beam splitter assembly and the mirror assembly, they hit the camera target surface.

[0041] The measurement module includes a camera, a detector for detecting the position of the light beam on the camera target surface, and a data processor 10 for acquiring the offset of the reference light on the camera target surface. The data processor 10 is connected to an electrically adjustable component, which adjusts the sway of the fast-reflecting mirror 1 according to the offset.

[0042] The working principle of this calibration device is as follows:

[0043] In the first stage: the fast-reflecting mirror 1 is adjusted to the zero position, and the second reference light is emitted to the beam splitter 2. After being reflected by the beam splitter 2, the second reference light enters the beam splitting module and is split into two beams with different propagation paths (light reflection path and light refraction path); the adjustable filter component on the light transmission path is controlled to the full cut-off position to cut off the first beam; the adjustable filter component on the light reflection path is controlled to the position that only allows the reference light to pass through, so that the second beam passes through the adjustable filter component and hits the mirror assembly; at this time, by adjusting the mirror assembly, the second beam passes through the beam splitting assembly and the mirror group, and forms a light spot on one side of the center line of the camera target surface;

[0044] The second reference beam is turned off, and the first reference beam is emitted to the fast-reflecting mirror 1. After being reflected by the fast-reflecting mirror 1, the first reference beam passes through the beam splitter 2 and then enters the beam splitting module, where it is split into the first beam and the second beam with different propagation paths. The adjustable filter component on the light reflection path is controlled to the full cut-off position to cut off the second beam. The adjustable filter component on the light transmission path is controlled to the position that only allows the reference beam to pass through, so that the first beam passes through the adjustable filter component and hits the mirror assembly. At this time, by adjusting the mirror assembly, the first beam passes through the beam splitting assembly and the mirror group and hits the other side of the center line of the camera target surface, forming the second spot.

[0045] In the second stage: turn off the first reference light, emit the light to be measured into the fast mirror 1, switch the adjustable filter component on the light transmission path to the setting that only allows the light to be measured to pass through, and then adjust the fast mirror 1 to close the loop to the position of the second spot formed by the first reference light on the camera target surface.

[0046] In the third stage: Before use, turn on the second reference light. If the optical axis of the second reference light is offset, the measurement module measures the amount of optical axis offset and feeds the offset back to the electrically adjustable component to control the swing of the fast-reflecting mirror 1 so that the measured light is closed-loop to the offset position.

[0047] This invention relates to an optical axis calibration device based on a reference light. By measuring the offset of the reference light, the measured light is brought to the offset position (producing the same offset) to calibrate the optical axis misalignment phenomenon of the optical axis camera, thereby improving environmental adaptability. The optical path design of this calibration device is simple and easy to implement, and the adjustment is convenient and fast. It requires few components to complete the adjustment and has low cost.

[0048] Example 2

[0049] Based on the optical axis calibration device based on reference light in Embodiment 1, this embodiment further describes each module in detail.

[0050] In this embodiment, the beam splitting component is a second folding mirror 4 that is partially transparent and partially reflective to both the reference light and the light being measured. This second folding mirror 4 splits the reference light or the light being measured into a first beam on the beam transmission path and a second beam on the beam reflection path.

[0051] In this embodiment, the reflector assembly includes a first total reflection mirror 7 and a second total reflection mirror 8, which are located on the beam transmission path and beam reflection path of the second folding mirror 4, respectively. The first total reflection mirror 7 and the second total reflection mirror 8 are reflectors capable of reflecting both the reference light and the measured light from one side.

[0052] In this embodiment, the adjustable filtering assembly includes filter A5 and filter B6. Filter A5 is disposed on the beam transmission path of the second folding mirror 4, located between the second folding mirror 4 and the first total reflection mirror 7; filter B6 is disposed on the beam reflection path of the second folding mirror 4, located between the second folding mirror 4 and the second total reflection mirror 8. In this scheme, both filter A5 and filter B6 have three settings: complete cutoff of beam splitting, allowing only the measured light to pass through, and allowing only the reference light to pass through.

[0053] Preferably, the first total reflection mirror 7 and the second total reflection mirror 8 deflect the incident light wave after it has passed through the filter light assembly at a certain angle to prevent the incident light wave from returning along its original path and causing damage to the light emitter.

[0054] Preferably, in this design, the frames of the fast-reflecting mirror 1, the beam splitter 2, the second folding mirror 4, the first total reflection mirror 7, and the second total reflection mirror 7 are made of Invar steel, which has an extremely low coefficient of thermal expansion, so that the mirrors are minimally affected by temperature.

[0055] In this solution, the measurement module includes an optical axis camera 9, a detector, and a data processor 10.

[0056] like Figure 2 As shown, the target surface of the optical axis camera 9 is aligned with the center line ( Figure 2 The target surface is divided into two regions, A and B, with the dashed line in the image as the axis. These regions are used to receive the light spots formed by the first and second beams after passing through the second folding mirror 4, respectively. Preferably, the two regions of the camera target surface are provided with crosshairs symmetrical about the center line. To improve the calibration effect, the camera should be correctly installed (the center of the camera target surface and the center of the lens group should be kept on the same line as much as possible). In the first stage of installation and adjustment, the light spots formed by the first and second reference lights on the target surface should be made to coincide as much as possible with the corresponding crosshairs. The detector is used to detect the center position parameter of the light spot formed by the beam on the camera target surface. The data processor 10 is connected to the optical axis camera 9 and the detector and is used to obtain the offset of the reference light on the camera target surface based on the center position parameter of the light spot detected by the detector. The data processor 10 is also connected to the electrically adjustable component of the fast-reflecting mirror 1 and is used to send the optical axis offset of the reference light to the electrically adjustable component of the fast-reflecting mirror 1, so that the electrically adjustable component adjusts the tilt of the fast-reflecting mirror 1 according to the offset, thereby controlling the measured light to close the loop to the offset position.

[0057] The working process of the calibration device of this utility model is as follows:

[0058] The working principle of this calibration device is as follows:

[0059] In the first stage: the fast-reflecting mirror 1 is adjusted to the zero position, and the second reference light is emitted to the beam splitter 2. After being reflected by the beam splitter 2, the second reference light enters the second folding mirror 4 and is split into two beams with different propagation paths. The filter A5 on the light transmission path is controlled to the full cut-off position to cut off the first beam. The filter B6 on the light reflection path is controlled to the position that only allows the reference light to pass through, so that the second beam passes through the filter B6 and hits the second total reflection mirror 8. At this time, by adjusting the second total reflection mirror 8, the second beam passes through the second folding mirror 4 and the mirror group and hits the crosshair reference line 11 of the camera target area B 15 to form a spot 12. The position parameters of the spot 12 are recorded.

[0060] The second reference beam is turned off, and the first reference beam is emitted to the fast-reflecting mirror 1. After being reflected by the fast-reflecting mirror 1, the first reference beam passes through the beam splitter 2 and enters the second folding mirror 4, splitting into two beams with different propagation paths. The filter B6 on the light reflection path is controlled to the full cut-off position to cut off the second beam. The filter A5 on the light transmission path is controlled to the position that only allows the reference beam to pass through, so that the first beam passes through the filter A4 and hits the first total reflection mirror 7. At this time, by adjusting the first total reflection mirror 7, the first beam passes through the second folding mirror 4 and the mirror group and hits the crosshair reference line 11 on the camera target surface A area 14 to form a second spot 13. The position parameters of the second spot are recorded.

[0061] At this stage, due to certain assembly and adjustment errors, spot 12 and spot 23 may not be centered on the two crosshair reference lines 11 in the target field of view. Figure 2 As shown.

[0062] In the second stage: turn off the first reference light, emit the light to be measured into the fast-reflecting mirror 1, switch the adjustable filter component on the light transmission path to a setting that only allows the light to be measured to pass through, and then adjust the fast-reflecting mirror 1 to close the loop to the position of the second light spot formed by the first reference light on the camera target surface, such as... Figure 3 As shown.

[0063] In the third stage: Before use, turn on the second reference beam. If the optical axis of the second reference beam shifts, the position of the corresponding spot formed on the target surface will also shift, such as... Figure 4 As shown. At this time, the offset pixel coordinates are obtained through the camera's optical axis detector and fed back to the data processor 10. These coordinates are compared with the original center position parameters of the offset light spot to obtain the horizontal miss distance as Δx and the vertical miss distance as Δy. These two miss distances are fed back to the electrically adjustable component of the fast-reflecting mirror 1 to control the tilt of the fast-reflecting mirror 1, so that the measured light is closed-loop to the offset position, as shown. Figure 4 As shown.

[0064] Example 3

[0065] Based on Embodiment 1 or Embodiment 2, in order to optimize the layout space of this calibration device, the beam incident front end of the second folding mirror 4 is further provided with a first folding mirror 3 for changing the transmission direction of the measured light and the reference light. The first folding mirror 3 is a reflector capable of reflecting the reference light and the measured light on one side to the whole, and is used to change the beam direction of the measured light and the reference light and guide them to the second folding mirror 4 in the beam splitting module.

[0066] Preferably, the first folding mirror 3 and the second folding mirror 4 are arranged in parallel and spaced apart, the fast-reflecting mirror 1, the beam splitter 2, and the first folding mirror 3 are arranged at intervals on the same horizontal plane, and the beam splitter 2 is located between the fast-reflecting mirror 1 and the first folding mirror 3.

[0067] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. An optical axis calibration device based on a reference light, characterized in that, include: The adjustable fast-reflecting mirror module includes an electrically adjustable component for adjusting the directionality of the light being measured and a fast-reflecting mirror connected thereto (1). The reference light module includes a reference light generator and a beam splitter for adjusting the directivity of the reference light (2); The beam splitting module includes a beam splitting component, an adjustable filter component, and a mirror component. The beam splitting component is used to split the light from the beam splitter (2) or the fast reflector (1) into two beams with different propagation paths. The adjustable filter component is respectively set on the propagation paths of the two beams and can be switched to achieve three levels: complete cut-off of the beams, allowing only the measured light to pass through, and allowing only the reference light to pass through. The mirror component is used to adjust the directivity of the beams after passing through the adjustable filter component, so that after passing through the beam splitting component and the mirror group, they hit the camera target surface. The measurement module includes a camera, a detector for detecting the position of a beam on the camera target surface, and a data processor (10) for acquiring the offset of a reference beam on the camera target surface. The data processor (10) is connected to an electrically adjustable component, which adjusts the sway of the fast-reflecting mirror (1) according to the offset.

2. The optical axis calibration device based on reference light as described in claim 1, characterized in that, The beam splitting component is a second folding mirror (4) that is semi-transparent and semi-reflective to the reference light and the light to be measured. The second folding mirror (4) splits the light to be measured or the reference light into a first beam on the beam transmission path and a second beam on the beam reflection path.

3. The optical axis calibration device based on reference light as described in claim 2, characterized in that, The filtering assembly includes a filter A (5) disposed on the beam transmission path and a filter B (6) disposed on the beam reflection path.

4. The optical axis calibration device based on reference light as described in claim 2, characterized in that, The reflector assembly includes a first total reflection mirror (7) arranged on the beam transmission path and a second total reflection mirror (8) arranged on the beam reflection path; the first total reflection mirror (7) and the second total reflection mirror (8) are reflectors that reflect the measured light and the reference light from one side.

5. The optical axis calibration device based on a reference light as described in claim 4, characterized in that, The reflecting surfaces of the first total reflection mirror (7) and the second total reflection mirror (8) are deflected at a certain angle from the incident direction of the light after the light is filtered by the light assembly. This deflection angle prevents the incident light from returning to the light generator along the original light path.

6. The optical axis calibration device based on a reference light as described in claim 2, characterized in that, The beam incident front end of the second folding mirror (4) is also provided with a first folding mirror (3) for changing the transmission direction of the measured light and the reference light. The first folding mirror (3) and the second folding mirror (4) are arranged in parallel and spaced apart.

7. The optical axis calibration device based on a reference light as described in claim 6, characterized in that, The fast reflector (1), beam splitter (2) and first folding mirror (3) are on the same horizontal plane. The beam splitter (2) is a reflector that is fully transparent to the light being measured and partially transparent and partially reflective to the reference light.

8. The optical axis calibration device based on a reference light as described in claim 4, characterized in that, The frames of the fast-reflecting mirror (1), beam splitter (2), second folding mirror (4), first total reflection mirror (7), and second total reflection mirror (8) are made of Invar steel.

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