Double-camera coaxial visual displacement measuring device

Abstract

The utility model relates to the technical field of visual displacement measurement, in particular to a double-camera coaxial visual displacement measuring device. The device comprises a beam splitter prism, a first camera and a second camera, the beam splitter prism is arranged in front of a measurement target and divides a target light beam emitted by the measurement target into a reflection light beam and a transmission light beam which are perpendicular to each other; the first camera is arranged on the reflected light beam; and the second camera is arranged on the transmitted light beam. According to the utility model, double-camera coaxial imaging can be realized, the displacement measurement precision is improved, and the problem of low displacement measurement precision caused by imaging aberration of the existing double-camera visual system installed in parallel is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of visual displacement measurement, in particular to a dual-camera coaxial visual displacement measurement device. Background Art

[0002] Visual displacement measurement is a new monitoring technology that uses non-contact sensors to track targets in videos or images and obtain structural displacement. It has shown good application prospects in the context of the rapid development of computer vision technology. At present, all visual displacement measurement methods assume that the system is stable and unaffected by temperature during the measurement process, and then use the first frame of the image sequence as a reference to calculate the relative displacement of the target. However, in actual displacement monitoring applications, it is impractical to always keep the camera stable (no unstable camera movement) or avoid the influence of temperature changes. For example, the camera's own weight, changes in wind force and wind direction, thermal expansion of the supporting structure, and ground vibration can all cause the camera to move unnecessarily; the thermal effect of the image sensor caused by temperature changes can also cause the image to deform. Academia and industry have studied and developed many methods for correcting the instability errors of visual displacement measurement systems. Among them, the dual-camera visual displacement measurement method is one of the commonly used and effective methods.

[0003] The dual-camera visual displacement measurement method uses two cameras installed in parallel to capture the deformation area of ​​the monitoring target and the stable area outside the monitoring target respectively, so as to use the displacement monitoring information of the stable area and the relative position relationship of the two cameras, and use differential calculation to eliminate the instability error of the visual displacement measurement system and improve the visual displacement measurement accuracy. However, the existing dual-camera visual displacement measurement system adopts the design of installing two cameras in parallel, which leads to certain aberrations in the horizontal or vertical directions of the imaging of the two cameras, that is, the imaging of the two cameras is not on the same axis. For details, see Figure 1 , the image B1 on the right side of the image center axis B is the image of the right camera installed in parallel, and the image B2 on the left side of the image center axis is the image of the left camera installed in parallel. It can be clearly seen that the images of the two cameras are not on the same axis and there is obvious aberration; this aberration will amplify the lens distortion and thus reduce the displacement measurement accuracy of the dual-camera vision system.

[0004] In summary, it is necessary to provide a dual-camera coaxial visual displacement measurement device to solve the problem of low displacement measurement accuracy caused by imaging aberration in the existing dual-camera visual system installed in parallel. Utility Model Content

[0005] The utility model aims to provide a dual-camera coaxial visual displacement measurement device, and the specific technical scheme is as follows:

[0006] A dual-camera coaxial visual displacement measuring device comprises a dichroic prism, a first camera and a second camera; the dichroic prism is arranged in front of a measurement target and divides a target light beam emitted by the measurement target into a vertical reflected light beam and a transmitted light beam; the first camera is arranged on the reflected light beam; and the second camera is arranged on the transmitted light beam.

[0007] Optionally, the beam splitter prism is a visible light beam splitter prism.

[0008] Optionally, the first camera and the second camera use the same type of image sensor and lens.

[0009] Optionally, the reflected light beam covers the field of view of the first camera.

[0010] Optionally, the transmitted light beam covers the field of view of the second camera.

[0011] Optionally, the ratio of the amount of reflected light of the reflected light beam to the amount of transmitted light of the transmitted light beam is 1:1.

[0012] Optionally, the distance between the optical center position of the lens of the first camera and the beam splitting prism is less than or equal to 450 mm.

[0013] Optionally, the distance between the optical center position of the lens of the second camera and the beam splitter prism is less than or equal to 450 mm.

[0014] Optionally, the dual-camera coaxial visual displacement measurement device also includes a mounting bracket; the mounting bracket includes a connecting frame, a first mounting seat and a second mounting seat; the first mounting seat is connected to the second mounting seat via the connecting frame; the first camera is set on the first mounting seat; the second camera is set on the second mounting seat.

[0015] Optionally, the mounting bracket further includes a third mounting seat; the third mounting seat is connected to the connecting frame; and the beam splitter prism is arranged on the third mounting seat.

[0016] The application of the technical solution of the utility model has at least the following beneficial effects:

[0017] The utility model provides a dual-camera coaxial visual displacement measuring device, which adopts a dichroic prism arranged in front of a measurement target to divide a target light beam emitted by the measurement target into a vertical reflected light beam and a transmitted light beam; a first camera is arranged on the reflected light beam; and a second camera is arranged on the transmitted light beam to achieve dual-camera coaxial imaging, improve displacement measurement accuracy, and solve the problem of low displacement measurement accuracy caused by imaging aberration in the existing parallel-mounted dual-camera visual system.

[0018] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0020] Figure 1 It is a schematic diagram of imaging of an existing dual-camera visual system installed in parallel in the background technology;

[0021] Figure 2 This is a schematic structural diagram of a dual-camera coaxial visual displacement measurement device in an embodiment of the utility model;

[0022] Figure 3 This is a schematic diagram of the working process of a dual-camera coaxial visual displacement measurement device in an embodiment of the utility model;

[0023] Figure 4 This is a schematic diagram of imaging of a dual-camera coaxial visual displacement measurement device in an embodiment of the utility model;

[0024] Among them, 1, beam splitter, 2, first camera, 3, second camera, 4, mounting bracket, 4.1, connecting frame, 4.2, first mounting seat, 4.3, second mounting seat, 4.4, third mounting seat, A, measurement target; B, image center axis, B1, right image, B2, left image, C, first image, D, second image, W1, target beam, W2, reflected beam, W3, transmitted beam. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the utility model.

[0026] Example:

[0027] See also Figure 2 and Figure 3A dual-camera coaxial visual displacement measuring device comprises a dichroic prism 1, a first camera 2 and a second camera 3; the dichroic prism 1 is arranged in front of a measuring target A, specifically 30 m in front of the measuring target A, to divide a target beam W1 emitted by the measuring target A into a vertical reflected beam W2 and a transmitted beam W3; the first camera 2 is arranged on the reflected beam W2; the second camera 3 is arranged on the transmitted beam W3.

[0028] The beam splitter prism 1 is a visible light beam splitter prism 1 , and has a size of 50 mm×50 mm×50 mm.

[0029] The first camera 2 and the second camera 3 use the same type of image sensor and lens; the size of the image sensor is 1 / 1.7 inches, and the resolution of the image sensor is 0.00185 mm / pixel; the lens imaging parameters of the first camera 2 and the second camera 3 are consistent, and the focal length used is 50 mm.

[0030] The reflected light beam W2 covers the field of view of the first camera 2 , thereby ensuring the imaging quality of the first camera 2 .

[0031] The transmitted light beam W3 covers the field of view of the second camera 3 , thereby ensuring the imaging quality of the second camera 3 .

[0032] The ratio of the reflected light amount of the reflected light beam W2 to the transmitted light amount of the transmitted light beam W3 is 1:1, that is, the reflected light amount and the transmitted light amount are both 50% of the total incoming light amount, achieving equal division of light amount, ensuring that the imaging brightness of the first camera and the second camera is consistent, and improving measurement accuracy.

[0033] The distance between the optical center of the lens of the first camera 2 and the beam splitter prism 1 is less than or equal to 450 mm, so that the reflected light beam W2 covers the field of view of the first camera 2, thereby avoiding interference from external light beams and ensuring the imaging quality of the first camera 2.

[0034] The distance between the optical center of the lens of the second camera 3 and the beam splitter prism 1 is less than or equal to 450 mm, so that the transmitted light beam W3 covers the field of view of the second camera 3 , thereby avoiding interference from external light beams and ensuring the imaging quality of the second camera 3 .

[0035] See also Figure 2The dual-camera coaxial visual displacement measurement device also includes a mounting bracket 4; the mounting bracket 4 includes a connecting frame 4.1, a first mounting seat 4.2 and a second mounting seat 4.3; the first mounting seat 4.2 is connected to the second mounting seat 4.3 through the connecting frame 4.1; the first camera 2 is arranged on the first mounting seat 4.2, which is convenient for fixing the first camera 2 to avoid imaging errors caused by shaking; the second camera 3 is arranged on the second mounting seat 4.3, which is convenient for fixing the second camera 3 to avoid imaging errors caused by shaking.

[0036] The mounting bracket 4 further comprises a third mounting seat 4.4; the third mounting seat 4.4 is connected to the connecting frame 4.1; the beam splitter prism 1 is arranged on the third mounting seat 4.4, so as to fix the beam splitter prism 1 and avoid imaging errors caused by shaking.

[0037] The imaging principle of the dual-camera coaxial visual displacement measurement device is as follows:

[0038] See also Figure 3 and Figure 4 , a beam splitter prism 1 is arranged in front of the measuring target A, and the target beam W1 emitted by the measuring target A is divided into a vertical reflected beam W2 and a transmitted beam W3; a first camera 2 is arranged on the reflected beam W2; and a second camera 3 is arranged on the transmitted beam W3 to realize dual-camera coaxial imaging; specifically, in Figure 4 In the figure, B is the central axis of the image, and the first image C formed by the first camera 2 is approximately coaxial with the second image D formed by the second camera 3. This shows that the dual-camera coaxial visual displacement measurement device composed of the first camera 2, the second camera 3 and the beam splitter prism 1 in this embodiment can realize dual-camera coaxial imaging, improve the displacement measurement accuracy, and solve the problem of low displacement measurement accuracy caused by imaging aberration in the existing parallel-mounted dual-camera visual system.

[0039] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A dual-camera coaxial visual displacement measurement device, characterized in that: The invention comprises a beam splitter prism (1), a first camera (2) and a second camera (3); the beam splitter prism (1) is arranged in front of a measurement target (A) to split a target light beam (W1) emitted by the measurement target (A) into a vertical reflection light beam (W2) and a transmission light beam (W3); the first camera (2) is arranged on the reflection light beam (W2); and the second camera (3) is arranged on the transmission light beam (W3).

2. The dual-camera coaxial visual displacement measurement device according to claim 1, characterized in that: The beam splitter prism (1) is a visible light beam splitter prism (1).

3. The dual-camera coaxial visual displacement measurement device according to claim 1, characterized in that: The first camera (2) and the second camera (3) use image sensors and lenses of the same type.

4. The dual-camera coaxial visual displacement measurement device according to claim 1, characterized in that: The reflected light beam (W2) covers the field of view of the first camera (2).

5. The dual-camera coaxial visual displacement measurement device according to claim 1, characterized in that: The transmitted light beam (W3) covers the field of view of the second camera (3).

6. The dual-camera coaxial visual displacement measurement device according to any one of claims 1 to 5, characterized in that: The ratio of the reflected light amount of the reflected light beam (W2) to the transmitted light amount of the transmitted light beam (W3) is 1:

1.

7. The dual-camera coaxial visual displacement measurement device according to claim 6, characterized in that: The distance between the optical center position of the lens of the first camera (2) and the beam splitting prism (1) is less than or equal to 450 mm.

8. The dual-camera coaxial visual displacement measurement device according to claim 6, characterized in that: The distance between the optical center position of the lens of the second camera (3) and the beam splitting prism (1) is less than or equal to 450 mm.

9. The dual-camera coaxial visual displacement measurement device according to claim 6, characterized in that: It also comprises a mounting bracket (4); the mounting bracket (4) comprises a connecting bracket (4.1), a first mounting seat (4.2) and a second mounting seat (4.3); the first mounting seat (4.2) is connected to the second mounting seat (4.3) via the connecting bracket (4.1); the first camera (2) is arranged on the first mounting seat (4.2); and the second camera (3) is arranged on the second mounting seat (4.3).

10. The dual-camera coaxial visual displacement measurement device according to claim 9, characterized in that: The mounting bracket (4) further comprises a third mounting seat (4.4); the third mounting seat (4.4) is connected to the connecting frame (4.1); and the beam splitter prism (1) is arranged on the third mounting seat (4.4).

Images