A continuous line laser active three-dimensional scanning system and scanning method

Abstract

The application provides a continuous line laser active three-dimensional scanning system and a scanning method, and aims at solving the technical problem that the length and volume of the rotating part of the existing laser triangulation measurement system are large, and it is difficult to rotate the whole part quickly and stably in the underwater high-resistance environment, which leads to the failure to realize high-frame-frequency three-dimensional scanning measurement in the underwater high-resistance environment. The continuous line laser active three-dimensional scanning system provided by the application sets a multi-rib rotating mirror on the basis of the traditional triangulation laser measurement, and sets a left camera and a right camera on the specific positions on the left and right sides of the multi-rib rotating mirror, so that the line laser active three-dimensional scanning can be realized by rotating the multi-rib rotating mirror, the volume of the rotating part is reduced, the scanning frame frequency in the high-resistance environment is improved, and the demand for high-frame-frequency three-dimensional scanning measurement in the underwater high-resistance environment is fully met. Meanwhile, the left camera and the right camera are used to image the left and right two areas respectively, so that the scanning range is effectively increased.

Description

TECHNICAL FIELD

[0001] The present application relates to a laser three-dimensional scanning device, in particular to a continuous line laser active three-dimensional scanning system and scanning method. BACKGROUND

[0002] The laser three-dimensional scanning technology is mainly used for laser radar, and the laser radar is a general term of laser detection and ranging system. At present, the principle of laser radar measurement mainly includes pulse method, coherence method and triangle method. The existing laser triangle method measurement system is generally composed of a continuous line laser, a camera and a support. The laser and the camera are fixed on the support at a certain distance and angle. The emission angle of the laser and the receiving angle of the camera are fixed, and the distance between the two is the baseline length. The laser emits a line laser to irradiate the measured target at a certain incident angle, and the camera receives the laser echo scattered by the measured object and forms an image on the camera sensor. The incident light of the laser, the reflected light of the measured target and the baseline (the line connecting the laser and the camera) form a triangle. Since the positions of the laser echo corresponding to the camera sensor on the measured target at different distances are different, the distance information of each point of the measured target in the illumination range of the line laser can be obtained according to the triangle geometric relationship.

[0003] As shown in Figure 1 , it is a measurement principle diagram of the existing laser triangle method measurement system. It is known that the angle between the line laser returned by point A on the measured target and the baseline is θ1, the baseline length is L, and the angle between the emitted laser of the laser and the baseline is β. Then the object distance D1 of point A on the measured target is D1=L / (cotβ+cotθ1).

[0004] As shown in Figure 2 , it is a schematic diagram of the existing laser triangle method measurement system. Based on the laser triangle ranging, the laser, the camera and the support are rotated as a whole with a certain point on the support as the center. During the rotation, the three-dimensional measurement of the scanned space is carried out. However, the length and volume of the rotating part of this laser triangle method measurement system are large, which makes it difficult to rotate quickly and stably in the underwater high resistance environment, and it is impossible to realize high frame rate three-dimensional scanning measurement in the underwater high resistance environment. SUMMARY

[0005] The present application aims to solve the technical problem that the length and volume of the rotating part of the existing laser triangle method measurement system are large, which makes it difficult to rotate quickly and stably in the underwater high resistance environment, and it is impossible to realize high frame rate three-dimensional scanning measurement in the underwater high resistance environment, and to provide a continuous line laser active three-dimensional scanning system and scanning method.

[0006] In order to achieve the above-mentioned purpose, the technical scheme provided by the present application is as follows:

[0007] The application discloses a continuous line laser active three-dimensional scanning system, which is characterized in that the system comprises a laser, a multi-rib rotating mirror, a rotating mirror motor, a left camera, a right camera, a controller and a data processing unit.

[0008] The laser is used for emitting continuous line laser.

[0009] The central axis of the multi-rib rotating mirror is vertically arranged with the horizontal plane, the reflecting surface of the multi-rib rotating mirror is located on the light path of the emitted line laser, the multi-rib rotating mirror is used for reflecting the line laser to form reflected line laser, and the rotating mirror motor is used for driving the multi-rib rotating mirror to rotate to form reflected line laser with different angles.

[0010] The target region to be scanned is located on the light path of the reflected line laser, the reflected line laser is reflected on different positions on the surface of the target region to be scanned to form target reflected light with different positions.

[0011] The left camera and the right camera are respectively located on the light paths of the target reflected light with different positions on the left and right sides of the multi-rib rotating mirror, the focal point of the left camera and the focal point of the right camera are arranged in a line with the intersection point of the central axis of the multi-rib rotating mirror and the horizontal plane in the horizontal direction, and the left camera and the right camera are respectively used for receiving and imaging the target reflected light with different positions.

[0012] An absolute angle encoder is arranged on the multi-rib rotating mirror and is used for measuring the absolute angle of the multi-rib rotating mirror in real time.

[0013] The controller is electrically connected with the absolute angle encoder, the left camera and the right camera, is used for receiving the absolute angle of the multi-rib rotating mirror and the imaging images of the left camera and the right camera in real time, and records the absolute angle of the multi-rib rotating mirror when each frame of image is shot.

[0014] The input end of the data processing unit is connected with the output end of the controller, and the data processing unit is used for calculating the three-dimensional coordinates of the corresponding points in the target region to be scanned according to the pixel coordinates of each point on the center line of the line laser in the imaging image of the left camera or the right camera, the corresponding absolute angle of the multi-rib rotating mirror, the focal length of the left camera or the right camera, the installation angle of the left camera or the right camera and the corresponding baseline length.

[0015] Further, the absolute angle encoder and the multi-rib rotating mirror are arranged on the rotating shaft of the rotating mirror motor.

[0016] Further, the number of reflecting surfaces in the multi-rib rotating mirror is greater than or equal to 3.

[0017] Further, the maximum rotating speed V of the multi-rib rotating mirror is less than or equal to (360° / n) / (6 / f). max

[0018] V max ≤(360° / n) / (6 / f)

[0019] ​Wherein, n is the number of the reflecting surface of the polygon mirror, and f is the camera frame frequency.

[0020] Further, the camera frame frequencies of the left camera and the right camera are the same.

[0021] In addition, the application also provides a continuous line laser active three-dimensional scanning method, which adopts the continuous line laser active three-dimensional scanning system.

[0022] Step 1, the polygon mirror motor is powered on to drive the polygon mirror to rotate, and the laser is turned on to emit continuous line laser, and the line laser is reflected to the target area to be scanned through the polygon mirror, and the target area to be scanned is scanned in cycles.

[0023] Step 2, the controller collects the absolute angle of the polygon mirror in real time, and judges the emission direction of the line laser according to the absolute angle; when the line laser is on the left side of the polygon mirror, the controller controls the left camera to receive the target reflected light returned by the left side of the target area to be scanned multiple times to shoot imaging, and when the line laser is on the right side of the polygon mirror, the controller controls the right camera to receive the target reflected light returned by the right side of the target area to be scanned multiple times to shoot imaging;

[0024] Step 3, the controller collects the shooting images of the left camera and the right camera in real time, and records the absolute angle of the polygon mirror when each frame of image is shot.

[0025] Step 4, the data processing unit calculates the three-dimensional coordinates of each point on the center line of the current line laser reflected light illumination position in the target area to be scanned according to the pixel coordinates of each point on the center line of the imaging image of the left camera or the right camera, the corresponding absolute angle of the polygon mirror, the focal length of the left camera or the right camera, the installation angle of the left camera or the right camera and the corresponding baseline length, combined with the triangulation method;

[0026] Step 5, the three-dimensional coordinates of each point at different positions in the target area to be scanned obtained by multiple line scanning when the polygon mirror rotates one circle are spliced to obtain a frame of three-dimensional scanning image of the target area to be scanned; the continuous line laser active three-dimensional scanning system continuously scans the target area to be scanned in rotation, and obtains the dynamic result of the target area to be scanned.

[0027] The beneficial effects of the application compared with the prior art are as follows:

[0028] 1. The continuous line laser active three-dimensional scanning system provided by the present application, on the basis of traditional triangulation laser measurement, is provided with a multi-rib rotating mirror, and a left camera and a right camera are respectively arranged on specific positions on the left and right sides of the multi-rib rotating mirror, so that the present application can realize line laser active three-dimensional scanning by rotating the multi-rib rotating mirror only, reduces the volume of the rotating part, and improves the scanning frame frequency in a high-resistance environment, and is not only suitable for the traditional laser three-dimensional scanning field, but also suitable for high-frame-frequency three-dimensional scanning measurement in an underwater high-resistance environment.

[0029] 2. Meanwhile, since the left camera and the right camera are used to image the left and right two areas respectively, the scanning range is effectively increased.

[0030] 3. The scanning method based on the continuous line laser active three-dimensional scanning system provided by the present application is simple and convenient to operate, has high practicability, and can be widely applied to three-dimensional scanning measurement of various targets. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 FIG. 1 is a schematic diagram of the measurement principle of an existing laser triangulation measurement system;

[0032] Figure 2 FIG. 2 is a schematic diagram of an existing laser triangulation measurement system;

[0033] Figure 3 FIG. 3 is a schematic diagram of an embodiment of the continuous line laser active three-dimensional scanning system of the present application;

[0034] Figure 4 FIG. 4 is a schematic diagram of the left camera receiving target reflection light returned by the left side area of a target to be scanned when the line laser is on the left side of the multi-rib rotating mirror in the embodiment of the present application;

[0035] Figure 5 FIG. 5 is a schematic diagram of the right camera receiving target reflection light returned by the right side area of a target to be scanned when the line laser is on the right side of the multi-rib rotating mirror in the embodiment of the present application.

[0036] Specific reference signs are as follows:

[0037] 1. laser; 2. multi-rib rotating mirror; 3. left camera; 4. right camera; 5. controller. DETAILED DESCRIPTION

[0038] In order to make the advantages and characteristics of the present application clearer, the present application is further described in detail below in combination with the drawings and specific embodiments.

[0039] As shown in FIG. 1, a continuous line laser active three-dimensional scanning system comprises a laser 1, a multi-rib rotating mirror 2, a rotating mirror motor, a left camera 3, a right camera 4, a controller 5, and a data processing unit. Figure 1

[0040] ​The laser 1 is used for emitting continuous linear laser; the multi-angled mirror 2 is in the shape of multi-angled prism, each side of which is a plane mirror, and each side plane mirror is a reflecting surface of the multi-angled mirror 2. In the embodiment, there are five reflecting surfaces of the multi-angled mirror 2. The central axis of the multi-angled mirror 2 is arranged perpendicularly to the horizontal plane, and the reflecting surfaces are located on the light path of the linear laser, and are used for reflecting the linear laser to form linear laser reflected light. The mirror motor is used for driving the multi-angled mirror 2 to rotate to form linear laser reflected light with different angles. Meanwhile, the absolute angle encoder is arranged on the multi-angled mirror 2, and is used for measuring the absolute angle of the multi-angled mirror 2 in real time. In the embodiment, the absolute angle encoder and the multi-angled mirror 2 are arranged on the rotating shaft of the mirror motor, and the multi-angled mirror 2 rotates with the rotating shaft of the mirror motor, and the absolute angle encoder is used for recording the rotating angle of the mirror motor, and then the absolute angle of the multi-angled mirror 2 is obtained according to the rotating angle of the mirror motor.

[0041] The target region to be scanned is located on the light path of the linear laser reflected light, and the linear laser reflected light is reflected at different positions on the surface of the target region to be scanned to form target reflected light at different positions.

[0042] Preferably, the camera frame frequencies of the left camera 3 and the right camera 4 are the same, and the left camera 3 and the right camera 4 are located on the light paths of the target reflected light at different positions on the left and right sides of the multi-angled mirror 2 respectively, and the intersection point of the focal point of the left camera 3, the focal point of the right camera 4 and the central axis of the multi-angled mirror 2 and the horizontal plane is arranged in the horizontal direction, and the left camera 3 and the right camera 4 are respectively used for receiving and imaging the target reflected light at different positions. The connecting line between the focal point of the left camera 3 and the center point of the multi-angled mirror 2 is the left baseline, and the connecting line between the focal point of the right camera 4 and the center point of the multi-angled mirror 2 is the right baseline. In each imaging image of the left camera 3 and the right camera 4, there is a linear laser corresponding to the linear laser.

[0043] It is worth noting that the rotating speed of the multi-angled mirror 2 cannot be too large, and if it is too large, the obtained image density is low, which affects the final scanning result, so the maximum rotating speed V max需 meets the following condition:

[0044] V max ≤(360° / n) / (6 / f)

[0045] Wherein, n is the number of reflecting surfaces of the multi-angled mirror 2, and f is the camera frame frequency.

[0046] The maximum rotating speed determined by the above formula can ensure that the minimum number of shooting times is six in one scanning from left to right.

[0047] The controller 5 is electrically connected with the absolute angle encoder, the left camera 3 and the right camera 4 respectively, for receiving the absolute angle of the polygon mirror 2 and the imaging images of the left camera 3 and the right camera 4 in real time, and the controller 5 is also used for controlling the imaging time of the left camera 3 and the right camera 4. The controller 5 can record the absolute angle of the polygon mirror 2 when each frame of image is shot according to the received absolute angle of the polygon mirror 2 and the imaging images of the left camera 3 and the right camera 4.

[0048] The input end of the data processing unit is connected with the output end of the controller 5, for calculating the three-dimensional coordinates of the corresponding points in the target area to be scanned according to the pixel coordinates of each point on the center line of the line laser in the imaging image of the left camera 3 or the right camera 4, the absolute angle of the corresponding polygon mirror 2, the focal length of the left camera 3 or the right camera 4, the installation angle of the left camera 3 or the right camera 4 and the corresponding left baseline length or right baseline length.

[0049] Based on the above-mentioned continuous line laser active three-dimensional scanning system, the application further provides a continuous line laser active three-dimensional scanning method, which specifically comprises the following steps:

[0050] Step 1: The polygon mirror motor is powered on to drive the polygon mirror 2 to rotate, and the laser 1 is turned on to emit continuous line laser, and the line laser is reflected to the target area to be scanned through the polygon mirror 2 to perform cyclic scanning on the target area to be scanned.

[0051] Step 2: The controller 5 collects the absolute angle of the polygon mirror 2 in real time, and judges the emission direction of the line laser according to the absolute angle of the polygon mirror 2; when the line laser is on the left side of the polygon mirror 2, the controller 5 controls the left camera 3 to receive the target reflected light returned by the left side area of the target to be scanned multiple times to shoot imaging, and when the line laser is on the right side of the polygon mirror 2, the controller 5 controls the right camera 4 to receive the target reflected light returned by the right side area of the target to be scanned multiple times to shoot imaging.

[0052] Step 3: The controller 5 collects the shooting images of the left camera 3 and the right camera 4 in real time, and records the absolute angle of the polygon mirror 2 when each frame of image is shot.

[0053] Step 4: The data processing unit calculates the three-dimensional coordinates of each point on the center line of the current line laser reflected light illumination position in the target area to be scanned according to the pixel coordinates of each point on the center line of the line laser in the imaging image of the left camera 3 or the right camera 4, the absolute angle of the corresponding polygon mirror 2, the focal length of the left camera 3 or the right camera 4, the installation angle of the left camera 3 or the right camera 4 and the corresponding left baseline length or right baseline length, and combines the triangulation method.

[0054] Step 5, the three-dimensional coordinates of each point at different positions in the target area to be scanned obtained by multiple line scanning when the multi-rib rotating mirror 2 rotates one circle are spliced to obtain one frame of three-dimensional scanning image of the target area to be scanned. The continuous line laser active three-dimensional scanning system continuously rotates and reciprocally scans the target area to be scanned to obtain the dynamic result of the target area to be scanned.

[0055] The above description is only used to illustrate the technical solutions of the present application, and is not intended to limit the same. For ordinary skilled in the art, the specific technical solutions described in the above embodiments can be modified, or some technical features can be replaced by equivalents, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions protected by the present application.

Claims

1. A continuous line laser active three-dimensional scanning system, characterized in that: It includes a laser (1), a multi-faceted rotating mirror (2), a rotating mirror motor, a left camera (3), a right camera (4), a controller (5), and a data processing unit; The laser (1) is used to emit a continuous line laser; The central axis of the multi-faceted rotating mirror (2) is set perpendicular to the horizontal plane, and its reflective surface is located on the output light path of the line laser, which is used to reflect the line laser and form line laser reflected light; the rotating mirror motor is used to drive the multi-faceted rotating mirror (2) to rotate and form line laser reflected light at different angles; The target area to be scanned is located on the optical path of the line laser reflected light. The line laser reflected light is reflected at different positions on the surface of the target area to be scanned, forming target reflected light at different positions. The left camera (3) and the right camera (4) are located on the target reflected light paths at different positions on the left and right sides of the prism rotating mirror (2), and the focal point of the left camera (3) and the focal point of the right camera (4) are collinear with the intersection of the central axis of the prism rotating mirror (2) and the horizontal plane in the horizontal direction, respectively, and are used to receive and image the target reflected light at different positions. The prism mirror (2) is equipped with an absolute angle encoder for real-time measurement of the absolute angle of the prism mirror (2); the number of reflecting surfaces in the prism mirror (2) is greater than or equal to 3, and the maximum rotational speed V of the prism mirror (2) is... max The following conditions must be met: V max ≤(360° / n) / (6 / f) Where n is the number of reflecting surfaces on the prism mirror (2), and f is the camera frame rate; The controller (5) is electrically connected to the absolute angle encoder, the left camera (3) and the right camera (4) respectively, and is used to receive the absolute angle of the multi-prism rotating mirror (2) in real time, as well as the imaging images of the left camera (3) and the right camera (4), and then record the absolute angle of the multi-prism rotating mirror (2) when each frame of image is captured. The input end of the data processing unit is connected to the output end of the controller (5) and is used to calculate the three-dimensional coordinates of the corresponding points in the target area to be scanned based on the pixel coordinates of each point on the center line of the laser of the image captured by the left camera (3) or the right camera (4) during a single line scan, the absolute angle of the corresponding prism mirror (2), the focal length of the left camera (3) or the right camera (4), the installation angle of the left camera (3) or the right camera (4), and the corresponding baseline length.

2. The continuous line laser active three-dimensional scanning system according to claim 1, characterized in that: The absolute angle encoder and the multi-faceted rotating mirror (2) are both mounted on the rotating shaft of the rotating mirror motor.

3. A continuous line laser active three-dimensional scanning system according to claim 1 or 2, characterized in that: The left camera (3) or the right camera (4) have the same frame rate.

4. A continuous line laser active three-dimensional scanning method, employing the continuous line laser active three-dimensional scanning system as described in any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Power on the rotating mirror motor to drive the multi-faceted rotating mirror (2) to rotate. At the same time, turn on the laser (1) to emit a continuous line laser. The line laser is reflected by the multi-faceted rotating mirror (2) to the target area to be scanned, and the target area to be scanned is scanned cyclically. Step 2: The controller (5) collects the absolute angle of the prism mirror (2) in real time and determines the emission direction of the line laser based on the absolute angle. When the line laser is on the left side of the prism mirror (2), the controller (5) controls the left camera (3) to receive the target reflected light returned from the left side of the target to be scanned multiple times to capture images. When the line laser is on the right side of the prism mirror (2), the controller (5) controls the right camera (4) to receive the target reflected light returned from the right side of the target to be scanned multiple times to capture images. Step 3: The controller (5) acquires the images captured by the left camera (3) and the right camera (4) in real time, and records the absolute angle of the prism mirror (2) when each frame of the image is captured. Step 4: The data processing unit calculates the three-dimensional coordinates of each point on the center line of the line laser in the image captured by the left camera (3) or right camera (4) during a single line scan, the absolute angle of the corresponding prism mirror (2), the focal length of the left camera (3) or right camera (4), the installation angle of the left camera (3) or right camera (4), and the corresponding baseline length, in combination with the triangulation method. Step 5: When the multi-faceted rotating mirror (2) rotates once, the three-dimensional coordinates of each point at different positions in the target area to be scanned obtained by multiple line scans are stitched together to obtain a frame of three-dimensional scan image of the target area to be scanned; the continuous line laser active three-dimensional scanning system continuously rotates and reciprocates to scan the target area to be scanned to obtain the dynamic result of the target area to be scanned.

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