Laser scanning device, laser scanning method, and laser scanning program

Abstract

To improve the efficiency of a technique for performing laser scanning and photography simultaneously.SOLUTION: A laser scanning apparatus 200 comprises: a horizontally rotatable horizontal rotation portion 213 including cameras 216 and 217 and a vertical rotation portion 214 that performs laser scanning in an upper-lower direction; a rotation control portion that controls rotation of the horizontal rotation portion 213; and a processing portion that performs processing of not generating part of laser scanning data obtained by laser scanning in the upper-lower direction. Laser scanning is performed while the horizontal rotation portion 213 is horizontally rotated, and photography is performed with the cameras 216 and 217. The rotation of the horizontal rotation portion 213 is decelerated for performing photography. The processing portion does not generate part of laser scanning data obtained by laser scanning in the upper-lower direction during the deceleration.SELECTED DRAWING: Figure 1

Description

Technical Field

[0004]

[0001] The present invention relates to laser scanning technology.

Background Art

[0002] A laser scanning device with a camera is known (for example, see Patent Document 1). For example, there is a technique of performing a full-circle scan using a laser scanning device with a camera, simultaneously taking a panoramic image with the camera, and superimposing the scanned point cloud and the panoramic image (for example, see Patent Document 2).

[0003] This laser scanning device with a camera has a horizontal rotation part, a camera and a vertical rotation part arranged on the horizontal rotation part, and an optical part including an emission part and a light receiving part of laser ranging light arranged on the vertical rotation part. Then, while horizontally rotating the horizontal rotation part, the vertical rotation part is vertically rotated to perform laser scanning, and a panoramic image is taken by the camera arranged on the horizontal rotation part.

Prior Art Documents

Patent Documents

[0004]

Patent Document No. 1

Patent Document No. 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] When acquiring a panoramic image simultaneously with the above laser scan, it is necessary to decelerate or stop the rotation of the horizontal rotation part when taking a still image constituting the panoramic image. This is to suppress the phenomenon that the captured image flows or the image blurs.

[0006] When the rotation of the horizontal rotating part described above is slowed down or stopped, the laser scan results in a relatively higher density of laser scan point clouds in the horizontal direction. In this case, when viewing the surroundings from the laser scanning device (the viewpoint of the laser scan), the density of laser scan point clouds in the horizontal direction becomes partially denser.

[0007] Laser-scanned point clouds should ideally be gridded (arranged in a grid pattern) with minimal variations in density. If the point cloud contains dense areas, processing for gridning is necessary. This processing is burdensome and undesirable in terms of work efficiency.

[0008] Therefore, until now, laser scanning and photography were performed as separate processes. However, this method also increases the workload and is undesirable in terms of work efficiency.

[0009] While it is possible to address the above problem by rotating the horizontal rotating part very slowly, this would reduce the efficiency of the laser scanning process and is therefore undesirable.

[0010] Against this backdrop, the present invention aims to improve the efficiency of a technology that performs laser scanning and simultaneous image capture. [Means for solving the problem]

[0011] The present invention is a laser scanning device comprising a laser scanning unit and a camera that perform laser scanning in the vertical direction, a horizontal rotation unit that can rotate horizontally, and a processing unit that performs processing without generating a portion of the scan data obtained by the laser scanning in the vertical direction. The laser scanning is performed while the horizontal rotation unit is rotated horizontally, and the camera takes photographs. The rotation of the horizontal rotation unit is decelerated in order to take the photographs, and in the deceleration, the processing unit does not generate a portion of the laser scan data obtained by the laser scanning in the vertical direction.

[0012] In the present invention, the reduction can be a negative acceleration that reduces the rotational speed or rotation at a lower speed.

[0013] In the present invention, the deceleration is performed from a state in which the horizontal rotating part is rotating at a constant speed, and the generation of a portion of the laser scan data by the vertical laser scan is not performed, thereby correcting the difference between the horizontal scan interval of the vertical laser scan during constant speed rotation and the horizontal scan interval of the vertical laser scan during deceleration.

[0014] In the present invention, one embodiment is characterized in which the spacing of scan data in the horizontal direction is equalized by a process that does not generate a portion of the scan data obtained by the laser scan in the vertical direction.

[0015] In the present invention, the deceleration is performed from a state in which the horizontal rotating part is rotating at a constant speed, and the process of not generating a portion of the scan data obtained by the laser scan in the vertical direction is characterized in that the vertical scan data is acquired based on the horizontal angular interval Δθ of the vertical scan data obtained by performing a laser scan in the vertical direction during the period of constant speed rotation.

[0016] In the present invention, one embodiment is one in which the vertical scan data of the angular interval closest to the angular interval Δθ is acquired. Here, the meaning of the term "closest" includes cases where it is identical. In the present invention, one embodiment is one in which the generation of a portion of the scan data obtained by the laser scan in the vertical direction is not performed, and this is an embodiment in which the emission or reception of light related to the laser scan in the vertical direction is not performed.

[0017] In the present invention, one aspect of the process that does not generate a portion of the scan data obtained by the laser scan in the vertical direction is to not detect the detection signal related to the laser scan in the vertical direction.

[0018] The present invention relates to a laser scanning method using a laser scanning device including a laser scanning unit that performs laser scanning in the vertical direction and a camera, and a horizontal rotation unit that can rotate horizontally. The method includes performing the laser scanning while horizontally rotating the horizontal rotation unit, performing imaging by the camera, decelerating the rotation of the horizontal rotation unit for performing the imaging, and in the deceleration, not generating a part of laser scan data by the laser scanning in the vertical direction.

[0019] The present invention is a program that is read and executed by a computer for controlling the operation of a laser scanning device including a laser scanning unit that performs laser scanning in the vertical direction and a camera, and a horizontal rotation unit that can rotate horizontally. The program includes performing the laser scanning while horizontally rotating the horizontal rotation unit, performing imaging by the camera, decelerating the rotation of the horizontal rotation unit for performing the imaging, and causing the computer to execute a process of not generating a part of laser scan data by the laser scanning in the vertical direction in the deceleration.

Effects of the Invention

[0020] According to the present invention, the technology of performing imaging simultaneously with laser scanning can be made more efficient.

Brief Description of the Drawings

[0021] [Figure 1] Figs. (A) and (B) showing the appearance of the laser scanning device. ) [Figure 2] A block diagram of the laser scanning device. [[ID=2~]] [Figure 3] A diagram for explaining horizontal rotation. [Figure 4] Figs. (A) and (B) showing an image of the vertical scan line. [Figure 5] A flowchart showing an example of the processing procedure.

Best Mode for Carrying Out the Invention

[0022] 1. First Embodiment (Hardware Configuration) FIG. 1 shows the appearance of a laser scanning device (laser scanner) 200. FIG. 1(A) shows the state as viewed from the front side, and FIG. 1(B) shows the state as viewed from the back side. The laser scanning device 200 includes a tripod 211, a base portion 212 fixed to the upper part of the tripod 211, a horizontal rotating portion 213 which is a rotating body capable of horizontal rotation on the base portion 212, a vertical rotating portion 214 which is a rotating body capable of vertical rotation with respect to the horizontal rotating portion 213, and cameras 216 and 217 disposed on the horizontal rotating portion 213. Further, an operation panel 218 is disposed on the back surface of the horizontal rotating portion 213.

[0023] The vertical rotating portion 214 includes an optical unit 215 that emits and receives laser scanning light. Laser scanning light is emitted in pulses from the optical unit 215. This pulsed emission is performed along a direction (vertical plane) orthogonal to the rotation axis (axis extending in the horizontal direction) while the vertical rotating portion 214 rotates. In this case, laser scanning light is emitted in pulses from the optical unit 215 along a direction at a right angle to the vertical (angle directions of elevation and depression).

[0024] By horizontally rotating the horizontal rotating portion 213 and vertically rotating the vertical rotating portion 214 while emitting laser scanning light in pulses from the optical unit 215 and receiving the reflected light from the object by the optical unit 215, laser scanning of the surroundings is performed.

[0025] That is, by vertically rotating the vertical rotating portion 2 while emitting laser scanning light in pulses from the optical unit 215, scanning along the direction at a right angle to the vertical (vertical direction scanning: vertical scan) is performed. The line of this scan along the direction at a right angle to the vertical is called a vertical scan line.

[0026] As the horizontal rotation unit 213 rotates horizontally simultaneously with the scan along the vertical angle (vertical scan), the scan line along the vertical angle (vertical scan line) moves in a way that causes it to shift along the horizontal angle. Note that if horizontal rotation is performed simultaneously with vertical rotation, the scan along the vertical angle (vertical scan line) will not be perfectly aligned with the vertical direction, but will be slightly slanted. Note that if the horizontal rotation unit 213 does not rotate, the scan along the vertical angle (vertical scan line) will be aligned with the vertical direction.

[0027] The rotation of the horizontal rotating section 213 and the vertical rotating section 214 is performed by motors. The horizontal rotation angle of the horizontal rotating section 213 and the vertical rotation angle of the vertical rotating section 214 are precisely measured by encoders.

[0028] Each laser scan beam is a single pulsed ranging beam, and one laser scan beam measures the distance to the scan point, which is the reflection point where the laser scan beam strikes. From this distance value and the direction of irradiation of the laser scan beam, the position of the scan point (reflection point of the laser scan beam) relative to the laser scanning device 200 is calculated.

[0029] Here, if the external orientation elements (position and orientation) of the laser scanning device 200 in the absolute coordinate system are known, the position of the scan point in the absolute coordinate system can be determined. The absolute coordinate system is the coordinate system used in maps and GNSS. In the absolute coordinate system, position is described by, for example, latitude, longitude, and elevation. It is also possible to obtain a laser scan point cloud in a local coordinate system with the optical origin of the laser scanning device 200 as the origin.

[0030] The laser scan point cloud output from the laser scanning device 200 can be configured to output distance and direction data for each point (each scan point). It is also possible for the laser scanning device 200 to calculate the position of each point in a specific coordinate system and output the 3D coordinate position of each point as point cloud data. Furthermore, the laser scan point cloud data also includes information on the brightness (intensity of reflected light) of each scan point.

[0031] Cameras 216 and 217 are digital cameras. A panoramic image can be obtained by changing the angular position of the horizontal rotation unit 213 and taking pictures with cameras 216 and 217. For example, with north as 0°, pictures are taken at 22.5° angular intervals so that adjacent images partially overlap, and a panoramic image consisting of 8 images is obtained.

[0032] Cameras 216 and 217 are oriented 180° apart. By using these two cameras for shooting, rotating the horizontal rotation unit 213 by 180° allows for a full-circumference scan and simultaneous 360° shooting. Of course, it is also possible to use a single camera and rotate the horizontal rotation unit 213 360° for shooting.

[0033] The control panel 218 is a touch panel display for operating the laser scanning device 200.

[0034] Figure 2 is a block diagram of the laser scanning device 200. The laser scanning device 200 comprises a light-emitting unit 201, a light-receiving unit 202, a distance-measuring unit 203, a direction acquisition unit 204, a light-emitting control unit 205, a drive control unit 206, a camera control unit 207, a rotation speed determination unit 208, a point cloud data creation unit 209, and a communication device 210.

[0035] The direction acquisition unit 204, light emission control unit 205, drive control unit 206, camera control unit 207, rotation speed determination unit 208, and point cloud data creation unit 209 are configured by a computer built into the laser scanning device 200. This computer includes a CPU, storage device, communication interface, and user interface, and has an operating program installed to implement the above-mentioned functions. It is also possible to configure some or all of the above-mentioned functions with dedicated hardware.

[0036] The light-emitting unit 201 includes a light-emitting element that emits laser scan light, an optical system related to light emission, and peripheral circuits. The laser scan light from the light-emitting unit 201 is emitted to the outside from the optical unit 215 via the optical system. The light-receiving unit 202 includes a light-receiving element that receives the laser scan light, an optical system related to light reception, and peripheral circuits. The reflected light of the laser scan light taken in from the optical unit 215 is guided to the light-receiving unit 202 via the optical system.

[0037] The distance measuring unit 203 calculates the distance from the laser scanning device 200 to the reflection point (scan point) of the laser scan light. In this example, a reference optical path is provided inside the laser scanning device 200. The laser scan light output from the light-emitting element is split into two; one is irradiated onto the target from the optical unit 215 as laser scan light, and the other is guided to the reference optical path as reference light.

[0038] The laser scan light reflected from the target and captured by the optical unit 215, along with the reference light propagated along the above-mentioned reference optical path, are combined and input to the light receiving unit 202. The laser scan light and the reference light have different propagation distances, so the reference light is detected by the light receiving element first, followed by the laser scan light.

[0039] Here, observing the output waveform of the photodetector, the detection waveform of the reference light is output first, followed by the detection waveform of the laser scan light after a time delay. The distance to the reflection point of the laser scan light is calculated from the phase difference (time difference) between these two waveforms. It is also possible to calculate the distance from the flight time of the laser scan light.

[0040] The direction acquisition unit 204 acquires the direction of the optical axis of the laser scan beam. The direction of the optical axis is obtained by measuring the angle of the horizontal optical axis and the angle of the vertical optical axis (elevation angle or depression angle). The direction acquisition unit 204 has a horizontal angle detection unit 204a and a vertical angle detection unit 204b.

[0041] The horizontal angle detection unit 204a detects the horizontal rotation angle of the horizontal rotation unit 213. Horizontal rotation is rotation with the vertical direction as the axis of rotation. The angle is detected by an encoder. The vertical angle detection unit 204b detects the vertical rotation angle (elevation angle or depression angle) of the vertical rotation unit 214. Vertical rotation is rotation with the horizontal direction as the axis of rotation. The angle is detected by an encoder.

[0042] By measuring the horizontal rotation angle of the horizontal rotating section 213 and the vertical rotation angle of the vertical rotating section 215, the direction of the optical axis of the laser scan beam as seen from the laser scanning device 200, i.e., the direction of the scan point, can be determined.

[0043] The light emission control unit 205 is an example of a scan control unit and controls the timing of light emission of the laser scan light in the light emission unit 201.

[0044] The drive control unit 206 includes a horizontal rotation drive control unit 206a that performs drive control for horizontal rotation of the horizontal rotation unit 213, and a vertical rotation drive control unit 206b that performs drive control for vertical rotation of the vertical rotation unit 214.

[0045] The horizontal rotation drive control unit 206 controls the rotation of the horizontal rotation unit 213 by repeatedly stopping, accelerating, maintaining a constant speed, decelerating, and stopping. Possible rotation control methods include: rotation control that repeatedly stops, accelerates, decelerates, and stops; rotation control that repeatedly accelerates, maintains a constant speed, and decelerates without stopping; rotation control that repeatedly accelerates and decelerates without stopping; rotation control that repeatedly rotates at a slow constant speed for filming, then accelerates, maintains a constant speed, decelerates, and then rotates at a slow constant speed for filming; and rotation control that repeatedly accelerates, decelerates, and then rotates at a slow constant speed for filming. At this point, filming is performed by cameras 216 and 217 when the unit stops or when the rotation speed is at its slowest.

[0046] Figure 3 shows an example of a case where constant speed ⇒ deceleration ⇒ stop ⇒ acceleration ⇒ constant speed is repeated (of course, there may be periods of constant speed rotation). Note that in Figure 3, the periods (angle ranges) of deceleration and acceleration are exaggerated for the sake of clarity.

[0047] In this case, the image is captured at the moment of stopping. For example, when capturing 24 images for a panoramic image within a 360° range with an angular difference of 15° using the method shown in Figure 3, the horizontal rotation drive control of the horizontal rotation unit 213 is performed in a repeating pattern of stop (shooting timing) ⇒ acceleration ⇒ constant speed ⇒ deceleration ⇒ stop (shooting timing)... so that the angular interval between stops is 15°. It is also possible to control the rotation without a period of constant speed. Furthermore, it is also possible to control the rotation to a slower constant speed at the timing of shooting.

[0048] The camera control unit 207 controls the timing of the cameras 216 and 217 to take pictures. In this example, a picture is taken when the rotation of the horizontal rotation unit 213 stops or slows down to its slowest point. This control is performed by the camera control unit 207.

[0049] The rotation speed determination unit 208 determines the rotation state of the horizontal rotation unit 213. This determination is made based on the change in the horizontal rotation angle of the horizontal rotation unit 213 detected by the horizontal angle detection unit 204a.

[0050] The point cloud data creation unit 209 creates point cloud data. The point cloud data creation unit 209 is an example of a processing unit that performs processing that does not generate a portion of the scan data obtained by laser scanning in the vertical direction. The point cloud data is created by associating the direction and distance data from the optical origin of the laser scanning device 200 to that point, as well as the intensity of the reflected light, for each point. The direction of the point is obtained from the direction acquisition unit 204. The distance of the point is obtained from the distance measurement unit 203. It is also possible to calculate the 3D position in an appropriate coordinate system and use that as point cloud data.

[0051] The point cloud data creation unit 209 performs a process that excludes the generation of some of the scan data obtained by the vertical laser scan described later. The details of this process are explained below.

[0052] Figure 4(A) shows a schematic image of the scan lines (vertical scan lines) of a vertical scan as seen from the laser scanning device 200 (the position of the origin (viewpoint) of the laser scan) when the timing of the laser scan is performed at normal equal intervals (during constant speed rotation), while the rotation of the horizontal rotating part 213 is performed horizontally at a constant speed (constant speed rotation) ⇒ deceleration ⇒ stop ⇒ acceleration ⇒ constant speed.

[0053] The vertical scan line is a linear scan line along the vertical plane obtained during one rotation of the vertical rotating unit 215. One vertical scan corresponds to one rotation of the vertical rotating unit 214. The vertical scan starts when the optical unit 215 of the vertical rotating unit 214 is facing vertically downward (straight down), and ends when, after one full rotation, the optical unit 215 is again facing vertically downward.

[0054] In Figure 4(A), the spacing between the vertically extending scan lines (vertical scan lines) becomes denser during the deceleration → stop → acceleration phase than during the constant-velocity phase. In this denser section, laser scanning is performed unnecessarily compared to the sparser section.

[0055] This method prevents the generation of some vertical scan lines in densely packed areas, ensuring that the vertical scan lines are evenly spaced (or at least as evenly spaced as possible). A similar objective can be achieved by disabling (making unusable) any vertical scan lines that are generated in densely packed areas.

[0056] An example of this is shown in Figure 4(B). Figure 4(B) shows a case where point cloud data is not obtained (not output) for a portion of the vertical scan lines shown in Figure 4(A) (the dashed portion in Figure 4(B)), so that the scan density in the horizontal direction does not change (remains constant) regardless of the acceleration, deceleration, and stopping of the horizontal rotation unit 213.

[0057] In this embodiment, the point cloud data creation unit 209 does not generate point cloud data corresponding to the dashed lines in Figure 4(B). That is, even if the rotation speed of the horizontal rotation unit 213 changes, a portion of the vertical scan lines are not generated so that the spacing of the vertical scan lines in space does not change compared to before the change in rotation speed. The same effect as when the data is not generated can be obtained even if the data is generated but is not usable, or if the generated data is not output externally (not output from the laser scanning device 200).

[0058] In the case of Figure 4(B), point cloud data for the dashed vertical scan lines is not generated. Naturally, point cloud data for the dashed vertical scan lines is not output from the laser scanning device 200.

[0059] The following is a specific example. For instance, suppose a deceleration rotation is detected as shown in Figure 4(B). In this case, the angular interval Δθ of the vertical scan lines during the period of constant-speed rotation is obtained. Then, during the deceleration period, the period of imaging, and the acceleration period, the vertical scan data with the interval closest to this angular interval Δθ is obtained (adopted). In other words, scan data sampling is performed so that vertical scan data that matches or matches as closely as possible to the interval of Δθ is obtained.

[0060] In this way, a process is executed that does not acquire point cloud data for vertical scan lines that are outside the interval of Δθ. That is, a process is performed that does not acquire point cloud data for the vertical scan lines in the dashed line portion of Figure 4(B).

[0061] By performing the above processing in the point cloud data generation unit 209, it is possible to obtain point cloud data in which point cloud data of extended scan lines are arranged at equal intervals, without generating point cloud data corresponding to the dashed lines in Figure 4(B).

[0062] The communication device 304 communicates with the laser scanning device 200 and other devices. Wireless LAN or mobile phone lines are used for communication.

[0063] (An example of processing) Figure 5 shows an example of the processing procedure. The program that performs the processing shown in Figure 5 is read and executed by a computer built into the laser scanning device 200. This program is stored in the computer's memory and read and executed by the computer's CPU. It is also possible to store the program in a suitable storage medium and read and use it from there.

[0064] First, the laser scanning device 200 is installed. Here, it is assumed that the external orientation elements (position and orientation) of the laser scanning device 200 are determined by a known method and are known. The coordinate system used may be an absolute coordinate system or a local coordinate system. An absolute coordinate system is the coordinate system used in maps and GNSS.

[0065] As a prerequisite, the angular position of the horizontal rotation angle for shooting is predetermined (for example, at angular intervals such as 15° or 22.5°). Furthermore, the rotation of the horizontal rotation unit 213 is assumed to repeat the cycle of stop ⇒ acceleration ⇒ constant speed rotation ⇒ deceleration ⇒ stop. Shooting by cameras 216 and 217 is performed when the unit is stopped. The timing of the rotation control that determines stop ⇒ acceleration ⇒ constant speed rotation ⇒ deceleration ⇒ stop is predetermined, and the rotation control unit 206 controls the rotation of the horizontal rotation unit 213 according to this predetermined procedure. The vertical rotation unit 214 continues to rotate at a constant speed.

[0066] After the laser scanning device 200 has been set up, a full-circumference scan is started. At this time, the vertical rotating part 214 is rotated first, and once the rotation of the vertical rotating part 214 is stable, the rotation of the horizontal rotating part 213 is started. At this stage, the process shown in Figure 5 is started.

[0067] Once processing begins, a determination is made as to whether the horizontal rotation unit 213 is rotating at a predetermined constant speed (rotation at a constant rotational speed) (step S101). The predetermined constant speed rotation is the rotation of the horizontal rotation unit 213 during laser scanning to obtain vertical scan lines at predetermined equal intervals (constant speed rotation portion in Figure 4).

[0068] If the horizontal rotating unit 213 is rotating at a constant speed, the acquisition of laser scan data is started (step S102). Next, it is determined whether the rotation speed of the horizontal rotating unit 213 is other than a predetermined rotation speed (step S103). If the rotation speed of the horizontal rotating unit 213 is other than a predetermined rotation speed, the process described in relation to Figure 4(B) is executed to partially prevent the generation of point clouds of the vertical scan lines (S104).

[0069] Next, it is determined whether the rotation of the horizontal rotating section 213 has reached a predetermined constant speed (step S105). If it has reached a constant speed, the process proceeds to step S106 and the process in step S104 is terminated. In this case, the process started in step S102 is resumed, and the processes from step S103 onwards are repeated.

[0070] This process allows for obtaining an array of point cloud data of vertical scan lines that are equally spaced horizontally. In other words, by not generating some of the laser scan data from the vertical laser scan, the difference between the horizontal spacing of the vertical scan lines during constant-speed rotation and the horizontal spacing of the vertical scan lines during deceleration, imaging, and acceleration is corrected.

[0071] This allows the spacing between vertical scan lines to remain constant or nearly constant, even if there are differences in the rotation speed of the horizontal rotating unit 213. In other words, gridded point cloud data can be obtained.

[0072] (Superiority) Laser scanning and image capture can be performed simultaneously, improving work efficiency. Furthermore, since gridded laser scan data is obtained, the burden of post-processing is reduced, further streamlining the work. Even if gridding is required in post-processing, the horizontal spacing of the point cloud is relatively uniform, reducing the burden of post-processing and improving efficiency.

[0073] 2. Second Embodiment In the first embodiment, the speed of the horizontal rotation unit 213 may be further controlled to adjust the vertical scan lines so that they are spaced as evenly as possible.

[0074] 3. Third Embodiment In addition to the rotation control, light emission control, and point cloud data processing described in relation to Figure 4, it is also possible to control the laser scanning device 200 from an external computer or control device by performing at least one of these functions.

[0075] 4. Fourth Embodiment The present invention can also be applied to a laser scanning device in which the vertically rotating part 214 is replaced with a mechanism that performs laser scanning in the vertical direction. Mechanisms for performing laser scanning in the vertical direction include a configuration in which the optical system is mechanically moved up and down, and a configuration in which there are no moving parts and the scanning is performed electronically in the vertical direction.

[0076] 5. Fifth Embodiment One method for obtaining some laser scan data is to not emit scan light (measurement light) at specific timings. In this case, the light emission control unit 205 controls the timing of laser scan light emission in the light emission unit 201, for example, by preventing the scanning lines in the dashed area shown in Figure 4(B) from emitting light.

[0077] 6. Sixth Embodiment As a method to avoid obtaining some laser scan data, it is possible to place an optical shutter in front of the photodetector, allowing light emission but preventing light reception by the photodetector. In this case, point cloud data at the time the optical shutter is ON cannot be obtained, resulting in the same outcome as if no laser scan had been performed. In this case, a photodetector control device is provided to control the optical shutter that blocks the received light. In this case, this photodetector control device is an example of a processing unit that performs a process that does not generate some of the scan data obtained by the vertical laser scan.

[0078] For example, if a vertical scan is performed, not performed, performed, not performed, etc., the above-mentioned light shutter is turned ON (opaque) at the timing when the scan is not performed, so that light is emitted from the light-emitting element, but the light-receiving element does not receive it as measurement light. It is also possible to place the light shutter in front of the light-emitting element to prevent the emission (exit) of measurement light to the outside at specific timings.

[0079] Furthermore, it is possible to perform light emission and reception by photodetectors with respect to the laser scan light, but not count (detect) the received signal output from the photodetector. In this case, point cloud data cannot be obtained, so the same result as when no laser scan was performed can be obtained. In this case, an electronic switch that blocks the received signal output from the photodetector and a photodetector signal control circuit that controls this electronic switch are prepared. In this case, the photodetector signal control device performs processing that does not generate a portion of the scan data obtained by the laser scan in the vertical direction.

[0080] For example, if the vertical scan is performed, not performed, performed, not performed, etc., the electronic switch mentioned above can be turned OFF at the time the scan is not performed, so that no point data is obtained at that time. Alternatively, the power supply or bias voltage of the photodetector can be turned OFF at a specific time, preventing the photodetector from functioning.

[0081] 7. Seventh Embodiment Figure 4(B) shows a case where there is a period of constant speed rotation other than the timing of the image capture, but a configuration without a period of constant speed is also possible. For example, it is possible that the horizontal rotation unit 213 performs horizontal rotation that repeatedly accelerates, decelerates, stops or reaches the minimum speed for image capture, and then accelerates again. In this case, a method for obtaining equally spaced vertical scan lines will be explained.

[0082] In this case, the first step is to set the interval Δθ of the vertical scans that will ultimately be acquired at equal intervals. Then, the vertical scan data closest to this angular interval Δθ is acquired (adopted). In other words, the scan data is sampled so that vertical scan data that matches or matches as closely as possible to the interval Δθ is acquired.

[0083] In this way, a process is executed that does not acquire point cloud data for vertical scan lines that deviate from the interval Δθ. This process is performed in the point cloud data creation unit 209. [Explanation of Symbols]

[0084] 200... Laser scanning device, 211... Tripod, 212... Base unit, 213... Horizontal rotation unit, 214... Vertical rotation unit, 215... Optical unit, 216... Camera.

Claims

1. It includes a laser scanning unit and camera that perform laser scanning in the vertical direction, and a horizontal rotating unit that can rotate horizontally, A processing unit that performs processing that does not generate a portion of the scan data obtained by the laser scan in the vertical direction. Equipped with, The laser scan is performed while the horizontal rotating part is rotated horizontally, and the camera takes photographs. In order to perform the aforementioned photography, the rotation of the horizontal rotating part is decelerated. In the deceleration process, the processing unit does not generate a portion of the laser scan data obtained by the vertical laser scan, thereby correcting the difference between the horizontal scan interval of the vertical laser scan before deceleration and the horizontal scan interval of the vertical laser scan during deceleration.

2. After the camera has taken a photograph, the rotation of the horizontal rotating part is accelerated, The laser scanning apparatus according to claim 1, wherein, in the acceleration, the processing unit does not generate a portion of the laser scanning data by the laser scanning in the vertical direction, thereby correcting the difference between the horizontal scan interval of the laser scanning in the vertical direction before deceleration and the horizontal scan interval of the laser scanning in the vertical direction during acceleration.

3. The deceleration is performed from a state in which the horizontal rotating part is rotating at a constant speed. The laser scanning apparatus according to claim 1 or 2, wherein the generation of a portion of the laser scanning data by the laser scanning in the vertical direction is omitted, thereby correcting the difference between the horizontal scan interval of the laser scanning in the vertical direction during constant speed rotation and the horizontal scan interval of the laser scanning in the vertical direction during deceleration.

4. The laser scanning apparatus according to any one of claims 1 to 3, wherein the spacing of scan data in the horizontal direction is made equal by a process that does not generate a portion of the scan data obtained by the laser scanning in the vertical direction.

5. The deceleration is performed from a state in which the horizontal rotating part is rotating at a constant speed. The process of not generating a portion of the scan data obtained by the laser scan in the vertical direction is: A laser scanning apparatus according to any one of claims 1 to 4, wherein the vertical scan data is acquired based on the horizontal angular interval Δθ of the vertical scan data obtained by performing a laser scan in the vertical direction during the period of constant speed rotation.

6. The laser scanning apparatus according to claim 5, wherein the vertical scan data with the angular interval closest to the angular interval Δθ is acquired.

7. As a process that does not generate a portion of the scan data obtained by the aforementioned vertical laser scan, A laser scanning apparatus according to any one of claims 1 to 6, wherein no light emission or reception is performed in relation to the laser scanning in the vertical direction.

8. As a process that does not generate a portion of the scan data obtained by the aforementioned vertical laser scan, A laser scanning apparatus according to any one of claims 1 to 7, wherein detection of a detection signal related to the laser scanning in the vertical direction is not performed.

9. A laser scanning method using a laser scanning device equipped with a laser scanning unit that performs laser scanning in the vertical direction and a camera, and a horizontal rotation unit that is capable of horizontal rotation, The laser scan is performed while the horizontal rotating part is rotated horizontally, and the camera takes photographs. In order to perform the aforementioned photography, the rotation of the horizontal rotating part is decelerated. A laser scanning method in which, during the deceleration, the generation of a portion of the laser scan data by the vertical laser scan is omitted, thereby correcting the difference between the horizontal scan interval of the vertical laser scan before deceleration and the horizontal scan interval of the vertical laser scan during deceleration.

10. A program to be read and executed by a computer that controls the operation of a laser scanning device, which includes a laser scanning unit that performs laser scanning in the vertical direction and a camera, and a horizontal rotation unit that is capable of horizontal rotation, The laser scan is performed while the horizontal rotating part is rotated horizontally, and the camera takes photographs. In order to perform the aforementioned photography, the rotation of the horizontal rotating part is decelerated. To the computer in question A laser scanning program that, during the deceleration, performs a process to correct the difference between the horizontal scan interval of the vertical laser scan before deceleration and the horizontal scan interval of the vertical laser scan during deceleration by not generating a portion of the laser scan data from the vertical laser scan.

Images