JP2017111118A - Registration calculation between three-dimensional(3d)scans based on two-dimensional (2d) scan data from 3d scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide registration calculation between three-dimensional (3D) scans based on two-dimensional (2D) scan data from a 3D scanner.SOLUTION: A method for measuring and registering a three-dimensional (3D) coordinate includes the steps of: measuring a 3D coordinate using a 3D scanner 20 in a first registration position; measuring a two-dimensional (2D) coordinate using the 3D scanner by projecting a beam of light in a plane onto an object while the 3D scanner is moving from the first registration position to a second registration position; measuring the 3D coordinate using the 3D scanner in the second registration position; and determining the correspondence between targets in the first and second registration positions while the 3D scanner is moving between the second registration position and the third registration position.SELECTED DRAWING: Figure 1

Description

  Alignment calculation between 3D (3D) scans based on 2D (2D) scan data from a 3D scanner.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of US patent application Ser. No. 14 / 559,311 filed Dec. 3, 2014, which is International Patent Application No. PCT No. 10/2012 109 481.0 filed Oct. 5, 2012 and US patent application 61/716 filed Oct. 22, 2012. , 845, all of which are incorporated herein by reference.

  U.S. Pat. No. 8,705,016 ('016) describes a laser scanner that emits a light beam into its environment by using a rotatable mirror to provide a three-dimensional Generate a (3D) scan. The contents of this patent are incorporated herein by reference.

  The subject matter disclosed herein relates to the use of a 3D laser scanner time-of-flight (TOF) coordinate measurement device. This type of 3D laser scanner steers a beam of light toward a non-cooperating target, such as a diffusely scattering surface of an object. A distance meter in the device measures the distance to the object, and an angle encoder measures the rotation angle of two axes in the device. The measured distance and the two angles allow the processor in the device to determine the 3D coordinates of the target.

  The TOF laser scanner is a scanner in which the distance to the target point is determined based on the speed of light in the air between the scanner and the target point. Laser scanners are typically used to scan closed or open spaces such as interior areas of buildings, industrial facilities, and tunnels. For example, laser scanners may be used in industrial and accident reproduction applications. A laser scanner optically scans and measures an object in this space by obtaining data points representing the object plane in the space around the scanner. Such data points send a beam of light to the object and collect reflected or scattered light to determine distance, two angles (ie azimuth and zenith angles), and optionally a grayscale value. Obtained by. This raw scan data is collected, stored and sent to one or more processors to generate a 3D image representing the scanned region or object.

  Generating an image requires at least three values for each data point. These three values may include distance and two angles, or may be transformed values such as x, y, z coordinates. In one embodiment, the image is also based on a fourth grayscale value, which is a value related to the irradiance of scattered light returning to the scanner.

  Most TOF scanners send a beam of light into the measurement space by steering the light using a beam steering mechanism. The beam steering mechanism includes a first motor that steers the beam of light about the first axis by a first angle measured by a first angle encoder (or other angle transducer). The beam steering mechanism also includes a second motor that steers the beam of light about the second axis by a second angle measured by a second angle encoder (or other angle transducer).

  Many modern laser scanners include a camera that is attached to the laser scanner to collect a digital camera image of the environment and present the digital camera image to the operator of the laser scanner. By looking at the camera image, the scanner operator can determine the field of view of the space to be measured and adjust the settings of the laser scanner to measure over a relatively large or small area of space. Further, the camera digital image may be transmitted to a processor to add color to the scanner image. To generate a color scanner image, at least three position coordinates (x, y, z, etc.) and three color values (red, green, blue “RGB”, etc.) are collected at each data point.

  A 3D image of a scene may require multiple scans from various alignment positions. For example, as described in US Patent Application Publication No. 2012/0069352 ('352), overlapping scans are registered in the combined coordinate system, the contents of which are incorporated herein by reference. Such alignment is performed by matching targets in overlapping areas of multiple scans. The target may be an artificial target such as a sphere or checkerboard, or may be a natural shape such as a corner or edge of a wall. Some alignment procedures include relatively time-consuming manual procedures such as the user identifying each target and matching the target obtained by the scanner at each of the various alignment positions. . Some alignment procedures also require establishing a “control network” outside the alignment target that is measured by an external device such as a total station. The alignment method disclosed in '352 does not require the user to perform alignment target matching and control network establishment.

  However, even if simplified by the '352 method, it is still difficult today to eliminate the need for the user to perform a manual alignment step as described above. In typical cases, only 30% of 3D scans can be automatically aligned to scans acquired from other alignment positions. Today, such alignment is rarely performed in the field of 3D measurements, but instead is performed in the office after the scanning procedure. Typically, a study that takes a week to scan requires 2-5 days to manually align multiple scans. This adds cost to scanning investigations. In addition, a manual alignment process may reveal that the overlap between adjacent scans was insufficient to achieve proper alignment. In other cases, a manual alignment process may reveal that certain areas of the scanning environment have been excluded. When such a problem occurs, the operator must return to the site to obtain additional scans. In some cases, it is impossible to return to the site. Buildings that were available for scanning at one time may become inaccessible after some time. Forensic scenes of car accidents or murders are often not available for scanning for some time after the incident.

US Patent Application Publication No. 2012/0069352

  Thus, while existing 3D scanners are suitable for their original purpose, there is a need for 3D scanners that have certain features of embodiments of the present invention.

  According to one aspect of the invention, a method for measuring and aligning three-dimensional (3D) coordinates is the step of fixedly placing a measuring device at a first alignment position, the measuring device comprising: Providing a 3D scanner on a movable platform, and using a 3D scanner to obtain 3D coordinates of a first set of points on an object when in a first alignment position, the 3D scanner Project the beam of light onto the object and accordingly determine the 3D coordinates of the first set of points by obtaining the distance and two angles for each point in the first set of points. And the distance is based at least in part on the speed of light in the air, and when the measuring device moves from the first alignment position to the second alignment position, the first plurality 2D Acquiring a cancel set with a 3D scanner, wherein each of the first plurality of 2D scan sets is a set of 2D coordinates of each point on the object, and each of the first plurality of 2D scan sets is a first Steps collected by the 3D scanner at different positions relative to the one alignment position, a first translation value corresponding to the first translation direction, a second translation value corresponding to the second translation direction, and Determining for the measuring device a first rotation value corresponding to one orientation axis, wherein the first translation value, the second translation value, and the first rotation value are at least partly A step determined based on the fitting of the first plurality of 2D scan sets according to the first mathematical criteria, and the 3D coordinates of the second set of points on the object when in the second alignment position The step of obtaining using a 3D scanner and the position present in both the first set of points and the second set of points when the measuring device moves from the second alignment position to the third alignment position. Determining a correspondence between alignment targets by means of a measuring device, the correspondence being based at least in part on the first translation value, the second translation value, and the first rotation value; Storing a first translation value, a second translation value, and a first rotation value.

  These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.

  The subject matter regarded as the invention is pointed out with particularity in the appended claims, particularly at the end of the specification. The above and other features and advantages of the present invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings.

1 is a perspective view of a laser scanner according to an embodiment of the present invention. It is a side view of the laser scanner which shows the measuring method. 1 is a schematic diagram of optical, mechanical and electrical components of a laser scanner. It is a top view of the image by which 3D scanning was carried out. FIG. 4 is a diagram illustrating an embodiment of a panoramic view of a 3D scanned image generated by mapping a plan view onto a sphere. It is a figure which shows embodiment of 3D display (3D view) of the 3D scanned image. It is a figure which shows embodiment of 3D display (3D view) of the image by which 3D scanning was carried out. It is a figure which shows embodiment of 3D display (3D view) of the image by which 3D scanning was carried out. FIG. 6B is an illustration of an embodiment of a 3D display composed of the image of the object of FIG. 6B but viewed from a different perspective and only partially shown. It is a perspective view of 3D measuring device by one embodiment. FIG. 3 is a front view of a 3D scanner used to collect 3D coordinate data while scanning along a horizontal plane, according to one embodiment. 1 is a block diagram illustrating a processor system according to one embodiment. FIG. FIG. 2 is a schematic diagram of a 3D scanner that measures an object from two alignment positions according to one embodiment. FIG. 3 is a schematic diagram of a 3D scanner that measures an object by scanning along a horizontal plane from a plurality of intermediate positions according to one embodiment. FIG. 3 is a diagram illustrating a 3D scanner that captures portions of an object by scanning along a horizontal plane from a plurality of positions according to one embodiment. FIG. 3 is a diagram illustrating a 3D scanner that captures portions of an object by scanning along a horizontal plane from a plurality of positions when viewed from a reference system of the 3D scanner according to one embodiment. FIG. 4 illustrates a method for finding changes in position and orientation of a 3D scanner over time according to one embodiment. FIG. 4 illustrates a method for finding changes in position and orientation of a 3D scanner over time according to one embodiment. FIG. 4 illustrates a method for finding changes in position and orientation of a 3D scanner over time according to one embodiment. FIG. 3 includes steps of a method for measuring 3D coordinates and aligning them using a 3D measurement device according to one embodiment. 1 is a perspective view of a 3D measurement device including a 3D scanner, a 2D scanner, a computing device, and a movable platform according to one embodiment. FIG. FIG. 3 includes steps of a method for measuring 3D coordinates and aligning them using a 3D measurement device according to one embodiment.

  The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.

  The present invention provides two modes: a first mode in which 3D coordinates of the object plane are obtained over each point in a 3D region of space, and a second mode in which 3D coordinates of the object plane are collected along a horizontal plane In conjunction with an apparatus comprising a 3D scanner used in the above, the two modes of this 3D scanner are used together to automatically align a 3D scan over a 3D area of space, including two or more scans of the 3D area of space. Realize.

  1-3, a laser scanner 20 for optically scanning and measuring the environment around the laser scanner 20 is shown. The laser scanner 20 has a measurement head 22 and a base 24. The measuring head 22 is attached to the base 24, so that the laser scanner 20 can rotate around the vertical axis 23. In one embodiment, the measurement head 22 includes a gimbal point 27, which is the center of rotation about the vertical axis 23 and the horizontal axis 25. The measuring head 22 has a rotating mirror 26, which can rotate about a horizontal axis 25. The rotation around the vertical axis may be around the center of the base 24. The terms vertical and horizontal axes are for scanners in a standard upright position. The 3D coordinate measuring device can be operated with its sides or top down, and to avoid confusion, the terms azimuth axis and zenith axis can be replaced by the terms vertical axis and horizontal axis, respectively. Good. As an alternative to the vertical axis, the terms pan axis or upright axis may be used.

  The measuring head 22 is further provided with an electromagnetic radiation emitting device, such as a light emitter 28 that emits the emitted light beam 30. In one embodiment, the emitted light beam 30 is a coherent light beam, such as a laser beam. The laser beam may have a wavelength band of approximately 300-1600 nanometers, for example, less than 790 nanometers, 905 nanometers, 1550 nanometers, or 400 nanometers. It should be understood that other electromagnetic radiation beams with longer or shorter wavelengths may be used. The emitted light beam 30 is amplitude-modulated or intensity-modulated using, for example, a sinusoidal waveform or a square wave. The emitted light beam 30 is emitted onto the rotating mirror 26 by the light emitter 28, and the beam is deflected by this mirror and sent to the environment. The reflected light beam 32 is reflected from the environment by the object 34. The reflected or scattered light is captured by the rotating mirror 26 and sent to the light receiver 36. The directions of the emitted light beam 30 and the reflected light beam 32 result from the angular position of the rotating mirror 26 and the measuring head 22 about axes 25 and 23, respectively. These angular positions then depend on the corresponding rotating device or motor.

  A controller 38 is coupled to the light emitter 28 and the light receiver 36. The controller 38 determines a corresponding number of distances d between the laser scanner 20 and each point X on the object 34 at a number of measurement points X. The distance to a particular point X is determined, at least in part, based on the speed of light in the air as electromagnetic radiation propagates from the device to point X on the object. In one embodiment, the modulation phase shift and point X in the light emitted by the laser scanner 20 is determined and evaluated to obtain the measurement distance d.

The speed of light in the air depends on air characteristics such as air temperature, atmospheric pressure, relative humidity, and carbon dioxide concentration. Such air characteristics affect the refractive index n of air. The speed of light in air is equal to the speed of light c in vacuum divided by the refractive index. That is, c _air = c / n. Laser scanners of the type discussed herein are based on the time of flight (TOF) of light in the air (the round trip time for light to propagate from the device to the object and back to the device). Examples of TOF scanners are scanners that measure the round-trip time using the time interval between the emission pulse and the return pulse (pulse TOF scanner), the light is modulated in a sine wave and the phase shift of the returned light is Scanners to measure (phase-based scanners), as well as many other types are included. The method of measuring distance based on the time of flight of light depends on the speed of light in the air and is therefore easily distinguished from the method of measuring distance based on triangulation. Triangulation-based methods require projecting light along a specific direction from a light source and then capturing the light on camera pixels along a specific direction. By knowing the distance between the camera and the projector, and by matching the projected angle with the received angle, the triangulation method makes a known triangle length and two known angles. Based on this, the distance to the object can be determined. Therefore, the triangulation method does not depend directly on the speed of light in the air.

  In a mode of operation, scanning the space around the laser scanner 20 causes the rotating mirror 26 to rotate relatively fast about the axis 25 and the measuring head 22 to rotate relatively slowly about the axis 23, thereby causing a helical pattern. This is done by moving the assembly. In one exemplary embodiment, the rotating mirror rotates at a maximum speed of 5820 revolutions per minute. In such a scan, the gimbal point 27 defines the origin of the local stationary reference system. The base 24 is located in this local stationary reference system.

  In addition to measuring the distance d from the gimbal point 27 to the object point X, the scanner 20 may also collect grayscale information (equal to the term “brightness”) related to the received optical power. . The gray scale value may be determined, at least in part, for example, by integrating a signal that has been bandpass filtered and amplified at the receiver 36 over a measurement period due to the point X of the object.

  The measurement head 22 may include a display device 40 incorporated in the laser scanner 20. The display device 40 may include a graphical touch screen 41 as shown in FIG. 1, which allows the operator to set parameters or start the operation of the laser scanner 20. For example, the screen 41 may include a user interface that allows an operator to present measurement instructions to the device, and this screen may display measurement results.

  The laser scanner 20 includes a measurement head 22 and a support structure 42 that realizes a platform frame for mounting the components of the laser scanner 20. In one embodiment, the support structure 42 is made from a metal such as aluminum. The support structure 42 includes a cross member 44 having a pair of walls 46, 48 at both ends. The walls 46 and 48 are parallel to each other and extend in a direction opposite to the base 24. The outer cases 50 and 52 are connected to the walls 46 and 48 and cover the components of the laser scanner 20. In the exemplary embodiment, the outer cases 50, 52 are made from a plastic material such as polycarbonate or polyethylene, for example. The outer cases 50, 52 cooperate with the walls 46, 48 to form a housing for the laser scanner 20.

  A pair of frames 54 and 56 are arranged at the ends of the outer cases 50 and 52 opposite to the walls 46 and 48 so as to partially cover the outer cases 50 and 52. In the exemplary embodiment, the frames 54, 56 are made from a reasonably durable material such as aluminum that helps protect the outer case 50, 52 during shipping and operation. Each of the frames 54, 56 includes a first arm portion 58 that is connected to the transverse member 44 adjacent to the base 24 using, for example, fasteners. The arm portions 58 for the frames 54 and 56 extend obliquely from the lateral member 44 to the outer corners of the outer cases 50 and 52, respectively. The frames 54 and 56 extend from the outer corners of the outer case to the outer corners on the opposite side of the outer case along the side edges of the outer case. Each frame 54, 56 further includes a second arm portion that extends diagonally to the walls 46, 48. It should be understood that the frames 54, 56 may be coupled to the transverse member 44, the walls 46, 48, and the outer cases 50, 52 at multiple locations.

  A pair of frames 54 and 56 cooperate to surround a convex space in which the two outer cases 50 and 52 are arranged. In the exemplary embodiment, the frames 54, 56 cooperate to cover all of the outer edges of the outer case 50, 52, and the upper and lower arm portions are the upper and lower edges of the outer case 50, 52. Extending over at least a portion of the. This provides an advantage in protecting the outer case 50, 52 and measuring head 22 from damage during transport and operation. In other embodiments, the frames 54, 56 may include additional features such as, for example, a handle to facilitate support of the laser scanner 20 and attachment points for accessories.

  A prism 60 is provided on the upper side of the horizontal member 44. This prism extends parallel to the walls 46, 48. In the exemplary embodiment, the prism 60 is integrally formed as part of the support structure 42. In other embodiments, the prism 60 is a separate component connected to the transverse member 44. As the mirror 26 rotates, the mirror 26 directs the emitted light beam 30 to the cross member 44 and the prism 60 during each rotation. Since the electronic component, for example the receiver 36, is non-linear, the measured distance d may depend on the signal intensity, which signal intensity is incident on, for example, the optical power incident on the scanner or on the photodetector in the receiver 36. You may measure with the optical power to do. In one embodiment, the distance to the measurement point, and the optical power returned from the measurement point and sent to the photodetector in the light receiver 36 (generally unadjusted optical power, sometimes referred to as “brightness”) The distance correction is stored in the scanner as a function (possibly a nonlinear function). Since the prism 60 is at a known distance from the gimbal point 27, the measured optical power level of the light reflected by the prism 60 may be used to correct the distance measurement for other measurement points, thereby Compensation for correcting the influence of environmental variables such as temperature can be realized. In the exemplary embodiment, the resulting distance correction is performed by the controller 38.

  In one embodiment, the base 24 is coupled to a swivel assembly (not shown), as is well described in US Pat. No. 8,705,012 ('012) owned by the right holder of this application. This patent is incorporated herein by reference. The swivel assembly includes a motor housed within the support structure 42 and configured to rotate the measurement head 22 about the shaft 23.

  The auxiliary image acquisition device 66 may be a device that captures parameters associated with the scanned space or the scanned object, measures it, and provides a signal representative of the measurement across the image acquisition region. The auxiliary image acquisition device 66 may be, but is not limited to, a pyrometer, thermal imaging device, ionizing radiation detector, or millimeter wave detector. In one embodiment, auxiliary image acquisition device 66 is a color camera.

  In one embodiment, a central color camera (first image acquisition device) 112 may be disposed inside the scanner and have the same optical axis as the 3D scanner device. In this embodiment, the first image acquisition device 112 is integrated into the measurement head 22 and is configured to acquire an image along the same optical path as the emitted light beam 30 and the reflected light beam 32. . In this embodiment, the light from the light emitter 28 reflects to the fixed mirror 116 and travels to the dichroic beam splitter 118, which reflects the light 117 from the light emitter 28 to the rotating mirror 26. The dichroic beam splitter 118 allows light to pass at a wavelength different from the wavelength of the light 117. For example, the light emitter 28 may be near-infrared laser light (for example, light having a wavelength of 780 nm or 1150 nm), and the dichroic beam splitter 118 transmits this infrared laser while transmitting visible light (for example, wavelength of 400 to 700 nm). Configured to reflect light. In other embodiments, the determination of whether light is transmitted through or reflected through the beam splitter 118 depends on the polarization of the light. The digital camera 112 takes a 2D photographic image of the scanned area, captures color data, and adds it to the scanned image. In the case of a built-in color camera having an optical axis that coincides with the optical axis of the 3D scanning device, by simply adjusting the steering mechanism of the scanner, for example, by adjusting the azimuth around axis 23, and axis 25 By steering the mirror 26 around, the direction of the camera field of view can be easily obtained.

  FIG. 4 shows an example of a plan view of a 3D scanned image 400. The plan view shown in FIG. 4 maps an image based on direct mapping of data collected by the scanner. The scanner collects data in a spherical pattern and the data points collected very close are more strongly compressed than the data points collected near the horizon. That is, each point collected near the pole has a smaller solid angle than each point collected near the horizon. Since data from the scanner may be represented directly in rows (rows: rows) and columns (columns: columns), it is convenient to represent the data in a planar image in a linear format as shown in FIG. When using the planar mapping described above, the straight line appears to be bent, for example, a straight fence railing 420 that appears to be bent in the plan view of the 3D image. The plan view may be a scanned image that has not been 3D processed and that displays only the grayscale values received from distance sensors arranged in columns and rows when recorded. Further, the 3D raw scan image of the plan view may be full resolution or reduced resolution depending on system characteristics (eg, display device, storage device, processor). The plan view is a 3D processed scanned showing either grayscale values (obtained from the light exposure measured by the distance sensor for each pixel) or color values (obtained from the camera image mapped on the scan). It may be an image. The plan view extracted from the 3D scanner is usually a grayscale image or a color image, but FIG. 4 is shown as a line drawing for clarity of document reproduction. The user interface associated with the display device may be integrated with the laser scanner and may implement a point selection mechanism, which is the cursor 410 in FIG. A point selection mechanism may be used to indicate dimensional information about the volume of space measured by the laser scanner. In FIG. 4, the row and column at the cursor position are indicated by 430 on the display device. Two measured angles and one measured distance (3D coordinates in a spherical coordinate system) at the cursor position are shown on the display device at 440. An orthogonal XYZ coordinate representation of the cursor position is shown at 450 on the display device.

  FIG. 5 shows an example of a full view (panoramic view) of a 3D scanned image 600 generated by mapping a plan view on a sphere or possibly a cylinder. The full view can be a scanned image that has been 3D processed (such as the image shown in FIG. 5) where 3D information (eg, 3D coordinates) is available. The full view may be full resolution or low resolution depending on system characteristics. Note that an image such as FIG. 5 is a 2D image representing a 3D scene when viewed from a particular viewpoint. In this sense, the image of FIG. 5 is similar to an image that may be captured by a 2D camera or the human eye. The full view extracted from the 3D scanner is usually a grayscale image or a color image, but FIG. 5 is shown as a line drawing for clarity of document reproduction.

  The term panoramic view refers to a display that is generally capable of angular motion around a point in space but is not capable of translational motion (in a single panoramic image). In contrast, the term 3D display (3D view) as used herein generally allows not only rotation around a fixed point (via user control) but also translational movement between points in space. Indicates the display to be performed.

  6A, 6B, and 6C show an example of 3D display of a 3D scanned image. In 3D display, the user can see the scan point from various viewpoints and angles away from the scan origin. A 3D display is an example of a scanned image that has been 3D processed. The 3D display may be full resolution or low resolution depending on system characteristics. In addition, 3D display allows multiple aligned scans to be displayed within a single display. FIG. 6A is a 3D display 710 with a selection mask 730 placed by the user. FIG. 6B is a 3D display 740 in which only a portion of the 3D display 710 covered by the selection mask 730 is retained. FIG. 6C shows the same 3D measurement data as in FIG. 6B except that it is rotated to obtain a different display. FIG. 7 shows a different display than FIG. 6B, in which case this display results from translation and rotation of the observer's viewpoint and a reduction of the observation area. The 3D display extracted from the 3D scanner is typically a grayscale image or a color image, but FIGS. 6A-6C and 7 are shown as line drawings for clarity of document reproduction.

  FIGS. 8A, 8B, and 9 illustrate one embodiment of a 3D measurement device 800 that includes a 3D scanner 20, a processor system 950, and an optional movable platform 820. FIG. The 3D measuring apparatus 800 may be the 3D TOF scanner 20 described with reference to FIG.

  The processor system 950 includes one or more processing elements that may include a 3D scanner processor (controller) 38, an external computer 970, and a cloud computer 980. The processor may be a microprocessor, a field programmable gate array (FPGA), a digital signal processor (DSP), and generally any device capable of performing computing functions. The one or more processors access the memory to store information. In one embodiment shown in FIG. 9, the controller 38 represents one or more processors distributed throughout the 3D scanner. Also included in the embodiment of FIG. 9 are an external computer 970 and one or more cloud computers 980 for remote computing functionality. In one alternative embodiment, only one or two of the processors 38, 970, and 980 are provided in the processor system. Communication between processors may be a wired link, a wireless link, or a combination of wired and wireless links. In one embodiment, after each scan session, the scan results are uploaded to the cloud (remote network) and stored for future use.

  In one mode of operation, the 3D scanner 20 measures 2D coordinates in the horizontal plane. In most cases, the 3D scanner 20 does this by steering light in a horizontal plane to illuminate each point of the object in the environment. The 3D scanner 20 collects reflected (scattered) light from each point of the object and determines 2D coordinates of each point of the object in the horizontal plane. In one embodiment, the 3D scanner scans a spot of light and measures the angle of rotation about the axis 23 using an angle encoder while simultaneously calculating a corresponding distance value to each illuminated object point in the horizontal plane. taking measurement. The 3D scanner 23 may rotate around the axis 23 at a relatively high speed without performing rotation around the axis 25. In one embodiment, the laser power is set within eye safety limits.

  Optional position / orientation sensors 920 within 3D scanner 20 may include inclinometers (accelerometers), gyroscopes, magnetometers, and altimeters. Typically, a device comprising one or more of an inclinometer and a gyroscope is called an inertial measurement unit (IMU). In some cases, the term IMU is used in a broad sense, and includes various additional devices that indicate position and / or orientation, such as a magnetometer that indicates the direction of travel based on changes in the direction of the magnetic field relative to the earth's magnetic north, and altitude ( Includes an altimeter indicating the height. An example of a widely used altimeter is a pressure sensor. By combining the readings from the position / orientation sensor combination with a fusion algorithm that may include a Kalman filter, a relatively low cost sensor device can be used to obtain a relatively accurate position and orientation. Measurements can be obtained.

  An optional moveable platform 820 allows the 3D measurement device 20 to be moved around, typically along a substantially horizontal floor. In one embodiment, the optional movable platform 820 is a tripod with wheels 822. In one embodiment, the wheel 822 may be locked in place using a wheel brake 824. In another embodiment, the wheel 822 is retractable and the tripod can be stably stationary with three legs attached to the tripod. In another embodiment, the tripod has no wheels and is simply pushed or pulled along a substantially horizontal surface, such as a floor surface. In another embodiment, the optional movable platform 820 is a wheeled cart that may be pushed or pulled by hand or motorized.

  In one embodiment, in one mode of operation, the 3D scanner 20 is configured to scan a beam of light over a range of angles in a horizontal plane. The 3D scanner 20 immediately returns the angle reading and the corresponding distance reading to present the 2D coordinates of each point of the object in the horizontal plane. In completing a scan over a range of angles, the 3D scanner 20 returns a set of paired angle and distance readings. As the 3D measuring device 800 moves, the 3D scanner 20 continues to return 2D coordinate values in the horizontal plane. These 2D coordinate values are used to position the 3D scanner 20 at each stationary alignment position, thereby enabling more accurate alignment.

  FIG. 10 shows the 3D measurement device 800 moved to a first alignment position 1112 in front of the object 1102 to be measured. The object 1102 may be an indoor wall, for example. In one embodiment, the 3D measurement device 800 is stopped and held in place using a brake. This brake is a brake 824 on wheels 822 in one embodiment. The 3D scanner 20 in the 3D measurement apparatus 800 takes a first 3D scan of the object 1102. In one embodiment, the 3D scanner 20 may acquire 3D measurements in all directions except where it is obstructed by the structure of the 3D measurement device 800, if necessary. However, in the example of FIG. 10 where the 3D scanner 20 measures a long and mostly flat structure 1102, a relatively small effective field of view (FOV) 1130 is selected to make the shape of the structure more front-facing. May be presented.

  When the first 3D scan is completed, the processor system 950 causes the 3D scanner 20 to change from the 3D scan mode to the 2D scan mode. In one embodiment, the processor system 950 does this by fixing the mirror 26 and sending the delivery beam 30 onto a horizontal plane. This mirror receives reflected light 32 traveling in the opposite direction. In one embodiment, the scanner starts a 2D scan as soon as the 3D scan stops. In another embodiment, the 2D scan begins when the processor receives a signal, such as a signal from the position / orientation sensor 920, a signal from a brake release sensor, or a signal transmitted in response to a command from an operator. The 3D scanner 20 may start collecting 2D scan data when the 3D measurement apparatus 800 starts moving. In one embodiment, 2D scan data is transmitted to the processor system 950 as it is collected.

  In one embodiment, 2D scan data is collected as the 3D measurement device 800 moves toward the second alignment position 1114. In one embodiment, 2D scan data is collected and processed as the 3D scanner 20 passes through a plurality of 2D measurement locations 1120. At each measurement location 1120, the 3D scanner collects 2D coordinate data over an effective field of view (FOV) 1140. Using the method described in more detail below, the processor system 950 uses a 2D scan data from a plurality of 2D scans at each position 1120 to use a second alignment position relative to the first alignment position 1112. The position and orientation of the 3D scanner 20 at 1114 is determined. Here, the first alignment position and the second alignment position are known in a 3D coordinate system common to both. In one embodiment, this common coordinate system is represented by 2D Cartesian coordinates x, y and a rotation angle θ relative to the x-axis or y-axis. In one embodiment, the x-axis and y-axis lie in the horizontal xy plane of the 3D scanner 20 and may be further based on the “front” direction of the 3D scanner 20. An example of such an (x, y, θ) coordinate system is the coordinate system 1410 of FIG. 14A.

  On the object 1102, there is an overlap between the first 3D scan (collected at the first alignment position 1112) and the second 3D scan (collected at the second alignment position 1114). There is a region 1150. In the overlap region 1150, there is an alignment target (which may be the natural shape of the object 1102) that is visible in both the first 3D scan and the second 3D scan. A problem that often occurs in practice is that when moving the 3D scanner 20 from the first alignment position 1112 to the second alignment position 1114, the processor system 950 loses track of the position and orientation trajectory of the 3D scanner 20, and thus The alignment procedure cannot be reliably performed by accurately associating the alignment targets within the overlap region. By using a series of 2D scans, the processor system 950 can determine the position and orientation of the 3D scanner 20 at the second alignment position 1114 relative to the first alignment position 1112. This information allows the processor system 950 to accurately match the alignment target in the overlap region 1150, thereby properly completing the alignment procedure.

  FIG. 12 illustrates a 3D scanner 20 that collects 2D scan data at a selected location 1120 over an effective field of view (FOV) 1140. At various positions 1120, the 3D scanner captures 2D scan data over a portion of the object 1102, which has been marked A, B, C, D, and E. FIG. 12 shows the 3D scanner 20 that moves in a timely manner with respect to the fixed reference system of the object 1102.

  FIG. 13 includes the same information as FIG. 12, but shows the information from the reference system of the 3D scanner 20 when acquiring a 2D scan instead of the reference system of the object 1102. From this figure, it becomes clear that the position of the shape on the object changes with time in the reference system of the scanner. Therefore, it is clear that the distance that the 3D scanner 20 moves between the registration position 1 and the registration position 2 can be determined from the 2D scan data transmitted from the 3D scanner 20 to the processor system 950.

  FIG. 14A shows a coordinate system that may be used in FIGS. 14B and 14C. In one embodiment, the 2D coordinates x and y are selected to lie in the plane from which the 2D scan is acquired, typically a horizontal plane. The angle θ is selected as the rotation angle in the plane and the rotation angle with respect to an axis such as x or y. In FIG. 14B and FIG. 14C, there is a realistic case where the 3D scanner 20 moves not only on a straight line, for example, nominally parallel to the object 1102 but also parallel to the side. It is shown. Further, the 3D scanner 20 may rotate as it moves.

  FIG. 14B shows the movement of the object 1102 when viewed from the reference system of the 3D scanner 20 when moving from the first alignment position to the second alignment position. In the reference system of the scanner (that is, when viewed from the viewpoint of the scanner), the object 1102 is moving and the 3D scanner 20 is fixed on a plane. In this reference system, each part of the object 1102 viewed from the 3D scanner 20 seems to translate and rotate over time. The 3D scanner 20 presents such a series of translated and rotated 2D scans to the processor system 950. In the example shown in FIGS. 14A and 14B, the scanner translates in the + y direction by a distance 1420 shown in FIG. 14B and rotates by an angle 1430. This angle is +5 degrees in this example. Of course, the scanner may have moved slightly in the + x or -x direction as well. As shown in FIG. 14B, in order to determine the movement of the 3D scanner 20 in the x, y, and θ directions, the processor system 950 captures data recorded in successive horizontal scans as can be seen in the reference system of the scanner 20. use. In one embodiment, the processor system 950 performs a best fit calculation using methods well known in the art to enable two scans or shapes in two scans. Match as close as possible.

  When the 3D scanner 20 takes successive 2D readings and performs a best fit calculation, the processor system 950 keeps a translation and rotation record of the 3D scanner 20. In this way, the processor system 950 accurately determines changes in the values of x, y, and θ as the measurement device 800 moves from the first alignment position 1112 to the second alignment position 1114. Can do.

  The processor system 950 does not perform 3D measurement based on a comparison of a series of 2D scans, rather than a fusion of 3D scan data and 2D scan data provided by the 3D scanner 20 at the first alignment position 1112 or the second alignment position 1114. It is important to understand that the position and orientation of the device 800 is determined.

  Instead, the processor system 950 is configured to determine a first translation value, a second translation value, and a first rotation value, which is a combination of the first 2D scan data and the second 2D scan data. Result in transformed first 2D data that matches as close as possible to the transformed second 2D data according to objective mathematical criteria To do. In general, translation and rotation may be applied to the first scan data, the second scan data, or a combination of the two. For example, in the sense that both operations produce the same match in the transformed data set, the translation applied to the first data set is equivalent to the negative translation number applied to the second data set. An example of an “objective mathematical criterion” is a criterion that minimizes the sum of squared residual errors for each portion of scan data that is determined to overlap. Another type of objective mathematical criterion may include matching multiple shapes identified on the object. For example, such a shape may be the edge transitions 1103, 1104, and 1105 shown in FIG. 11B. This mathematical criterion may include processing raw 2D scan data provided by the 3D scanner 20 to the processor system 950 or based on methods known in the art, eg, Iterative Closest Point (ICP). The method may be used to include a first intermediate level of processing in which each shape is represented as a collection of line segments. Such a method based on ICP is described by Censi, A. et al. "An ICP variant using a point-to-line metric", IEEE International Conference on Robotics and Automation (ICRA) 2008.

In one embodiment, the first translation value is dx, the second translation value is dy, and the first rotation value is dθ. If the first 2D scan data has translational coordinates and rotational coordinates (in the reference coordinate system) of (x ₁ , y ₁ , θ ₁ ), the second 2D scan data collected at the second position is , (X ₂ , y ₂ , θ ₂ ) = (x ₁ + dx, y ₁ + dy, θ ₁ + dθ). In one embodiment, the processor system 950 is further configured to determine a third translation value (eg, dz) and second and third rotation values (eg, pitch and roll). The third translation value, the second rotation value, and the third rotation value may be determined based at least in part on readings from the position / orientation sensor 920.

  The 3D scanner 20 collects 2D scan data at the first alignment position 1112 and further collects 2D scan data at the second alignment position 1114. In some cases, these 2D scans may be sufficient to determine the position and orientation of the 3D measurement device at the second alignment position 1114 relative to the first alignment position 1112. In other cases, two sets of 2D scan data are not sufficient to allow the processor system 950 to accurately determine the first translation value, the second translation value, and the first rotation value. . By collecting 2D scan data at the intermediate scan position 1120, this problem can be avoided. In one embodiment, 2D scan data is collected and processed at regular intervals, eg, once per second. In this way, each shape is easily identified in successive 2D scans 1120. If more than two 2D scans are obtained, the processor system 950 determines that the translation and rotation values when moving from the first alignment position 1112 to the second alignment position 1114 are all consecutive. You may choose to use information from the 2D scan. Alternatively, the processor can simply use an intermediate 2D scan to ensure proper correspondence of the matching shapes, and choose to use only the first and last scans in the final calculation. Also good. In most cases, the accuracy of matching is improved by incorporating information from multiple consecutive 2D scans.

  The 3D measurement apparatus 800 moves to the second alignment position 1114. In one embodiment, the 3D measurement device 800 stops and the brake is locked to hold the 3D scanner stationary. In an alternative embodiment, the processor system 950 automatically initiates a 3D scan when the movable platform stops, for example, by the position / orientation sensor 920 notifying the lack of motion. The 3D scanner 20 in the 3D measurement apparatus 800 takes a 3D scan of the object 1102. This 3D scan is called a second 3D scan and is distinguished from the first 3D scan acquired at the first alignment position.

  The processor system 950 applies the already calculated first translation value, second translation value, and first rotation value to adjust the position and orientation of the second 3D scan relative to the first 3D scan. . This adjustment may be considered to achieve “first alignment” and brings the alignment target (which may be a natural shape in the overlap region 1150) closer together. The processor system 950 performs fine alignment, where it makes fine adjustments to the six degrees of freedom of the second 3D scan relative to the first 3D scan. The processor system 950 makes fine adjustments based on objective mathematical criteria, which may be the same as or different from the mathematical criteria applied to the 2D scan data. For example, this objective mathematical criterion may be a criterion that minimizes the sum of squared residual errors for each portion of the scan data that is determined to overlap. Alternatively, this objective mathematical criterion may be applied to multiple shapes in the overlap region. Alignment mathematical calculations may be applied to raw 3D scan data or geometric representations of 3D scan data, for example by a set of line segments.

  Outside the overlap region 1150, the aligned values of the first 3D scan and the second 3D scan are combined in the aligned 3D data set. Inside the overlap region, the 3D scan values contained in the aligned 3D data set are based on some combination of 3D scanner data from the aligned values of the first and second scans.

  FIG. 15 shows elements of a method 1500 for measuring and aligning 3D coordinates.

  Element 1505 includes providing a processor system, a 3D scanner, and a 3D measurement device comprising a movable platform. The processor system includes at least one of a 3D scanner controller, an external computer, and a cloud computer for remote network access. Any of these processing elements in a processor system may comprise a single processor or multiple distributed processing elements, which may be a microprocessor, digital signal processor, FPGA, or any other type of computing It may be a device. This processing element accesses a computer storage device. The 3D scanner has a first light source, a first beam steering device, a first angle measuring device, a second angle measuring device, and a first light receiver. The first light source is configured to emit a first beam of light, which in one embodiment is a beam of laser light. A first beam steering device is provided to steer the first beam of light to the first object point in the first direction. The beam steering device may be a rotating mirror, such as mirror 26, or another type of beam steering mechanism. For example, the 3D scanner may include a base on which a first structure that rotates about a vertical axis is disposed, and the structure may include a second structure that rotates about a horizontal axis. Good. When using this type of mechanical assembly, the beam of light may be emitted directly from the second structure and the point in the desired direction. Numerous other types of beam steering mechanisms are possible. In most cases, the beam steering mechanism comprises one or two motors. The first direction is determined by the first rotation angle around the first axis and the second rotation angle around the second axis. The first angle measurement device is configured to measure the first rotation angle, and the second angle measurement device is configured to measure the second rotation angle. The first light receiver is configured to receive the first reflected light, the first reflected light being a portion of the first beam of light reflected by the first object point. The first light receiver is further configured to generate a first electrical signal in response to the first reflected light. The first receiver is further configured to cooperate with the processor system to determine a first distance to the first object point based at least in part on the first electrical signal. The scanner cooperates with the processor system to determine the 3D coordinates of the first object point based at least in part on the first distance, the first rotation angle, and the second rotation angle. Configured. The movable platform is configured to carry a 3D scanner.

  Element 1510 includes using a processor system and cooperating with the 3D scanner to determine the 3D coordinates of the first set of points on the object plane, the 3D scanner being fixed at the first alignment position. Be placed.

  Element 1515 includes obtaining a plurality of 2D scan sets by the 3D scanner in cooperation with the processor system. Each of the plurality of 2D scan sets is a set of 2D coordinates of points on the object plane collected as the 3D scanner moves from the first alignment position to the second alignment position. Each of the plurality of 2D scan sets is collected by the 3D scanner at a different position with respect to the first alignment position. In one embodiment, each 2D scan set is in a horizontal plane.

  Element 1520 provides a processor system with a first translation value corresponding to the first translation direction, a second translation value corresponding to the second translation direction, and a first rotation value corresponding to the first orientation axis. The first translation value, the second translation value, and the first rotation value are based at least in part on fitting of a plurality of 2D scan sets according to a first mathematical criterion. It is determined. In one embodiment, the first orientation axis is a vertical axis perpendicular to the plane in which the 2D scan set is collected.

  Element 1525 includes determining a 3D coordinate of a second set of points on the object plane using a processor system and cooperating with the 3D scanner, the 3D scanner fixed to a second alignment position. Be placed.

  Element 1535 includes identifying, by the processor system, correspondences between alignment targets that exist in both the first set of points and the second set of points, the correspondences being at least in part. , Based on the first translation value, the second translation value, and the first rotation value.

  Element 1545 includes a 3D coordinate of the aligned 3D set of points, a correspondence between the alignment targets, a 3D coordinate of the first set of points, based at least in part on a second mathematical criterion, and Determining the 3D coordinates of the second set of points. Element 1550 includes storing the 3D coordinates of the aligned 3D set of points.

  In most methods used today to scan large objects (eg, large buildings), data is collected at each alignment location and the quality of the alignment is later evaluated. One problem with this approach is that there is no way to detect alignment failure, which can be easily corrected in the field, but is corrected at a later time when the scan site is no longer available. Difficult to do. In addition, this method requires registration of multiple scans in software running on an external computer. In some cases, natural or artificial targets observed by the scanner at successive alignment positions may be automatically recognized and matched by software, but in many cases the scan is manually aligned. There must be. In many cases, the time and effort in aligning and processing 3D scan data exceeds the time required to collect this scan data in the field.

  In one embodiment described herein, processing of 2D and 3D scanner data is performed when measurements are performed, thereby eliminating time consuming post-processing and further required before leaving the field. Scanner data can be collected reliably.

  An example of a measurement device 800 that may be used to perform this measurement is described earlier in this specification with reference to FIG. Another example of a measuring device 1600 that may be used to perform this measurement will now be described with reference to FIG. The 3D measuring device 1600 includes a 3D TOF scanner 20 that measures a distance based at least in part on the speed of light in the air. This type of scanner also measures two angles using an angle transducer such as an angle encoder. Two measured angles and one measured distance give a 3D coordinate of each point on the object. In one embodiment, the scanner comprises a motor and servo system for driving the beam of light to any desired point on the object. In one embodiment previously described herein with reference to FIGS. 1-3, the scanner also rapidly sends a beam of light in a continuously changing pattern, thereby providing 3D coordinates over a large space. Includes modes that allow for rapid collection.

  The 3D measurement device 20 is further configured to emit a beam of light in a plane 1622, which may be a horizontal plane. In one embodiment, the beam of light is swept over a 360 degree angle at a rate of 10 Hz. In one embodiment, the 3D scanner 20 emits a beam of light onto the object, receives the reflected light from the object, and determines a set of distances to the object based on the reflected light. In one embodiment, in its planar emission mode, 3D scanner 1610 measures distance as a function of sweep angle. In one embodiment, the 3D measurement device further comprises an assembly 1620 having a computing device 1630 that receives 2D scan sets and 3D coordinate data from the 3D scanner 20. In one embodiment, the computing device 1630 further performs processing of the 2D and 3D scan data to determine a correspondence between the targets measured at the first alignment position and the second alignment position. In other embodiments, using other computing devices, such as a computer 1640 or an external computer 1650 not attached to the 3D measurement device, between targets measured at the first and second alignment positions. The correspondence relationship may be determined. In another embodiment, all processing of 3D and 2D data is performed by an internal processor in the 3D measurement device 20.

  The communication channel for transferring information between the 2D scanner, the 3D scanner, and the computing device may be a wireless or wired communication channel 1660. In one embodiment, a wireless access point (AP) is included in the 3D scanner 20. In one embodiment, the AP connects to a wireless device such as a 2D scanner 1610 or one or more of computing devices 1630, 1640, and 1650. In an alternative embodiment, the 3D scanner 20 includes an automation adapter having an Ethernet interface and a switch. This automation adapter connects to 2D scanner 1610 Ethernet cables and computing devices such as 1630, 1640, 1650. The automated interface enables wired communication between the elements of the measurement device 1600 and the external computing device. In one embodiment, the 3D scanner 20 includes both an AP and an automation adapter to provide both wireless and wired communication between the various components of the system. In other embodiments, the AP and automation adapter are not included in the 3D scanner 20, but are included elsewhere in the system.

  The measuring device further comprises a movable platform 1605, which may be pushed by an operator or moved under computer control by motorized wheels. The 3D scanner is attached to a movable platform 1605.

  In one embodiment, a first 3D scan is acquired at a first alignment position. The scanner moves between a first alignment position and a second alignment position using motorized wheels with its own power or pushed by an operator. As the 3D scanner moves between the first alignment position and the second alignment position, it obtains 2D scan data as described earlier in this specification and then mathematically stores this data. Evaluate to determine the motion vector (distance in each of the two directions) and the rotation angle. At the second alignment position, the 3D scanner 20 acquires a second 3D scan. As previously described herein, one of the computing devices (ie, processors) uses a plurality of acquired 2D scan sets to generate a first alignment position and a second alignment position. The correspondence between the alignment targets visible from the 3D scanner is determined. At a later time, the computing device performs a combination of 3D data collected at the first and second alignment positions and any other steps necessary to complete the processing. This process of combination further includes additional data collected, such as color data obtained from an internal color camera in the scanner.

  The measuring device 1600 moves to successive alignment positions, acquires 3D measurements at each alignment position, and collects 2D data by emitting planar mode light between each alignment position. One aspect of the present invention is that the processing is executed between the second alignment position and the third alignment position, and the correspondence between the alignment targets observed at the first and second alignment positions. Is to determine the relationship. In this process, 2D data collected between the first alignment position and the second alignment position is used together with 3D data obtained at the first and second alignment positions.

  Thus, when the scanner reaches the third alignment position, the computing device determines (at least partially if not complete) the correspondence between each target at the first and second alignment positions. become. If the correspondence is not successfully established by the computing device, a notification may be issued indicating that a problem exists. As a result, the operator may be notified or the measurement may be interrupted. In one embodiment, if the alignment of the target observed by the 3D scanner at the first and second alignment positions fails, the scanner will return to the previous step and repeat the measurement.

  In one embodiment, when the computing device determines a correspondence between targets in the overlap region of the first and second alignment locations, the measurement device further determines the quality of this correspondence. In one embodiment, the measurement device issues a notification when the quality of the correspondence is below a quality threshold. This notification may be, for example, a notification to the user, a computer message, emitted sound, emitted light, or a stop of the inspection procedure.

  In one embodiment, the scanner determines the distance by which the measuring device 1600 is moved between the first alignment position and the second alignment position based at least in part on one of the 2D scan sets. You may decide. In one embodiment, each of the 2D scan sets includes information about shapes that are observable in a horizontal 2D scan. Examples of such shapes are the shapes 1102 to 1105 in FIG. In one embodiment, the determination of the distance traveled between the first alignment position and the second alignment position is collected exclusively between the first alignment position and the second alignment position. Based on the first 2D scan set. In another embodiment, the moving distance determination is based on a plurality of first 2D scan sets, and the moving distance determination is moved between a first alignment position and a second alignment position. Made inside.

  In one embodiment, computing device 1640 is a laptop computer or notebook computer, which provides the user with an interface to a computer program that allows advanced processing and display of scan data. In one embodiment, using the computing device 1640 is optional and is merely presented to give the operator more analysis tools. In another embodiment, the computing device 1640 is used to perform the correspondence calculation described earlier herein or to perform other 3D processing steps.

  In one embodiment, the computing device 1630 serializes the position of the measuring device 1600 based at least in part on data from the 2D scanner and optionally based on data provided by the position / orientation sensor. To calculate. The sensors may include multi-axis inclinometers, multi-axis gyroscopes, and magnetometers (electronic compass) for providing direction of travel information. In one embodiment, data from the 2D scanner is acquired at a rate of 10 Hz. In one embodiment, after each scan, a difference is calculated for one or more 2D scans obtained so far. In one embodiment, this information is provided to a Kalman filter, which performs an “intelligent averaging” calculation that smooths the noise within the constraints caused by the moving geometry.

  In one embodiment, application software is executed on a notebook computer 1640 or similar device. In one embodiment, the user selects a button on the application software user interface to initiate processing of the collected data. In one embodiment, after collecting 3D scan data at the second alignment position, the software requests 2D position information from the processed 2D scan data, which may be obtained from computing device 1630, for example. Good. The processed 2D scan data may be provided as metadata for the 3D scan. The software uses an alignment algorithm to determine the correspondence between alignment targets in the overlap region between the first alignment position and the second alignment position. The software completes the 3D alignment by combining the 3D coordinates obtained at the first and second alignment positions.

  In other embodiments, the calculation is performed without requiring the user to press a button on the user interface of an application program running on the notebook computer 1640. In one embodiment, measurements are performed in an integrated automated manner without requiring operator assistance. In one embodiment, the additional steps of the alignment step may include additional mathematical operations, such as combining the aligned 3D data, and may require adding texture to the aligned 3D data. It may be executed later. In one embodiment, these subsequent processing steps may be performed in parallel by a network computer, for example, to provide a completed 3D scan at the end of data collection by the measurement device 1600.

  FIG. 17 is a flow diagram of a method 1700 that may be performed in accordance with the description previously described herein. At element 1705, the measurement device 1600 is fixedly positioned at a first alignment position, such as position 1112 in FIG. The measuring device comprises a 3D scanner 20 configured to operate in both a 3D scan mode and a 2D planar scanner mode. The 3D scanner 20 is attached to a movable platform 1605, which in FIG. 16 is a tripod attached to a platform with three wheels. In one embodiment, in its planar scan mode, the 3D scanner emits a beam of light that is swept in various directions within the horizontal plane 1622.

  At element 1710, the 3D scanner obtains the 3D coordinates of the first set of points on the object when in the first alignment position. In the embodiment shown in FIGS. 10 and 11, this object is the side of a building. In one embodiment, the 3D scanner is a TOF scanner, which may be of various types. One example of a feasible TOF scanner is the scanner 20 discussed with reference to FIGS.

  At element 1715, the 3D scanner operates in its planar scan mode to acquire a first plurality of 2D scan sets, and the first measurement device moves from the first alignment position to the second alignment position. Moving. Each of the first plurality of 2D scan sets includes a set of 2D coordinates of points on the object. The 2D coordinates of each point on the object may be given in an arbitrary coordinate system, for example, as an xy value or as a distance value and an angle value. Each of the first plurality of 2D scan sets is collected by the 3D scanner at a different position relative to the first alignment position.

  At element 1720, the measuring device includes a first translation value corresponding to the first translation direction, a second translation value corresponding to the second translation direction, and a first rotation value corresponding to the first orientation axis. To decide. The first translation direction and the second translation direction may be, for example, xy coordinates in a coordinate system established with respect to the object being measured. For example, the xy coordinates may correspond to coordinates along the floor on which the measuring device moves. Alternatively, other coordinate systems may be used to represent the first translation direction and the second translation direction. The first orientation axis has a given direction relative to the first and second translation directions. A convenient choice for the first orientation axis is the direction perpendicular to the plane containing the vectors along the first and second translation directions. The first translation value, the second translation value, and the first rotation angle provide a good initial estimate of the scanner attitude at the second alignment position relative to the scanner attitude at the first alignment position. Provide the information you need to obtain. This provides a good basis for matching alignment targets visible from the first and second alignment positions, whether natural targets or artificial targets. The determination of the first translation value, the second translation value, and the first rotation angle is performed according to a first mathematical criterion. Such a mathematical standard is also called an objective mathematical standard. A commonly used mathematical criterion is the least square criterion. In this case, according to this criterion, the 2D shapes observed in the first set of 2D scan sets are aligned so as to minimize the sum of the residual error squares in shape matching.

  At element 1725, the 3D scanner obtains 3D coordinates of a second set of points on the object when in the second alignment position. In general, the first set of points measured by the 3D scanner at the first alignment position is not necessarily the same as the second set of points measured by the 3D scanner at the second alignment position. However, each point provides the information needed to identify the shape of the target, and this shape may be natural or artificial.

  At element 1730, when the measurement device moves from the second alignment position to the third alignment position, the alignment target as seen in the first set of 3D points observed at the first alignment position; Determining a correspondence between the alignment target seen in the second set of 3D points observed at the second alignment position. This alignment is based at least in part on the first translation value, the second translation value, and the first rotation value, whereby the initial conditions under which the mathematical matching of the 3D shape is performed are Provided.

  In element 1735, the first translation value, the second translation value, and the first rotation value are stored.

  Terms such as processor, controller, computer, DSP, FPGA, etc. may be located within the document, within the device, distributed within multiple elements throughout the device, or located outside the device. It is understood to mean a computing device that may be.

  Although the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to the embodiments thus disclosed. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions, or equivalent arrangements not previously described, which are within the spirit and scope of the invention. . Furthermore, while various embodiments of the invention have been described, it should be understood that each aspect of the invention includes only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope described in the appended claims.

  20 laser scanner, 3D scanner, 22 measuring head, 23 vertical axis, 24 base, 25 horizontal axis, 26 rotating mirror, 27 gimbal point, 28 illuminant, 30 emitted light beam, outgoing beam, 32 reflected light Beam, reflected light, 34 object, 36 light receiver, 38 control device, 40 display device, 41 graphical touch screen, 42 support structure, 44 lateral member, 46 wall, 48 wall, 50 outer case, 52 outer case, 54 frame , 56 frame, 58 first arm portion, 60 prism, 66 image acquisition device, 112 first image acquisition device, 116 fixed mirror, 117 light, 118 dichroic beam splitter, 400 image, 410 cursor, 420 handrail, 430 rows And column, 440 two angles measured and measured 1 distance, 450 Cartesian XYZ coordinate representation, 710 3D display, 730 selection mask, 740 3D display, 800 3D measuring device, 820 movable platform, 822 wheel, 824 wheel brake, 920 position / orientation sensor, 950 processor system, 960 Processor, 970 external computer, 980 cloud computer, 1102 object, 1112 first alignment position, 1114 second alignment position, 1120 2D measurement position, 1130 effective field of view (FOV), 1140 effective field of view (FOV), 1150 overlap region, 1410 coordinate system, 1500 method, 1505 elements, 1510 elements, 1515 elements, 1520 elements, 1525 elements, 1535 elements, 1545 elements, 1550 elements, 1600 3 Measuring device, 1605 movable platform, 1610 2D scanner, 3D scanner, 1622 horizontal plane, 1620 assembly, 1630 computing device, 1640 computer, 1650 external computer, 1660 communication channel, 1700 method, 1705 element, 1710 element, 1715 element , 1720 elements, 1725 elements, 1730 elements, 1735 elements.

Claims (16)

A method for measuring and aligning three-dimensional (3D) coordinates, comprising:
Fixing the measuring device at a first alignment position, the measuring device comprising a 3D scanner on a movable platform;
Using the 3D scanner to obtain 3D coordinates of a first set of points on the object when in the first alignment position, wherein the 3D scanner projects a beam of light onto the object And correspondingly configured to determine the 3D coordinates of the first set of points by obtaining a distance and two angles for each point in the first set of points, the distance A step based at least in part on the speed of light in the air;
Acquiring a first plurality of 2D scan sets by the 3D scanner when the measuring device moves from the first alignment position to a second alignment position, the first plurality of 2Ds; Each of the scan sets is a set of 2D coordinates of each point on the object, and each of the first plurality of 2D scan sets is by the 3D scanner at a different position with respect to the first alignment position. Collected steps;
A first translation value corresponding to the first translation direction, a second translation value corresponding to the second translation direction, and a first rotation value corresponding to the first orientation axis are determined for the measuring device. Said first translation value, said second translation value, and said first rotation value, at least in part, according to a first mathematical criterion, said first plurality of 2D scan sets Steps determined based on the fitting of
Using the 3D scanner to obtain 3D coordinates of a second set of points on the object when in the second alignment position;
Correspondence between alignment targets present in both the first set of points and the second set of points when the measuring device moves from the second alignment position to a third alignment position. Wherein the correspondence is based at least in part on the first translation value, the second translation value, and the first rotation value;
Storing the first translation value, the second translation value, and the first rotation value.   The method of claim 1, wherein the 3D coordinates of a first aligned 3D set of points based at least in part on a second mathematical criterion, the first set of points and the Determining the correspondence between alignment targets present in both of the second set of points, the 3D coordinates of the first set of points, and the 3D coordinates of the second set of points; A method characterized by comprising.   2. The method of claim 1, wherein the movable platform comprises a motorized wheel configured to move under computer control when the measuring device is fixedly positioned at the first alignment position. A method characterized by that.   2. The method according to claim 1, wherein when the 3D coordinates of the second set of points on the object are obtained using the 3D scanner when in the second alignment position, the measuring device. Is further configured to cause the 3D scanner to automatically start measuring the second set of points in response to a stop signal.   The method according to claim 1, wherein when the measurement apparatus moves from the first alignment position to the second alignment position, the first plurality of 2D scan sets are acquired by the 3D scanner. The 2D scan set is obtained by the 3D scanner by projecting the beam of light in a horizontal plane onto the object.   The method according to claim 1, wherein when the measurement apparatus moves from the first alignment position to the second alignment position, the first plurality of 2D scan sets are acquired by the 3D scanner. And the distance moved between the first alignment position and the second alignment position is based at least in part on one of the first plurality of 2D scan sets. Feature method.   The method of claim 1, wherein when the measuring device moves from the second alignment position to a third alignment position, the first set of points and the second set of points. A method wherein the measuring device further determines the quality of the correspondence when the measuring device determines a correspondence between alignment targets present in both.   8. The method of claim 7, wherein when the measuring device moves from the second alignment position to a third alignment position, the first set of points and the second set of points. In determining a correspondence between alignment targets existing in both by the measuring device, the measuring device issues a notification when the quality of the correspondence falls below a quality threshold.   3. The method of claim 2, wherein when the measuring device moves from the second alignment position to a third alignment position, the first set of points and the second set of points. In determining the correspondence between the alignment targets existing in both by the measurement apparatus, the measurement apparatus moves to the corrected second alignment position, and the corrected second alignment position is The method is characterized in that it is closer to the first alignment position than to the second alignment position.   The method of claim 1, wherein when the measuring device moves from the second alignment position to a third alignment position, the first set of points and the second set of points. In determining the correspondence between alignment targets existing in both by the measurement device, the determining step is performed at least in part by a computing device disposed in the measurement device. And how to.   3. The method of claim 2, wherein when the measuring device moves from the second alignment position to a third alignment position, the first set of points and the second set of points. In determining the correspondence between the alignment targets present in both by the measuring device, the computing device is able to move from the 3D scanner to the first plurality of 2D scan sets, the 3D coordinates of the first set of points. And receiving the 3D coordinates of the second set of points.   3. The method of claim 2, wherein in determining the 3D coordinates of a first aligned 3D set of points based at least in part on a second mathematical criterion. Wherein the method is performed at least in part by an external computing device that is not part of the measurement device.   3. The method according to claim 2, wherein a second plurality of 2D scan sets are acquired by the 3D scanner when the measuring device moves from the second alignment position to a third alignment position. And wherein each of the second plurality of 2D scan sets is collected by the 3D scanner at a different position with respect to the second alignment position.   14. The method of claim 13, further comprising obtaining 3D coordinates of a third set of points on the object using the 3D scanner when in the third alignment position. Feature method.   15. The method of claim 14, further comprising the step of determining, by the measuring device, correspondences between alignment targets that are present in both the second set of points and the third set of points. The determined correspondence is at least in part, the second plurality of 2D scan sets, the 3D coordinates of the second set of points on the object, and a third of the points on the object. A method characterized in that it is based on the 3D coordinates of a set.   16. The method of claim 15, wherein at least in part, the determined correspondence between the alignment targets present in both the second set of points and the third set of points. Determining a 3D coordinate of a 3D set of second aligned points based on the 3D coordinate of the second set of points.

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