Survey device with an image evaluator for determining the spatial attitude of a target axis

Abstract

The present invention relates to a surveying device having an image evaluator for determining the spatial attitude of a target axis. The present invention relates to a surveying device (1) for determining the coordinate position of a spatial point, wherein the surveying device (1) comprises a camera (5) which is fixedly mounted to a transmitting unit in such a way that the field of view of the camera moves with an alignment member (2). The surveying device (1) further comprises an image evaluator which is configured to automatically identify corresponding image features (13) in different images of the camera (5), wherein the corresponding image features (13) represent reference points in the environment, and the image evaluator is configured to obtain spatial transformation parameters from the movement of the corresponding features (13), wherein the spatial transformation parameters enable determination of the spatial attitude difference of the target axis of the surveying device (1) between different distance measurements corresponding to different images.

Description

Technical Field

[0001] The present invention relates to a surveying device for determining the coordinate position of a spatial point. Background Art

[0002] Surveying devices are used in various fields that require measuring the coordinate position of a spatial point or determining geometric relationships, such as at a construction site, an industrial facility, or a land survey.

[0003] For example, a surveying device (e.g., implemented as a total station) is used to measure the coordinates of the position of a spatial point relative to the surveying device, e.g., to generate a set of spatial measurement points referenced to a common coordinate system. Another common function of a surveying device involves staking out points in an environment, e.g., where a first person aligns the telescope target axis of the surveying device to match a calculated pose and guides a second person carrying a staking device (e.g., including a retroreflector) towards a target point defined by the target axis of the surveying device and a calculated distance from the surveying device.

[0004] Generally, at each installation position of a surveying device, its accurate external orientation must be correctly determined in order to accurately measure the 3D coordinates of the measurement points relative to the surveying device and / or accurately set the pose of the target axis of the staking process. The general setup workflow includes using GNSS, plumb determination, and / or measurement of one or more reference points with known geometric relationships.

[0005] By way of example, for coordinate measurement, today's total stations are typically fully horizontally aligned, e.g., with the help of a bubble level or an inclination sensor, where the coordinates of the measurement point are obtained by measuring the distance, horizontal angle, and vertical angle while aiming at the point with an alignment component (commonly referred to as a "telescope"). The alignment component provides for the transmission and reception of a laser beam, and the distance in the direction of the laser beam is measured by an electro-optical distance measuring device. Electro-optical distance measurement is performed by emitting a laser beam to provide a pulse time-of-flight (TOF) measurement method, a phase-shift measurement method, or an interferometric measurement method. The orientation of the alignment component is determined by an angle measuring device of the surveying device (e.g., a theodolite including an angle encoder (such as an absolute or incremental rotary encoder)).

[0006] Once the surveying device is set at a specific location, the 3D coordinates of multiple points in the environment can be determined, where the absolute 3D coordinates of the measurement points are determined as follows: by measuring the spatial alignment change of the alignment component from an initial known spatial alignment to the spatial alignment when aiming at the measurement point, provided that all the multiple points to be measured have a direct line of sight to the surveying device and are within the measurement range of the surveying device.

[0007] Typically, the measurement project requires repositioning the surveying device, for example because the line of sight to all relevant measurement points is not given at once. Then the surveying device must be repositioned and updated so as to measure all relevant points.

[0008] Typically, multiple spatial points are measured from one measurement position of the surveying device such that they can be referenced (e.g., in a rather straightforward manner) to a common coordinate system relative to the surveying device.

[0009] Measurement points (spatial points of coordinate measurement) measured from different positions of the surveying device must be correlated with each other using a process commonly referred to as reference, point set registration, or scan matching. For example, this can be done based solely on data of 3D coordinate points utilizing electronic distance measurement included in the surveying device. By way of example, known methods for referencing total station data at different measurement positions involve using a polygonal route or the so-called free station method.

[0010] Both setting up the surveying instrument and providing data that can reference a local or global coordinate system of the environment typically involve a measurement process in which reference points with known coordinates are measured. These are generally tedious and error-prone tasks. SUMMARY OF THE INVENTION

[0011] Accordingly, it is an object of the present invention to provide an improved and / or simplified setup of the surveying instrument and an improved and / or simplified reference of the data of the surveying instrument.

[0012] A specific object is to provide a setup of the surveying instrument and a reference measurement of the surveying instrument that are faster and at the same time less error-prone.

[0013] Another object is to provide a surveying instrument with enhanced application and operation possibilities.

[0014] These objects are achieved by implementing at least some features of the present invention. The present invention describes features for further developing the present invention in an alternative or advantageous manner.

[0015] The present invention relates to a surveying device for determining the coordinate position of spatial points, wherein the surveying device includes a transmitting unit having an alignment member capable of rotating about two rotation axes. The alignment member is configured to provide a distance measurement that includes the alignment member transmitting measurement radiation so as to define a target axis, and the alignment member receiving the returned measurement radiation.

[0016] The surveying device includes a camera that is fixedly mounted to the transmitting unit in such a way that the field of view of the camera moves with the alignment member. Accordingly, a fixed spatial reference of the camera field of view relative to the target axis is provided.

[0017] The camera is configured to take two images, wherein each of the two images is associated with a different distance measurement, and each of the different distance measurements includes the transmission and reception of corresponding measurement radiation. Thus, the two images are associated with different instants in time.

[0018] By way of example, the camera has a field of view of 90 degrees or more (e.g., 180 degrees), for example, wherein the camera has a fish-eye lens. More particularly, the camera is implemented to provide a field of view cone with an opening angle of 90 degrees or more (e.g., 180 degrees).

[0019] The surveying device includes an image evaluator that is configured to automatically identify corresponding image features that are present in both images. The corresponding image features represent reference points within the environment, such as significant points like edges, corners, or high-intensity points, or more generally, points that can be detected by a general feature detector. The image evaluator is also configured to obtain spatial transformation parameters from the movement of the corresponding image features (by utilizing a fixed spatial reference of the camera field of view relative to the target axis), wherein the spatial transformation parameters enable determination of the spatial attitude difference of the target axis between different distance measurements corresponding to the two images.

[0020] Thus, according to one aspect of the invention, the orientation and position (so-called six-degree-of-freedom attitude or simply attitude) of the alignment member can be continuously tracked, for example, wherein the camera acquires an image each time a distance measurement is made. Thus, for example, for each distance measurement, the attitude difference between the actual attitude of the alignment member and the previous attitude can be determined.

[0021] The attitude of the alignment member is tracked relative to the environment, i.e., not necessarily relative to the instrument zero point or the instrument base. Thus, precise horizontal alignment of the instrument base is no longer required. In the case of a surveying device constructed in a conventional manner (wherein the surveying device includes a base and a support member that is rotatably mounted to the base about a first (so-called vertical) rotation axis, and wherein the alignment member is rotatably mounted to the support member about a second (so-called horizontal) rotation axis), no angle encoder or tilt sensor is required to determine the orientation of the alignment member.

[0022] In an alternative arrangement, feature tracking is combined with data from tilt sensors and / or angle encoders. By way of example, there may be an angle sensor that measures the horizontal angle of the target axis, but no angle sensor that measures the vertical angle of the target axis. The vertical angle is determined based on the camera image data and the tracking of image features. Additionally, the image data and the data from the angle sensors and tilt sensors can be fused together to determine the orientation of the alignment member.

[0023] In the case where the survey device encounters jolts or is deliberately moved to a new position, the position and orientation of the new setting can be determined relative to the previous setting. For example, this can be done by a conventional SLAM process (e.g., a visual SLAM process). Thus, not only the orientation is determined, but also all six degrees of freedom (6-DoF), i.e., three coordinates (X, Y, Z) and three orientation angles.

[0024] In one embodiment, the survey device includes a base and a support member, the support member being mounted to the base in such a way that the support member can move relative to the base about a first axis of rotation in a motorized manner, wherein an alignment member is mounted to the support member in such a way that the alignment member can move relative to the support member about a second axis of rotation in a motorized manner, and a camera is mounted at the alignment member and has a field of view of 90 degrees or greater (e.g., 180 degrees), more particularly, wherein the camera provides a field of view cone having an opening angle of 90 degrees or greater (e.g., 180 degrees).

[0025] By way of example, the camera is arranged such that the second axis of rotation intersects the field of view of the camera, e.g., wherein the camera is arranged such that the optical axis of the objective lens of the camera is parallel to the second axis of rotation. In particular, the camera is arranged such that the optical axis of the objective lens of the camera is coaxial with the second axis of rotation. Generally, such a camera placement corresponds to a side-view camera, e.g., in a direction orthogonal to the alignment axis.

[0026] For example, the survey device includes an additional camera, the additional camera being arranged such that both cameras side-view in opposite directions. In the case where the fields of view of both cameras are 180 degrees, such an arrangement can provide an omnidirectional field of view.

[0027] Thus, in a further embodiment, the survey device includes an additional camera, the additional camera being fixedly mounted to the sending unit in such a way that the field of view of the additional camera moves with the alignment member, wherein the additional camera is arranged such that the optical axis of the objective lens of the additional camera is parallel to the second axis of rotation, e.g., coaxial with the second axis of rotation. Here, the previously described camera and the additional camera face in opposite directions. Similar to the previously described camera, the additional camera is configured to capture two images, wherein each of the two images is associated with a different distance measurement, and each of the different distance measurements includes the sending and receiving of corresponding measurement radiation.

[0028] For example, the camera and the additional camera are arranged and configured such that the fields of view of the camera and the additional camera overlap in all peripheral regions of the fields of view of the camera and the additional camera, e.g., wherein the survey device is configured to generate a full-dome panoramic image taking into account the images captured from both the camera and the additional camera.

[0029] In another embodiment, the camera is mounted at the alignment member such that the optical axis of the objective lens of the camera is perpendicular to the second rotation axis. For example, this allows for a camera field of view in the direction of the alignment axis, for example, where the camera is arranged in a so-called forward viewing position (towards the target). Similar to the laterally viewing camera described above, an additional camera can be used in a so-called backward viewing position (opposite to the forward viewing position).

[0030] In one embodiment, the survey device is configured to use spatial transformation parameters to determine the angular change of the orientation of the alignment member between different distance measurements corresponding to two images with respect to rotation about at least one of the first rotation axis and the second rotation axis. Thus, the spatial transformation parameters can be used to determine the orientation of the alignment member with respect to at least one of the first rotation axis and the second rotation axis.

[0031] In another embodiment, the survey device is configured to use spatial transformation parameters to determine the position change of the survey device between different distance measurements corresponding to two images. Thus, this embodiment allows for accounting for accidental collisions with the survey device or intentional repositioning of the survey device.

[0032] In a further embodiment, the survey device includes an inertial measurement unit and / or an inclination sensor arranged in the alignment member, wherein the survey device is configured to determine the absolute alignment with respect to the gravitational field by utilizing the inertial measurement unit and / or the inclination sensor. For example, this allows for making the coordinate position determination of a plurality of spatial points refer to a common coordinate system having a known alignment with respect to the gravity vector.

[0033] In a further embodiment, the survey device is configured to trigger image capture by the camera and (if applicable) by an additional camera at each instant of performing a distance measurement, and to provide an image associated with the image capture to the image evaluator.

[0034] In a further embodiment, the survey device includes an acceleration sensor configured to measure linear acceleration and / or angular acceleration, wherein the survey device is configured to trigger image capture by the camera and (if applicable) by an additional camera when the acceleration sensor detects a linear acceleration and / or an angular acceleration with an absolute value higher than a threshold, and to provide an image associated with the image capture to the image evaluator. By way of example, this allows for ensuring that the respective orientation and / or position changes of the alignment member can be taken into account before each distance measurement (and thus the coordinate position determination of the target point).

[0035] For example, the survey device is configured to identify the movement state of the alignment component based on an acceleration sensor and trigger image capture at a defined frame rate (e.g., ten frames per second) during the movement state. Then, a feature tracking algorithm (e.g., Lukas-Kanade-Tracking) can be used to track image features.

[0036] In a further embodiment, the survey device includes a relocalization mode, in which, during relocalization from a first position of the survey device to a second position of the survey device, the camera captures a series of images. A Simultaneous Localization and Mapping (SLAM) process is performed using the series of images, and based thereon, the difference between the spatial pose of the target axis at the first position, e.g., corresponding to a distance measurement performed from the first position, and the spatial pose of the target axis corresponding to a distance measurement performed from the second position is determined.

[0037] In particular, the survey device includes a movement sensor configured to detect the start and stop of the movement of the survey device as a whole, and the relocalization mode is triggered and stopped by the movement sensor.

[0038] Optionally, in a new setup where the survey device is in the second position, an automatic measurement process can be performed in order to provide a reference between the coordinate data acquired at the second position and the coordinate data acquired at a previous position (e.g., the first position). The survey device identifies a subset of the points that have been measured at the previous position. Then, the survey device automatically aims at these points and measures the coordinates of these points from the current position. Then, these coordinates can be used to more accurately determine the position of the new setup.

[0039] By way of example, in the case of having an inertial measurement unit as described above, the SLAM process (in particular, the initialization of the scale) can be based on the acceleration measured using the inertial measurement unit. Alternatively or additionally, the SLAM process can be based on the measurement points measured at the first position and / or on the stereo measurements in the overlapping area of the camera and another camera. For example, the camera and the other camera can be implemented as fish-eye cameras.

[0040] Thus, in another embodiment, the survey device includes an automatic target search function configured to automatically find spatial reference points within the environment, where the spatial reference points are spatial points associated with known visual attributes, e.g., points associated with specific geometric features such as the corners of a window. For example, the survey device is configured such that during the distance measurement to the spatial reference points by means of measuring radiation, the visual attributes are automatically provided by the visual pickup unit of the survey device, e.g., by a camera or another specific pickup device (e.g., another camera), where the survey device is configured to associate the visual attributes with the coordinate positions determined by the survey device by means of measuring radiation. The reference points can be spatial points for which the visual attributes have been determined as described above (e.g., regular target points to be measured), or the reference points can be dedicated points with known coordinates and visual attributes, e.g., where a data set including dedicated spatial points with associated visual attributes and known coordinates is provided to the survey device.

[0041] In this embodiment, the survey device is further configured to perform distance measurements from a first position to three spatial reference points and automatically perform distance measurements from a second position to the three spatial reference points based on the target search function. Thus, the survey device is configured to measure the 3D coordinates of three different spatial reference points from both the first position and (automatically) from the second position, and to refine the acquisition of the spatial transformation parameters by considering the 3D coordinates of the three different spatial reference points measured from the first position and the second position based on the position resection technique.

[0042] In particular, the difference in the attitude of the target axis at the first position and the attitude of the target axis at the second position is determined by means of a SLAM process, where from the second position, the three spatial reference points are targeted taking into account the difference in the attitude of the target axis.

[0043] On the other hand, it relates to the use of reference markers for referencing measurement points generated from different set-up positions of the survey device relative to a common coordinate system. By way of example, dedicated markers (e.g., implemented as matrix barcodes such as QR codes) can be used to establish reference points at the survey site. The coordinates of these markers can be measured once (e.g., using a high-end total station). Then, the coordinates of these markers are given in the common coordinate system of the entire site, e.g., where the z-axis of such a coordinate system is parallel to the gravity vector.

[0044] In another embodiment, the surveying device is configured to access reference data providing an external coordinate system and identify the imaging visual properties of markers in an image captured by a camera. By assuming that the visual properties of the markers provide an indication of the principal axes of the external coordinate system, the surveying device is configured to obtain the orientation of a target axis in the external coordinate system by analyzing the imaging visual properties of the markers.

[0045] By way of example, the reference data further includes the coordinates of the markers in the external coordinate system, and the surveying device is configured to identify the markers and obtain the pose of the target axis in the external coordinate system by analyzing the imaging visual properties, for example, by obtaining the position of the markers in a local coordinate system obtained by the SLAM process of the surveying device and comparing the position of the markers in the local coordinate system with the coordinates of the markers in the external coordinate system.

[0046] Another aspect of the present invention relates to a surveying device for determining the coordinate position of a spatial point, wherein the surveying device includes: a base; a support member rotatably mounted to the base about a first rotation axis. The surveying device further includes an alignment member rotatably mounted to the support member about a second rotation axis and configured to provide a distance measurement, the distance measurement including: the alignment member transmitting measurement radiation via a beam exit, thereby defining a target axis; and the alignment member receiving return measurement radiation via a beam entrance.

[0047] The support member has a leg member rising from the base in a direction parallel to the first rotation axis, and the leg member is pierced by the second rotation axis. The alignment member is disposed at a position rising from the base and is pierced by both the first rotation axis and the second rotation axis, wherein the alignment member is connected to the leg member via a shaft that provides rotation of the alignment member about the second rotation axis.

[0048] According to this aspect, the surveying device includes a camera fixedly mounted on the distal axial end of the shaft, the distal axial end being the axial end remote from the alignment member, and the camera is mounted in such a way that the camera opening points away from the alignment member and provides a field of view of the camera such that the second rotation axis intersects the field of view of the camera and the field of view of the camera moves with the movement of the shaft. By way of example, the camera is arranged such that the optical axis of the objective lens of the camera is parallel to the second rotation axis, for example, coaxial with the second rotation axis.

[0049] By way of example, this particular configuration of the surveying device provides a compact opto-mechanical and electro-mechanical package for the alignment member while ensuring an effective and robust acquisition of the spatial transformation parameters as described above. For example, the generally temperature-sensitive sensor of the camera, which requires a rather cool environment (e.g., an infrared sensor), is placed far from the center of the alignment member, the center of which typically generates a large amount of heat due to the laser components of the laser rangefinder for distance measurement.

[0050] The technical teachings described for the above aspects apply directly to that aspect. For example, in one embodiment, the camera has a field of view with a horizontal aperture angle of at least 90° and a vertical aperture angle of at least 90°, in particular where the horizontal aperture angle is at least 180° and the vertical aperture angle is at least 180°. By way of example, the camera is implemented as a fish-eye camera.

[0051] In a further embodiment, the survey device includes an inertial measurement unit and / or an inclination sensor arranged in an alignment member, and the survey device is configured to determine the absolute alignment with the gravitational field by using the inertial measurement unit and / or the inclination sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Hereinafter, the survey device according to different aspects of the present invention will be described or explained in more detail only by way of example and with reference to working examples schematically shown in the drawings. The same elements are denoted by the same reference numerals in the figures. The described embodiments are generally not shown to scale in reality, and they should not be construed as limiting the present invention. In particular,

[0053] Figure 1 are embodiments of the survey device from two different perspectives, where, for feature tracking, two cameras are mounted to the alignment member such that the second rotation axis intersects the fields of view of the two cameras;

[0054] Figure 2 is an exemplary workflow using the survey device according to the present invention, where the orientation of the alignment member is determined by tracking image features in the camera image;

[0055] Figure 3 is a further exemplary workflow using the survey device according to the present invention, where the survey device is repositioned and a SLAM process is performed between a first position and a second position and calibration measurements are made on three spatial reference points to refine the acquisition of the spatial transformation parameters;

[0056] Figure 4 Figure 4

[0057] Figure 5 is an exemplary 360° panoramic image generated by the survey device according to the present invention, which is merged into a full-dome panoramic image (top) and merged at one side of two captured images (bottom). DETAILED DESCRIPTION OF THE EMBODIMENTS

[0058] Figure 1Exemplary embodiments of the surveying device 1 according to the invention are depicted from two different side views. Here, the surveying device 1 is implemented as a total station having a telescope 2, a support 3, and a base 4. A pair of fisheye cameras 5 are integrated into the telescope 2, for example, where each camera 5 has a field of view greater than 180°, and each of the cameras 5 rotates together with the telescope 2.

[0059] The telescope 2 can be rotated in a motorized manner, whereby the support 3 is attached to the base 4 so as to be rotatable about a vertical rotation axis 6, and the telescope 2 is attached to two opposite leg members 7 of the support 3 so as to be rotatable about a horizontal rotation axis 8.

[0060] The total station 1 is configured to perform distance measurements by means of a laser beam 9, which is emitted via a beam exit 10 of the telescope 2, thereby defining a target axis. In the example shown, the beam exit 10 is also a beam inlet for receiving the return portion of the laser beam 9.

[0061] By way of example, the telescope 2 is connected to two opposite leg members 7 via two shafts 11 located on opposite sides of the telescope 2, where the cameras 5 are mounted on the far axial ends of the shafts 11, and the optical axes 12 of the objectives of the cameras are coaxial with the horizontal rotation axis 8. The two cameras 5 together provide for the acquisition of a full-dome panoramic image.

[0062] Figure 2 An exemplary workflow using the surveying device 1 according to the invention is schematically depicted, which in the example shown is implemented as previously described with reference to Figure 1 To measure a spatial point by means of the laser beam 9 (not shown, see Figure 1 ), the telescope is moved relative to the horizontal rotation axis 8 and the vertical rotation axis 6 so as to aim the laser beam at one or more different spatial points (not shown). During the rotation of the telescope about the horizontal and vertical axes, point features 13 are tracked in the panoramic image taken by the fisheye cameras 5. The point features 13 are significant points detected by a feature detector, for example, edges, corners, or high-intensity reflection areas. Based on the movement of the feature 13, changes in the measured orientation (e.g., horizontal and vertical angles relative to the initial orientation of the telescope) are measured.

[0063] After triggering the measurement, for example, after triggering the electro-optical distance measurement by the laser beam, the coordinates of the spatial point to be measured are calculated based on the measured distance and the determined changes in the horizontal and vertical angles relative to the initial orientation of the telescope.

[0064] By way of example, the determination of the orientation change is based on a "simplified" SLAM process, where only the orientation angles are calculated, and the position of the telescope is considered fixed.

[0065] Therefore, an angle encoder or a tilt sensor is not required to determine the orientation of the telescope.

[0066] In an alternative arrangement, the camera data is combined with data from a tilt sensor and / or an angle encoder. By way of example, there may be an angle encoder for two rotational axes 6, 8 or for only one of the rotational axes. For example, there may be one angle sensor that measures the horizontal angle, but no angle sensor that measures the vertical angle. In this way, the vertical angle will be determined based on the tracking of features 13 in the image data of the camera 5. In addition, the image data and the data from the angle sensors and tilt sensors can be fused together to determine the orientation of the telescope.

[0067] Figure 3 is schematically depicted as being located away from Figure 2 the depicted position at another position of the survey device. For illustrative purposes, the previous arrangement is still shown in the figure. Since the position of the survey device (and thus the telescope and the support) has also changed now, in the new arrangement, not only the orientation of the telescope 2 but also all six degrees of freedom (three coordinates (X, Y, Z) and three orientation angles) are determined relative to the previous position and orientation of the telescope at the previous position of the survey device 1. Again, this is done by performing a SLAM process between the first position and the second position.

[0068] Optionally, an automatic measurement process is performed in the new arrangement, in which three spatial reference points with known coordinates are measured to refine the acquisition of the spatial transformation parameters.

[0069] The survey device 1 identifies a subset of the points that have been measured at the previous position based on the image data of the camera 5. Here, for example, it is assumed that the spatial points 13 used for feature tracking are also the actual measurement points at which the survey device determines the exact coordinates by means of the laser beam 9. Therefore, these spatial points can be used in a dual manner, namely, as features 13 for feature tracking and as spatial reference points 14 to refine the acquisition of the spatial transformation parameters.

[0070] The survey device 1 then automatically aims at these spatial reference points 14, for example by using the position information provided by the SLAM process and an automatic target search function, and measures the coordinates of these points from the current position by means of the laser beam 9. These coordinates are then used to more accurately determine the position and orientation of the support 3 in the new arrangement.

[0071] Figure 4Another embodiment is shown, in which dedicated markers 15 are used to reference measurement points generated from different positions of the survey device 1. The coordinates of these markers 15 are given in a common coordinate system for the entire site. For example, the coordinates of these markers 15 (e.g., using a high-end total station) are measured once.

[0072] The survey device 1 is configured to identify the imaging visual properties 16 of the markers 15 in the images captured by the camera 5. By using the visual properties 16 (here, an indication of the horizontal and vertical axes of the common coordinate system), the survey device obtains the orientation of the telescope 2 in the common coordinate system.

[0073] By way of example, it may also be sufficient to provide only an indication of the gravity vector to the survey device 1 to provide a reference for the gravity vector. This makes it possible to dispense with the tilt sensor.

[0074] The characteristics of the markers 15 are known to the survey device 1 and the markers are fixedly attached to the survey site. Alignment of the markers can be performed using an eyepiece or using the optoelectronic image pickup of the survey device, where the alignment image is displayed to the user on a mobile device (e.g., a tablet). Alternatively or additionally, the survey device is configured to automatically search for, identify, and measure the markers 15.

[0075] To monitor the construction progress, it may be desirable to survey the construction site multiple times, e.g., every month. Assuming that the markers 15 do not change their position and / or orientation, the survey device 1 can be set up at different positions on the construction site at different times, while using the markers to reference the measurement points to the common coordinate system, e.g., by aligning the same markers again. By way of example, the survey device 1 is provided with reference data that includes the coordinates of the markers 15 in the common coordinate system. Thus, by performing coordinate measurements of different markers 15 from the current measurement position, the survey device 1 is able to absolutely reference the measurement points from this current position with respect to the common coordinate system.

[0076] Figure 5 An exemplary 360° panoramic image generated by the survey device 1 according to the present invention is shown, which is merged into a full-dome panoramic image (top) and merged at one side of two captured images (bottom).

[0077] By way of example, the panoramic image depicted in the top of the figure is obtained by using two fish-eye cameras, each fish-eye camera exhibiting a field of view with a horizontal aperture angle greater than 180° and a vertical aperture angle greater than 180°, wherein the two cameras are mounted to the telescope such that the two cameras have opposite fields of view. The two cameras both take images from the same position and orientation of the surveying instrument simultaneously. Since the two cameras exhibit fields of view with an overlapping area in the edge region of the image, the images of the two cameras can be easily merged, for example, based on corresponding features found in the edge region.

[0078] For example, the two cameras are mounted at the distal end of an axis that provides rotation of the telescope about a horizontal axis, for example, as Figure 1 depicted. Another possibility is to mount the two cameras on the body of the telescope, for example, in a back-to-back configuration, wherein the fields of view of the cameras differ by 180 degrees. It is also possible to generate a panoramic image by using only one camera.

[0079] The bottom of the figure depicts the same panoramic view, which is again obtained by using two cameras. However, the image is merged only on one side to provide a better overview for the observer.

[0080] Although the present invention has been illustrated above with reference to some preferred embodiments, it must be understood that various modifications and combinations of different features of the embodiments can be made. All such modifications are within the scope of the appended claims.

Claims

1. A surveying device (1) for determining the coordinate position of a spatial point, wherein, The surveying device (1) comprises: a transmitting unit having an alignment member (2) capable of rotating about two rotational axes, the two rotational axes including a first rotational axis (6) and a second rotational axis (8), wherein the alignment member (2) is configured to provide a distance measurement, the distance measurement including the alignment member (2) transmitting a measurement radiation (9) so as to define a target axis, and the alignment member (2) receiving a returned measurement radiation, a base (4), a support (3) rotatably mounted to the base (4) about the first rotational axis (6), wherein the alignment member (2) is rotatably mounted to the support (3) about the second rotational axis (8), a camera (5) fixedly mounted to the transmitting unit such that the field of view of the camera moves with the alignment member (2), wherein the camera (5) is configured to capture two images, wherein each of the two images is associated with a different distance measurement, each of the different distance measurements including transmission and reception of a corresponding measurement radiation (9), and an image evaluator configured to automatically identify corresponding image features (13) present in both of the two images, the corresponding image features (13) representing reference points within the environment, and the image evaluator being configured to obtain spatial transformation parameters from the movement of the corresponding image features (13), wherein the spatial transformation parameters enable determination of a spatial attitude difference of the target axis between different distance measurements corresponding to the two images.

2. The surveying device (1) according to claim 1, characterized in that the support (3) is mounted to the base (4) such that the support is capable of moving relative to the base (4) about the first rotational axis (6) in a motorized manner, wherein the alignment member (2) is mounted to the support (3) such that the alignment member (2) is capable of moving relative to the support (3) about the second rotational axis (8) in a motorized manner, and the camera (5) is mounted at the alignment member (2) and has a field of view of 90 degrees.

3. The surveying device (1) according to claim 2, characterized in that the camera (5) is arranged such that the second rotational axis (8) intersects the field of view of the camera (5), wherein the camera (5) is arranged such that the optical axis (12) of the objective lens of the camera (5) is parallel to the second rotational axis (8).

4. The surveying device (1) according to claim 2, characterized in that the optical axis (12) of the objective lens of the camera (5) is perpendicular to the second rotational axis (8).

5. The surveying device (1) according to any one of claims 2 to 4, characterized in that The survey device (1) is configured to use the spatial transformation parameters to determine an angular change of the orientation of the alignment member (2) relative to a rotation about at least one of the first rotation axis (6) and the second rotation axis (8) between different distance measurements corresponding to the two images.

6. The survey device (1) according to claim 1, wherein, the survey device (1) is configured to use the spatial transformation parameters to determine a position change of the survey device (1) between different distance measurements corresponding to the two images.

7. The survey device (1) according to claim 1, wherein, the survey device (1) includes an inertial measurement unit and / or an inclination sensor arranged in the alignment member (2), and the survey device (1) is configured to determine an absolute alignment with the gravitational field by utilizing the inertial measurement unit and / or the inclination sensor.

8. The survey device (1) according to claim 1, wherein, the survey device (1) is configured to trigger image capture by the camera (5) and, if applicable, by an additional camera (5) at respective instants of performing distance measurements, and the survey device (1) is configured to provide an image associated with the image capture to the image evaluator.

9. The survey device (1) according to claim 1, wherein, the survey device (1) includes an acceleration sensor configured to measure linear acceleration and / or angular acceleration, wherein the survey device (1) is configured to trigger image capture by the camera (5) and, if applicable, by an additional camera (5) when the acceleration sensor detects a linear acceleration and / or an angular acceleration with an absolute value higher than a threshold, and the survey device (1) is configured to provide an image associated with the image capture to the image evaluator.

10. The survey device (1) according to claim 1, wherein, the survey device (1) includes a relocalization mode, wherein · during relocalization from a first position of the survey device (1) to a second position of the survey device (1), the camera (5) captures a series of images, · an instant localization and mapping SLAM process is performed using the series of images, and based thereon, · a difference between a spatial pose of the target axis corresponding to a distance measurement performed from the first position at the first position and a spatial pose of the target axis corresponding to a distance measurement performed from the second position at the second position is determined.

11. The survey device (1) according to claim 10, wherein, · the survey device (1) includes an automatic target search function configured to automatically find a spatial reference point (14) within the environment, wherein the spatial reference point (14) is a spatial point associated with known visual attributes, and · The surveying device (1) is configured to perform distance measurements from the first position to three spatial reference points (14), and automatically perform distance measurements from the second position to the three spatial reference points (14) based on the target search function, thereby measuring the 3D coordinates of three different spatial reference points (14) from both the first position and the second position, and refining the acquisition of the spatial transformation parameters by considering the 3D coordinates of the three different spatial reference points (14) measured from the first position and the second position based on the resection technique.

12. The surveying device (1) according to claim 1, wherein, the surveying device (1) is configured to · access reference data providing an external coordinate system, · identify the imaging visual attributes (16) of the markers (15) in the images captured by the camera (5), and · obtain the orientation of the target axis in the external coordinate system by analyzing the imaging visual attributes (16) of the markers (15) by assuming that the imaging visual attributes (16) of the markers (15) provide an indication of the main axis of the external coordinate system.

13. The surveying device (1) according to claim 2, wherein, the camera (5) has a field of view of 180 degrees.

14. The surveying device (1) according to claim 3, wherein, the optical axis (12) of the objective lens of the camera (5) is coaxial with the second rotation axis.

15. The surveying device (1) according to claim 3, wherein, the surveying device (1) includes an additional camera (5), the additional camera (5) being fixedly mounted to the sending unit in such a way that the field of view of the additional camera follows the movement of the alignment member (2), wherein the additional camera (5) is arranged such that the optical axis (12) of the objective lens of the additional camera (5) is parallel to the second rotation axis (8), wherein the camera (5) and the additional camera (5) face in opposite directions, and the additional camera is configured to capture two images, wherein each of the two images is associated with a different distance measurement, and each of the different distance measurements includes the transmission and reception of corresponding measurement radiation (9).

16. The surveying device (1) according to claim 15, wherein, the optical axis (12) of the objective lens of the additional camera (5) is coaxial with the second rotation axis.

17. The surveying device (1) according to claim 9, wherein, the surveying device (1) is configured to identify the movement state of the alignment member (2) based on the acceleration sensor and trigger the image capture at a defined frame rate during the movement state.

18. The surveying device (1) according to claim 10, wherein, The survey device (1) includes a motion sensor configured to detect the start and stop of the movement of the survey device (1) as a whole, and the relocalization mode is triggered and stopped by the motion sensor.

19. The survey device (1) according to claim 11, wherein, Among them, during the distance measurement of the spatial reference point (14) by means of the measurement radiation (9), the visual attributes are automatically provided by the visual pickup unit of the survey device (1).

20. The survey device (1) according to claim 11, wherein, the difference in the attitude of the target axis at the first position and the attitude of the target axis at the second position is determined by means of a SLAM process, wherein, from the second position, the three spatial reference points (14) are aimed at taking into account the difference in the attitude of the target axis.

21. The survey device (1) according to claim 12, wherein, the reference data further includes the coordinates of the marker (15) in the external coordinate system, and the survey device (1) is configured to identify the marker (15) and obtain the attitude of the target axis in the external coordinate system by analyzing the imaging visual attributes (16).

22. The survey device (1) according to claim 21, wherein, the survey device (1) is configured to obtain the attitude of the target axis in the external coordinate system by obtaining the position of the marker (15) in the local coordinate system obtained by the SLAM process of the survey device (1) and by comparing the position of the marker (15) in the local coordinate system with the coordinates of the marker (15) in the external coordinate system.

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