Abstract: The present invention provides a method and a geodetic scanner for determining the appearance of a target. In the method and geodetic scanner of the present invention, an initial can is performed to calculate or determine a set of optimal gain values for each one of a number of predetermined positions (151-166) at the surface of the target (150). Once gain values (g151-g166) have been determined for all predetermined positions, distances to each one of the predetermined positions are calculated using the gain values. The present invention is advantageous in that the measurement rate and the overall efficiency are increased.

Abstract: It is disclosed a method for driving a laser diode such as to enable mitigation or elimination of so called spiking effects related to the number of injected carriers in the laser overshooting the equilibrium value at the beginning of the lasing process. In this manner, among other things, the efficiency of a master oscillator power amplifier that may be utilized in range finding applications will be improved. It is further disclosed an optical pulse transmitter comprising such a laser diode.

Abstract: An optical device is disclosed that may be employed in distance measuring devices. In at least one embodiment, the optical device includes a control unit that is adapted to cause at least one control signal generator unit to generate at least one control signal according to a predetermined temporal function on the basis of an elapsed time from a predetermined point in time. On the basis of the generated at least one control signal, at least one parameter of a receiver unit may be adjusted during the travel time of the optical pulse, wherein the at least one parameter affects the dynamic range of the receiver unit. In this way, the dynamic range of the receiver unit may be increased. A method is further disclosed for operating such an optical device, along with a distance measuring device including such an optical device and a surveying instrument including such a distance measuring device.

Abstract: The present invention provides devices and methods for multi-dimensional scanning of a scene. In particular, this invention provides scanning devices and methods employing controllable light beam scanning devices capable of sending a light beam onto a scene, and of receiving corresponding light returned from the scene, and controllers capable of operating the scanning device at selected beam orientations, and of gaining distance information from the scanning device at the beam orientations. The controller can dynamically define beam orientations using the distance information gained from preceding beam orientations.

Abstract: A method for determining rotational position of a target in a target tracking System is disclosed. The target comprises a plurality of light emitting elements arranged circumferentially around the target. The target tracking System further comprises a tracker unit capable of detecting light emitted by said light emitting elements.

Abstract: A method for aiming a surveying instrument towards a selected target is disclosed. The method includes, in at least one embodiment, capturing an image using a camera in the surveying instrument; selecting a target by identifying an object point in the image captured by the surveying instrument; calculating first horizontal and vertical rotation angles based on the object point identified in the image; rotating the surveying instrument over the first horizontal and vertical rotation angles to an intermediate line of sight; measuring a distance to a point along the intermediate line of sight; and calculating second horizontal and vertical rotation angles based on the object point in the image and on the measured distance. In at least one embodiment, the method may be implemented using computer software, hardware, firmware or a combination thereof. There is also disclosed a surveying instrument in which at least one embodiment of the method is implemented.

Abstract: One embodiment of the present invention concerns a target for use with a measuring instrument in distance measuring and surveying applications. The target includes a base element, at least one light reflecting area arranged at the base element, the at least one light reflecting area being arranged to reflect light beams being incident in an angular area of substantially 360° degrees in plane, and an identification unit arranged at the base element and being adapted to emit signals having predetermined characteristics, wherein the predetermined characteristics may be used to identify the target.

Abstract: A geodetic instrument is disclosed, wherein an image sensor is used for locating the instrument above a desired point on the ground. The positioning of the image sensor with respect to the instrument vertical rotation axis is determined, or calibrated, using a method where two images are captured at different horizontal rotational positions for the instrument, and where the center pixel of the image sensor is related to the vertical rotation axis by means of image processing. It is also disclosed how reflecting elements, such as prisms, may be used for providing stereoscopic vision that can be used for determining the instrument height above the ground.

Abstract: A position-determining apparatus, such as measuring or surveying instruments, is disclosed. In at least one embodiment, the present invention relates to a tilt sensor for a measuring instrument including a movable housing that is controllably rotatable around a rotational axis, wherein the rotational axis may be positioned so that it deviates from a true vertical axis being parallel with a gravitational axis. In at least one embodiment, the tilt sensor includes a gravity sensitive gradient indicating element arranged such that a surface of the element is positioned orthogonally to the true vertical axis during movements of the measuring instrument, wherein the gravity sensitive gradient indicating element is arranged in connection to the non-rotating base; and a detecting device adapted to produce at least one detecting signal and to receive at least one response signal, wherein a deviation between the rotational axis and the true vertical axis is detectable using the at least one response signal.

Abstract: Methods and devices for processing image data stored as three-dimensional point clouds related to a scene by selecting a profile definable in a two-dimensional surface, and matching the profile to one or more subsets of the cloud of points to identify surfaces in the scene having the same profile so that data sets representing the successive matched surface portions can be generated to provide a surface model of all or part of the scene.

Abstract: A method is disclosed for localizing a surveying instrument having a housing including at least one camera in relation to a mark located at a ground level. The method comprises the steps of capturing a first image of the ground below the housing in a first camera position and orientation, wherein the first camera position is eccentric to a vertical rotational axis of the surveying instrument, identifying an object point corresponding to the mark in the first image, measuring first image coordinates of the object point in the first image. The method further comprises the steps of capturing a second image of the ground below the housing in a second camera position and orientation, identifying in the second image, an object point corresponding to the mark, and measuring second image coordinates of the object point in the second image.

Abstract: There is disclosed methods and apparatus for compensated measurement of angular displacement within an instrument (600), such as a total station. Improved and compensated measurement of angular displacement is obtained by using a combination of e.g. an angular resolver (145) and an inertial sensor (645). A compensated angular position measurement is produced by combining at least portions of the output signals obtained from the angular resolver and the inertial sensor, respectively.

Abstract: The present invention relates to a measuring instrument and methods for such a measuring instrument for tracking a moving object, measuring a distance to an object. According to the invention, sets of target position data including at least horizontal (Ha) and vertical angle (Va) between the measuring instrument (1) and said at least one target (9) in consecutive measurements during a measurement session are obtained (40; 50; 60; 70); a model describing a path of and/or a distance to the target (9) is calculated; at least a present position of the target is estimated (44; 53; 65; 74) using the model; and, the estimated position of the target (9) is used (45; 56; 67; 79) when searching for the target (9).

Abstract: A surveying instrument performs tracking of a target by controlling an orientation of a measuring unit relative to the target in two different angular directions. The control in one angular direction is based on detected light intensities which are modulated according to a first time pattern, and control of the orientation in the other angular direction is based on detected light intensities modulated according to a second time pattern just different from the first time pattern.

Abstract: An absolute optical encoder apparatus for measuring an absolute position comprises an optical disk or scale element (100) having both incremental and absolute code tracks formed thereon. In the embodiment, a photoemitter light source (110, 111) illuminates the tracks onto a CCD area array sensor (115, 116) such that an image is formed from a pixel matrix having of rows and columns. Two detector line rows (410, 420) of the pixel matrix are each read out from the portion of the matrix comprising the incremental and absolute code tracks respectively. Inaccurate mounting of the disk or scale element can cause fluctuations in the period of the code tracks resulting from the rotation of the disk or movement of the scale element. The mounting inaccuracies are compensated for either by matching the spatial frequency by dynamically changing row of detector line read from the incremental image of the code track or by altering the numerical value of the pattern period used in the Fourier phase algorithm.

Abstract: A method for determining, in relation to a surveying instrument, target coordinates of a point of interest, or target, identified in two images captured by a camera in the surveying instrument. The method comprises determining coordinates of the surveying instrument, capturing a first image using the camera in the first camera position; identifying, in the first image, an object point associated with the target; measuring first image coordinates of the object point in the first image; rotating the surveying instrument around the horizontal axis and the vertical axis in order to position the camera in a second camera position; capturing a second image using the camera in the second camera position; identifying, in the second image, the object point identified in the first image; measuring second image coordinates of the object point in the second image; and determining the coordinates of the target in relation to the surveying instrument.

Abstract: An electro optic distance measurement apparatus using time of flight measurements and a method therefore are provided for determining a distance to a target of two or more targets located along a common line of sight from the distance measurement apparatus. Approximate distances to the two or more targets are determined by means of the distance measurement apparatus, one of the two or more targets is selected, and an accurate distance to the selected target is determined by means of the distance measurement apparatus.

Abstract: The invention relates to a method and device for contactless or touch-free measurement of a tool by imaging. A processor makes calculations based on image points on the tool, imaged onto an imaging area. Optics present the image of the image points on the tool on the imaging area. The processor calculates the momentary position and/or orientation along at least one axis of the tool making use of the image points. A number of measuring markers have predetermined mutual positions and are on the tool. Each measuring marker comprises at least one measuring point. At least one of the points is identifiable. Each measuring marker to be used as position and/or orientation indicator has a size making it restorable by the processor even if a part of it on the tool is obscured from the image area, for example by dust.

Abstract: The invention relates to a method of operating a surveying instrument (10) placed in a orthogonal XYZ-system at (0,0,0) having a movable unit (20), said instrument defining a sight line (128) that is controllably rotatable around a first axis (50), essentially horizontal, and around a second axis (90), essentially vertical, wherein said second axis (90) may be inaccurately positioned so that it deviates from a true vertical axis, and said first axis (50) may deviate from being orthogonal to the second axis (90); the method comprising the steps of determining at least one of the following group of errors relating to the instrument and/or its location: a) a trunnion axis error T as a function of the deviation from 90 degrees between the first axis (50) and the second axis; b) a horizontal collimation error CH, being the deviation between the sight line (128) and the perpendicular angle as related to the first axis (50); and c) a total plumb error defined by components, PI and PII, being two separate angular val

Abstract: A surveying instrument and method determine a duration of a measuring period for obtaining readings of angle values of an angle measuring system in dependence of readings of an error signal produced by a tracking system. It is thus possible to determine a value of the angle represented by the readings of the angle signal with a desired accuracy in the presence of air turbulence wherein the measuring period is shorter at low degrees of air turbulence and longer at higher degrees of air turbulence.