Laserscanning

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the term laser scanning or English Laserscanning designates the scanning of surfaces or bodies by means of laser technology. Hereexist different proceedings and areas of application.

Table of contents

procedures and areas of application

Laseraltimetrie

Laseraltimetrie is a method of geodesy,with the objects by point-wise rangings to be seized. There is e.g. terrestrial Laserscanning, with a measuring instrument. before a building and the object thereby is installed is scanned point for point. Besides there is the air-based Laserscanning, with that the sensorsin an airplane or a helicopter to be installed. This procedure serves generally for the collection of area heights and objects on the area and replaces increasingly classical photogrammetry.

With the determination of the distance to the object which can be seized can depending uponused system two different measuring procedures are used. Concerns either the pulse process or the phase procedure. During the measurement after the pulse process a short laser light impulse is sent and the radiation at the sensor, reflected by the object, is registered.The time, which elapses with the propagation of the signal by the atmosphere, is a measure for the double distance between the sending and receipt unit.

For a correct geo correlation of the ranging it is necessary that position and orientation of the sensor inArea at the time of the measurement admits is. In case of the air-based Laserscanning a combination becomes from at least a government inspection department - receiver and inertial navigation system (IN) use. Here it is important that the different measured values of the different sensors synchronouslyto be determined or over suitable procedures be at least synchronized can. With the air-based Laserscanning leave themselves in accordance with manufacturer data and/or. Service enterprise under favorable conditions (vegetationless surfaces, weak to middle Geländeneigung) accuracies at a value of 5-15 cm and in the situation of 30-50cm reach.

By means of suitable procedures then three-dimensional cartesian coordinates of the measured points can be derived from the data of the ranging and the component GOVERNMENT INSPECTION DEPARTMENT/IN.

A laser scanner, that apart from the three-dimensional position (coordinates) also the intensity of the reflected signalseized, illustrating laser scanner is called. The admission of the intensity values of the laser light reflected by the augenommenen surfaces takes place with today's Lasermessystemen in 16bit gray tones. In the result one keeps an image of the surfaces similar to that of a black-and-white photo.

3D-Laserscanning

with 3D-Laserscanning become the outlines (surfaces) of bodies (humans, articles) and areas seized by means of the so-called light cut triangulation digitally. Develops a discrete quantity of 3D-Abtastpunkten, which is called Punktwolke. The coordinates of the measured points become from the angles and thatDistance in purchase for origin (equipment location) determines. On the basis the Punktwolke either computations are accomplished (e.g. Measured of humans, classification of bodies) or it is reckoned back into a surface (Meshing) and e.g. in the 3D-Computergrafik uses. The scanning ofHumans is well-known also under the term Bodyscanning.

The employment of the Laserscanning finds increasing in the architecture measurement with emphasis in the building research and care of monuments application. In particular deformed and damaged buildings with spatially complicated structures can be seized fast and completely.Modern Lasermessysteme reaches a point accuracy of up to 1 mm at the object. A laser scanner with phase measuring procedures takes up additionally to the point coordinates the intensity values of the surfaces.

confocal Laserscanning

is a special three-dimensional Laserscanning procedure, that in the microscopy(Laser Scanning of microscopes) and the eye medicine (laser Scanning Ophthalmoskope) one uses. The principle of the confocal Laserscanninges is based on the fact that a focused laser beam becomes sometimes scanned over a sample (in the microscopy becomes instead the object moves) and the dropping back light behinda small point screen one detects. Only light from the fuel level is detected by the arrangement of the screen and one receives a sectional view only from this level. This level is as thick depends on the sharpness depth of the used microscope. Changesone between individual photographs the focusing, then can one a whole picture pile take up and receives so a 3D-Datensatz (see also confocal microscope).

material processing and manufacturing

with the scanning of surfaces with lasers hang it only of thatAchievement of the laser off, which happens thereby. Like that the laser achievement is so small in the ranges specified above that the scanned surface is not changed. If lasers with larger achievement are used, then one can engrave with these, separates, welds andother more, the procedure falls however still under the same term. Also with rapidly the prototyping a Laserscanningverfahren can be used, so for example, if a Protoyp is produced by means of laser scanners in the laser interprocedure so mentioned.

The structure in principle oneLaserscanningsystems looks with the fact in such a way that on the one hand one on a PC - or Embedded system current scanner often commodity a scanner map responds. This again heads for the Scankopf, which consists of two mirrors, those the laser diverts around so the desiredTo scan range. Which the result of a Scanvorganges is, thereby by the scanner often commodity one steers, which addresses and controls the attached components.

The moreover Scanköpfe exist to the 3D-Lasermarkieren, those beside the two mirrors for x and y axis still another adjustable opticspossess the Z-axis for the depth, thus. Thus it is then possible to head for the laser focussierten on a certain point also in the third dimension. Possible areas of application for it are the rapidly prototyping or in-Glass-Marking.

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