Wednesday, May 5, 2010

Fast 3D scanning methods for laser measurement systems

In this paper (writed by Oliver Wulf, Bernardo Wagner) present a laser time-of-flight method, it can provide distance measurements at 50 meters with error of centimeters.

They combines a 2D laser scanner with a servo drive, it allow different arrangements of scan planes and rotation axis that lead to different fields of view.

First defines 4 diferents combinations of the scanner and servo drive, then discuse the measurement density of each one and the measured points are not placed ina regular grid, the density is minimal for laser beams orthogonal to the rotation axis and maximal for beams parallel to this axis
example:






in this case there are two regions
with high measurement density







Then they show diferences in a experimental comarison, whith de same number of points and the same time of scanning the result was diferent, the region more detailed correspond whit the region of mayor density.

They show what case is better for indor or outdor scan depending in the choosed method (combination of scanner and axis of rotation).

To calculate 3D point cloud is needed a transformation whith input: 2D raw scan and the position of the 2D scanner.

Posible aplications for 3D laser scanners are: object localization and recognition for an automated system, safety systems, surveillance, navigation etc.

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