Nonlinear calibration of a laser stripe profiler

Abstract

The calibration of a laser stripe profiler consisting of a laser stripe projector, camera, and linear motion table is considered. A nonlinear system model is used, which accommodates radial distortion in the camera lens. The way in which stripe data is extracted from the camera images leads to a natural formulation of the calibration problem as a nonlinear least squares problem. This can then be solved using standard techniques. The use of this nonlinear model reduces the error in the generated 3-D data by over an order of magnitude.

Laser imaging and approximation networks for calibration of three-dimensional vision

“…This resolution is good according to reported methods in the recent years with similar distances to our setup [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. From these reported methods, paint brush laser range scanner reports 0.57 mm as the best resolution [6].…”

“…For the distance ' p , the data h 1 , h 2 and x ip are substituted in Eq. (16) to obtain the next equation system…”

“…In optical metrology, the three-dimensional measurement is performed based on the calibration of vision parameters [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. The proposed technique provides the data for the calibration by means of a Bezier network.…”

“…By detecting the laser line on calibrated points, the vision parameters are computed via transformation matrix. Another method of laser projection is calibrated by means of calibrated marks on the surface [16]. This method computes the vision parameters by detecting the laser line in the marks and a transformation matrix.…”

“…The calibration provides parameters such as camera orientation, focal distance, setup distances, pixel scale and image centre. Several researches have been developed for the calibration of laser line projection via perspective projection [7][8][9][10][11][12][13][14][15][16][17]. One of these methods is implemented by projecting a laser line on black and white rectangles [7].…”