create_sheet_of_light_calib_object — Create a calibration object for sheet-of-light calibration.
create_sheet_of_light_calib_object creates a CAD model of a calibration object for sheet-of-light calibration with calibrate_sheet_of_light and stores it in FileName.
The calibration object consists of a ramp with a truncated pyramid rotated by 45 degrees. The calibration object contains an orientation mark in the form of a circular hole. The dimensions of the calibration target in Width, Length, HeightMin, and HeightMax must be given in meters. Length must be at least 10% larger than Width. The Z coordinate of the highest point on the truncated pyramid is at most HeightMax. The calibration object might not be found by calibrate_sheet_of_light if the height difference between the truncated pyramid and the ramp is too small. In this case, adjust HeightMin and HeightMax accordingly or increase the sampling rate when acquiring the calibration data.
The dimensions of the calibration object should be chosen such that it is possible to cover the measuring volume of the sheet-of-light setup. In addition, when selecting the Length of the calibration object, the speed of the sheet-of-light setup should be considered such that the calibration object is sampled with enough profile measurements.
Set the parameter 'calibration_object' to FileName with set_sheet_of_light_param to use the generated calibration object in a subsequent call to calibrate_sheet_of_light.
Note that MVTec does not offer 3D calibration objects. Instead, use create_sheet_of_light_calib_object to generate a customized CAD model of a calibration object. This CAD model can then be used to produce the calibration object. Milled aluminum is an established material for this. However, depending on the required precision, its thermal stability may be a problem. Note that the surface should be bright. Its color may have to be adjusted depending on the color of the laser to provide a sufficient contrast to the color of the laser. Additionally, the surface must not be translucent nor reflective. To achieve this, you can anodize or lacquer it. Please note that when lacquering it, the accuracy might be decreased due to the applied paintwork. However, a surface that is too rough leads to a decreasing precision as well. It is advisable to have the produced calibration object remeasured to determine whether the required accuracy can be achieved. The accuracy of the calibration object should be ten times higher than the required accuracy of measurement. After having the object measured, the results can be manually inserted into the DXF file that can then be used for the calibration with calibrate_sheet_of_light.
Width of the object.
Default value: 0.1
Length of the object.
Default value: 0.15
Minimum height of the ramp.
Default value: 0.005
Maximum height of the ramp.
Default value: 0.04
Filename of the model of the calibration object.
Default value: 'calib_object.dxf'
File extension: .dxf
The operator create_sheet_of_light_calib_object returns the value 2 (H_MSG_TRUE) if the given parameters are correct. Otherwise, an exception will be raised.