Operator Reference

HALCON Operator Reference / 3D Reconstruction / Sheet of Light
ClassesClasses | | Operators

create_sheet_of_light_calib_objectcreate_sheet_of_light_calib_objectCreateSheetOfLightCalibObjectCreateSheetOfLightCalibObjectcreate_sheet_of_light_calib_object (Operator)

create_sheet_of_light_calib_objectcreate_sheet_of_light_calib_objectCreateSheetOfLightCalibObjectCreateSheetOfLightCalibObjectcreate_sheet_of_light_calib_object — Create a calibration object for sheet-of-light calibration.

Signature

create_sheet_of_light_calib_object( : : Width, Length, HeightMin, HeightMax, FileName : )

Herror create_sheet_of_light_calib_object(double Width, double Length, double HeightMin, double HeightMax, const char* FileName)

Herror T_create_sheet_of_light_calib_object(const Htuple Width, const Htuple Length, const Htuple HeightMin, const Htuple HeightMax, const Htuple FileName)

void CreateSheetOfLightCalibObject(const HTuple& Width, const HTuple& Length, const HTuple& HeightMin, const HTuple& HeightMax, const HTuple& FileName)

static void HOperatorSet.CreateSheetOfLightCalibObject(HTuple width, HTuple length, HTuple heightMin, HTuple heightMax, HTuple fileName)

def create_sheet_of_light_calib_object(width: float, length: float, height_min: float, height_max: float, file_name: str) -> None

Description

create_sheet_of_light_calib_objectcreate_sheet_of_light_calib_objectCreateSheetOfLightCalibObjectCreateSheetOfLightCalibObjectcreate_sheet_of_light_calib_object creates a CAD model of a calibration object for sheet-of-light calibration with calibrate_sheet_of_lightcalibrate_sheet_of_lightCalibrateSheetOfLightCalibrateSheetOfLightcalibrate_sheet_of_light and stores it in FileNameFileNameFileNamefileNamefile_name.

image/svg+xml HeightMax Length HeightMin Width X Y Z
A calibration object for sheet-of-light calibration

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 WidthWidthWidthwidthwidth, LengthLengthLengthlengthlength, HeightMinHeightMinHeightMinheightMinheight_min, and HeightMaxHeightMaxHeightMaxheightMaxheight_max must be given in meters. LengthLengthLengthlengthlength must be at least 10% larger than WidthWidthWidthwidthwidth. The Z coordinate of the highest point on the truncated pyramid is at most HeightMaxHeightMaxHeightMaxheightMaxheight_max. The calibration object might not be found by calibrate_sheet_of_lightcalibrate_sheet_of_lightCalibrateSheetOfLightCalibrateSheetOfLightcalibrate_sheet_of_light if the height difference between the truncated pyramid and the ramp is too small. In this case, adjust HeightMinHeightMinHeightMinheightMinheight_min and HeightMaxHeightMaxHeightMaxheightMaxheight_max 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 LengthLengthLengthlengthlength 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.

image/svg+xml Width HeightMin HeightMax b t α h d 2⋅c 0.5⋅Width Length Ø c 2⋅c
Technical drawing of the calibration object, where c is the diameter of the orientation mark, d is the distance of the pyramid from the front of the calibration object, h is the height of the truncated pyramid, b is the length of the diagonal of the pyramid at the bottom, t is the corresponding length at the top, and is the angle of the ramp as seen in the drawing. You can calculate these dimensions with the procedure get_sheet_of_light_calib_object_dimensions.

Set the parameter 'calibration_object'"calibration_object""calibration_object""calibration_object""calibration_object" to FileNameFileNameFileNamefileNamefile_name with set_sheet_of_light_paramset_sheet_of_light_paramSetSheetOfLightParamSetSheetOfLightParamset_sheet_of_light_param to use the generated calibration object in a subsequent call to calibrate_sheet_of_lightcalibrate_sheet_of_lightCalibrateSheetOfLightCalibrateSheetOfLightcalibrate_sheet_of_light.

Note that MVTec does not offer 3D calibration objects. Instead, use create_sheet_of_light_calib_objectcreate_sheet_of_light_calib_objectCreateSheetOfLightCalibObjectCreateSheetOfLightCalibObjectcreate_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_lightcalibrate_sheet_of_lightCalibrateSheetOfLightCalibrateSheetOfLightcalibrate_sheet_of_light.

Execution Information

  • Multithreading type: reentrant (runs in parallel with non-exclusive operators).
  • Multithreading scope: global (may be called from any thread).
  • Processed without parallelization.

Parameters

WidthWidthWidthwidthwidth (input_control)  number → HTuplefloatHTupleHtuple (real) (double) (double) (double)

Width of the object.

Default: 0.1

LengthLengthLengthlengthlength (input_control)  number → HTuplefloatHTupleHtuple (real) (double) (double) (double)

Length of the object.

Default: 0.15

HeightMinHeightMinHeightMinheightMinheight_min (input_control)  number → HTuplefloatHTupleHtuple (real) (double) (double) (double)

Minimum height of the ramp.

Default: 0.005

HeightMaxHeightMaxHeightMaxheightMaxheight_max (input_control)  number → HTuplefloatHTupleHtuple (real) (double) (double) (double)

Maximum height of the ramp.

Default: 0.04

FileNameFileNameFileNamefileNamefile_name (input_control)  filename.write → HTuplestrHTupleHtuple (string) (string) (HString) (char*)

Filename of the model of the calibration object.

Default: 'calib_object.dxf' "calib_object.dxf" "calib_object.dxf" "calib_object.dxf" "calib_object.dxf"

File extension: .dxf

Result

The operator create_sheet_of_light_calib_objectcreate_sheet_of_light_calib_objectCreateSheetOfLightCalibObjectCreateSheetOfLightCalibObjectcreate_sheet_of_light_calib_object returns the value 2 ( H_MSG_TRUE) if the given parameters are correct. Otherwise, an exception will be raised.

Module

3D Metrology

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