sim_caltab🔗
Short description🔗
sim_caltab — Simulate an image with calibration plate.
Signature🔗
sim_caltab( out image SimImage, filename.read CalPlateDescr, campar CameraParam, pose CalPlatePose, integer GrayBackground, integer GrayPlate, integer GrayMarks, real ScaleFac )
Description🔗
sim_caltab is used to generate a simulated calibration
image. The calibration plate description is read from the file
CalPlateDescr and will be projected into the image plane
using the given camera parameters, thus internal camera parameters
CameraParam and external camera parameters
CalPlatePose (see also project_3d_point).
Thereby the pose is expected to be in the form
\(\mvPoseVar{{ccs}}{wcs}\), where
ccs denotes the camera coordinate system and
wcs the world coordinate system (see
Transformations / Poses
and “Solution Guide III-C - 3D Vision”).
In the simulated image only the calibration plate is shown. The
image background is set to the gray value GrayBackground,
the calibration plate background is set to GrayPlate, and
the calibration marks are set to the gray value GrayMarks.
The parameter ScaleFac influences the number of supporting
points to approximate the elliptic contours of the calibration
marks, see also disp_caltab. Increasing the number of
supporting points causes a more accurate determination of the mark
boundary, but increases the computation time, too. For each pixel
of the simulated image which touches a subpixel-boundary of this
kind, the gray value is set linearly between GrayMarks and
GrayPlate dependent on the proportion Inside/Outside.
By applying the operator sim_caltab you can generate
synthetic calibration images (with known camera parameters!) to test
the quality of the calibration algorithm (see
Calibration).
Execution information🔗
Execution information
-
Multithreading type: reentrant (runs in parallel with non-exclusive operators).
-
Multithreading scope: global (may be called from any thread).
-
Automatically parallelized on internal data level.
Parameters🔗
SimImage (output_object) image → object (byte)
Simulated calibration image.
CalPlateDescr (input_control) filename.read → (string)
File name of the calibration plate description.
Default: 'calplate_320mm.cpd'
List of values: 'calplate_10mm.cpd', 'calplate_1200mm.cpd', 'calplate_160mm.cpd', 'calplate_20mm.cpd', 'calplate_20mm_dark_on_light.cpd', 'calplate_320mm.cpd', 'calplate_40mm.cpd', 'calplate_40mm_dark_on_light.cpd', 'calplate_5mm.cpd', 'calplate_640mm.cpd', 'calplate_80mm.cpd', 'calplate_80mm_dark_on_light.cpd', 'caltab_100mm.descr', 'caltab_10mm.descr', 'caltab_200mm.descr', 'caltab_2500um.descr', 'caltab_30mm.descr', 'caltab_650um.descr', 'caltab_6mm.descr', 'caltab_800mm.descr', 'caltab_big.descr', 'caltab_small.descr'
File extension: .cpd, .descr
CameraParam (input_control) campar → (real / integer / string)
Internal camera parameters.
CalPlatePose (input_control) pose → (real / integer)
External camera parameters (3D pose of the calibration plate in camera coordinates).
Number of elements: 7
GrayBackground (input_control) integer → (integer)
Gray value of image background.
Default: 128
Suggested values: 0, 32, 64, 96, 128, 160
Restriction: 0 <= GrayBackground <= 255
GrayPlate (input_control) integer → (integer)
Gray value of calibration plate.
Default: 80
Suggested values: 144, 160, 176, 192, 208, 224, 240
Restriction: 0 <= GrayPlate <= 255
GrayMarks (input_control) integer → (integer)
Gray value of calibration marks.
Default: 224
Suggested values: 16, 32, 48, 64, 80, 96, 112
Restriction: 0 <= GrayMarks <= 255
ScaleFac (input_control) real → (real)
Scaling factor to reduce oversampling.
Default: 1.0
Suggested values: 1.0, 0.5, 0.25, 0.125
Recommended increment: 0.05
Restriction: 1.0 >= ScaleFac
Example🔗
(HDevelop)
* Read calibration image.
read_image(Image1, 'calib-01')
* Find calibration pattern.
CameraType := 'area_scan_division'
StartCamPar := [CameraType, Focus, Kappa, Sx, Sy, Cx, Cy, \
ImageWidth, ImageHeight]
create_calib_data ('calibration_object', 1, 1, CalibDataID)
set_calib_data_cam_param (CalibDataID, 0, [], StartCamPar)
set_calib_data_calib_object (CalibDataID, 0, 'calplate.cpd')
find_caltab(Image1, CalPlate1, 'caltab.descr', 3, 112, 5)
* Find calibration marks and initial pose.
find_calib_object (Image1, CalibDataID, 0, 0, 0, [], [])
* Camera calibration.
calibrate_cameras (CalibDataID, Error)
* Simulate calibration image.
get_calib_data (CalibDataID, 'calib_obj_pose', [0, 0], 'pose', FinalPose)
get_calib_data (CalibDataID, 'camera', 0, 'params', CameraParam)
sim_caltab(Image1Sim, 'calplate.cpd', CameraParam, FinalPose, 128, \
80, 224, 1)
Result🔗
sim_caltab returns 2 (H_MSG_TRUE) if all parameter values are
correct. If necessary, an exception is raised.
Combinations with other operators🔗
Combinations
Possible predecessors
camera_calibration, find_marks_and_pose, read_pose, read_cam_par, hom_mat3d_to_pose
Possible successors
See also
find_caltab, find_marks_and_pose, camera_calibration, disp_caltab, create_pose, hom_mat3d_to_pose, project_3d_point, gen_caltab
Module🔗
Calibration