Simulate an image with calibration plate.
sim_caltab is used to generate a simulated calibration image. The calibration plate description is read from the file CalTabDescrFile and will be projected into the image plane using the given camera parameters (interior camera parameters CamParam and exterior camera parameters CaltabPose), see also project_3d_point.
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 GrayCaltab, 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 GrayCaltab 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 camera_calibration).
|
SimImage (output_object) |
image -> object : byte |
| Simulated calibration image. | |
|
CalTabDescrFile (input_control) |
string -> string |
| File name of the calibration plate description. | |
| Default value: 'caltab.descr' | |
|
CamParam (input_control) |
number-array -> real / integer |
| Interior camera parameters. | |
| Number of elements: 8 | |
|
CaltabPose (input_control) |
pose-array -> real / integer |
| Exterior 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 value: 128 | |
| Suggested values: 0, 32, 64, 96, 128, 160 | |
| Restriction: (0 <= GrayBackground) <= 255 | |
|
GrayCaltab (input_control) |
integer -> integer |
| Gray value of calibration plate. | |
| Default value: 224 | |
| Suggested values: 144, 160, 176, 192, 208, 224, 240 | |
| Restriction: (0 <= GrayCaltab) <= 255 | |
|
GrayMarks (input_control) |
integer -> integer |
| Gray value of calibration marks. | |
| Default value: 80 | |
| Suggested values: 16, 32, 48, 64, 80, 96, 112 | |
| Restriction: (0 <= GrayMarks) <= 255 | |
|
ScaleFac (input_control) |
real -> real |
| Scaling factor to reduce oversampling. | |
| Default value: 1.0 | |
| Suggested values: 1.0, 0.5, 0.25, 0.125 | |
|
Recommended increment: 0.05 | |
| Restriction: 1.0 >= ScaleFac | |
* read calibration image
read_image(Image1, 'calib-01')
* find calibration pattern
find_caltab(Image1, Caltab1, 'caltab.descr', 3, 112, 5)
* find calibration marks and initial pose
StartCamPar := [Focus, Kappa, Sx, Sy, Cx, Cy, ImageWidth, ImageHeight]
find_marks_and_pose(Image1, Caltab1, 'caltab.descr', StartCamPar,
128 ,10, 18, 0.9, 15.0, 100.0, RCoord1, CCoord1,
StartPose1)
* read 3D positions of calibration marks
caltab_points('caltab.descr', NX, NY, NZ)
* camera calibration
camera_calibration(NX, NY, NZ, RCoord1, CCoord1, StartCamPar,
StartPose1, 11, CamParam, FinalPose, Errors)
* simulate calibration image
sim_caltab(Image1Sim, 'caltab.descr', CamParam, FinalPose, 128, 224, 80, 1)sim_caltab returns 2 (H_MSG_TRUE) if all parameter values are correct. If necessary, an exception handling is raised.
sim_caltab is processed under mutual exclusion against itself and without parallelization.
camera_calibration, find_marks_and_pose, read_pose, read_cam_par, hom_mat3d_to_pose
find_caltab, find_marks_and_pose, camera_calibration, disp_caltab, create_pose, hom_mat3d_to_pose, project_3d_point, create_caltab
Camera calibration
