Operator Reference

binocular_calibrationT_binocular_calibrationBinocularCalibrationBinocularCalibrationbinocular_calibration (Operator)

binocular_calibrationT_binocular_calibrationBinocularCalibrationBinocularCalibrationbinocular_calibration — Determine all camera parameters of a binocular stereo system.

Signature

binocular_calibration( : : NX, NY, NZ, NRow1, NCol1, NRow2, NCol2, StartCamParam1, StartCamParam2, NStartPose1, NStartPose2, EstimateParams : CamParam1, CamParam2, NFinalPose1, NFinalPose2, RelPose, Errors)

Description

In general, binocular calibration means the exact determination of the parameters that model the 3D reconstruction of a 3D point from the corresponding images of this point in a binocular stereo system. This reconstruction is specified by the internal parameters CamParam1CamParam1CamParam1camParam1cam_param_1 of camera 1 and CamParam2CamParam2CamParam2camParam2cam_param_2 of camera 2 describing the underlying camera model, and the external parameters RelPoseRelPoseRelPoserelPoserel_pose describing the relative pose of camera system 2 in relation to camera system 1.

Thus, known 3D model points (with coordinates NXNXNXNXnx, NYNYNYNYny, NZNZNZNZnz) are projected in the image planes of both cameras (camera 1 and camera 2) and the sum of the squared distances between these projections and the corresponding measured image points (with coordinates NRow1NRow1NRow1NRow1nrow_1, NCol1NCol1NCol1NCol1ncol_1 for camera 1 and NRow2NRow2NRow2NRow2nrow_2, NCol2NCol2NCol2NCol2ncol_2 for camera 2) is minimized. It should be noted that all these model points must be visible in both images. The used camera model is described in Calibration. The camera model is represented (for each camera separately) by a tuple of 9 to 16 parameters that correspond to perspective or telecentric area scan or telecentric line scan cameras (see Calibration). The projection uses the initial values StartCamParam1StartCamParam1StartCamParam1startCamParam1start_cam_param_1 and StartCamParam2StartCamParam2StartCamParam2startCamParam2start_cam_param_2 of the internal parameters of camera 1 and camera 2, which can be obtained from the camera data sheets. In addition, the initial guesses NStartPose1NStartPose1NStartPose1NStartPose1nstart_pose_1 and NStartPose2NStartPose2NStartPose2NStartPose2nstart_pose_2 of the poses of the 3D calibration model in relative to the camera coordinate systems (ccs) of camera 1 and camera 2 are needed as well. These poses are expected in the form , where wcs denotes the world coordinate system (see Transformations / Poses and “Solution Guide III-C - 3D Vision”). They can be determined by the operator find_marks_and_posefind_marks_and_poseFindMarksAndPoseFindMarksAndPosefind_marks_and_pose. Since this calibration algorithm simultaneously handles correspondences between measured image and known model points from different image pairs, poses (NStartPose1NStartPose1NStartPose1NStartPose1nstart_pose_1,NStartPose2NStartPose2NStartPose2NStartPose2nstart_pose_2), and measured points (NRow1NRow1NRow1NRow1nrow_1,NCol1NCol1NCol1NCol1ncol_1,NRow2NRow2NRow2NRow2nrow_2, NCol2NCol2NCol2NCol2ncol_2) must be passed concatenated in a corresponding order.

The input parameter EstimateParamsEstimateParamsEstimateParamsestimateParamsestimate_params is used to select the parameters to be estimated. Usually this parameter is set to 'all'"all""all""all""all", i.e., all external camera parameters (translation and rotation) and all internal camera parameters are determined. Otherwise, EstimateParamsEstimateParamsEstimateParamsestimateParamsestimate_params contains a tuple of strings indicating the combination of parameters to estimate. For instance, if the internal camera parameters already have been determined (e.g., by previous calls to binocular_calibrationbinocular_calibrationBinocularCalibrationBinocularCalibrationbinocular_calibration), it is often desired to only determine relative the pose of the two cameras to each other (RelPoseRelPoseRelPoserelPoserel_pose). In this case, EstimateParamsEstimateParamsEstimateParamsestimateParamsestimate_params can be set to 'pose_rel'"pose_rel""pose_rel""pose_rel""pose_rel". The internal parameters can be subsumed by the parameter values 'cam_param1'"cam_param1""cam_param1""cam_param1""cam_param1" and 'cam_param2'"cam_param2""cam_param2""cam_param2""cam_param2" as well. Note that if the polynomial model is used to model the lens distortions, the values 'k1_i'"k1_i""k1_i""k1_i""k1_i", 'k2_i'"k2_i""k2_i""k2_i""k2_i" and 'k3_i'"k3_i""k3_i""k3_i""k3_i" can be specified individually, whereas 'p1'"p1""p1""p1""p1" and 'p2'"p2""p2""p2""p2" can only be specified in the group 'poly_tan_2_i'"poly_tan_2_i""poly_tan_2_i""poly_tan_2_i""poly_tan_2_i" (with 'i'"i""i""i""i" indicating the index of the camera). 'poly_i'"poly_i""poly_i""poly_i""poly_i" specifies the group 'k1_i'"k1_i""k1_i""k1_i""k1_i", 'k2_i'"k2_i""k2_i""k2_i""k2_i", 'k3_i'"k3_i""k3_i""k3_i""k3_i" and 'poly_tan_2_i'"poly_tan_2_i""poly_tan_2_i""poly_tan_2_i""poly_tan_2_i".

The following list contains all possible strings that can be passed to the tuple:

Allowed strings for EstimateParamsEstimateParamsEstimateParamsestimateParamsestimate_params Determined parameters

'all'"all""all""all""all" (default) All internal camera parameters, as well as the relative pose of both cameras and the poses of the calibration objects.

'pose'"pose""pose""pose""pose" Relative pose between the two cameras and poses of the calibration objects.

'pose_rel'"pose_rel""pose_rel""pose_rel""pose_rel" Relative pose between the two cameras.

'alpha_rel'"alpha_rel""alpha_rel""alpha_rel""alpha_rel", 'beta_rel'"beta_rel""beta_rel""beta_rel""beta_rel", 'gamma_rel'"gamma_rel""gamma_rel""gamma_rel""gamma_rel", 'transx_rel'"transx_rel""transx_rel""transx_rel""transx_rel", 'transy_rel'"transy_rel""transy_rel""transy_rel""transy_rel", 'transz_rel'"transz_rel""transz_rel""transz_rel""transz_rel" Rotation angles and translation parameters of the relative pose between the two cameras.

'pose_caltabs'"pose_caltabs""pose_caltabs""pose_caltabs""pose_caltabs" Poses of the calibration objects.

'alpha_caltabs'"alpha_caltabs""alpha_caltabs""alpha_caltabs""alpha_caltabs", 'beta_caltabs'"beta_caltabs""beta_caltabs""beta_caltabs""beta_caltabs", 'gamma_caltabs'"gamma_caltabs""gamma_caltabs""gamma_caltabs""gamma_caltabs", 'transx_caltabs'"transx_caltabs""transx_caltabs""transx_caltabs""transx_caltabs", 'transy_caltabs'"transy_caltabs""transy_caltabs""transy_caltabs""transy_caltabs", 'transz_caltabs'"transz_caltabs""transz_caltabs""transz_caltabs""transz_caltabs" Rotation angles and translation parameters of the relative poses of the calibration objects.

'cam_param1'"cam_param1""cam_param1""cam_param1""cam_param1", 'cam_param2'"cam_param2""cam_param2""cam_param2""cam_param2" All internal camera parameters of camera 1 and camera 2, respectively.

'focus1'"focus1""focus1""focus1""focus1", 'magnification1'"magnification1""magnification1""magnification1""magnification1", 'kappa1'"kappa1""kappa1""kappa1""kappa1", 'poly_1'"poly_1""poly_1""poly_1""poly_1", 'k1_1'"k1_1""k1_1""k1_1""k1_1", 'k2_1'"k2_1""k2_1""k2_1""k2_1", 'k3_1'"k3_1""k3_1""k3_1""k3_1", 'poly_tan_2_1'"poly_tan_2_1""poly_tan_2_1""poly_tan_2_1""poly_tan_2_1", 'image_plane_dist1'"image_plane_dist1""image_plane_dist1""image_plane_dist1""image_plane_dist1", 'tilt1'"tilt1""tilt1""tilt1""tilt1", 'cx1'"cx1""cx1""cx1""cx1", 'cy1'"cy1""cy1""cy1""cy1", 'sx1'"sx1""sx1""sx1""sx1", 'sy1'"sy1""sy1""sy1""sy1", 'focus2'"focus2""focus2""focus2""focus2", 'magnification2'"magnification2""magnification2""magnification2""magnification2", 'kappa2'"kappa2""kappa2""kappa2""kappa2", 'poly_2'"poly_2""poly_2""poly_2""poly_2", 'k1_2'"k1_2""k1_2""k1_2""k1_2", 'k2_2'"k2_2""k2_2""k2_2""k2_2", 'k3_2'"k3_2""k3_2""k3_2""k3_2", 'poly_tan_2_2'"poly_tan_2_2""poly_tan_2_2""poly_tan_2_2""poly_tan_2_2", 'image_plane_dist2'"image_plane_dist2""image_plane_dist2""image_plane_dist2""image_plane_dist2", 'tilt2'"tilt2""tilt2""tilt2""tilt2", 'cx2'"cx2""cx2""cx2""cx2", 'cy2'"cy2""cy2""cy2""cy2", 'sx2'"sx2""sx2""sx2""sx2", 'sy2'"sy2""sy2""sy2""sy2" Individual internal camera parameters of camera 1 and camera 2, respectively.

'common_motion_vector'"common_motion_vector""common_motion_vector""common_motion_vector""common_motion_vector" Determines whether two line scan cameras have a common motion vector. This is the case if the two cameras are mounted rigidly and the object is moved linearly in front of the cameras or if the two rigidly mounted cameras are moved by the same linear actuator. This is assumed to be the default. Therefore, you only need to set '~common_motion_vector' if the cameras are moving independently in different directions.

In addition, parameters can be excluded from estimation by using the prefix '~'. For example, the values ['pose_rel', '~transx_rel']["pose_rel", "~transx_rel"]["pose_rel", "~transx_rel"]["pose_rel", "~transx_rel"]["pose_rel", "~transx_rel"] have the same effect as ['alpha_rel','beta_rel','gamma_rel','transy_rel','transz_rel']. On the other hand, ['all','~focus1']["all","~focus1"]["all","~focus1"]["all","~focus1"]["all","~focus1"] determines all internal and external parameters except the focus of camera 1, for instance. The prefix '~' can be used with all parameter values except 'all'"all""all""all""all".

The underlying camera model is explained in the chapter Calibration. The calibrated internal camera parameters are returned in CamParam1CamParam1CamParam1camParam1cam_param_1 for camera 1 and in CamParam2CamParam2CamParam2camParam2cam_param_2 for camera 2.

The external parameters are returned analogously to camera_calibrationcamera_calibrationCameraCalibrationCameraCalibrationcamera_calibration, the 3D transformation poses of the calibration model to the respective camera coordinate system (ccs) are returned in NFinalPose1NFinalPose1NFinalPose1NFinalPose1nfinal_pose_1 and NFinalPose2NFinalPose2NFinalPose2NFinalPose2nfinal_pose_2. Thus, the poses are in the form , where wcs denotes the world coordinate system of the 3D calibration model (see Transformations / Poses and “Solution Guide III-C - 3D Vision”). The relative pose , RelPoseRelPoseRelPoserelPoserel_pose, specifies the transformation of points in ccs2 into ccs1. Therewith, the final poses are related with each other (neglecting differences due to the balancing effects of the multi image calibration) by: HomMat3D_NFinalPose2 = INV(HomMat3D_RelPose) * HomMat3D_NFinalPose1 , where HomMat3D_* denotes a homogeneous transformation matrix of the respective poses and INV() inverts a homogeneous matrix.

The computed average errors returned in ErrorsErrorsErrorserrorserrors give an impression of the accuracy of the calibration. Using the determined camera parameters, they denote the average euclidean distance between the projection of the mark centers to their extracted image coordinates.

For cameras with telecentric lenses, additional conditions must be fulfilled for the setup. They can be found in the chapter Calibration.

Attention

Stereo setups that contain cameras with and without hypercentric lenses at the same time are not supported. Furthermore, stereo setups that contain area scan and line scan cameras at the same time are not supported.

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

NXNXNXNXnx (input_control) number-array → (real / integer)

Ordered Tuple with all X-coordinates of the calibration marks (in meters).

NYNYNYNYny (input_control) number-array → (real / integer)

Ordered Tuple with all Y-coordinates of the calibration marks (in meters).

Number of elements: NY == NX

NZNZNZNZnz (input_control) number-array → (real / integer)

Ordered Tuple with all Z-coordinates of the calibration marks (in meters).

Number of elements: NZ == NX

NRow1NRow1NRow1NRow1nrow_1 (input_control) number-array → (real / integer)

Ordered Tuple with all row-coordinates of the extracted calibration marks of camera 1 (in pixels).

NCol1NCol1NCol1NCol1ncol_1 (input_control) number-array → (real / integer)

Ordered Tuple with all column-coordinates of the extracted calibration marks of camera 1 (in pixels).

Number of elements: NCol1 == NRow1

NRow2NRow2NRow2NRow2nrow_2 (input_control) number-array → (real / integer)

Ordered Tuple with all row-coordinates of the extracted calibration marks of camera 2 (in pixels).

Number of elements: NRow2 == NRow1

NCol2NCol2NCol2NCol2ncol_2 (input_control) number-array → (real / integer)

Ordered Tuple with all column-coordinates of the extracted calibration marks of camera 2 (in pixels).

Number of elements: NCol2 == NRow1

StartCamParam1StartCamParam1StartCamParam1startCamParam1start_cam_param_1 (input_control) campar → (real / integer / string)

Initial values for the internal parameters of camera 1.

StartCamParam2StartCamParam2StartCamParam2startCamParam2start_cam_param_2 (input_control) campar → (real / integer / string)

Initial values for the internal parameters of camera 2.

NStartPose1NStartPose1NStartPose1NStartPose1nstart_pose_1 (input_control) pose(-array) → (real / integer)

Ordered tuple with all initial values for the poses of the calibration model in relation to camera 1.

Number of elements: NStartPose1 == 7 * NRow1 / NX

NStartPose2NStartPose2NStartPose2NStartPose2nstart_pose_2 (input_control) pose(-array) → (real / integer)

Ordered tuple with all initial values for the poses of the calibration model in relation to camera 2.

Number of elements: NStartPose2 == 7 * NRow1 / NX

EstimateParamsEstimateParamsEstimateParamsestimateParamsestimate_params (input_control) string-array → (string)

Camera parameters to be estimated.

Default: 'all' "all" "all" "all" "all"

List of values: 'all'"all""all""all""all", 'alpha_caltabs'"alpha_caltabs""alpha_caltabs""alpha_caltabs""alpha_caltabs", 'alpha_rel'"alpha_rel""alpha_rel""alpha_rel""alpha_rel", 'beta_caltabs'"beta_caltabs""beta_caltabs""beta_caltabs""beta_caltabs", 'beta_rel'"beta_rel""beta_rel""beta_rel""beta_rel", 'cam_param1'"cam_param1""cam_param1""cam_param1""cam_param1", 'cam_param2'"cam_param2""cam_param2""cam_param2""cam_param2", 'common_motion_vector'"common_motion_vector""common_motion_vector""common_motion_vector""common_motion_vector", 'cx1'"cx1""cx1""cx1""cx1", 'cx2'"cx2""cx2""cx2""cx2", 'cy1'"cy1""cy1""cy1""cy1", 'cy2'"cy2""cy2""cy2""cy2", 'focus1'"focus1""focus1""focus1""focus1", 'focus2'"focus2""focus2""focus2""focus2", 'gamma_caltabs'"gamma_caltabs""gamma_caltabs""gamma_caltabs""gamma_caltabs", 'gamma_rel'"gamma_rel""gamma_rel""gamma_rel""gamma_rel", 'image_plane_dist1'"image_plane_dist1""image_plane_dist1""image_plane_dist1""image_plane_dist1", 'image_plane_dist2'"image_plane_dist2""image_plane_dist2""image_plane_dist2""image_plane_dist2", 'k1_1'"k1_1""k1_1""k1_1""k1_1", 'k1_2'"k1_2""k1_2""k1_2""k1_2", 'k2_1'"k2_1""k2_1""k2_1""k2_1", 'k2_2'"k2_2""k2_2""k2_2""k2_2", 'k3_1'"k3_1""k3_1""k3_1""k3_1", 'k3_2'"k3_2""k3_2""k3_2""k3_2", 'kappa1'"kappa1""kappa1""kappa1""kappa1", 'kappa2'"kappa2""kappa2""kappa2""kappa2", 'magnification1'"magnification1""magnification1""magnification1""magnification1", 'magnification2'"magnification2""magnification2""magnification2""magnification2", 'poly_1'"poly_1""poly_1""poly_1""poly_1", 'poly_2'"poly_2""poly_2""poly_2""poly_2", 'poly_tan_2_1'"poly_tan_2_1""poly_tan_2_1""poly_tan_2_1""poly_tan_2_1", 'poly_tan_2_2'"poly_tan_2_2""poly_tan_2_2""poly_tan_2_2""poly_tan_2_2", 'pose'"pose""pose""pose""pose", 'pose_caltabs'"pose_caltabs""pose_caltabs""pose_caltabs""pose_caltabs", 'pose_rel'"pose_rel""pose_rel""pose_rel""pose_rel", 'sx1'"sx1""sx1""sx1""sx1", 'sx2'"sx2""sx2""sx2""sx2", 'sy1'"sy1""sy1""sy1""sy1", 'sy2'"sy2""sy2""sy2""sy2", 'tilt1'"tilt1""tilt1""tilt1""tilt1", 'tilt2'"tilt2""tilt2""tilt2""tilt2", 'transx_caltabs'"transx_caltabs""transx_caltabs""transx_caltabs""transx_caltabs", 'transx_rel'"transx_rel""transx_rel""transx_rel""transx_rel", 'transy_caltabs'"transy_caltabs""transy_caltabs""transy_caltabs""transy_caltabs", 'transy_rel'"transy_rel""transy_rel""transy_rel""transy_rel", 'transz_caltabs'"transz_caltabs""transz_caltabs""transz_caltabs""transz_caltabs", 'transz_rel'"transz_rel""transz_rel""transz_rel""transz_rel"

CamParam1CamParam1CamParam1camParam1cam_param_1 (output_control) campar → (real / integer / string)

Internal parameters of camera 1.

CamParam2CamParam2CamParam2camParam2cam_param_2 (output_control) campar → (real / integer / string)

Internal parameters of camera 2.

NFinalPose1NFinalPose1NFinalPose1NFinalPose1nfinal_pose_1 (output_control) pose(-array) → (real / integer)

Ordered tuple with all poses of the calibration model in relation to camera 1.

Number of elements: NFinalPose1 == 7 * NRow1 / NX

NFinalPose2NFinalPose2NFinalPose2NFinalPose2nfinal_pose_2 (output_control) pose(-array) → (real / integer)

Ordered tuple with all poses of the calibration model in relation to camera 2.

Number of elements: NFinalPose2 == 7 * NRow1 / NX

RelPoseRelPoseRelPoserelPoserel_pose (output_control) pose → (real / integer)

Pose of camera 2 in relation to camera 1.

ErrorsErrorsErrorserrorserrors (output_control) real(-array) → (real)

Average error distances in pixels.

Example (HDevelop)

* Open image source.
open_framegrabber ('File', 1, 1, 0, 0, 0, 0, 'default', -1, 'default', -1, \
                   'default', 'images_l.seq', 'default', 0, -1, AcqHandle1)
open_framegrabber ('File', 1, 1, 0, 0, 0, 0, 'default', -1, 'default', -1, \
                   'default', 'images_r.seq', 'default', 1, -1, AcqHandle2)

* Initialize the start parameters.
caltab_points ('caltab_30mm.descr', X, Y, Z)
StartCamParam1 := ['area_scan_division', 0.0125, 0, 7.4e-6, 7.4e-6, \
                   Width/2.0, Height/2.0, Width, Height]
StartCamParam2 := StartCamParam1
Rows1 := []
Cols1 := []
StartPoses1 := []
Rows2 := []
Cols2 := []
StartPoses2 := []

* Find calibration marks and startposes.
for i := 0 to 11 by 1
  grab_image_async (Image1, AcqHandle1, -1)
  grab_image_async (Image2, AcqHandle2, -1)
  find_caltab (Image1, CalPlate1, 'caltab_30mm.descr', 3, 120, 5)
  find_caltab (Image2, CalPlate2, 'caltab_30mm.descr', 3, 120, 5)
  find_marks_and_pose (Image1, CalPlate1, 'caltab_30mm.descr', \
                       StartCamParam1, 128, 10, 20, 0.7, 5, 100, \
                       RCoord1, CCoord1, StartPose1)
  Rows1 := [Rows1,RCoord1]
  Cols1 := [Cols1,CCoord1]
  StartPoses1 := [StartPoses1,StartPose1]
  find_marks_and_pose (Image2, CalPlate2, 'caltab_30mm.descr', \
                       StartCamParam2, 128, 10, 20, 0.7, 5, 100, \
                       RCoord2, CCoord2, StartPose2)
  Rows2 := [Rows2,RCoord2]
  Cols2 := [Cols2,CCoord2]
  StartPoses2 := [StartPoses2,StartPose2]
endfor

* Calibrate the stereo rig.
binocular_calibration (X, Y, Z, Rows1, Cols1, Rows2, Cols2, StartCamParam1, \
                       StartCamParam2, StartPoses1, StartPoses2, 'all', \
                       CamParam1, CamParam2, NFinalPose1, NFinalPose2, \
                       RelPose, Errors)
* Archive the results.
write_cam_par (CamParam1, 'cam_left-125.dat')
write_cam_par (CamParam2, 'cam_right-125.dat')
write_pose (RelPose, 'rel_pose.dat')

* Rectify the stereo images.
gen_binocular_rectification_map (Map1, Map2, CamParam1, CamParam2, \
                                 RelPose, 1, 'viewing_direction', 'bilinear', \
                                 CamParamRect1, CamParamRect2, \
                                 CamPoseRect1, CamPoseRect2, \
                                 RelPoseRect)
map_image (Image1, Map1, ImageMapped1)
map_image (Image2, Map2, ImageMapped2)

Example (HDevelop)

* Open image source.
open_framegrabber ('File', 1, 1, 0, 0, 0, 0, 'default', -1, 'default', -1, \
                   'default', 'images_l.seq', 'default', 0, -1, AcqHandle1)
open_framegrabber ('File', 1, 1, 0, 0, 0, 0, 'default', -1, 'default', -1, \
                   'default', 'images_r.seq', 'default', 1, -1, AcqHandle2)

* Initialize the start parameters.
caltab_points ('caltab_30mm.descr', X, Y, Z)
StartCamParam1 := ['area_scan_division', 0.0125, 0, 7.4e-6, 7.4e-6, \
                   Width/2.0, Height/2.0, Width, Height]
StartCamParam2 := StartCamParam1
Rows1 := []
Cols1 := []
StartPoses1 := []
Rows2 := []
Cols2 := []
StartPoses2 := []

* Find calibration marks and startposes.
for i := 0 to 11 by 1
  grab_image_async (Image1, AcqHandle1, -1)
  grab_image_async (Image2, AcqHandle2, -1)
  find_caltab (Image1, CalPlate1, 'caltab_30mm.descr', 3, 120, 5)
  find_caltab (Image2, CalPlate2, 'caltab_30mm.descr', 3, 120, 5)
  find_marks_and_pose (Image1, CalPlate1, 'caltab_30mm.descr', \
                       StartCamParam1, 128, 10, 20, 0.7, 5, 100, \
                       RCoord1, CCoord1, StartPose1)
  Rows1 := [Rows1,RCoord1]
  Cols1 := [Cols1,CCoord1]
  StartPoses1 := [StartPoses1,StartPose1]
  find_marks_and_pose (Image2, CalPlate2, 'caltab_30mm.descr', \
                       StartCamParam2, 128, 10, 20, 0.7, 5, 100, \
                       RCoord2, CCoord2, StartPose2)
  Rows2 := [Rows2,RCoord2]
  Cols2 := [Cols2,CCoord2]
  StartPoses2 := [StartPoses2,StartPose2]
endfor

* Calibrate the stereo rig.
binocular_calibration (X, Y, Z, Rows1, Cols1, Rows2, Cols2, StartCamParam1, \
                       StartCamParam2, StartPoses1, StartPoses2, 'all', \
                       CamParam1, CamParam2, NFinalPose1, NFinalPose2, \
                       RelPose, Errors)
* Archive the results.
write_cam_par (CamParam1, 'cam_left-125.dat')
write_cam_par (CamParam2, 'cam_right-125.dat')
write_pose (RelPose, 'rel_pose.dat')

* Rectify the stereo images.
gen_binocular_rectification_map (Map1, Map2, CamParam1, CamParam2, \
                                 RelPose, 1, 'viewing_direction', 'bilinear', \
                                 CamParamRect1, CamParamRect2, \
                                 CamPoseRect1, CamPoseRect2, \
                                 RelPoseRect)
map_image (Image1, Map1, ImageMapped1)
map_image (Image2, Map2, ImageMapped2)

Example (C++)

HTuple   AcqHandle1, AcqHandle2;
HTuple   X, Y, Z, StartCamParam1, StartCamParam2;
HTuple   Rows1, Cols1, StartPoses1, Rows2, Cols2, StartPoses2;
HTuple   i, RCoord1, CCoord1, StartPose1, RCoord2, CCoord2;
HTuple   StartPose2, CamParam1, CamParam2, NFinalPose1, NFinalPose2;
HTuple   c1Pc2, Errors, CamParamRect1, CamParamRect2, CamPoseRect1;
HTuple   CamPoseRect2, RelPoseRect;
Hobject  Image1, Image2, CalPlate1, CalPlate2, Map1, Map2, ImageMapped1;
Hobject  ImageMapped2;

// Open image source.
open_framegrabber("File",1,1,0,0,0,0,"default",-1,"default",-1,"default",
                  "images_l.seq","default",0,-1,&AcqHandle1);
open_framegrabber("File",1,1,0,0,0,0,"default",-1,"default",-1,"default",
                  "images_r.seq","default",0,-1,&AcqHandle2);
// Initialize the start parameters.
caltab_points("caltab_30mm.descr",&X,&Y,&Z);
StartCamParam1[8] = 640;                  // ImageHeight
StartCamParam1[7] = 480;                  // ImageWidth
StartCamParam1[6] = 320;                  // Cy
StartCamParam1[5] = 240;                  // Cx
StartCamParam1[4] = 7.4e-6;               // Sy
StartCamParam1[3] = 7.4e-6;               // Sx
StartCamParam1[2] = 0.0;                  // Kappa
StartCamParam1[1] = 0.0125;               // Focus
StartCamParam1[0] = "area_scan_division"; // CameraType
StartCamParam2 = StartCamParam1;    // identic camera
Rows1 = HTuple();
Cols1 = HTuple();
StartPoses1 = HTuple();
Rows2 = HTuple();
Cols2 = HTuple();
StartPoses2 = HTuple();

// Find calibration marks and startposes.
for (i=0; i<=11; i+=1)
{
  grab_image_async(&Image1,AcqHandle1,-1);
  grab_image_async(&Image2,AcqHandle2,-1);
  find_caltab(Image1,&CalPlate1,"caltab_30mm.descr",3,120,5);
  find_caltab(Image2,&CalPlate2,"caltab_30mm.descr",3,120,5);
  find_marks_and_pose(Image1,CalPlate1,"caltab_30mm.descr",StartCamParam1,
                      128,10,20,0.7,5,100,&RCoord1,&CCoord1,&StartPose1);
  Rows1.Append(RCoord1);
  Cols1.Append(CCoord1);
  StartPoses1.Append(StartPose1);
  find_marks_and_pose(Image2,CalPlate2,"caltab_30mm.descr",StartCamParam2,
                      128,10,18,0.7,2,100,&RCoord2,&CCoord2,&StartPose2);
  Rows2.Append(RCoord2);
  Cols2.Append(CCoord2);
  StartPoses2.Append(StartPose2);
}

// Find calibration marks and start poses.
binocular_calibration(X,Y,Z,Rows1,Cols1,Rows2,Cols2,StartCamParam1,
                      StartCamParam2,StartPoses1,StartPoses2,"all",
                      &CamParam1,&CamParam2,&NFinalPose1,&NFinalPose2,
                      &RelPose,&Errors);
// Archive the results.
write_cam_par(CamParam1,"cam_left-125.dat");
write_cam_par(CamParam2,"cam_right-125.dat");
write_pose(RelPose,"rel_pose.dat");
// Rectify the stereo images.
gen_binocular_rectification_map(&Map1,&Map2,CamParam1,CamParam2,RelPose,1,
                                "viewing_direction","bilinear",&CamParamRect1,
                                &CamParamRect2,&CamPoseRect1,
                                &CamPoseRect2,&RelPoseRect);
map_image(Image1,Map1,&ImageMapped1);
map_image(Image2,Map2,&ImageMapped2);

Example (HDevelop)

* Open image source.
open_framegrabber ('File', 1, 1, 0, 0, 0, 0, 'default', -1, 'default', -1, \
                   'default', 'images_l.seq', 'default', 0, -1, AcqHandle1)
open_framegrabber ('File', 1, 1, 0, 0, 0, 0, 'default', -1, 'default', -1, \
                   'default', 'images_r.seq', 'default', 1, -1, AcqHandle2)

* Initialize the start parameters.
caltab_points ('caltab_30mm.descr', X, Y, Z)
StartCamParam1 := ['area_scan_division', 0.0125, 0, 7.4e-6, 7.4e-6, \
                   Width/2.0, Height/2.0, Width, Height]
StartCamParam2 := StartCamParam1
Rows1 := []
Cols1 := []
StartPoses1 := []
Rows2 := []
Cols2 := []
StartPoses2 := []

* Find calibration marks and startposes.
for i := 0 to 11 by 1
  grab_image_async (Image1, AcqHandle1, -1)
  grab_image_async (Image2, AcqHandle2, -1)
  find_caltab (Image1, CalPlate1, 'caltab_30mm.descr', 3, 120, 5)
  find_caltab (Image2, CalPlate2, 'caltab_30mm.descr', 3, 120, 5)
  find_marks_and_pose (Image1, CalPlate1, 'caltab_30mm.descr', \
                       StartCamParam1, 128, 10, 20, 0.7, 5, 100, \
                       RCoord1, CCoord1, StartPose1)
  Rows1 := [Rows1,RCoord1]
  Cols1 := [Cols1,CCoord1]
  StartPoses1 := [StartPoses1,StartPose1]
  find_marks_and_pose (Image2, CalPlate2, 'caltab_30mm.descr', \
                       StartCamParam2, 128, 10, 20, 0.7, 5, 100, \
                       RCoord2, CCoord2, StartPose2)
  Rows2 := [Rows2,RCoord2]
  Cols2 := [Cols2,CCoord2]
  StartPoses2 := [StartPoses2,StartPose2]
endfor

* Calibrate the stereo rig.
binocular_calibration (X, Y, Z, Rows1, Cols1, Rows2, Cols2, StartCamParam1, \
                       StartCamParam2, StartPoses1, StartPoses2, 'all', \
                       CamParam1, CamParam2, NFinalPose1, NFinalPose2, \
                       RelPose, Errors)
* Archive the results.
write_cam_par (CamParam1, 'cam_left-125.dat')
write_cam_par (CamParam2, 'cam_right-125.dat')
write_pose (RelPose, 'rel_pose.dat')

* Rectify the stereo images.
gen_binocular_rectification_map (Map1, Map2, CamParam1, CamParam2, \
                                 RelPose, 1, 'viewing_direction', 'bilinear', \
                                 CamParamRect1, CamParamRect2, \
                                 CamPoseRect1, CamPoseRect2, \
                                 RelPoseRect)
map_image (Image1, Map1, ImageMapped1)
map_image (Image2, Map2, ImageMapped2)

Result

binocular_calibrationbinocular_calibrationBinocularCalibrationBinocularCalibrationbinocular_calibration returns 2 ( H_MSG_TRUE) if all parameter values are correct and the desired parameters have been determined by the minimization algorithm. If necessary, an exception is raised.

Possible Predecessors

find_marks_and_posefind_marks_and_poseFindMarksAndPoseFindMarksAndPosefind_marks_and_pose, caltab_pointscaltab_pointsCaltabPointsCaltabPointscaltab_points, read_cam_parread_cam_parReadCamParReadCamParread_cam_par

Possible Successors

write_posewrite_poseWritePoseWritePosewrite_pose, write_cam_parwrite_cam_parWriteCamParWriteCamParwrite_cam_par, pose_to_hom_mat3dpose_to_hom_mat3dPoseToHomMat3dPoseToHomMat3dpose_to_hom_mat3d, disp_caltabdisp_caltabDispCaltabDispCaltabdisp_caltab, gen_binocular_rectification_mapgen_binocular_rectification_mapGenBinocularRectificationMapGenBinocularRectificationMapgen_binocular_rectification_map

Module

3D Metrology

Operators

Operator Reference

binocular_calibrationT_binocular_calibrationBinocularCalibrationBinocularCalibrationbinocular_calibration (Operator)

Signature

Description

Attention

Execution Information

Parameters

Example (HDevelop)

Example (HDevelop)

Example (C++)

Example (HDevelop)

Result

Possible Predecessors

Possible Successors

See also

Module