project_object_model_3d🔗
Short description🔗
project_object_model_3d — Project a 3D object model into image coordinates.
Signature🔗
project_object_model_3d( out xld_cont ModelContours, object_model_3d ObjectModel3D, campar CamParam, pose Pose, string GenParamName, string GenParamValue )
Description🔗
The operator project_object_model_3d projects a
3D object model into the image coordinate system and returns the
projected contours in ModelContours. This operator is
particularly useful for the visualization of 3D object models.
Note that primitives are not projected but silently ignored.
The coordinates of the 3D object model are given in the model coordinate
system (mcs), a 3D world coordinate system.
First, they are transformed into the camera coordinate system (ccs)
using the given Pose.
Then, these coordinates are projected into the
image coordinate system based on the internal camera parameters
CamParam.
Thereby the pose is needed in the form
\(\mvPoseVar{{ccs}}{mcs}\), see Transformations / Poses
and “Solution Guide III-C - 3D Vision”.
Thus, the Pose describes the position
and orientation of the world coordinate system with respect to the
camera coordinate system.
The internal camera parameters CamParam describe the
projection characteristics of the camera (see
Calibration).
There are some generic parameters that can optionally be used to
influence the projection. If desired, these parameters and their
corresponding values can be specified by using GenParamName
and GenParamValue, respectively. The following values for
GenParamName are possible:
-
'data': This parameter specifies which geometric data of the 3D object model should be projected. If 'data' is set to 'faces', the faces of the 3D object model are projected. The faces are represented by their border lines in
ModelContours. If 'data' is set to 'lines', the 3D lines of the 3D object model are projected. If 'data' is set to 'points', the points of the 3D object model are projected. The projected points can be represented inModelContoursin different ways. The point representation can be selected by using the generic parameter 'point_shape' (see below). Finally, if 'data' is set to 'auto', HALCON automatically chooses the most descriptive geometry data that is available in the 3D object model for visualization.List of values: 'auto', 'faces', 'lines', 'points'.
Default: 'auto'.
-
'point_shape': This parameter specifies how points are represented in the output contour
ModelContours. Consequently, this parameter only has an effect if the points of the 3D object model are selected for projection (see above). If 'point_shape' is set to 'circle', points are represented by circles, whereas if 'point_shape' is set to 'cross', points are represented by crosses. In both cases the size of the points (i.e., the size of the circles or the size of the crosses) can be specified by the generic parameter 'point_size' (see below). The orientation of the crosses can be specified by the generic parameter 'point_orientation' (see below).List of values: 'circle', 'cross'.
Default: 'circle'.
-
'point_size': This parameter specifies the size of the point representation in the output contour
ModelContours, i.e., the size of the circles or the size of the crosses depending on the selected 'point_shape'. Consequently, this parameter only has an effect if the points of the 3D object model are selected for projection (see above). The size must be given in pixel units. If 'point_size' is set to 0, each point is represented by a contour that contains a single contour point.Suggested values: 0, 2, 4.
Default: 4.
-
'point_orientation': This parameter specifies the orientation of the crosses in radians. Consequently, this parameter only has an effect if the points of the 3D object model are selected for projection and 'point_shape' is set to 'cross' (see above).
Suggested values: 0, 0.39, 0.79.
Default: 0.79.
-
'union_adjacent_contours': This parameter specifies if adjacent projected contours should be joined or not. Activating this option is equivalent to calling
union_adjacent_contours_xldafter this operator, but significantly faster.List of values: 'true', 'false'.
Default: 'true'.
-
'hidden_surface_removal': This parameter can be used to switch on or off the removal of hidden surfaces. If 'hidden_surface_removal' is set to 'true', only those projected edges are returned that are not hidden by faces of the 3D object model. If 'hidden_surface_removal' is set to 'false', all projected edges are returned. This is faster than a projection with 'hidden_surface_removal' set to 'true'.
If the system variable (see
set_system) 'opengl_hidden_surface_removal_enable' is set to 'true' (which is the default if it is available) and 'hidden_surface_removal' is set to 'true', the projection of the model is accelerated using the graphics card. Depending on the graphics card this is significantly faster than the non accelerated algorithm. Be aware that the results of the OpenGL projection are slightly different compared to the analytic projection. Notable, only the contours visible throughCamParamare projected in this mode.List of values: 'true', 'false'.
Default: 'true'.
-
'min_face_angle': 3D edges are only projected if the angle between the two 3D faces that are incident with the 3D edge is at least 'min_face_angle'. If 'min_face_angle' is set to 0.0, all edges are projected. If 'min_face_angle' is set to \(\pi\) (equivalent to 180 degrees), only the silhouette of the 3D object model is returned. This parameter can be used to suppress edges within curved surfaces, e.g., the surface of a cylinder or cone.
Suggested values: 0.17, 0.26, 0.35, 0.52.
Default: 0.52.
Attention🔗
Cameras with hypercentric lenses are not supported.
For displaying large faces with a non-zero distortion
in CamParam, note that the distortion is only applied to the
points of the model. In the projection, these points are subsequently
connected by straight lines. For a good approximation of the distorted
lines, please use a triangulation with sufficiently small triangles.
Execution information🔗
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🔗
ModelContours (output_object) xld_cont(-array) → object
Projected model contours.
ObjectModel3D (input_control) object_model_3d → (handle)
Handle of the 3D object model.
CamParam (input_control) campar → (real / integer / string)
Internal camera parameters.
Pose (input_control) pose → (real / integer)
3D pose of the world coordinate system in camera coordinates.
Number of elements: Pose == 7
GenParamName (input_control) string(-array) → (string)
Name of the generic parameter.
Default: []
List of values: 'data', 'false', 'hidden_surface_removal', 'min_face_angle', 'point_orientation', 'point_shape', 'point_size', 'true', 'union_adjacent_contours'
GenParamValue (input_control) string(-array) → (string / integer / real)
Value of the generic parameter.
Default: []
Suggested values: 0.17, 0.26, 0.35, 0.52, 'true', 'false', 'auto', 'points', 'faces', 'lines', 'circle', 'cross', 1, 2, 3, 4, 0.785398
Result🔗
project_object_model_3d returns 2 (H_MSG_TRUE) if all parameters are
correct. If necessary, an exception is raised. If the geometric
data that was selected for the projection is not available in the
3D object model, the error 9514 is raised.
Combinations with other operators🔗
Combinations
Possible predecessors
read_object_model_3d, affine_trans_object_model_3d, prepare_object_model_3d
Possible successors
See also
Module🔗
3D Metrology