create_deformable_surface_modelcreate_deformable_surface_modelCreateDeformableSurfaceModelCreateDeformableSurfaceModel (Operator)

Name

create_deformable_surface_modelcreate_deformable_surface_modelCreateDeformableSurfaceModelCreateDeformableSurfaceModel — Create the data structure needed to perform deformable surface-based matching.

Signature

Description

The operator create_deformable_surface_modelcreate_deformable_surface_modelCreateDeformableSurfaceModelCreateDeformableSurfaceModelCreateDeformableSurfaceModel creates a model for deformable surface-based matching for the 3D object stored in the 3D object model ObjectModel3DObjectModel3DObjectModel3DObjectModel3DobjectModel3D. The 3D object model can, for example, have been read previously from a file by using read_object_model_3dread_object_model_3dReadObjectModel3dReadObjectModel3dReadObjectModel3d or it can have been created by using xyz_to_object_model_3dxyz_to_object_model_3dXyzToObjectModel3dXyzToObjectModel3dXyzToObjectModel3d. The created surface model is returned in DeformableSurfaceModelDeformableSurfaceModelDeformableSurfaceModelDeformableSurfaceModeldeformableSurfaceModel.

The creation of the deformable surface model requires that the 3D object model contains points and normals. The following combinations are possible:

• points and point normals, e.g., from a call to surface_normals_object_model_3dsurface_normals_object_model_3dSurfaceNormalsObjectModel3dSurfaceNormalsObjectModel3dSurfaceNormalsObjectModel3d

• points and a triangular or polygon mesh, e.g., from a CAD file

• points and a 2D-Mapping, e.g., from an XYZ image triple converted with xyz_to_object_model_3dxyz_to_object_model_3dXyzToObjectModel3dXyzToObjectModel3dXyzToObjectModel3d

Note that the direction and orientation (inward or outward) of the normals of the model are important for matching.

The deformable surface model is created by sampling the 3D object model with a certain distance. The sampling distance must be specified in the parameter RelSamplingDistanceRelSamplingDistanceRelSamplingDistanceRelSamplingDistancerelSamplingDistance and is parametrized relative to the diameter of the axis-parallel bounding box of the 3D object model. For example, if RelSamplingDistanceRelSamplingDistanceRelSamplingDistanceRelSamplingDistancerelSamplingDistance is set to 0.05 and the diameter of ObjectModel3DObjectModel3DObjectModel3DObjectModel3DobjectModel3D is 10 cm, the points sampled from the object's surface will be approximately 5 mm apart. The sampled points can be obtained with the operator get_deformable_surface_model_paramget_deformable_surface_model_paramGetDeformableSurfaceModelParamGetDeformableSurfaceModelParamGetDeformableSurfaceModelParam using the value 'sampled_model'"sampled_model""sampled_model""sampled_model""sampled_model". Note that outlier points in the object model should be avoided, as they would corrupt the diameter. Reducing RelSamplingDistanceRelSamplingDistanceRelSamplingDistanceRelSamplingDistancerelSamplingDistance leads to more points, and in turn to a more stable but slower matching. Increasing RelSamplingDistanceRelSamplingDistanceRelSamplingDistanceRelSamplingDistancerelSamplingDistance leads to less points, and in turn to a less stable but faster matching.

By default, deformable surface models created with create_deformable_surface_modelcreate_deformable_surface_modelCreateDeformableSurfaceModelCreateDeformableSurfaceModelCreateDeformableSurfaceModel can handle a moderate amount of deformation. The operator add_deformable_surface_model_sampleadd_deformable_surface_model_sampleAddDeformableSurfaceModelSampleAddDeformableSurfaceModelSampleAddDeformableSurfaceModelSample can be used to add additional training samples, thus expanding the range of possible deformations. The amount of deformation that can be found can also be controlled with the generic parameters 'scale_min'"scale_min""scale_min""scale_min""scale_min", 'scale_max'"scale_max""scale_max""scale_max""scale_max" and 'bending_max'"bending_max""bending_max""bending_max""bending_max" (see below).

The generic parameter pair GenParamNameGenParamNameGenParamNameGenParamNamegenParamName and GenParamValueGenParamValueGenParamValueGenParamValuegenParamValue is used to set additional parameters for the model generation. GenParamNameGenParamNameGenParamNameGenParamNamegenParamName contains the tuple of parameter names that shall be set and GenParamValueGenParamValueGenParamValueGenParamValuegenParamValue contains the corresponding values. The following values are possible for GenParamNameGenParamNameGenParamNameGenParamNamegenParamName:

'model_invert_normals'"model_invert_normals""model_invert_normals""model_invert_normals""model_invert_normals":

Invert the orientation of the surface normals of the model. The normal orientation needs to be known for the model generation. If both the model and the scene are aquired with the same setup, the normals will already point in the same direction. If the model was loaded from a CAD file, the normals might point into the opposite direction. If you experience the effect that the model is found on the 'outside' of the scene surface and the model was created from a CAD file, try to set this parameter to 'true'"true""true""true""true". Also, make sure that the normals in the CAD file all point either outward or inward, i.e., are oriented consistently.

Possible values: 'false'"false""false""false""false", 'true'"true""true""true""true"

Default value: 'false'"false""false""false""false"

'scale_min'"scale_min""scale_min""scale_min""scale_min" and 'scale_max'"scale_max""scale_max""scale_max""scale_max":

The minimum and maximum allowed scaling of the model. Note that if you set one of the two parameters, the other one must be set too.

Suggested values: 0.8, 1, 1.2

Default value: No scaling

Assertion: 0 < 'scale_min'"scale_min""scale_min""scale_min""scale_min" < 'scale_max'"scale_max""scale_max""scale_max""scale_max"

'bending_max'"bending_max""bending_max""bending_max""bending_max":

Controls the maximum automatic deformation of the model. The model is deformed automatically by bending it with an angle up to the value of 'bending_max'"bending_max""bending_max""bending_max""bending_max". This allows for deformations to be found that are within this bending range. The angle is passed in degrees.

Suggested values: 5, 10, 30

Default value: 20

Assertion: 0 <= 'bending_max'"bending_max""bending_max""bending_max""bending_max" < 90

'stiffness'"stiffness""stiffness""stiffness""stiffness":

Control the stiffness of the model when performing the refinement. Larger values of this parameter lead to a more stiff model that can be less deformed. Smaller values lead to a less stiff model that allows more deformation.

Suggested values: 0.2, 0.5, 0.8

Default value: 0.5

Assertion: 0 < 'stiffness'"stiffness""stiffness""stiffness""stiffness" <= 1

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.

This operator returns a handle. Note that the state of an instance of this handle type may be changed by specific operators even though the handle is used as an input parameter by those operators.

This operator supports cancelling timeouts.

Parameters

Result

create_deformable_surface_modelcreate_deformable_surface_modelCreateDeformableSurfaceModelCreateDeformableSurfaceModelCreateDeformableSurfaceModel returns 2 (H_MSG_TRUE) if all parameters are correct. If necessary, an exception is raised.

Possible Predecessors

read_object_model_3dread_object_model_3dReadObjectModel3dReadObjectModel3dReadObjectModel3d, xyz_to_object_model_3dxyz_to_object_model_3dXyzToObjectModel3dXyzToObjectModel3dXyzToObjectModel3d, get_object_model_3d_paramsget_object_model_3d_paramsGetObjectModel3dParamsGetObjectModel3dParamsGetObjectModel3dParams

Possible Successors

add_deformable_surface_model_sampleadd_deformable_surface_model_sampleAddDeformableSurfaceModelSampleAddDeformableSurfaceModelSampleAddDeformableSurfaceModelSample, add_deformable_surface_model_reference_pointadd_deformable_surface_model_reference_pointAddDeformableSurfaceModelReferencePointAddDeformableSurfaceModelReferencePointAddDeformableSurfaceModelReferencePoint, find_deformable_surface_modelfind_deformable_surface_modelFindDeformableSurfaceModelFindDeformableSurfaceModelFindDeformableSurfaceModel, refine_deformable_surface_modelrefine_deformable_surface_modelRefineDeformableSurfaceModelRefineDeformableSurfaceModelRefineDeformableSurfaceModel, get_deformable_surface_model_paramget_deformable_surface_model_paramGetDeformableSurfaceModelParamGetDeformableSurfaceModelParamGetDeformableSurfaceModelParam, write_deformable_surface_modelwrite_deformable_surface_modelWriteDeformableSurfaceModelWriteDeformableSurfaceModelWriteDeformableSurfaceModel, clear_deformable_surface_modelclear_deformable_surface_modelClearDeformableSurfaceModelClearDeformableSurfaceModelClearDeformableSurfaceModel

Alternatives

read_deformable_surface_modelread_deformable_surface_modelReadDeformableSurfaceModelReadDeformableSurfaceModelReadDeformableSurfaceModel

See also

find_deformable_surface_modelfind_deformable_surface_modelFindDeformableSurfaceModelFindDeformableSurfaceModelFindDeformableSurfaceModel, refine_deformable_surface_modelrefine_deformable_surface_modelRefineDeformableSurfaceModelRefineDeformableSurfaceModelRefineDeformableSurfaceModel, read_deformable_surface_modelread_deformable_surface_modelReadDeformableSurfaceModelReadDeformableSurfaceModelReadDeformableSurfaceModel, add_deformable_surface_model_sampleadd_deformable_surface_model_sampleAddDeformableSurfaceModelSampleAddDeformableSurfaceModelSampleAddDeformableSurfaceModelSample, add_deformable_surface_model_reference_pointadd_deformable_surface_model_reference_pointAddDeformableSurfaceModelReferencePointAddDeformableSurfaceModelReferencePointAddDeformableSurfaceModelReferencePoint, write_deformable_surface_modelwrite_deformable_surface_modelWriteDeformableSurfaceModelWriteDeformableSurfaceModelWriteDeformableSurfaceModel, clear_deformable_surface_modelclear_deformable_surface_modelClearDeformableSurfaceModelClearDeformableSurfaceModelClearDeformableSurfaceModel

References

Bertram Drost, Slobodan Ilic: “Graph-Based Deformable 3D Object Matching.” Proceedings of the 37th German Conference on Pattern Recognition, pp. 222-233, 2015.

Module

3D Metrology