projective_trans_contour_xldT_projective_trans_contour_xldProjectiveTransContourXldProjectiveTransContourXldprojective_trans_contour_xld (Operator)

Name

projective_trans_contour_xldT_projective_trans_contour_xldProjectiveTransContourXldProjectiveTransContourXldprojective_trans_contour_xld — Apply a projective transformation to an XLD contour.

Signature

Description

projective_trans_contour_xldprojective_trans_contour_xldProjectiveTransContourXldProjectiveTransContourXldProjectiveTransContourXldprojective_trans_contour_xld applies the projective transformation specified by the homogeneous matrix HomMat2DHomMat2DHomMat2DHomMat2DhomMat2Dhom_mat_2d on the contours in ContoursContoursContoursContourscontourscontours and returns the transformed contours in ContoursProjTransContoursProjTransContoursProjTransContoursProjTranscontoursProjTranscontours_proj_trans.

For creation and interpretation details of this matrix see also projective_trans_imageprojective_trans_imageProjectiveTransImageProjectiveTransImageProjectiveTransImageprojective_trans_image.

Attention

The used coordinate system is the same as in affine_trans_pixelaffine_trans_pixelAffineTransPixelAffineTransPixelAffineTransPixelaffine_trans_pixel. This means that in fact not HomMat2DHomMat2DHomMat2DHomMat2DhomMat2Dhom_mat_2d is applied but a modified version. Therefore, applying projective_trans_contour_xldprojective_trans_contour_xldProjectiveTransContourXldProjectiveTransContourXldProjectiveTransContourXldprojective_trans_contour_xld corresponds to the following chain of transformations, which is applied to each point of the contour (input and output pixels as homogeneous vectors):

As an effect, you might get unexpected results when creating projective transformations based on coordinates that are derived from the contour, e.g., by operators like area_center_xldarea_center_xldAreaCenterXldAreaCenterXldAreaCenterXldarea_center_xld. For example, if you use this operator to calculate the center of gravity of a rotationally symmetric XLD contour and then rotate the contour around this point using hom_mat2d_rotatehom_mat2d_rotateHomMat2dRotateHomMat2dRotateHomMat2dRotatehom_mat2d_rotate, the resulting contour will not lie on the original one. In such a case, you can compensate this effect by applying the following translations to HomMat2DHomMat2DHomMat2DHomMat2DhomMat2Dhom_mat_2d before using it in projective_trans_contour_xldprojective_trans_contour_xldProjectiveTransContourXldProjectiveTransContourXldProjectiveTransContourXldprojective_trans_contour_xld:

hom_mat2d_translate(HomMat2D, 0.5, 0.5, HomMat2DTmp) hom_mat2d_translate_local(HomMat2DTmp, -0.5, -0.5, HomMat2DAdapted) projective_trans_contour_xld(Contours, ContoursAffineTrans, HomMat2DAdapted)

For an explanation of the different 2D coordinate systems used in HALCON, see the introduction of chapter Transformations / 2D Transformations.

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

Possible Predecessors

vector_to_proj_hom_mat2dvector_to_proj_hom_mat2dVectorToProjHomMat2dVectorToProjHomMat2dVectorToProjHomMat2dvector_to_proj_hom_mat2d, hom_vector_to_proj_hom_mat2dhom_vector_to_proj_hom_mat2dHomVectorToProjHomMat2dHomVectorToProjHomMat2dHomVectorToProjHomMat2dhom_vector_to_proj_hom_mat2d, proj_match_points_ransacproj_match_points_ransacProjMatchPointsRansacProjMatchPointsRansacProjMatchPointsRansacproj_match_points_ransac, proj_match_points_ransac_guidedproj_match_points_ransac_guidedProjMatchPointsRansacGuidedProjMatchPointsRansacGuidedProjMatchPointsRansacGuidedproj_match_points_ransac_guided, hom_mat3d_projecthom_mat3d_projectHomMat3dProjectHomMat3dProjectHomMat3dProjecthom_mat3d_project

See also

projective_trans_imageprojective_trans_imageProjectiveTransImageProjectiveTransImageProjectiveTransImageprojective_trans_image, projective_trans_image_sizeprojective_trans_image_sizeProjectiveTransImageSizeProjectiveTransImageSizeProjectiveTransImageSizeprojective_trans_image_size, projective_trans_regionprojective_trans_regionProjectiveTransRegionProjectiveTransRegionProjectiveTransRegionprojective_trans_region, projective_trans_point_2dprojective_trans_point_2dProjectiveTransPoint2dProjectiveTransPoint2dProjectiveTransPoint2dprojective_trans_point_2d, projective_trans_pixelprojective_trans_pixelProjectiveTransPixelProjectiveTransPixelProjectiveTransPixelprojective_trans_pixel

Module

Foundation