projective_trans_regionT_projective_trans_regionProjectiveTransRegionProjectiveTransRegion (Operator)

Name

projective_trans_regionT_projective_trans_regionProjectiveTransRegionProjectiveTransRegion — Apply a projective transformation to a region.

Signature

projective_trans_region(Regions : TransRegions : HomMat2D, Interpolation : )

Herror T_projective_trans_region(const Hobject Regions, Hobject* TransRegions, const Htuple HomMat2D, const Htuple Interpolation)

void ProjectiveTransRegion(const HObject& Regions, HObject* TransRegions, const HTuple& HomMat2D, const HTuple& Interpolation)

HRegion HRegion::ProjectiveTransRegion(const HHomMat2D& HomMat2D, const HString& Interpolation) const

HRegion HRegion::ProjectiveTransRegion(const HHomMat2D& HomMat2D, const char* Interpolation) const

HRegion HRegion::ProjectiveTransRegion(const HHomMat2D& HomMat2D, const wchar_t* Interpolation) const   (Windows only)

HRegion HHomMat2D::ProjectiveTransRegion(const HRegion& Regions, const HString& Interpolation) const

HRegion HHomMat2D::ProjectiveTransRegion(const HRegion& Regions, const char* Interpolation) const

HRegion HHomMat2D::ProjectiveTransRegion(const HRegion& Regions, const wchar_t* Interpolation) const   (Windows only)

static void HOperatorSet.ProjectiveTransRegion(HObject regions, out HObject transRegions, HTuple homMat2D, HTuple interpolation)

HRegion HRegion.ProjectiveTransRegion(HHomMat2D homMat2D, string interpolation)

HRegion HHomMat2D.ProjectiveTransRegion(HRegion regions, string interpolation)

Description

projective_trans_regionprojective_trans_regionProjectiveTransRegionProjectiveTransRegionProjectiveTransRegion applies the projective transformation specified by the homogeneous matrix HomMat2DHomMat2DHomMat2DHomMat2DhomMat2D on the regions in RegionsRegionsRegionsRegionsregions and returns the transformed regions in TransRegionsTransRegionsTransRegionsTransRegionstransRegions.

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

If 'clip_region'"clip_region""clip_region""clip_region""clip_region" is set to its default value 'true'"true""true""true""true" by set_system('clip_region', 'true')set_system("clip_region", "true")SetSystem("clip_region", "true")SetSystem("clip_region", "true")SetSystem("clip_region", "true") or if the transformation is degenerated and thus produces infinite regions, the output region is clipped by the rectangle with upper left corner (0, 0) and lower right corner ('width'"width""width""width""width", 'height'"height""height""height""height"), where 'width'"width""width""width""width" and 'height'"height""height""height""height" are system variables (see also get_systemget_systemGetSystemGetSystemGetSystem). If 'clip_region'"clip_region""clip_region""clip_region""clip_region" is 'false'"false""false""false""false", the output region is not clipped except by the maximum supported coordinate size 'MAX_FORMAT'"MAX_FORMAT""MAX_FORMAT""MAX_FORMAT""MAX_FORMAT". This may result in extremely memory and time intensive computations, so use with care.

Attention

The used coordinate system is the same as in affine_trans_pixelaffine_trans_pixelAffineTransPixelAffineTransPixelAffineTransPixel. This means that in fact not HomMat2DHomMat2DHomMat2DHomMat2DhomMat2D is applied but a modified version. Therefore, applying projective_trans_regionprojective_trans_regionProjectiveTransRegionProjectiveTransRegionProjectiveTransRegion corresponds to the following chain of transformations, which is applied to each point (Row_i, Col_i) of the region (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 region, e.g., by operators like area_centerarea_centerAreaCenterAreaCenterAreaCenter. For example, if you use this operator to calculate the center of gravity of a rotationally symmetric region and then rotate the region around this point using hom_mat2d_rotatehom_mat2d_rotateHomMat2dRotateHomMat2dRotateHomMat2dRotate, the resulting region will not lie on the original one. In such a case, you can compensate this effect by applying the following translations to HomMat2DHomMat2DHomMat2DHomMat2DhomMat2D before using it in projective_trans_regionprojective_trans_regionProjectiveTransRegionProjectiveTransRegionProjectiveTransRegion:

hom_mat2d_translate(HomMat2D, 0.5, 0.5, HomMat2DTmp) hom_mat2d_translate_local(HomMat2DTmp, -0.5, -0.5, HomMat2DAdapted) projective_trans_region(Region, TransRegion, HomMat2DAdapted, 'bilinear')

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

Execution Information

Parameters

RegionsRegionsRegionsRegionsregions (input_object)  region(-array) objectHRegionHRegionHobject

Input regions.

TransRegionsTransRegionsTransRegionsTransRegionstransRegions (output_object)  region(-array) objectHRegionHRegionHobject *

Output regions.

HomMat2DHomMat2DHomMat2DHomMat2DhomMat2D (input_control)  hom_mat2d HHomMat2D, HTupleHTupleHtuple (real) (double) (double) (double)

Homogeneous projective transformation matrix.

InterpolationInterpolationInterpolationInterpolationinterpolation (input_control)  string HTupleHTupleHtuple (string) (string) (HString) (char*)

Interpolation method for the transformation.

Default value: 'bilinear' "bilinear" "bilinear" "bilinear" "bilinear"

List of values: 'bilinear'"bilinear""bilinear""bilinear""bilinear", 'nearest_neighbor'"nearest_neighbor""nearest_neighbor""nearest_neighbor""nearest_neighbor"

Possible Predecessors

vector_to_proj_hom_mat2dvector_to_proj_hom_mat2dVectorToProjHomMat2dVectorToProjHomMat2dVectorToProjHomMat2d, hom_vector_to_proj_hom_mat2dhom_vector_to_proj_hom_mat2dHomVectorToProjHomMat2dHomVectorToProjHomMat2dHomVectorToProjHomMat2d, proj_match_points_ransacproj_match_points_ransacProjMatchPointsRansacProjMatchPointsRansacProjMatchPointsRansac, proj_match_points_ransac_guidedproj_match_points_ransac_guidedProjMatchPointsRansacGuidedProjMatchPointsRansacGuidedProjMatchPointsRansacGuided, hom_mat3d_projecthom_mat3d_projectHomMat3dProjectHomMat3dProjectHomMat3dProject

See also

projective_trans_imageprojective_trans_imageProjectiveTransImageProjectiveTransImageProjectiveTransImage, projective_trans_image_sizeprojective_trans_image_sizeProjectiveTransImageSizeProjectiveTransImageSizeProjectiveTransImageSize, projective_trans_contour_xldprojective_trans_contour_xldProjectiveTransContourXldProjectiveTransContourXldProjectiveTransContourXld, projective_trans_point_2dprojective_trans_point_2dProjectiveTransPoint2dProjectiveTransPoint2dProjectiveTransPoint2d, projective_trans_pixelprojective_trans_pixelProjectiveTransPixelProjectiveTransPixelProjectiveTransPixel

Module

Foundation