ClassesClasses | | Operators

affine_trans_regionT_affine_trans_regionAffineTransRegionAffineTransRegion (Operator)

Name

affine_trans_regionT_affine_trans_regionAffineTransRegionAffineTransRegion — Apply an arbitrary affine 2D transformation to regions.

Signature

affine_trans_region(Region : RegionAffineTrans : HomMat2D, Interpolate : )

Herror T_affine_trans_region(const Hobject Region, Hobject* RegionAffineTrans, const Htuple HomMat2D, const Htuple Interpolate)

void AffineTransRegion(const HObject& Region, HObject* RegionAffineTrans, const HTuple& HomMat2D, const HTuple& Interpolate)

HRegion HRegion::AffineTransRegion(const HHomMat2D& HomMat2D, const HString& Interpolate) const

HRegion HRegion::AffineTransRegion(const HHomMat2D& HomMat2D, const char* Interpolate) const

HRegion HHomMat2D::AffineTransRegion(const HRegion& Region, const HString& Interpolate) const

HRegion HHomMat2D::AffineTransRegion(const HRegion& Region, const char* Interpolate) const

static void HOperatorSet.AffineTransRegion(HObject region, out HObject regionAffineTrans, HTuple homMat2D, HTuple interpolate)

HRegion HRegion.AffineTransRegion(HHomMat2D homMat2D, string interpolate)

HRegion HHomMat2D.AffineTransRegion(HRegion region, string interpolate)

Description

affine_trans_regionaffine_trans_regionAffineTransRegionAffineTransRegionAffineTransRegion applies an arbitrary affine 2D transformation, i.e., scaling, rotation, translation, and slant (skewing), to the regions given in RegionRegionRegionRegionregion and returns the transformed regions in RegionAffineTransRegionAffineTransRegionAffineTransRegionAffineTransregionAffineTrans. The affine transformation is described by the homogeneous transformation matrix given in HomMat2DHomMat2DHomMat2DHomMat2DhomMat2D, which can be created using the operators hom_mat2d_identityhom_mat2d_identityHomMat2dIdentityHomMat2dIdentityHomMat2dIdentity, hom_mat2d_scalehom_mat2d_scaleHomMat2dScaleHomMat2dScaleHomMat2dScale, hom_mat2d_rotatehom_mat2d_rotateHomMat2dRotateHomMat2dRotateHomMat2dRotate, hom_mat2d_translatehom_mat2d_translateHomMat2dTranslateHomMat2dTranslateHomMat2dTranslate, etc., or be the result of operators like vector_angle_to_rigidvector_angle_to_rigidVectorAngleToRigidVectorAngleToRigidVectorAngleToRigid.

The components of the homogeneous transformation matrix are interpreted as follows: The row coordinate of the image corresponds to x and the column coordinate corresponds to y of the coordinate system in which the transformation matrix was defined. This is necessary to obtain a right-handed coordinate system for the image. In particular, this assures that rotations are performed in the correct direction. Note that the (x,y) order of the matrices quite naturally corresponds to the usual (row,column) order for coordinates in the image.

The parameter InterpolateInterpolateInterpolateInterpolateinterpolate determines whether the transformation is to be done by using interpolation internally. The interpolation modes 'nearest_neighbor'"nearest_neighbor""nearest_neighbor""nearest_neighbor""nearest_neighbor" and 'constant'"constant""constant""constant""constant", which are described in detail for affine_trans_imageaffine_trans_imageAffineTransImageAffineTransImageAffineTransImage, can be used. An interpolation can lead to smoother region boundaries, especially if regions are enlarged. However, the runtime increases drastically.

Attention

affine_trans_regionaffine_trans_regionAffineTransRegionAffineTransRegionAffineTransRegion in general is not reversible (clipping and discretization during rotation and scaling).

affine_trans_regionaffine_trans_regionAffineTransRegionAffineTransRegionAffineTransRegion does not use the HALCON standard coordinate system (with the origin in the center of the upper left pixel), but instead uses the same coordinate system as in affine_trans_pixelaffine_trans_pixelAffineTransPixelAffineTransPixelAffineTransPixel, i.e., the origin lies in the upper left corner of the upper left pixel. Therefore, applying affine_trans_regionaffine_trans_regionAffineTransRegionAffineTransRegionAffineTransRegion corresponds to a chain of transformations (see affine_trans_pixelaffine_trans_pixelAffineTransPixelAffineTransPixelAffineTransPixel), which is applied to each point of the region (input and output pixels as homogeneous vectors). As an effect, you might get unexpected results when creating affine 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 affine_trans_regionaffine_trans_regionAffineTransRegionAffineTransRegionAffineTransRegion:

  hom_mat2d_translate(HomMat2D, 0.5, 0.5, HomMat2DTmp)
  hom_mat2d_translate_local(HomMat2DTmp, -0.5, -0.5, HomMat2DAdapted)
  affine_trans_region(Region, RegionAffineTrans, HomMat2DAdapted, 'false')

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

Execution Information

Parameters

RegionRegionRegionRegionregion (input_object)  region(-array) objectHRegionHRegionHobject

Region(s) to be rotated and scaled.

RegionAffineTransRegionAffineTransRegionAffineTransRegionAffineTransregionAffineTrans (output_object)  region(-array) objectHRegionHRegionHobject *

Transformed output region(s).

Number of elements: RegionAffineTrans == Region

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

Input transformation matrix.

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

Should the transformation be done using interpolation?

Default value: 'nearest_neighbor' "nearest_neighbor" "nearest_neighbor" "nearest_neighbor" "nearest_neighbor"

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

Result

If the matrix HomMat2DHomMat2DHomMat2DHomMat2DhomMat2D represents an affine transformation (i.e., not a projective transformation), affine_trans_regionaffine_trans_regionAffineTransRegionAffineTransRegionAffineTransRegion returns 2 (H_MSG_TRUE). The behavior in case of empty input (no regions given) can be set via set_system('no_object_result',<Result>)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>), the behavior in case of an empty input region via set_system('empty_region_result',<Result>)set_system("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>), and the behavior in case of an empty result region via set_system('store_empty_region',<'true'/'false'>)set_system("store_empty_region",<"true"/"false">)SetSystem("store_empty_region",<"true"/"false">)SetSystem("store_empty_region",<"true"/"false">)SetSystem("store_empty_region",<"true"/"false">). If necessary, an exception is raised.

Possible Predecessors

hom_mat2d_identityhom_mat2d_identityHomMat2dIdentityHomMat2dIdentityHomMat2dIdentity, hom_mat2d_scalehom_mat2d_scaleHomMat2dScaleHomMat2dScaleHomMat2dScale, hom_mat2d_translatehom_mat2d_translateHomMat2dTranslateHomMat2dTranslateHomMat2dTranslate, hom_mat2d_inverthom_mat2d_invertHomMat2dInvertHomMat2dInvertHomMat2dInvert, hom_mat2d_rotatehom_mat2d_rotateHomMat2dRotateHomMat2dRotateHomMat2dRotate, hom_mat2d_reflecthom_mat2d_reflectHomMat2dReflectHomMat2dReflectHomMat2dReflect

Possible Successors

select_shapeselect_shapeSelectShapeSelectShapeSelectShape

Alternatives

move_regionmove_regionMoveRegionMoveRegionMoveRegion, mirror_regionmirror_regionMirrorRegionMirrorRegionMirrorRegion, zoom_regionzoom_regionZoomRegionZoomRegionZoomRegion

See also

affine_trans_imageaffine_trans_imageAffineTransImageAffineTransImageAffineTransImage

Module

Foundation


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