affine_trans_pixelT_affine_trans_pixelAffineTransPixelAffineTransPixelaffine_trans_pixel (Operator)

Name

affine_trans_pixelT_affine_trans_pixelAffineTransPixelAffineTransPixelaffine_trans_pixel — Apply an arbitrary affine 2D transformation to pixel coordinates.

Signature

affine_trans_pixel( : : HomMat2D, Row, Col : RowTrans, ColTrans)

Description

affine_trans_pixelaffine_trans_pixelAffineTransPixelAffineTransPixelAffineTransPixelaffine_trans_pixel applies an arbitrary affine 2D transformation, i.e., scaling, rotation, translation, and slant (skewing), to the input pixels (RowRowRowRowrowrow,ColColColColcolcol) and returns the resulting pixels in (RowTransRowTransRowTransRowTransrowTransrow_trans,ColTransColTransColTransColTranscolTranscol_trans); the input and output pixels are subpixel precise coordinates. The affine transformation is described by the homogeneous transformation matrix given in HomMat2DHomMat2DHomMat2DHomMat2DhomMat2Dhom_mat_2d.

In contrast to affine_trans_point_2daffine_trans_point_2dAffineTransPoint2dAffineTransPoint2dAffineTransPoint2daffine_trans_point_2d, affine_trans_pixelaffine_trans_pixelAffineTransPixelAffineTransPixelAffineTransPixelaffine_trans_pixel first converts the input coordinates from HALCON's standard coordinate system (with the origin in the center of the upper left pixel) to a coordinate system with the origin in the upper left corner of the upper left pixel. After the transformation with HomMat2DHomMat2DHomMat2DHomMat2DhomMat2Dhom_mat_2d the result is converted back to the standard coordinate system. This way, affine_trans_pixelaffine_trans_pixelAffineTransPixelAffineTransPixelAffineTransPixelaffine_trans_pixel is compatible with affine_trans_imageaffine_trans_imageAffineTransImageAffineTransImageAffineTransImageaffine_trans_image, affine_trans_image_sizeaffine_trans_image_sizeAffineTransImageSizeAffineTransImageSizeAffineTransImageSizeaffine_trans_image_size, affine_trans_regionaffine_trans_regionAffineTransRegionAffineTransRegionAffineTransRegionaffine_trans_region, affine_trans_contour_xldaffine_trans_contour_xldAffineTransContourXldAffineTransContourXldAffineTransContourXldaffine_trans_contour_xld, and affine_trans_polygon_xldaffine_trans_polygon_xldAffineTransPolygonXldAffineTransPolygonXldAffineTransPolygonXldaffine_trans_polygon_xld.

Applying affine_trans_pixelaffine_trans_pixelAffineTransPixelAffineTransPixelAffineTransPixelaffine_trans_pixel corresponds to the following chain of transformations (input and output pixels as homogeneous vectors):

Hence,

affine_trans_pixel(HomMat2D, Row, Col, RowTrans, ColTrans)affine_trans_pixel(HomMat2D, Row, Col, RowTrans, ColTrans)AffineTransPixel(HomMat2D, Row, Col, RowTrans, ColTrans)AffineTransPixel(HomMat2D, Row, Col, RowTrans, ColTrans)AffineTransPixel(HomMat2D, Row, Col, RowTrans, ColTrans)affine_trans_pixel(HomMat2D, Row, Col, RowTrans, ColTrans)

corresponds to the following operator sequence:

affine_trans_point_2d(HomMat2D, Row+0.5, Col+0.5, RowTmp, ColTmp)affine_trans_point_2d(HomMat2D, Row+0.5, Col+0.5, RowTmp, ColTmp)AffineTransPoint2d(HomMat2D, Row+0.5, Col+0.5, RowTmp, ColTmp)AffineTransPoint2d(HomMat2D, Row+0.5, Col+0.5, RowTmp, ColTmp)AffineTransPoint2d(HomMat2D, Row+0.5, Col+0.5, RowTmp, ColTmp)affine_trans_point_2d(HomMat2D, Row+0.5, Col+0.5, RowTmp, ColTmp)

RowTrans := RowTmp-0.5

ColTrans := ColTmp-0.5

Further Information

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).
Automatically parallelized on internal data level.

Parameters

HomMat2DHomMat2DHomMat2DHomMat2DhomMat2Dhom_mat_2d (input_control) hom_mat2d → (real)

Input transformation matrix.

RowRowRowRowrowrow (input_control) point.x(-array) → (real / integer)

Input pixel(s) (row coordinate).

Default value: 64

Suggested values: 0, 16, 32, 64, 128, 256, 512, 1024

ColColColColcolcol (input_control) point.y(-array) → (real / integer)

Input pixel(s) (column coordinate).

Default value: 64

Suggested values: 0, 16, 32, 64, 128, 256, 512, 1024

RowTransRowTransRowTransRowTransrowTransrow_trans (output_control) point.x(-array) → (real)

Output pixel(s) (row coordinate).

ColTransColTransColTransColTranscolTranscol_trans (output_control) point.y(-array) → (real)

Output pixel(s) (column coordinate).

Result

If the matrix HomMat2DHomMat2DHomMat2DHomMat2DhomMat2Dhom_mat_2d represents an affine transformation (i.e., not a projective transformation), affine_trans_pixelaffine_trans_pixelAffineTransPixelAffineTransPixelAffineTransPixelaffine_trans_pixel returns 2 (H_MSG_TRUE). Otherwise, an exception is raised.

Possible Predecessors

hom_mat2d_translatehom_mat2d_translateHomMat2dTranslateHomMat2dTranslateHomMat2dTranslatehom_mat2d_translate, hom_mat2d_translate_localhom_mat2d_translate_localHomMat2dTranslateLocalHomMat2dTranslateLocalHomMat2dTranslateLocalhom_mat2d_translate_local, hom_mat2d_scalehom_mat2d_scaleHomMat2dScaleHomMat2dScaleHomMat2dScalehom_mat2d_scale, hom_mat2d_scale_localhom_mat2d_scale_localHomMat2dScaleLocalHomMat2dScaleLocalHomMat2dScaleLocalhom_mat2d_scale_local, hom_mat2d_rotatehom_mat2d_rotateHomMat2dRotateHomMat2dRotateHomMat2dRotatehom_mat2d_rotate, hom_mat2d_rotate_localhom_mat2d_rotate_localHomMat2dRotateLocalHomMat2dRotateLocalHomMat2dRotateLocalhom_mat2d_rotate_local, hom_mat2d_slanthom_mat2d_slantHomMat2dSlantHomMat2dSlantHomMat2dSlanthom_mat2d_slant, hom_mat2d_slant_localhom_mat2d_slant_localHomMat2dSlantLocalHomMat2dSlantLocalHomMat2dSlantLocalhom_mat2d_slant_local, hom_mat2d_reflecthom_mat2d_reflectHomMat2dReflectHomMat2dReflectHomMat2dReflecthom_mat2d_reflect, hom_mat2d_reflect_localhom_mat2d_reflect_localHomMat2dReflectLocalHomMat2dReflectLocalHomMat2dReflectLocalhom_mat2d_reflect_local

Alternatives

affine_trans_point_2daffine_trans_point_2dAffineTransPoint2dAffineTransPoint2dAffineTransPoint2daffine_trans_point_2d

Module

Foundation

Operators