Project pixel coordinates using a homogeneous projective transformation matrix.

projective_trans_pixel applies the homogeneous projective transformation matrix HomMat2D to all input pixels (Row,Col) and returns an array of output pixels (RowTrans,ColTrans). The transformation is described by the homogeneous transformation matrix given in HomMat2D.

The difference between projective_trans_pixel and projective_trans_point_2d lies in the used coordinate system: projective_trans_pixel uses a coordinate system with origin in the upper left corner of the image, while projective_trans_point_2d uses the standard image coordinate system, whose origin lies in the middle of the upper left pixel and which is also used by operators like area_center.

projective_trans_pixel corresponds to the following steps (input and output points as homogeneous vectors):

  / RTrans \   / 1 0 -0.5 \              / 1 0 +0.5 \   / Row \
  | CTrans | = | 0 1 -0.5 | * HomMat2D * | 0 1 +0.5 | * | Col |
  \ WTrans /   \ 0 0   1  /              \ 0 0   1  /   \  1  /

  ( RowTrans, ColTrans ) = ( RTrans/WTrans, CTrans/WTrans )

If a point at infinity (WTrans = 0) is created by the transformation, an error is returned.

projective_trans_pixel is reentrant and processed without parallelization.

vector_to_proj_hom_mat2d, hom_vector_to_proj_hom_mat2d, proj_match_points_ransac, hom_mat3d_project

projective_trans_image, projective_trans_image_size, projective_trans_region, projective_trans_contour_xld, projective_trans_point_2d

Foundation