hom_mat2d_slantT_hom_mat2d_slantHomMat2dSlantHomMat2dSlanthom_mat2d_slant (算子)

名称

hom_mat2d_slantT_hom_mat2d_slantHomMat2dSlantHomMat2dSlanthom_mat2d_slant — 向齐次二维变换矩阵添加倾斜。

签名

描述

hom_mat2d_slanthom_mat2d_slantHomMat2dSlantHomMat2dSlantHomMat2dSlanthom_mat2d_slant adds a slant by the angle ThetaThetaThetaThetathetatheta to the homogeneous 2D transformation matrix HomMat2DHomMat2DHomMat2DHomMat2DhomMat2Dhom_mat_2d and returns the resulting matrix in HomMat2DSlantHomMat2DSlantHomMat2DSlantHomMat2DSlanthomMat2DSlanthom_mat_2dslant. A slant is an affine transformation in which one coordinate axis remains fixed, while the other coordinate axis is rotated counterclockwise by an angle ThetaThetaThetaThetathetatheta. The parameter AxisAxisAxisAxisaxisaxis determines which coordinate axis is slanted. For AxisAxisAxisAxisaxisaxis = 'x'"x""x""x""x""x", the x-axis is slanted and the y-axis remains fixed, while for AxisAxisAxisAxisaxisaxis = 'y'"y""y""y""y""y" the y-axis is slanted and the x-axis remains fixed. The slanting is performed relative to the global (i.e., fixed) coordinate system; this corresponds to the following chains of transformation matrices:

The point (PxPxPxPxpxpx,PyPyPyPypypy) is the fixed point of the transformation, i.e., this point remains unchanged when transformed using HomMat2DSlantHomMat2DSlantHomMat2DSlantHomMat2DSlanthomMat2DSlanthom_mat_2dslant. To obtain this behavior, first a translation is added to the input transformation matrix that moves the fixed point onto the origin of the global coordinate system. Then, the slant is added, and finally a translation that moves the fixed point back to its original position. This corresponds to the following chain of transformations for AxisAxisAxisAxisaxisaxis = 'x'"x""x""x""x""x"：

To perform the transformation in the local coordinate system, i.e., the one described by HomMat2DHomMat2DHomMat2DHomMat2DhomMat2Dhom_mat_2d, use hom_mat2d_slant_localhom_mat2d_slant_localHomMat2dSlantLocalHomMat2dSlantLocalHomMat2dSlantLocalhom_mat2d_slant_local。

注意

It should be noted that homogeneous transformation matrices refer to a general right-handed mathematical coordinate system. If a homogeneous transformation matrix is used to transform images, regions, XLD contours, or any other data that has been extracted from images, the row coordinates of the transformation must be passed in the x coordinates, while the column coordinates must be passed in the y coordinates. Consequently, the order of passing row and column coordinates follows the usual order (RowRowRowRowrowrow,ColumnColumnColumnColumncolumncolumn). This convention is essential to obtain a right-handed coordinate system for the transformation of iconic data, and consequently to ensure in particular that rotations are performed in the correct mathematical direction.

Note that homogeneous matrices are stored row-by-row as a tuple; the last row is usually not stored because it is identical for all homogeneous matrices that describe an affine transformation. For example, the homogeneous matrix is stored as the tuple [ra, rb, tc, rd, re, tf]. However, it is also possible to process full 3×3 matrices, which represent a projective 2D transformation.

执行信息

• 多线程类型：可重入（与非独占算子并行运行）。
• 多线程作用域：全局（可从任何线程调用）。
• 未采用并行化处理。

参数

结果

如果参数有效，算子 hom_mat2d_slanthom_mat2d_slantHomMat2dSlantHomMat2dSlantHomMat2dSlanthom_mat2d_slant 返回 2 ( H_MSG_TRUE )。如有必要，则抛出异常。

可能的前趋

hom_mat2d_identityhom_mat2d_identityHomMat2dIdentityHomMat2dIdentityHomMat2dIdentityhom_mat2d_identity, hom_mat2d_translatehom_mat2d_translateHomMat2dTranslateHomMat2dTranslateHomMat2dTranslatehom_mat2d_translate, hom_mat2d_scalehom_mat2d_scaleHomMat2dScaleHomMat2dScaleHomMat2dScalehom_mat2d_scale, hom_mat2d_rotatehom_mat2d_rotateHomMat2dRotateHomMat2dRotateHomMat2dRotatehom_mat2d_rotate, hom_mat2d_slanthom_mat2d_slantHomMat2dSlantHomMat2dSlantHomMat2dSlanthom_mat2d_slant, hom_mat2d_reflecthom_mat2d_reflectHomMat2dReflectHomMat2dReflectHomMat2dReflecthom_mat2d_reflect

可能的后继

hom_mat2d_translatehom_mat2d_translateHomMat2dTranslateHomMat2dTranslateHomMat2dTranslatehom_mat2d_translate, hom_mat2d_scalehom_mat2d_scaleHomMat2dScaleHomMat2dScaleHomMat2dScalehom_mat2d_scale, hom_mat2d_rotatehom_mat2d_rotateHomMat2dRotateHomMat2dRotateHomMat2dRotatehom_mat2d_rotate, hom_mat2d_slanthom_mat2d_slantHomMat2dSlantHomMat2dSlantHomMat2dSlanthom_mat2d_slant, hom_mat2d_reflecthom_mat2d_reflectHomMat2dReflectHomMat2dReflectHomMat2dReflecthom_mat2d_reflect

另见

hom_mat2d_slant_localhom_mat2d_slant_localHomMat2dSlantLocalHomMat2dSlantLocalHomMat2dSlantLocalhom_mat2d_slant_local

模块

基础

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