get_grayval_contour_xld — 返回 XLD 轮廓位置处的图像灰度值。
get_grayval_contour_xld(Image, Contour : : Interpolation : Grayval)
算子 get_grayval_contour_xld returns interpolated
gray values at several subpixel positions of the Image.
The coordinates of the positions are specified via one XLD contour
Contour. The gray values are returned in Grayval。
The interpolation method can be selected via the parameter
Interpolation:
The results are
the gray values of the nearest pixels to the selected coordinates.
For images of type byte, direction, cyclic, uint2, int1, int2,
int4, and int8, the parameter Grayval is a tuple of
integer numbers. For images of type real and complex, the
parameter Grayval is a tuple of floating point numbers.
The parameter
Grayval is computed using a bilinear interpolation of the
four neighboring gray values of the selected coordinates. The
result is a tuple of floating point numbers. The runtime
increases significantly compared to 'nearest_neighbor'.
Direction and cyclic images are treated like byte images.
The parameter
Grayval is computed using a bicubic interpolation of
sixteen neighboring gray values of the selected coordinates. The
result is a tuple of floating point numbers. The runtime
increases significantly compared to 'bilinear'.
Direction and cyclic images are treated like byte images. In this
mode, the resulting gray values may contain values that lie
outside of the range of numbers that can be represented by the
input image type.
The parameter
Grayval is computed using a bicubic interpolation of
sixteen neighboring gray values of the selected coordinates. The
result is a tuple of floating point numbers. The runtime
increases significantly compared to 'bilinear'.
Direction and cyclic images are treated like byte images. In this
mode, resulting gray values that lie outside of the range of
numbers that can be represented by the input image type are
clipped to that range.
Note that get_grayval_contour_xld does not take the domain of
the image into account, i.e., if the domain has been reduced, e.g.,
with reduce_domain, gray values are returned even for points
that lie outside the domain.
Please note also that each point of the XLD contour must be in the
range -0.5 <= row coordinate <
height(Image)-0.5 and -0.5 <= column
coordinate < width(Image)-0.5.
Image (输入对象) singlechannelimage → object (byte / direction / cyclic / int1 / int2 / uint2 / int4 / real / complex)
Image whose gray values are to be accessed.
Contour (输入对象) xld_cont → object
Input XLD contour with the coordinates of the positions.
Interpolation (输入控制) string → (string)
Interpolation method.
默认值： 'nearest_neighbor'
值列表： 'bicubic', 'bicubic_clipped', 'bilinear', 'nearest_neighbor'
Grayval (输出控制) grayval(-array) → (real / integer)
Gray values of the selected image coordinates.
如果参数有效，算子
get_grayval_contour_xld 返回值 2 ( H_MSG_TRUE )。如有必要，则抛出异常。
read_image,
draw_xld,
gen_contour_polygon_xld,
edges_sub_pix
基础