hysteresis_threshold — 对图像执行滞后阈值运算。
hysteresis_threshold(Image : RegionHysteresis : Low, High, MaxLength : )
hysteresis_threshold performs a hysteresis threshold
operation (introduced by Canny) on an image. All points in the input image
Image having a gray value larger than or equal to High are
immediately accepted (“secure” points). Conversely, all points
with gray values less than Low are immediately rejected.
“Potential” points with gray values between both thresholds are
accepted if they are connected to “secure” points by a path of
“potential” points having a length of at most MaxLength
points. This means that “secure” points influence their
surroundings (hysteresis).
For images of type byte, uint2, or int4 the lower threshold must be
Low > 0.
Image (输入对象) singlechannelimage(-array) → object (byte / uint2 / int4 / real)
输入图像。
RegionHysteresis (输出对象) region(-array) → object
Segmented region.
Low (输入控制) number → (integer / real)
Lower threshold for the gray values.
默认值： 30
建议值： 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100
High (输入控制) number → (integer / real)
Upper threshold for the gray values.
默认值： 60
建议值： 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130
限制：
High >= Low
MaxLength (输入控制) integer → (integer)
Maximum length of a path of “potential” points to reach a “secure” point.
默认值： 10
建议值： 1, 2, 3, 5, 7, 10, 12, 14, 17, 20, 25, 30, 35, 40, 50
值范围：
1
≤
MaxLength
最小增量： 1
建议增量： 5
hysteresis_threshold 在所有参数正确时返回 2 ( H_MSG_TRUE )。 The behavior with respect to the input images and
output regions can be determined by setting the values of the flags
'no_object_result', 'empty_region_result', and
'store_empty_region' with set_system。如有必要，则抛出异常。
dyn_threshold,
threshold,
class_2dim_sup,
fast_threshold
edges_image,
sobel_dir,
background_seg
J. Canny, “Finding Edges and Lines in Images”; Report, AI-TR-720, M.I.T. Artificial Intelligence Lab., Cambridge, MA, 1983.
基础