set_fuzzy_measure_norm_pair — Specify a normalized fuzzy function for edge pairs.
set_fuzzy_measure_norm_pair specifies a normalized fuzzy function passed in Function. The specified fuzzy functions enables fuzzy_measure_pos, fuzzy_measure_pairs and fuzzy_measure_pairing to evaluate and select the detected candidates of edges and edge pairs. For this purpose, weighting characteristics for different edge features can be defined by one function each. Such a specified feature is called fuzzy set. Specifying no function for a fuzzy set means not to use this feature for the final edge evaluation. Setting a second fuzzy function to a fuzzy set means to discard the first defined function and replace it by the second one. In difference to set_fuzzy_measure, the abscissa x of these functions must be defined relative to the desired size s of the edge pairs (passed in PairSize). This enables a generalized usage of the defined functions. A previously defined normalized fuzzy function can be discarded completely by reset_fuzzy_measure.
Functions for three different fuzzy set types selected by the SetType parameter can be defined, the sub types of a set being mutual exclusive:
'size' denotes a fuzzy set that valuates the normalized distance of two edges of a pair in pixels:
Specifying an upper bound x_max for the size by terminating the function with a corresponding fuzzy value of 0.0 will speed up fuzzy_measure_pairs / fuzzy_measure_pairing because not all possible pairs must be considered. Additionally, this fuzzy set can also be specified as a normalized size difference by 'size_diff'
and a absolute normalized size difference by 'size_abs_diff'
The reference point is located at the beginning whereas 'position_center' or 'position_end' sets the reference point to the middle or the end of the one-dimensional gray value profile, instead. If the fuzzy position valuation depends on the position of the object along the profile 'position_first_edge' / 'position_last_edge' sets the referece point at the position of the first/last extracted edge. When extracting edge pairs, the position of a pair is referenced by the geometric average of the fuzzy position scores of both edges.
Similar to 'position', 'position_pair' evaluates the signed distance of each edge pair to the reference point of the measure object. The position of a pair is defined by the center point between both edges. The object's reference can be set by 'position_pair_center', 'position_pair_end' and 'position_first_pair', 'position_last_pair', respectively. Contrary to 'position', this set is only used by fuzzy_measure_pairs/fuzzy_measure_pairing.
A normalized fuzzy function is defined as a piecewise linear function by at least two pairs of values, sorted in an ascending order by their x value. The y values of the fuzzy function represent the weight of the corresponding feature value and must satisfy the range of 0.0 <= y <= 1.0. Outside of the function's interval, defined by the smallest and the greatest x value, the y values of the interval borders are continued constantly. Such Fuzzy functions can be generated by create_funct_1d_pairs.
If more than one set is defined, fuzzy_measure_pos / fuzzy_measure_pairs / fuzzy_measure_pairing yield the overall fuzzy weighting by the geometric mean of the weights of each set.
This operator modifies the state of the following input parameter:
Measure object handle.
Favored width of edge pairs.
Default value: 10.0
List of values: 4.0, 6.0, 8.0, 10.0, 15.0, 20.0, 30.0
Typical range of values: 0.0 ≤ PairSize
Minimum increment: 0.1
Recommended increment: 1.0
Selection of the fuzzy set.
Default value: 'size_abs_diff'
List of values: 'position', 'position_center', 'position_end', 'position_first_edge', 'position_first_pair', 'position_last_edge', 'position_last_pair', 'position_pair_center', 'position_pair_end', 'size', 'size_abs_diff', 'size_diff'
* how to use a fuzzy function * ... gen_measure_rectangle2 (50, 100, 0, 200, 100, 512, 512, 'nearest_neighbor', \ MeasureHandle) * create a generalized fuzzy function to evaluate edge pairs * * (30% uncertainty). create_funct_1d_pairs ([0.7,1.0,1.3], [0.0,1.0,0.0], SizeFunction) * and set it for an expected pair size of 13.45 pixels set_fuzzy_measure_norm_pair (MeasureHandle, 13.45, 'size', SizeFunction) fuzzy_measure_pairs (Image, MeasureHandle, 1, 30, 0.5, 'all', RowEdgeFirst, \ ColumnEdgeFirst, AmplitudeFirst, RowEdgeSecond, \ ColumnEdgeSecond, AmplitudeSecond, RowEdgeCenter, \ ColumnEdgeCenter, FuzzyScore, IntraDistance, \ InterDistance)
gen_measure_arc, gen_measure_rectangle2, create_funct_1d_pairs