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.
For an explanation of the concept of 1D measuring see the introduction of chapter 1D Measuring.
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
Suggested 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