fuzzy_measure

fuzzy_measure_pairing ( Image : : MeasureHandle, Sigma, AmpThresh, FuzzyThresh, Transition, Pairing, NumPairs : RowEdgeFirst, ColumnEdgeFirst, AmplitudeFirst, RowEdgeSecond, ColumnEdgeSecond, AmplitudeSecond, RowPairCenter, ColumnPairCenter, FuzzyScore, IntraDistance )

Extract straight edge pairs perpendicular to a rectangle or an annular arc.

fuzzy_measure_pairing serves to extract straight edge pairs that lie perpendicular to the major axis of a rectangle or an annular arc. In addition to measure_pos it uses fuzzy member functions to evaluate and select the edge pairs.

The extraction algorithm is identical to fuzzy_measure_pos. In addition, the edges are grouped to pairs: If Transition = 'positive', the edge points with a dark-to-light transition in the direction of the major axis of the rectangle or the annular arc are returned in RowEdgeFirst and ColumnEdgeFirst. In this case, the corresponding edges with a light-to-dark transition are returned in RowEdgeSecond and ColumnEdgeSecond. If Transition = 'negative', the behavior is exactly opposite. If Transition = 'all', the first detected edge defines the transition for RowEdgeFirst and ColumnEdgeFirst.

Having extracted subpixel edge locations, the edges are paired. The features of a possible edge pair are evaluated by a fuzzy function, set by set_fuzzy_measure. Which edge pairs are selected can be determined with the parameter FuzzyThresh, which constitutes a threshold on the weight over all fuzzy sets, i.e., the geometric mean of the weights of the defined fuzzy membership functions. As an extension to fuzzy_measure_pairs, the pairing algorithm can be restricted by Pairing. Currently only 'no_restriction' is available, which returns all possible edge pairs, allowing interleaving and inclusion of pairs. Finally, the best scored NumPairs edge pairs are returned, whereas 0 indicates to return all possible found edge combinations.

The selected edges are returned as single points, which lie on the major axis of the rectangle or annular arc. The corresponding edge amplitudes are returned in AmplitudeFirst and AmplitudeSecond, the fuzzy scores in FuzzyScore. In addition, the distance between each edge pair is returned in IntraDistance, corresponding to the distance between EdgeFirst[i] and EdgeSecond[i].

Attention

fuzzy_measure_pairing only returns meaningful results if the assumptions that the edges are straight and perpendicular to the major axis of the rectangle or annular arc are fulfilled. Thus, it should not be used to extract edges from curved objects, for example. Furthermore, the user should ensure that the rectangle or annular arc is as close to perpendicular as possible to the edges in the image. Additionally, Sigma must not become larger than approx. 0.5 * Length1 (for Length1 see gen_measure_rectangle2).

It should be kept in mind that fuzzy_measure_pairing ignores the domain of Image for efficiency reasons. If certain regions in the image should be excluded from the measurement a new measure object with appropriately modified parameters should be generated.

Parameters

`Image` (input_object)	singlechannelimage `->` object : byte / uint2
Input image.

`MeasureHandle` (input_control)	measure_id `->` integer
Measure object handle.

`Sigma` (input_control)	number `->` real
Sigma of Gaussian smoothing.
Default value: 1.0
Suggested values: 0.4, 0.6, 0.8, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0, 7.0, 10.0
Typical range of values: `0.4 <= Sigma <= 100` (lin)
Minimum increment: 0.01
Recommended increment: 0.1
Restriction: `Sigma >= 0.4`

`AmpThresh` (input_control)	number `->` real
Minimum edge amplitude.
Default value: 30.0
Suggested values: 5.0, 10.0, 20.0, 30.0, 40.0, 50.0, 60.0, 70.0, 90.0, 110.0
Typical range of values: `1 <= AmpThresh <= 255` (lin)
Minimum increment: 0.5
Recommended increment: 2

`FuzzyThresh` (input_control)	number `->` real
Minimum fuzzy value.
Default value: 0.5
Suggested values: 0.1, 0.3, 0.5, 0.7, 0.9
Typical range of values: `0.0 <= FuzzyThresh <= 1.0` (lin)
Recommended increment: 0.1

`Transition` (input_control)	string `->` string
Select the first gray value transition of the edge pairs.
Default value: 'all'
List of values: 'all', 'positive', 'negative'

`Pairing` (input_control)	string `->` string
Constraint of pairing.
Default value: 'no_restriction'
List of values: 'no_restriction'

`NumPairs` (input_control)	number `->` integer
Number of edge pairs.
Default value: 10
Suggested values: 0, 1, 10, 20, 50
Typical range of values: `0 <= NumPairs`
Recommended increment: 1

`RowEdgeFirst` (output_control)	point.y-array `->` real
Row coordinate of the first edge.

`ColumnEdgeFirst` (output_control)	point.x-array `->` real
Column coordinate of the first edge.

`AmplitudeFirst` (output_control)	real-array `->` real
Edge amplitude of the first edge (with sign).

`RowEdgeSecond` (output_control)	point.y-array `->` real
Row coordinate of the second edge.

`ColumnEdgeSecond` (output_control)	point.x-array `->` real
Column coordinate of the second edge.

`AmplitudeSecond` (output_control)	real-array `->` real
Edge amplitude of the second edge (with sign).

`RowPairCenter` (output_control)	point.y-array `->` real
Row coordinate of the center of the edge pair.

`ColumnPairCenter` (output_control)	point.x-array `->` real
Column coordinate of the center of the edge pair.

`FuzzyScore` (output_control)	real-array `->` real
Fuzzy evaluation of the edge pair.

`IntraDistance` (output_control)	real-array `->` real
Distance between the edges of the edge pair.

Result

If the parameter values are correct the operator fuzzy_measure_pairing returns the value 2 (H_MSG_TRUE). Otherwise an exception handling is raised.

Parallelization Information

fuzzy_measure_pairing is reentrant and processed without parallelization.

Possible Predecessors

gen_measure_rectangle2, gen_measure_arc, set_fuzzy_measure

Possible Successors

close_measure

Alternatives

edges_sub_pix, fuzzy_measure_pairs, measure_pairs

See also

fuzzy_measure_pos, measure_pos

Module

1D Metrology