# AVL.FitArcToRidges

Performs a series of 1D ridge detections and finds an arc that best matches the detected points.

Namespace: AvlNet AVL.NET.dll

### Syntax

C++
C#

public static void FitArcToRidges
(
AvlNet.Image inImage,
AvlNet.ArcFittingMap inFittingMap,
AvlNet.RidgeScanParams inRidgeScanParams,
AvlNet.Selection inRidgeSelection,
AvlNet.LocalBlindness? inLocalBlindness,
float inMaxIncompleteness,
AvlNet.CircleFittingMethod inFittingMethod,
AvlNet.MEstimator? inOutlierSuppression,
out AvlNet.Arc2D? outArc,
IList<AvlNet.Ridge1D?> outRidges,
INullable<AvlNet.Profile> outDeviationProfile,
IList<AvlNet.Point2D> outInliers,
IList<AvlNet.Profile> diagBrightnessProfiles,
IList<AvlNet.Profile> diagResponseProfiles
)


### Parameters

Name Type Range Default Description
inImageAvlNet.ImageInput image to fit arc to.
inFittingMapAvlNet.ArcFittingMapInput fitting map.
inRidgeScanParamsAvlNet.RidgeScanParamsParameters controlling the ridge extraction process.
inRidgeSelectionAvlNet.Selectionavl::Selection::BestSelection mode of ridges. Default value: avl::Selection::Best.
inLocalBlindnessAvlNet.LocalBlindness?Defines conditions in which weaker ridges can be detected in the vicinity of stronger ridges. Default value: atl::NIL.
inFittingMethodAvlNet.CircleFittingMethodAlgebraicTaubinMethod used to fit an arc. Default value: AlgebraicTaubin.
inOutlierSuppressionAvlNet.MEstimator?Selects a method for ignoring incorrectly detected points. Default value: atl::NIL.
outArcAvlNet.Arc2D?Fitted arc or nothing if the fitting fails.
outRidgesSystem.Collections.Generic.IList<AvlNet.Ridge1D?>Found ridges.
outDeviationProfileAvlNet.INullable<AvlNet.Profile>Profile of distances between the actual arc points and the corresponding reference arc points. This parameter cannot be null.
diagBrightnessProfilesSystem.Collections.Generic.IList<AvlNet.Profile>Extracted image profiles.
diagResponseProfilesSystem.Collections.Generic.IList<AvlNet.Profile>Profiles of the ridge operator response.

### Description

The operation tries to fit a given arc to ridges present in the inImage image. Internally, it performs a series of scans with the ScanSingleRidge filter using inFittingMap previously generated from the object being fitted. The found points are then used to determine the actual position of the arc in the image. Only inMaxIncompleteness fraction of these scans may fail. If the fitting according to the given parameters is not possible, outArc is set to Nil.

### Examples

Fitting an arc to a curved wall of a plastic capsule
(inRidgeScanParams.RidgeWidth = 3, inRidgeScanParams.Polarity = Dark).

### Remarks

Read more about Local Coordinate Systems in Machine Vision Guide: Local Coordinate Systems.

This filter is a part of the Shape Fitting toolset. To read more about this technique, one can refer to the Shape Fitting chapter of our Machine Vision Guide

### Hardware Acceleration

This operation supports automatic parallelization for multicore and multiprocessor systems.

Hardware acceleration settings may be manipulated with Settings class.