ORBCreate Method

public static ORB Create(
	int nFeatures = 500,
	float scaleFactor = 1.2f,
	int nLevels = 8,
	int edgeThreshold = 31,
	int firstLevel = 0,
	int wtaK = 2,
	ORBScoreType scoreType = ORBScoreType.Harris,
	int patchSize = 31,
	int fastThreshold = 20
)

Public Shared Function Create ( 
	Optional nFeatures As Integer = 500,
	Optional scaleFactor As Single = 1.2F,
	Optional nLevels As Integer = 8,
	Optional edgeThreshold As Integer = 31,
	Optional firstLevel As Integer = 0,
	Optional wtaK As Integer = 2,
	Optional scoreType As ORBScoreType = ORBScoreType.Harris,
	Optional patchSize As Integer = 31,
	Optional fastThreshold As Integer = 20
) As ORB

public:
static ORB^ Create(
	int nFeatures = 500, 
	float scaleFactor = 1.2f, 
	int nLevels = 8, 
	int edgeThreshold = 31, 
	int firstLevel = 0, 
	int wtaK = 2, 
	ORBScoreType scoreType = ORBScoreType::Harris, 
	int patchSize = 31, 
	int fastThreshold = 20
)

static member Create : 
        ?nFeatures : int * 
        ?scaleFactor : float32 * 
        ?nLevels : int * 
        ?edgeThreshold : int * 
        ?firstLevel : int * 
        ?wtaK : int * 
        ?scoreType : ORBScoreType * 
        ?patchSize : int * 
        ?fastThreshold : int 
(* Defaults:
        let _nFeatures = defaultArg nFeatures 500
        let _scaleFactor = defaultArg scaleFactor 1.2f
        let _nLevels = defaultArg nLevels 8
        let _edgeThreshold = defaultArg edgeThreshold 31
        let _firstLevel = defaultArg firstLevel 0
        let _wtaK = defaultArg wtaK 2
        let _scoreType = defaultArg scoreType ORBScoreType.Harris
        let _patchSize = defaultArg patchSize 31
        let _fastThreshold = defaultArg fastThreshold 20
*)
-> ORB 

Parameters

nFeatures (Optional)

Type: SystemInt32
The maximum number of features to retain.

scaleFactor (Optional)

Type: SystemSingle
Pyramid decimation ratio, greater than 1. scaleFactor==2 means the classical pyramid, where each next level has 4x less pixels than the previous, but such a big scale factor will degrade feature matching scores dramatically. On the other hand, too close to 1 scale factor will mean that to cover certain scale range you will need more pyramid levels and so the speed will suffer.

nLevels (Optional)

Type: SystemInt32
The number of pyramid levels. The smallest level will have linear size equal to input_image_linear_size/pow(scaleFactor, nlevels - firstLevel).

edgeThreshold (Optional)

Type: SystemInt32
This is size of the border where the features are not detected. It should roughly match the patchSize parameter.

firstLevel (Optional)

Type: SystemInt32
The level of pyramid to put source image to. Previous layers are filled with upscaled source image.

wtaK (Optional)

Type: SystemInt32
The number of points that produce each element of the oriented BRIEF descriptor. The default value 2 means the BRIEF where we take a random point pair and compare their brightnesses, so we get 0/1 response. Other possible values are 3 and 4. For example, 3 means that we take 3 random points (of course, those point coordinates are random, but they are generated from the pre-defined seed, so each element of BRIEF descriptor is computed deterministically from the pixel rectangle), find point of maximum brightness and output index of the winner (0, 1 or 2). Such output will occupy 2 bits, and therefore it will need a special variant of Hamming distance, denoted as NORM_HAMMING2 (2 bits per bin). When WTA_K=4, we take 4 random points to compute each bin (that will also occupy 2 bits with possible values 0, 1, 2 or 3).

scoreType (Optional)

Type: OpenCvSharpORBScoreType
The default HARRIS_SCORE means that Harris algorithm is used to rank features (the score is written to KeyPoint::score and is used to retain best nfeatures features); FAST_SCORE is alternative value of the parameter that produces slightly less stable keypoints, but it is a little faster to compute.

patchSize (Optional)

Type: SystemInt32
size of the patch used by the oriented BRIEF descriptor. Of course, on smaller pyramid layers the perceived image area covered by a feature will be larger.

fastThreshold (Optional)

Type: SystemInt32
the fast threshold

Return Value

[Missing <returns> documentation for "M:OpenCvSharp.ORB.Create(System.Int32,System.Single,System.Int32,System.Int32,System.Int32,System.Int32,OpenCvSharp.ORBScoreType,System.Int32,System.Int32)"]

Reference