public SURF(
	double hessianThresh,
	int nOctaves = 4,
	int nOctaveLayers = 2,
	bool extended = true,
	bool upright = false
)

Public Sub New ( 
	hessianThresh As Double,
	Optional nOctaves As Integer = 4,
	Optional nOctaveLayers As Integer = 2,
	Optional extended As Boolean = true,
	Optional upright As Boolean = false
)

public:
SURF(
	double hessianThresh, 
	int nOctaves = 4, 
	int nOctaveLayers = 2, 
	bool extended = true, 
	bool upright = false
)

new : 
        hessianThresh : float * 
        ?nOctaves : int * 
        ?nOctaveLayers : int * 
        ?extended : bool * 
        ?upright : bool 
(* Defaults:
        let _nOctaves = defaultArg nOctaves 4
        let _nOctaveLayers = defaultArg nOctaveLayers 2
        let _extended = defaultArg extended true
        let _upright = defaultArg upright false
*)
-> SURF

Parameters

hessianThresh

Type: SystemDouble
Only features with keypoint.hessian larger than that are extracted. good default value is ~300-500 (can depend on the average local contrast and sharpness of the image). user can further filter out some features based on their hessian values and other characteristics

nOctaves (Optional)

Type: SystemInt32
The number of octaves to be used for extraction. With each next octave the feature size is doubled

nOctaveLayers (Optional)

Type: SystemInt32
The number of layers within each octave

extended (Optional)

Type: SystemBoolean
false means basic descriptors (64 elements each), true means extended descriptors (128 elements each)

upright (Optional)

Type: SystemBoolean
False means that detector computes orientation of each feature. True means that the orientation is not computed (which is much, much faster). For example, if you match images from a stereo pair, or do image stitching, the matched features likely have very similar angles, and you can speed up feature extraction by setting upright=true.

Reference