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function [varargout] = detectSURFFeatures(image, varargin)
// This function is used to detect SURF(Speeded Up Robust Features) Features in a grayscale Image.
//
// Calling Sequence
// result = detectSURFFeatures(Image);
// result = detectSURFFeatures(Image, Name, Value, ...)
//
// Parameters
// result: SURFPoints struct which contains Location of KeyPoints, Orientation, Metric, SignOfLaplacian, Scale and Count of the features.
// Image : Input image, specified as a A-by-N 2D grayscale.
// MetricThreshold : (Optional) With default value equal to 1000, it is to be specified as a scalar. Every interest point detected has a strength associated with it. In case, only the stronget ones are needed, this parameter has to be given a larger value. To get more no of interest points/blobs, it is to be reduced.
// NumOctaves : (Optional)With default value equal to 3, it is to be specified as a scalar. Larger the number of octaves, larger is the size of blobs detected. This is because higher octave use large sized filters. Value must be an integer scalar in between 1 and 4.
// NumScaleLevels : (Optional)With default value equal to 4, it is to be specified as a scalar. It denotes the number of scale level for each octave. The Value must be an integer scalar greater than or equal to 3.
// ROI : (Optional) Region Of Interest. This is taken as a vector [u v width height]. When specified, the function detects the key points within region of area width*height with u and v being the top left corner coordinates.
// Description
// This function return the SURF(Speeded Up Robust Features) Interest Points for a 2D Grayscale image. It is scale- and rotation- invariant point detector and descriptor and its application include Camera Calibration, 3D Reconstruction, Object Recognition to name a few.
//
// Examples
// image = imread('sample.jpg');
// results = detectSURFFeatures(image);
//
// Authors
// Shashank Shekhar
image_list = mattolist(image);
[ lhs, rhs ] = argn(0)
if rhs > 9 then
error(msprintf("Too many input arguments"))
end
if lhs > 1 then
error(msprintf("Not enough input arguments"))
end
select rhs
case 1 then
[a b c d e f] = ocv_detectSURFFeatures(image_list)
case 3 then
[a b c d e f] = ocv_detectSURFFeatures(image_list, varargin(1), varargin(2))
case 5 then
[a b c d e f] = ocv_detectSURFFeatures(image_list, varargin(1), varargin(2), varargin(3), varargin(4))
case 7 then
[a b c d e f] = ocv_detectSURFFeatures(image_list, varargin(1), varargin(2), varargin(3), varargin(4), varargin(5), varargin(6))
case 9 then
[a b c d e f] = ocv_detectSURFFeatures(image_list, varargin(1), varargin(2), varargin(3), varargin(4), varargin(5), varargin(6), varargin(7), varargin(8))
end
varargout(1) = struct('KeyPoints', a, 'Orientation', b, 'Metric', c ,'SignOfLaplacian', d,'Scale', e, 'Count', f );
endfunction
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