gusucode.com > vision工具箱matlab源码程序 > vision/BRISKPoints.m
%BRISKPoints Object for storing BRISK interest points
%
% BRISKPoints object describes BRISK interest points.
%
% points = BRISKPoints(location, Name, Value, ...) constructs a
% BRISKPoints object from an M-by-2 array of [x y] coordinates, location,
% and additional name-value pairs described below. Note that each
% additional value can be specified as a scalar or a vector whose
% length matches the number of coordinates in location.
%
% The available parameters are:
%
% 'Scale' Specifies scale at which the interest points were
% detected. The scale value represents the radius of the
% BRISK sampling pattern used during feature extraction.
% For single-scale features, the BRISK sampling pattern has
% a radius of ~12 pixels.
%
% Default: 12
%
% 'Metric' Value describing the strength of the detected feature.
% The BRISK algorithm uses the FAST corner score as a
% metric.
%
%
% Default: 0.0
%
% 'Orientation' Value, in radians, describing orientation of the detected
% feature. It is typically set during the detection
% process.
%
% Default: 0.0
%
% Notes:
% ======
% - The main purpose of this class is to pass the data between
% detectBRISKFeatures and extractFeatures functions. It can also be
% used to manipulate and plot the data returned by these functions.
% Using the class to fill the points interactively is considered an
% advanced maneuver. It is useful in situations where you might want to
% mix a non-BRISK interest point detector with the BRISK descriptor.
%
% - 'Orientation' is specified as an angle, in radians, as measured
% counter-clockwise from the X-axis with the origin at 'Location'.
% 'Orientation' should not be set manually. It is typically set during
% the extraction process. If BRISK interest points are used to extract
% a non-BRISK descriptor (e.g. SURF, FREAK, etc.), the Orientation
% values may be altered during the extraction process depending on the
% selected descriptor.
%
% - Note that BRISKPoints is always a scalar object which may hold many
% points. Therefore, NUMEL(BRISKPoints) always returns 1. This may be
% different from LENGTH(BRISKPoints), which returns the true number
% of points held by the object.
%
% BRISKPoints methods:
% selectStrongest - Select N interest points with strongest metrics
% selectUniform - Select N uniformly spaced interest points
% plot - Plot BRISK points
% length - Return number of stored points
% isempty - Return true for empty BRISKPoints object
% size - Return size of the BRISKPoints object
%
% BRISKPoints properties:
% Count - Number of points held by the object
% Location - Matrix of [X,Y] point coordinates
% Scale - Scale at which the feature was detected
% Metric - Strength of each feature
% Orientation - Orientation assigned to the feature
%
% Example 1
% ---------
% % Detect BRISK features
% I = imread('cameraman.tif');
% points = detectBRISKFeatures(I);
% strongest = points.selectStrongest(10);
% imshow(I); hold on;
% plot(strongest); % show location and scale
% strongest.Location % display [x y] coordinates
%
% See also detectBRISKFeatures, detectSURFFeatures, extractFeatures,
% matchFeatures, detectHarrisFeatures, detectMinEigenFeatures,
% detectFASTFeatures, MSERRegions, cornerPoints
% References
% ----------
% S. Leutenegger, M. Chli and R. Siegwart, BRISK: Binary Robust Invariant
% Scalable Keypoints, to appear in Proceedings of the IEEE International
% Conference on Computer Vision (ICCV) 2011.
classdef BRISKPoints < vision.internal.BRISKPointsImpl & vision.internal.FeaturePoints
methods(Access=private, Static)
function name = matlabCodegenRedirect(~)
name = 'vision.internal.BRISKPoints_cg';
end
end
methods
function this = BRISKPoints(varargin)
this = this@vision.internal.BRISKPointsImpl(varargin{:});
end
function varargout = plot(this, varargin)
%plot Plot feature points
%
% BRISKPoints.plot plots feature points in the current axis.
%
% BRISKPoints.plot(AXES_HANDLE,...) plots using axes with
% the handle AXES_HANDLE instead of the current axes (gca).
%
% BRISKPoints.plot(AXES_HANDLE, PARAM1, VAL1, PARAM2,
% VAL2, ...) controls additional plot parameters:
%
% 'showScale' true or false. When true, a circle
% proportional to the scale of the detected
% feature is drawn around the point's
% location
%
% Default: true
%
% 'showOrientation' true or false. When true, a line
% corresponding to the point's orientation
% is drawn from the point's location to the
% edge of the circle indicating the scale
%
% Default: false
%
% Example
% -------
% I = imread('cameraman.tif');
% featurePoints = detectBRISKFeatures(I);
% imshow(I); hold on;
% plot(featurePoints);
nargoutchk(0,1);
supportsScaleAndOrientation = true;
this.PlotScaleFactor = 1;
h = plot@vision.internal.FeaturePoints(this, ...
supportsScaleAndOrientation, varargin{:});
if nargout == 1
varargout{1} = h;
end
end
end
methods (Access = protected)
%------------------------------------------------------------------
% Copy data for subsref. This method is used in subsref
function this = subsref_data(this, option)
this = subsref_data@vision.internal.FeaturePoints(this,option);
% Scale is a Mx1 vector. When the indices for sub-referencing
% is a 1-D array, we explicitly specify the size for the second
% dimension.
if length(option.subs) == 1
option.subs{2} = 1;
end
this.pScale = subsref(this.pScale,option);
this.pOrientation = subsref(this.pOrientation,option);
end
%------------------------------------------------------------------
% Copy data for subsasgn. This method is used in subsasgn
function this = subsasgn_data(this, option, in)
this = subsasgn_data@vision.internal.FeaturePoints(this, option, in);
if isempty(in)
this.pScale = ...
subsasgn(this.pScale, option, in);
this.pOrientation = ...
subsasgn(this.pOrientation, option, in);
else
this.pScale = ...
subsasgn(this.pScale, option, in.pScale);
this.pOrientation = ...
subsasgn(this.pOrientation, option, in.pOrientation);
end
end
%------------------------------------------------------------------
% Concatenate data for vertcat. This method is used in vertcat.
%------------------------------------------------------------------
function obj = vertcatObj(varargin)
obj = varargin{1};
for i=2:nargin
obj.pLocation = [obj.pLocation; varargin{i}.pLocation];
obj.pMetric = [obj.pMetric ; varargin{i}.pMetric];
obj.pScale = [obj.pScale ; varargin{i}.pScale];
obj.pOrientation = [obj.pOrientation ; varargin{i}.pOrientation];
end
end
end
end % classdef