www.gusucode.com > matlab 案例源码 matlab代码程序 > matlab/AlphaSpectrumFor2DPointCloudExample.m
%% Find Alpha Spectrum for 2-D Point Cloud % Create and plot a set of 2-D points. % Copyright 2015 The MathWorks, Inc. th = (pi/12:pi/12:2*pi)'; x1 = [reshape(cos(th)*(1:5), numel(cos(th)*(1:5)),1); 0]; y1 = [reshape(sin(th)*(1:5), numel(sin(th)*(1:5)),1); 0]; x = [x1; x1+15;]; y = [y1; y1]; plot(x,y,'.') axis equal %% % Create an alpha shape for the point cloud using the default alpha radius. shp = alphaShape(x,y); %% % Find the spectrum of critical alpha values that produces unique alpha % shapes for the point cloud. alphaspec = alphaSpectrum(shp); %% % Plot the alpha shape corresonding to the smallest alpha value in the spectrum. shp.Alpha = alphaspec(length(alphaspec)); plot(shp) %% % Compare this alpha shape to the one produced by the next smallest critical alpha % value. The alpha shapes are unique. shp.Alpha = alphaspec(length(alphaspec)-1); plot(shp)