www.gusucode.com > 用于人脸识别和人脸定位的主动形状模型（asm）matlab工具箱 > asm toolbox\GetNormalAngle.m

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%(c) Ghassan Hamarneh 1999
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function AngleNormal=GetNormalAngle(pt1,pt2,X)
%function AngleNormal=GetNormalAngle(pt1,pt2,X)

x1=X(pt1);
y1=X(pt1+size(X,1)/2);

x2=X(pt2);
y2=X(pt2+size(X,1)/2);

dx=x2-x1;dy=y2-y1;

angle=atan2(dy,dx);

AngleNormal=angle+pi/2;