基于Matlab的点到任意直线的投影点坐标的实现

uqHZau

【写在前面】因为图像坐标系和我们平时用的直角坐标系还是有不同的。因此在求点到直线投影点坐标的时候，不敢随便把直线用点斜式表示。为此采用向量的方法求投影点。

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代码实现
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4 l$ D/ j+ Q; `* R8 B3 E6 Q7 rfunction proj_point = ProjPoint( point,line_p )
6 C. I+ E2 \  W' y7 a/ z9 Lx1 = line_p(1);
1 @1 J: v- m- I4 B) {. r+ Z! ?y1 = line_p(2);
x2 = line_p(3);
0 \. G; |& s% D# |+ v! S- Sy2 = line_p(4);
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x3 = point(1);
y3 = point(2);
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; F! V4 s5 d( t2 n/ o/ \. |* F- Hyk = ((x3-x2)*(x1-x2)*(y1-y2) + y3*(y1-y2)^2 + y2*(x1-x2)^2) / (norm([x1-x2,y1-y2])^2);
6 N$ t5 F6 P  n! \( _% l; B+ D4 [0 wxk = ((x1-x2)*x2*(y1-y2) + (x1-x2)*(x1-x2)*(yk-y2)) / ((x1-x2)*(y1-y2));
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if x1 == x2
+ A; G8 G+ M4 }( g  r/ \    xk = x1;
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" w# U8 C9 I2 [, T4 `2 c. ?if y1 == y2
5 V& p- ]+ j' p/ X! z    xk = x3;
end
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proj_point = [xk,yk];
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" O' R! P* ]: `: k/ q$ m" T: aend
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ybing12

这个代码详细