To find intersection point of two lines?

      x1=7.8;
      x2=8.5;
      y1=0.96;
      y2=0.94;
      p1 = polyfit([x1 x2], [y1 y2], 2);
      b1= polyval(p1,1);
      m1=polyval(p1,2)-b1;
      x3=8.25;
      x4=8.25;
      y3=0;
      y4=.99;
      p2 = polyfit([x3 x4], [y3 y4], 2);
      b2 = polyval(p2, 1);
      m2 = polyval(p2, 2) - b2;

I got x value = -1.2867; from which co-ordinate this value corresponds to? Actually I want to compute intersection of two line with respect to x=[7.8 8.25 8.5]; y=[0.96 0.99 0.94]; over which those two lines are plotted?

x=[7.8 8.25 8.5];
y=[0.96 0.99 0.94];
p=polyfit(x,y,2);
f=polyval(p,x);
plot(x,y,'o',x,f,'-');
hold on;
line([7.8 8.5],[0.96 0.94]);
hold on;
line([8.25 8.25],[0 0.99]);

[Image Analyst]

Do you want to do it numerically (using quantized arrays), or analytically (using algebraic equations)? Why did you tag this as digital image processing?

[RS]

I want numerically.

Answer 1

[Jing]

'polyxpoly' can get intersect points for lines. Is this what you want?