results of 2 plots seem to be overlapping each other

Question

Sat m 2013-3-17

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/67505-results-of-2-plots-seem-to-be-overlapping-each-other

i have generated a virtual 3D cube. after that i am asked to capture an image of that virtual cube in at 4 meters distance and 30 degree tilted. i am able to do that too. but in both cases 2 plots of 2 images are supposed to be generated. but the result of the second plotting seems to be overlapping the previous plotting image. if i give a 'break' command in between these 2 code then i can see the previous plot again. but if i delete the break command then i can only see the 2nd plot. please let me know how to solve this.

    %question 6(3)(a)
      %generating a virtual 3D cube 
      %%Generating 3D calibration pattern: 
      %%Pw holds 32 points on two surfaces (Xw = 1 and Yw = 1) of a cube 
      %%Values are measured in meters.
      %%There are 4x4 uniformly distributed points on each surface.
      cnt = 1;
      %%plane : Xw = 1
      Pw = zeros(4,3);%preallocating Pw
      for i=0.2:0.2:0.8,
       for j=0.2:0.2:0.8,
         Pw(cnt,:) = [1 i j];
         cnt = cnt + 1;
       end
      end
      %%plane : Yw = 1
      for i=0.2:0.2:0.8,
       for j=0.2:0.2:0.8,
         Pw(cnt,:) = [i 1 j];
         cnt = cnt + 1;
       end
      end
      N = cnt;
      %%plot3(Pw(:,1), Pw(:,2), Pw(:,3), '+');
      %%Virtual camera model 
       %%Extrinsic parameters : R = RaRbRr
      gamma = 40.0*pi/180.0;
      Rr = [ [cos(gamma) -sin(gamma) 0];
             [sin(gamma) cos(gamma)  0];
             [  0          0         1]; ];
      beta = 0.0*pi/180.0;
      Rb = [ [cos(beta) 0 -sin(beta)];
             [0         1       0];
             [sin(beta) 0  cos(beta)]; ];
      alpha = -120.0*pi/180.0;
      Ra = [ [1      0                0];
             [0   cos(alpha)  -sin(alpha)];
             [0   sin(alpha)   cos(alpha)]; ];
      R = Ra*Rb*Rr;
      T = [0 0 4]';
      %%Intrinsic parameters
      fa = 0.016;
      Ox = 256;
      Oy = 256;
      Sx = 0.0088/512.0;
      Sy = 0.0066/512.0;
      Fx = fa/Sx;
      Fy = fa/Sy;
      %%asr is the aspect ratio
      asr = Fx/Fy;
      %%Generate Image coordinates
      %%surface Xw = 1
      cnt = 1;
      Pc = zeros(16,3);
      n=length([(Ox - Fx*Pc(cnt,1)/Pc(cnt,3)) (Oy - Fy*Pc(cnt,2)/Pc(cnt,3))]);
       p=zeros(16,n);
      for cnt = 1:1:16,
         Pc(cnt,:) = (R*Pw(cnt,:)' + T)';
         p(cnt,:)  = [(Ox - Fx*Pc(cnt,1)/Pc(cnt,3)) (Oy - Fy*Pc(cnt,2)/Pc(cnt,3))];
      end
      plot(p(:,1), p(:,2), 'r+');
      axis([0 512 0 512]);
      grid;
      hold;
      %%surface Yw = 1
      for cnt = 17:1:32,
         Pc(cnt,:) = (R*Pw(cnt,:)' + T)';
         p(cnt,:)  = [(Ox - Fx*Pc(cnt,1)/Pc(cnt,3)) (Oy - Fy*Pc(cnt,2)/Pc(cnt,3))];
      end
      plot(p(17:32,1), p(17:32,2), 'g+');
      %%plot3(Pc(:,1), Pc(:,2), Pc(:,3), '+');
      grid;
  %3D point generated from the 3D virtual cube
  xvals = Pc(:,1);
  yvals = Pc(:,2);
  zvals = Pc(:,3);
  %..6.3.b
  cnt1 = 1;
%%plane : Xw = 1
Pw1 = zeros(4,3);%preallocating Pw
for i=0.2:0.2:0.8,
 for j=0.2:0.2:0.8,
   Pw1(cnt1,:) = [1 i j]; 
   cnt1 = cnt1 + 1;
   end
  end
%%plane : Yw = 1
for i=0.2:0.2:0.8,
 for j=0.2:0.2:0.8,
   Pw1(cnt1,:) = [i 1 j];
   cnt1 = cnt1 + 1;
 end
end
N1 = cnt1;
%%plot3(Pw(:,1), Pw(:,2), Pw(:,3), '+');
%%Virtual camera model 
   %%Extrinsic parameters : in a certain pose where R = 30 degree and T is 4 meters 
Rb1 = 30.0*pi/180.0;
Tb = [0 0 4]';
%%Intrinsic parameters
fb = 0.016;
Ox = 256;
Oy = 256;
Sx = 0.0088/512.0;
Sy = 0.0066/512.0;
Fxb = fb/Sx;
Fyb = fb/Sy;
%%asr is the aspect ratio
asrb = Fxb/Fyb;
%%Generate Image coordinates
%%surface Xw = 1
cnt1 = 1;
Pc1 = zeros(16,3);
n1=length([(Ox - Fxb*Pc1(cnt1,1)/Pc1(cnt1,3)) (Oy - Fyb*Pc1(cnt1,2)/Pc1(cnt1,3))]);
 p1=zeros(16,n1);
for cnt = 1:1:16,
   Pc1(cnt,:) = (Rb1*Pw1(cnt1,:)' + Tb)';
   p1(cnt,:)  = [(Ox - Fxb*Pc1(cnt1,1)/Pc1(cnt1,3)) (Oy - Fyb*Pc1(cnt1,2)/Pc1(cnt1,3))];
end
plot(p1(:,1), p1(:,2), 'r+');
axis([0 512 0 512]);
grid;
hold;
%%surface Yw = 1
for cnt1 = 17:1:32,
   Pc1(cnt1,:) = (Rb*Pw1(cnt1,:)' + Tb)';
   p1(cnt1,:)  = [(Ox - Fxb*Pc1(cnt1,1)/Pc1(cnt1,3)) (Oy - Fyb*Pc1(cnt1,2)/Pc1(cnt1,3))];
end
plot(p1(17:32,1), p1(17:32,2), 'g+');
%%plot3(Pc1(:,1), Pc(:,2), Pc(:,3), '+');
grid;