How calculate the points inside the square and triangle?

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Neda
Neda 2018-6-6
评论： Neda Azarmehr 2018-6-10
I did calculate the points (scatteres) located inside the circle as presented in the code. I'm wondering how I can do it for square and triangle?
I cannot find proper tag for this question.
Phantom.x_size = 50/1000; % Width of phantom [mm]
Phantom.y_size = 10/1000; % Transverse width of phantom [mm]
Phantom.z_size = 60/1000; % Height of phantom [mm]
Phantom.z_start = 30/1000; % Start of phantom surface [mm];
N = Calculate_number_of_scatterers(Phantom);
N = 1000*ceil(N/1000);
% Create the general scatterers
x = (rand (N,1)-0.5)*Phantom.x_size;
y = (rand (N,1)-0.5)*Phantom.y_size;
z = rand (N,1)*Phantom.z_size + Phantom.z_start;
% Generate the amplitudes with a Gaussian distribution
amplitudes = randn(N,1);
%Make the cyst
r = 15/2/1000; %radius of cyst[mm]
xc = 10/1000; %place of the cyst
zc = 40/1000 + Phantom.z_start;
inside = ( ((x-xc).^2 + (z-zc).^2) < r^2); % scatteres inside the cyst
amplitudes = amplitudes .* (1-inside); % amplitude of the scatteres inside the cyst
Phantom.positions = [x y z];
Phantom.amplitudes = amplitudes;
figure; plot3(Phantom.positions(:,1), Phantom.positions(:,3),Phantom.amplitudes,'.')

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回答（1 个）

KSSV
KSSV 2018-6-6
Read about inpolygon. This function will give you indices of the points lying inside a polygon.
  2 个评论
Neda
Neda 2018-6-10
thank you for the comment, it's true, but it inpolygon didn't solve my issue. I used
[in,out] = inpolygon(xc,zc,x,z);
amplitudes = amplitudes .* (1-in);% amplitude of the scatteres inside the cyst
Image Analyst
Image Analyst 2018-6-10
You forgot to include Calculate_number_of_scatterers() so we can't do much. Give us code that at least runs and demonstrates why inpolygon() does not solve your problem.

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