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Wrap noisy periodic line into circular mask

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Nick K
Nick K on 11 Dec 2020
Edited: Nick K on 11 Dec 2020
Hi all,
I'm trying to generate a mask based off a periodic noisy line that is wrapped into a circle.
I can generate a path for the circle around the x,y plane. However I'm stuggling on making it into a mask.
Essentially, I want everything inside the circle to have value 0 and everything outside it to have value 1.
This mask should be returned as an array of dimensions (x,y)
I really need this doing without any fancy inbuilt functions, as I will be porting this to another language.
I feel there must be some solution using loops but I cant quite get it.
Please find the code to generate the noisy circle below:
%% Setup and grid
clear all ; clc; clf
N=256
L=128
x=L*(-(N-1)/2:N/2)/N;
y=x;
%% Generate noisy periodic line through fourier modes
M=10 %number of modes
kmax=N/2
kx=(randi(kmax,1,M)-kmax/2);%random wave numbers
x=L*(-(N-1)/2:N/2)/N;
y=x;
V=zeros(1,N);
A=rand(M)*2-1; %random amplitudes
B=rand(M)*2-1;
for i=1:M
V=V+A(i)*sin((2*pi/L)*kx(i)*x)+B(i)*cos((2*pi/L)*kx(i)*x);
end
%% Generate circular mask
radius = 50; % Choose base circle radius
Pot_rad = radius + V;
for i=1:N
xnew(i) = Pot_rad(i)*cos(x(i)*(2*pi/L));
ynew(i) = Pot_rad(i)*sin(x(i)*(2*pi/L));
end
plot(xnew,ynew)
TLDR; Make Array mask V2D(x,y) from noisy line V(x) wrapped into circle.
Thanks in advance :)

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