binary mask for the coordinates using MATLAB - matlab

Question

I need to create a binary mask. I have some coordinates and I make those coordinates and inside that region equal to 1, and background equal to zero.
Here is what I have done, but the problem is ROI located not in the correct position and located on the right bottom of the image. I appreciate if someone could point me to the right direction.
function [X,Y, BW] = Create_mask(X,Y,im)
X = round(X);
Y = round(Y);
X ( X < 1 ) = 1;
Y ( Y < 1 ) = 1;
BW = im > 255;
for p = 1:length(X)
BW(Y(p),X(p)) = 1;
end
for n = 0:(1/round(sqrt((X(end)-X(1))^2 + (Y(end)-Y(1))^2 ))):1
xn = round(X(1) +(X(end) - X(1))*n);
yn = round(Y(1) +(Y(end) - Y(1))*n);
BW(yn,xn) = 1;
end
se = strel('disk',10);
BW = imclose(BW,se);
BW = imdilate(BW,se);
BW = imfill(BW,'holes');
im( im < 255 ) = 0;
im = imclose(im,se);
BW = BW * 255;
BW = im2uint8(BW);
% BW = imresize(BW, [256 256],'nearest');
figure;
imshow(BW);
% close all;
end
Here is the output the function:
I was expecting to be similar to this image. This is not the exact solution but it shows my expectation.
X and Y coordinates are attached here, The first col is X and the second Y.

Answer 1

you can do this by calling function inpolygon, try this
function mask=createmask(x,y, cmin, cmax, dx)
if(nargin<3)
cmin=min([x(:) y(:)]);
end
if(nargin<4)
cmax=max([x(:) y(:)]);
end
if(nargin<5)
dx=(cmax-cmin)/100;
end
if(length(dx)==1)
dx=[dx dx];
end
[xi,yi]=meshgrid(cmin(1):dx(1):cmax(1),cmin(2):dx(2):cmax(2));
mask=reshape(inpolygon(xi(:),yi(:),x(:),y(:)), size(xi));
to test
xv = [0 3 3 0 0 NaN 1 1 2 2 1];
yv = [0 0 3 3 0 NaN 1 2 2 1 1];
mask=createmask(xv,yv, [-1 -1], [4 4]);
imagesc(mask)