binary mask for the coordinates using MATLAB

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. The image size is 600*800
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.
X and Y coordinates are attached here, The first col is X and the second Y. Basically, [X(1) Y(1)] is refereing to the pixels on the image.
Here the left is what snippet did produce and the right image is my expectation
Here is my snippet:
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
%connect the end of curve
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);
figure;
imshow(BW);
% close all;
end

4 Comments

Can you illustrate again please, lets suppuse you have the following co-ordinates(cod) and image1
cod=(1,2),(2,3),(3,4),(2,2)
Image1 is 4x4, do you any more inputs data % Just example
What exactly you are looking for?
The inputs are im(images) which is a 600 * 800 wich is filled with zeros, and X, Y inside the H_D.mat (attached in the post) are the coordinate need to display on image and filled with 1. The problem is my snippet put the mask always on bottom right side of image insetad of in the right postion which are coordinate. I hoep it clarifies my issue.
Can you attach the im image here?
Image is 600 * 800 filled with zeros

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Answers (1)

What about just shifting the x and y coordinates
x = H_D{1}(:,1);
y = H_D{1}(:,2);
im = zeros(600, 800);
mask = Create_mask(x-300, y-300, im);
Also, I recommend that instead of creating your own function to convert x, y coordinates to mask, you can do it with built-in function in a single line
x = H_D{1}(:,1);
y = H_D{1}(:,2);
im = poly2mask(x-300, y-300, 600, 800);

2 Comments

Thank you for your suggestion. Why shifting by 300?
I just made a guess. It appeared similar to the image you have shown in the question. I think that the actual points themself cannot create the mask you want. Some sort of shifting is necessary.

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Asked:

on 1 May 2020

Edited:

on 1 May 2020

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