MATLAB: How to find x and y coordinates in a black and white image

black and whiteimage analysis

I have a black and white image. I want to find the coordinates of the outline of the black blob. I want these coordinates so that I can draw the same shape in the CAD software.

How can I do that?

Best Answer

Try this. It give coordinates of image pixels on the edge

im = rgb2gray(imread('map_phydesign_Celest_65_M04_W800_H1000_Close_new.png'));
im_edge = edge(im);
[x, y] = find(im_edge==1);
coordinates = [x y];

Related Solutions

MATLAB: Black and white image

Try this

[counts, grayLevels] = imhist(grayImage, 256);
if sum(counts(2:end-1)) > 0
  % It's not pure black and white
end
% Get map of non-0 and non-255 pixels
grayPixels = grayImage > 0 & grayImage < 255;
% Get pure black and white image
bw = grayImage; % Initialize

bw(grayPixels) = 0; % Zero out any gray pixels.
% Get gray pixels only
grayOnly = grayImage; % Initialize
grayOnly(~grayPixels) = 0; % Zero out any pure 0 or pure 255 pixels.

MATLAB: Black pixels to white

%I is your image
M = repmat(all(~I,3),[1 1 3]); %mask black parts
I(M) = 255; %turn them white

This is only setting parts that are pure black to white, it could easily be modified to dark parts etc. with:

M = repmat(all(I<20,3),[1 1 3]); %mask values less than 20 in RGB

Best Answer

Related Solutions

MATLAB: Black and white image

MATLAB: Black pixels to white

Related Question