how to draw a line from the centre of the image to its border

In the given image, i plotted 6 points on its border manually. a random point is selected in the image. My objective is to connect all those 6 points with this random point. how to connect those by lines.

Answer 1

[Image Analyst]

Did you try the line() function? That will plot in the overlay. If you want the line burned into the image use the imline() function's createMask() method.

% Demo to write a line into the overlay of an image,
% and then to burn the overlay into the image.

%----- Initializing steps -----
% Clean up
clc;
clear all;
close all;
workspace; % Display the workspace panel.

hasIPT = license('test', 'image_toolbox');
if ~hasIPT
  % User does not have the toolbox installed.
  message = sprintf('Sorry, but you do not seem to have the Image Processing Toolbox.\nDo you want to try to continue anyway?');
  reply = questdlg(message, 'Toolbox missing', 'Yes', 'No', 'Yes');
  if strcmpi(reply, 'No')
    % User said No, so exit.
    return;
  end
end

% Display images to prepare for the demo.
monochromeImage = imread('pout.tif');
subplot(2, 2, 1);
imshow(monochromeImage);
title('Original Image');
subplot(2, 2, 2);
imshow(monochromeImage);
title('Original Image with line in overlay');
set(gcf, 'units','normalized','outerposition',[0 0 1 1]); % Maximize figure.
set(gcf,'name','Image Analysis Demo','numbertitle','off') 

%----- Burn line into image -----
burnedImage = imread('pout.tif');
% Create line mask, h, as an ROI object over the image.
hLine = imline(gca,[10 100],[10 100]); % Second argument defines line endpoints.
% Create a binary image ("mask") from the ROI object.
binaryImage2 = hLine.createMask();
% Display the line mask.
subplot(2, 2, 3);
imshow(binaryImage2);
title('Binary mask of the line');
% Burn line into image by setting it to 255 wherever the mask is true.
burnedImage(binaryImage2) = 255;
% Display the image with the "burned in" line.
subplot(2, 2, 4);
imshow(burnedImage);
title('New image with line burned into image');

[Sivakumaran Chandrasekaran]

Thanks Image Analyst. It works fine.

[Sivakumaran Chandrasekaran]

i found that the code works for a single line. can we use for drawing multiple lines

[Image Analyst]

Of course. Why don't you just package it into a function where you can pass in the two endpoint coordinates?