How to fill edges only in Blob area

I am able to draw a blob inside an image and then i want to extend the blob until it hit's black line or edge,simple suggestions on how to do it?

for example i had a circle edge here black i want to extend red blob if hit to an edge then stop extending.note only fill those areas where i place these blob.

Answer 1

[Image Analyst]

What is that? It looks like a tomato worm or something. You can use imfill() to fill binary blobs. You don't have a binary image yet. And even if you did, there would be lots of regions that would fill and you'd end up with a pretty solid image. I think you need to do a better job on your initial segmentation.

[Hash ir]

the white blob is the detector i am working on but to fill it in the exact shape in need to do edges fill how to do it ?

[Image Analyst]

OK, if you think it's working good enough...

So did you try imfill() like I already suggested? If not, why not?

[Image Analyst]

Why did you delete the picture? Now no one else knows what we're talking about.

[Image Analyst]

Sorry, I don't believe that if you applied imfill() to the top image, it would produce the bottom image. imfill() works on binary images. How did you get your Sobel image: from edge() or imgradient()?

[Hash ir]

thanks for the help.I think i cannot explain clear enough or there is some other issue.I changed the post i hope you can help me on what i wanted.

Answer 2

[Image Analyst]

Regarding your total change of image, see this code:

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 15;

%===============================================================================
% Get the name of the image the user wants to use.
baseFileName = 'red_spot.png';
% Get the full filename, with path prepended.
folder = pwd
fullFileName = fullfile(folder, baseFileName);

%===============================================================================
% Read in a demo image.
rgbImage = imread(fullFileName);
% Get the dimensions of the image.  numberOfColorChannels should be = 3.
[rows, columns, numberOfColorChannels] = size(rgbImage);
% Display the original color image.
subplot(2, 2, 1);
imshow(rgbImage, []);
axis on;
caption = sprintf('Original RGB Color Image, %s', baseFileName);
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');

% Set up figure properties:
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);
% Get rid of tool bar and pulldown menus that are along top of figure.
set(gcf, 'Toolbar', 'none', 'Menu', 'none');
% Give a name to the title bar.
set(gcf, 'Name', 'Demo by ImageAnalyst', 'NumberTitle', 'Off') 

drawnow;
hp = impixelinfo(); % Set up status line to see RGB values when you mouse over the image.

% Extract the individual red, green, and blue color channels.
redChannel = rgbImage(:, :, 1);
greenChannel = rgbImage(:, :, 2);
blueChannel = rgbImage(:, :, 3);

% Get a mask for the white pixels.
mask = redChannel == 255 & greenChannel == 255 & blueChannel == 255;
% Display the image.
subplot(2, 2, 2);
imshow(mask, []);
axis on;
caption = sprintf('Mask Image');
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
drawnow;

% Get rid of portion hitting the edges of the image.
mask = imclearborder(mask);
% Display the image.
subplot(2, 2, 3);
imshow(mask, []);
axis on;
caption = sprintf('Final Mask Image');
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
drawnow;

% Find the middle of the image
midRow = round(rows/2);
midCol = round(columns/2);
% Find the color of the red spot in the middle
r = redChannel(midRow, midCol);
g = greenChannel(midRow, midCol);
b = blueChannel(midRow, midCol);

% Make the mask pixels the same reddish color as in the original image.
redChannel(mask) = r;
greenChannel(mask) = g;
blueChannel(mask) = b;
% Recombine separate color channels into a single, true color RGB image.
rgbImage = cat(3, redChannel, greenChannel, blueChannel);
% Display the image.
subplot(2, 2, 4);
imshow(rgbImage, []);
axis on;
caption = sprintf('Final RGB Image');
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
drawnow;