Dear Izuru,
I made a code for you, where first the color 'blue' is detected at a certain threshold. (here 200) Then with a for loop, all points where the color is below the threshold are neglected. The image I used has been put in the attachment.
clc; clear all; close all;
% Read standard MATLAB demo image.
rgbImage = imread('board.jpg');
% Display the original image.
subplot(1, 3, 1);
imshow(rgbImage);
title('Original RGB Image');
% Maximize figure.
set(gcf, 'Position', get(0, 'ScreenSize'));
% Split into color bands.
redBand = rgbImage(:,:, 1);
greenBand = rgbImage(:,:, 2);
blueBand = rgbImage(:,:, 3);
% Display them.
subplot(1, 3, 2);
imshow(blueBand);
title('Blue Band');
% here objects which are parly blue make totaly blue
for i=1:152
for j=1:229
if blueBand(i,j)>200
redBand(i,j)=0.1;
greenBand(i,j)=0.1;
blueBand(i,j)=200;
end
end
end
% here objects which are not blue to dark
for i=1:152
for j=1:229
if blueBand(i,j)<200
redBand(i,j)=redBand(i,j)*0.2;
greenBand(i,j)=greenBand(i,j)*0.2;
blueBand(i,j)=blueBand(i,j)*0.2;
end
end
end
% Display them.
subplot(1, 3, 3);
im = cat(3,redBand,greenBand,blueBand);
imshow(im);
title('Blue Objects');
A second possibility would be using a tool from the File Exchange. A nice feature is 'imoverlay'. If you call this tool by writing in the prompt : >>imoverlay_tool and then use as a background 'blueband' (0-255), in the foreground'blueband' (200-250) and in the overlay (alpha 0.8) you obtain a figure that is blue where the objects are blue and the rest is gray.
Good luck! Christiaan
