How to Seperate Channels in Color Image in Matlab

The human visual system can perceive thousands of colors in a small spatial area, but only about 100 gray levels. Color contrast can be more dramatic than gray level contrast, and various colors have different degrees of psychological impact on the observer.  A subset of Physical images (Color Images) is multi-spectral images-those having more than one local property defined at each point (trispectral-RGB image, reproduced in color photography,).  Color images have three values of brightness, one each for Red, Green, and Blue. The three values represent intensity in different spectral bands, which the eye perceives as different colors. We can also say channel to the specific brightness value, so the color image has three channel [ Red, Green, Blue].

 

Follow these steps to make Program for Separation Channels of color Image’s

  1. Run Matlab, First window you will get something like below
Matlab Main Window
Matlab Main Window

2. Type “guide” in command window, “GUIDE Quick Start” window will appear

3. Select “Blank GUI (Default)” and press Okay, see in below picture

GUI in matalb
GUI in Matlab

4. In GUI window select “Static Text”  from left sidebar then double click on “Static Text”

5. “Inspector window” will appear, Type your desired Text in String Field

6. Then drag a “Button” from sidebar and Rewrite desired text, GUI will look like below picture

 

RGBChannel Sepration.PNG
GUI: RGB Channel Separation

 

7. Save GUI with “Ctrl + S” then write code for color to grayscale conversion after pushbutton1_Callback

function varargout = GUI(varargin)
% GUI MATLAB code for GUI.fig
% GUI, by itself, creates a new GUI or raises the existing
% singleton*.
%
% H = GUI returns the handle to a new GUI or the handle to
% the existing singleton*.
%
% GUI(‘CALLBACK’,hObject,eventData,handles,…) calls the local
% function named CALLBACK in GUI.M with the given input arguments.
%
% GUI(‘Property’,’Value’,…) creates a new GUI or raises the
% existing singleton*. Starting from the left, property value pairs are
% applied to the GUI before GUI_OpeningFcn gets called. An
% unrecognized property name or invalid value makes property application
% stop. All inputs are passed to GUI_OpeningFcn via varargin.
%
% *See GUI Options on GUIDE’s Tools menu. Choose “GUI allows only one
% instance to run (singleton)”.
%
% See also: GUIDE, GUIDATA, GUIHANDLES

% Edit the above text to modify the response to help GUI

% Last Modified by GUIDE v2.5 22-Apr-2017 21:13:23

% Begin initialization code – DO NOT EDIT
gui_Singleton = 1;
gui_State = struct(‘gui_Name’, mfilename, …
‘gui_Singleton’, gui_Singleton, …
‘gui_OpeningFcn’, @GUI_OpeningFcn, …
‘gui_OutputFcn’, @GUI_OutputFcn, …
‘gui_LayoutFcn’, [] , …
‘gui_Callback’, []);
if nargin && ischar(varargin{1})
gui_State.gui_Callback = str2func(varargin{1});
end

if nargout
[varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});
else
gui_mainfcn(gui_State, varargin{:});
end
% End initialization code – DO NOT EDIT
% — Executes just before GUI is made visible.
function GUI_OpeningFcn(hObject, eventdata, handles, varargin)
% This function has no output args, see OutputFcn.
% hObject handle to figure
% eventdata reserved – to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
% varargin command line arguments to GUI (see VARARGIN)

% Choose default command line output for GUI
handles.output = hObject;

% Update handles structure
guidata(hObject, handles);

% UIWAIT makes GUI wait for user response (see UIRESUME)
% uiwait(handles.figure1);
% — Outputs from this function are returned to the command line.
function varargout = GUI_OutputFcn(hObject, eventdata, handles)
% varargout cell array for returning output args (see VARARGOUT);
% hObject handle to figure
% eventdata reserved – to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)

% Get default command line output from handles structure
varargout{1} = handles.output;
% — Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
% hObject handle to pushbutton1 (see GCBO)
% eventdata reserved – to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
[Filename Path] = uigetfile({‘*.*’},’File Selector’);
FullFilePath = strcat(Path,Filename);
Matrix = imread(FullFilePath);

red = Matrix(:,:,1); % Red channel
green = Matrix(:,:,2); % Green channel
blue = Matrix(:,:,3); % Blue channel
new = zeros(size(Matrix, 1), size(Matrix, 2)); %making new of same size (original Image)
just_red = cat(3, red, new, new);
just_green = cat(3, new, green, new);
just_blue = cat(3, new, new, blue);
back_to_original_img = cat(3, red, green, blue);
figure, imshow(Matrix), title(‘Original image’)
figure, imshow(just_red), title(‘Red channel’)
figure, imshow(just_green), title(‘Green channel’)
figure, imshow(just_blue), title(‘Blue channel’)
function min_Callback(hObject, eventdata, handles)
% hObject handle to min (see GCBO)
% eventdata reserved – to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)

% Hints: get(hObject,’String’) returns contents of min as text
% str2double(get(hObject,’String’)) returns contents of min as a double
% — Executes during object creation, after setting all properties.
function min_CreateFcn(hObject, eventdata, handles)
% hObject handle to min (see GCBO)
% eventdata reserved – to be defined in a future version of MATLAB
% handles empty – handles not created until after all CreateFcns called

% Hint: edit controls usually have a white background on Windows.
% See ISPC and COMPUTER.
if ispc && isequal(get(hObject,’BackgroundColor’), get(0,’defaultUicontrolBackgroundColor’))
set(hObject,’BackgroundColor’,’white’);
end

function max_Callback(hObject, eventdata, handles)
% hObject handle to max (see GCBO)
% eventdata reserved – to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)

% Hints: get(hObject,’String’) returns contents of max as text
% str2double(get(hObject,’String’)) returns contents of max as a double
% — Executes during object creation, after setting all properties.
function max_CreateFcn(hObject, eventdata, handles)
% hObject handle to max (see GCBO)
% eventdata reserved – to be defined in a future version of MATLAB
% handles empty – handles not created until after all CreateFcns called

% Hint: edit controls usually have a white background on Windows.
% See ISPC and COMPUTER.
if ispc && isequal(get(hObject,’BackgroundColor’), get(0,’defaultUicontrolBackgroundColor’))
set(hObject,’BackgroundColor’,’white’);
end

Input Image:

Color Image
Color Image

Image with Red Channel:

 

Red Channel.PNG
Red Channel

 

Image with Green Channel:

 

Green Channel.PNG
Green Channel

 

Image with Blue Channel:

 

Blue Channel.PNG
Blue Channel

 

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