How to detect the area of the Ellipse using imellipse in MATLAB - matlab

Question

I would be very grateful If anyone could help me to solve this problem.
Initially an Image to be loaded to the MATLAB. Image must contain an oval or circular shape object. I choose and draw the circle/ellipse there.
I have completed the above mentioned job. I have attached the MATLAB code and for figure just get full mooon image or egg for ellipse.
Now I want to calculate the area of that ellipse. Anybody there to sort me out from this situation.
Thank you
Here is the Code
function varargout = stack_overflow(varargin)
gui_Singleton = 1;
gui_State = struct('gui_Name', mfilename, ...
'gui_Singleton', gui_Singleton, ...
'gui_OpeningFcn', #stack_overflow_OpeningFcn, ...
'gui_OutputFcn', #stack_overflow_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
%%
function stack_overflow_OpeningFcn(hObject, eventdata, handles, varargin)
handles.output = hObject;
guidata(hObject, handles);
%%
function varargout = stack_overflow_OutputFcn(hObject, eventdata, handles)
varargout{1} = handles.output;
%%
function load_image_Callback(hObject, eventdata, handles)
axes(handles.view);
global im
[path, user_cancel] = imgetfile();
if user_cancel
msgbox(sprintf('Error !!! \n Please upload the image'),'Error','Error');
return
end
im = imread(path);
imshow(im);
%%
function draw_circle_Callback(hObject, eventdata, handles)
axes(handles.view);
global temp;
global fcn;
temp = imellipse(gca, []);
fcn = makeConstrainToRectFcn('imellipse',get(gca,'XLim'),get(gca,'YLim'));
setPositionConstraintFcn(temp,fcn);
%%
function result_Callback(hObject, eventdata, handles)
%%
function result_CreateFcn(hObject, eventdata, handles)
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
set(hObject,'BackgroundColor','white');
end

Answer 1

You could use the createMask method of the imroi class to create a logical mask with the ellipse just drawn, and then sum all the pixels whose value is 1 (or 0...) in order to get the area. You can add something like this in your draw_circle_Callback:
Simple example which you can modify to adapt with your current code:
%// Create dummy image with logical false values.
Im = false(500,500);
imshow(Im);
hold on
%// Draw ellipse
hEllipse = imellipse
%// Create a logical mask
roi = createMask(hEllipse);
%// Sum the values equal to 1;
Area = sum(roi(:))