Save image with same resolution

Hello, I've drawn some circles on an image and i wish to save that image...Though the image was saved with imwrite() command, the image became blur (the resolution reduced). How can I save the image without its quality reduced?

The coding used is as follows:

%Risk Contour
I = imread('Plant latest layout.jpg') ; 
imshow(I)
th = linspace(0,2*pi) ; 
hold on
message = sprintf('Click where you want the center to be');
uiwait(helpdlg(message));
[xCenter, yCenter] = ginput(1);
for radius =Y
    x = radius * cos(th) + xCenter; 
    y = radius * sin(th) + yCenter; 
    plot(x, y, '-');
end
hold off
imwrite(F.cdata,'Plant latest layout.jpg') %Save the contour drawn

[Rik]

There is no guarantee that your figure will have the same resolution as your image. You will have to ensure that yourself.

[Walter Roberson]

F is undefined. Presumably your real code has

F = getframe();

[HAINGKHARRAN GUNASEKARAN]

Yeah, i missed that line here....Thee problem is the image quality ..

[Walter Roberson]

In my brief test, I am not observing any reduction in image quality, under the conditions:

• that the original image fit within the screen without reduction
• that the "blur" being talked about is not the fact that you cannot get sharp edges when you use .jpg (unless you turn the quality up a lot). JPEG is nice for scenes, but not good for preserving edges.

After you do the imshow(), ask

disp(size(I))
ax = gca;

oldunits = ax.Units;
ax.Units = 'pixels';
axpos = ax.InnerPosition;
ax.Units = oldunits;
disp(axpos(3:4))

and then after the getframe, ask

disp(size(F.cdata))

and tell us what show up.