I want to adjust the brightness of an image using slider.What can I do to make the slider start at middle position. What function should I use to make the image brighter if slider moved to the right and darker to the left?

%this is my current slider callback

axes(handles.axes2);

hChildAxes2 = get(handles.axes2,'Children');

a=get(hChildAxes2(1),'CData');

b=get(hObject,'Value');

c=imadd(a,b);

imshow(c);

Answer 1

[SCOTT LIM]

In the GUIDE builder there is a slider icon. You can adjust the settings of the slider when you double click on the slider. You can change: 'Value' which is the starting position. 'Max' ' Min' which are your boundaries.

Im = imread('mypic.jpg');  
offset = get(hObject,'Value');
Im = Im + offset ; %but u have to change the offset values to the correct data type as Im. e.g. uint8 or uint16(offset)