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How to program a slider tool to adjust image contrast?

Asked by Louise Cullen on 12 Aug 2019
Latest activity Answered by Bhargavi Maganuru on 20 Aug 2019
I have designed an app using GUIDE and I have just added a slider tool. I want it to be able to adjust the contrast of an image that has been imported and displayed on the app, like what the imcontrast function can do. Does anyone have any idea how to do this or can point me in the direction of some helpful documentation? I have not found anything so far.

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Louise - do you need code to adjust the contrast or are you unsure how to create a slider callback?
I am unsure how to create a slider callback! At the moment, I have found a way to program a button with imcontrast() so it opens a new window that can adjust the contrast of the image, but it would be much more ideal if there was no need for a new window, and instead the slider tool was on the GUI.
A slider callback will be created for you in GUIDE. Then you can add your code in there.
Exactly what code you put in there depends on how you are doing the contrast and what you are doing with the result.
get( hObject, 'Value' )
in the callback will give you your slider value to work with though.

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1 Answer


You can edit slider_callback in order to adjust contrast of the image using slider value.
get(hObject,'Value') command returns the value of the slider.
You can add following lines of code:
In Opening function:
I=imread('image.jpg');
handles.I=I;
guidata(hObject, handles);
axes(handles.axes1);
imshow(I);
In slider callback function:
I=handles.I;
I=I*get(hObject,'Value');
axes(handles.axes1);
imshow(I);
Hope this helps.

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