Displaying an image on UIAxes in App Designer that doesn't appear

Hey there,

I've been trying to design a GUI in the app designer that estimates noise, it:

1. Takes an image specified by the user, image appears on UIAxes2
2. User selects a type of noise to add
3. Image with noise added is displayed again on UIAxes2

Please advise.

The original selected image appears just fine but when I want the noisy image to appear, it doesn't. Here are screenshots of the code + the App

1. Original Image button callback code

    function UploadImageButtonPushed(app, event)
                [filename,filepath] = uigetfile({ '*.*;*.jpg;*.png;*.bmp;*.oct' }, 'Select File to Open');
                fullname = [filepath, filename];
                file = imread(fullname);
                global pic
                pic=im2gray(file);            
                image1=im2double(pic);
               imshow(image1, 'parent', app.UIAxes2)
        end

2. Noisy image button callback code

         % Button pushed function: ApplyNoiseButton
        function ApplyNoiseButtonPushed(app, event)
            global image1
            global noisy
            if (strcmp(app.SelectTypeofNoisetoAddDropDown.Value,'Salt & Pepper'))
                noisy = imnoise(image1, 'salt & pepper');                
            elseif(strcmp(app.SelectTypeofNoisetoAddDropDown.Value, 'Gaussian'))
                noisy = imnoise(image1, 'gaussian', 0, 0.01);
            elseif(strcmp(app.SelectTypeofNoisetoAddDropDown.Value,'Speckle'))
                noisy = imnoise(image1, 'speckle');
            else
                noisy=image1;
            end
            imshow(noisy,'parent', app.UIAxes2)
        end

Screenshots of GUI:

Answer 1

[Geoff Hayes]

Ahmed - I suspect the problem is with your variable for image1. It is declared as a global variable in ApplyNoiseButtonPushed function, but it is a local variable in the UploadImageButtonPushed function. I suppose that you could use pic instead or find an alternative to using global variables. Perhaps save the image as a property to the app object.

[Ahmed Mukhtar]

I globalized image1 and the entire app worked, thank you very much!