Trouble with Raspberry Pi 4B in GUI design

So the problem is i was trying to take a snap shot and display the snapped picture on the Axes1 in the GUI that I design.

the code suppose to be recognize mypi and cam, variable as a value, but in this case there aren't any variable shown when the button1 is pushed. Please help. thank you

% --- Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
clear all
mypi=raspi;
cam = cameraboard(mypi,'Resolution', '1280x720');
img=snapshot(cam);

axes(handles.axes1);
imagesc(img);