Installed, and it works ofc. Good job!

Some points:

Do you kill the process directly? I guess you do, since the front camera indicator led doesn't shut down as it should. You have to stop it with terminate() and after few secs you kill it. In this way it has time to handle its own close events (like shutting down front camera led indicator).

Window title is "MainWindow", guess you have already realized it.

Settings don't get saved between one session and another one: you may use QSettings to do it.

Ui is fingerfoe: have you set a main layout in desiner? Top right corner (object subwindow) > right click on main window > layout> vertical layout.

ShowDebug button is not so needed, it can be swapped with maemo standard banners (QMaemo5InformationBox, and add QT += maemo5 in project file, than run qmake) to save space.

The calibrate window is in window style? Use a message box with detailed text instead (QMessageBox) to be more hildon oriented.

Binary is a bit big just to be a front end. Have you compiled it as release or debug?

Package is not optified, it installs in /usr/local/bin