Take a picture of the tubes you want to count and the app will highlight and count them. You can manually add or remove tubes by tapping on the screen. The result will also update as you adjust various settings.
Settings include a "Capped Tube Mode," which turns on manual radius detection and turns off center verification. You can also adjust the brightness control to account for varying lighting conditions. There is also a confidence threshold slider for when you want to adjust the sensitivity of the algorithm.