1. It lets you know how to slant the camera so that the camera becomes flat.
2. It takes the picture when you make a noise instead of when you press a button. This is helpful since you need to hold the camera with both hands to make the camera stable.
With a high resolution camera and this tool you no longer need a scanning device.
1. Place the document to scan on a flat surface. The picture will become best if light comes from far away (like from the sun on a cloudy day) so that there will be no shadows.
2. Start the Flat Camera app
3. Center the camera above the paper
4. Follow the guideline arrows to slant the device. The less the arrows are visible the more flat the camera.
5. When you cannot see any arrows it means the camera is perfectly flat. If you have the full paper in view - Make a sound - a white square will blink when it takes the picture and while storing the data.
The pictures are stored to the Pictures folder and can viewed by for instance the Gallery app.
Note: There is no automatic calibration but you can calibrate the software manually by monitoring the sensor data and adjusting the limits accordingly.
Also you need a camera with 5 Megapixels or more to get the photo good enough.