What is the angle the WP7 Camera sees?

Question

Same question as Determine angle of view of smartphone camera, applied for WP7. Can't seem to find an appropriate method, and I don't want to put my users through calibrating it themselves (if possible). Thanks

Answer 1

I dont know how to get the angle of the camera, but I do have an app that will calculate the tilt of the phone based on the Yaw/Roll/Pitch.

namespace PhoneUtilities.Utilities
{
    public class AccelerometerMath
    {
        public static double RadianToDegree(double radians)
        {

            return radians * (180 / Math.PI);
        }

        public static double Pitch(AccelerometerReading e)
        {
            return RadianToDegree((Math.Atan(e.Acceleration.X / Math.Sqrt(Math.Pow(e.Acceleration.Y, 2) + Math.Pow(e.Acceleration.Z, 2)))));
        }

        public static double Roll(AccelerometerReading e)
        {
            return RadianToDegree((Math.Atan(e.Acceleration.Y / Math.Sqrt(Math.Pow(e.Acceleration.X, 2) + Math.Pow(e.Acceleration.Z, 2)))));
        }

        public static double Yaw(AccelerometerReading e)
        {
            return RadianToDegree((Math.Atan(Math.Sqrt(Math.Pow(e.Acceleration.X, 2) + Math.Pow(e.Acceleration.Y, 2)) / e.Acceleration.Z)));
        }
    }
}

The calculations were able to get me the angle of the tilt, here is an example I use for some trig calculation Cos(angle) = adj/hyp:

private double CalcUpAdj(AccelerometerReading reading)
{
    double angle = PhoneUtilities.Utilities.AccelerometerMath.Yaw(reading);

    //Get the angleNeeded for calculation
    double angleNeeded = Math.Abs(angle);
    double adj = CalcAdj(angleNeeded);

    tbAngle.Text = String.Format("{0:0.00}", angleNeeded) + (char)176;
    textBlockAdj.Text = adj.ToString();

    return adj;
}

private double CalcAdj(double angleNeeded)
{
    double number;
    if (double.TryParse(tbHyp.Text, out number))
    {
        double hyp = number;
        double adj = Math.Cos(Math.PI * angleNeeded / 180) * hyp;

        tbAngle.Text = String.Format("{0:0.00}", angleNeeded) + (char)176;

        textBlockAdj.Text = adj.ToString();
        return adj;
    }

    return 0;
}

I dont know if this will help you with your camera, but I imagine if you knew the dimensions of the screen you could calculate the angle based on the tilt of the phone. Hopefully you find this helpful.

Answer 2

Please see this post

How to find out the aperture angle of an android camera

in WP7, there is no API function to get that, and no other option than

• Ask user introduce it (they never know)
• Make a list of phones you support and obtain/measure it for each one. Store it in your app. (crazy!)

(I am doing the same kind of stuff and we invested a lot in finding automatic calibration methods, without success.)

EDIT

Cheers and love for bill and microsoft co.