get Rotation Vector From Gyro - Android java.lang

Android examples for java.lang:Math Vector

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Description

get Rotation Vector From Gyro

Demo Code


//package com.java2s;

public class Main {
    private static final float EPSILON = 0.000000001f;

    /**//from   www  .j av a 2s. co m
     *  This is taken from the Android reference at:
     *
     *  http://developer.android.com/reference/android/hardware/SensorEvent.html#values
     *  It calculates a rotation vector from the gyroscope angular speed values.
     */

    public static void getRotationVectorFromGyro(float[] gyroValues,
            float[] deltaRotationVector, float timeFactor) {

        float[] normValues = new float[3];

        // Calculate the angular speed of the sample
        float omegaMagnitude = (float) Math.sqrt(gyroValues[0]
                * gyroValues[0] + gyroValues[1] * gyroValues[1]
                + gyroValues[2] * gyroValues[2]);

        // Normalize the rotation vector if it's big enough to get the axis
        if (omegaMagnitude > EPSILON) {
            normValues[0] = gyroValues[0] / omegaMagnitude;
            normValues[1] = gyroValues[1] / omegaMagnitude;
            normValues[2] = gyroValues[2] / omegaMagnitude;
        }

        // Integrate around this axis with the angular speed by the timestep
        // in order to get a delta rotation from this sample over the timestep
        // We will convert this axis-angle representation of the delta rotation
        // into a quaternion before turning it into the rotation matrix.
        float thetaOverTwo = omegaMagnitude * timeFactor;
        float sinThetaOverTwo = (float) Math.sin(thetaOverTwo);
        float cosThetaOverTwo = (float) Math.cos(thetaOverTwo);
        deltaRotationVector[0] = sinThetaOverTwo * normValues[0];
        deltaRotationVector[1] = sinThetaOverTwo * normValues[1];
        deltaRotationVector[2] = sinThetaOverTwo * normValues[2];
        deltaRotationVector[3] = cosThetaOverTwo;
    }
}

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