使用getRotationMatrix()和getOrientation()查找方向 [英] finding orientation using getRotationMatrix() and getOrientation()
问题描述
我试图相对于磁北获得指向摄像机的矢量方向.我的印象是我需要使用从getOrientation()返回的值,但是我不确定它们代表什么.当我更改手机的方向时,从getOrientation()获得的值不会发生可预测的更改(旋转90度不会将值更改90度).我需要知道getOrientation()返回的值是什么意思.我到目前为止所写的内容如下:
Im trying to get the direction of the vector pointing out of the camera, with respect to magnetic north. I'm under the impression that I need to use the values returned from getOrientation(), but I'm not sure what they represent. The values I get from getOrientation() don't change predictably when I change the orientation of the phone (rotating 90 degrees does not change values by 90 degrees). I need to know what the values returned by getOrientation() mean. What I have so far is written below:
package com.example.orientation;
import android.app.Activity;
import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.widget.Toast;
public class Orientation extends Activity{
private SensorManager mSM;
private mSensorEventListener mSEL;
float[] inR = new float[16];
float[] outR= new float[16];
float[] I = new float[16];
float[] gravity = new float[3];
float[] geomag = new float[3];
float[] orientVals = new float[3];
final float pi = (float) Math.PI;
final float rad2deg = 180/pi;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mSM = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
mSEL = new mSensorEventListener();
mSM.registerListener(mSEL,
mSM.getDefaultSensor(Sensor.TYPE_ACCELEROMETER),
SensorManager.SENSOR_DELAY_NORMAL);
mSM.registerListener(mSEL,
mSM.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD),
SensorManager.SENSOR_DELAY_NORMAL);
}
private class mSensorEventListener implements SensorEventListener{
@Override
public void onAccuracyChanged(Sensor arg0, int arg1) {}
@Override
public void onSensorChanged(SensorEvent event) {
// If the sensor data is unreliable return
if (event.accuracy == SensorManager.SENSOR_STATUS_UNRELIABLE)
return;
// Gets the value of the sensor that has been changed
switch (event.sensor.getType()){
case Sensor.TYPE_ACCELEROMETER:
gravity = event.values.clone();
break;
case Sensor.TYPE_MAGNETIC_FIELD:
geomag = event.values.clone();
break;
}
// If gravity and geomag have values then find rotation matrix
if (gravity != null && geomag != null){
// checks that the rotation matrix is found
boolean success = SensorManager.getRotationMatrix(inR, I, gravity, geomag);
if (success){
// Re-map coordinates so y-axis comes out of camera
SensorManager.remapCoordinateSystem(inR, SensorManager.AXIS_X,
SensorManager.AXIS_Z, outR);
// Finds the Azimuth and Pitch angles of the y-axis with
// magnetic north and the horizon respectively
SensorManager.getOrientation(outR, orientVals);
float azimuth = orientVals[0]*rad2deg;
float pitch = orientVals[1]*rad2deg;
float roll = orientVals[2]*rad2deg;
// Displays a pop up message with the azimuth and inclination angles
String endl = System.getProperty("line.separator");
Toast.makeText(getBaseContext(),
"Rotation:" +
outR[0] + " " + outR[1] + " " + outR[2] + endl +
outR[4] + " " + outR[5] + " " + outR[6] + endl +
outR[8] + " " + outR[9] + " " + outR[10] + endl +endl +
"Azimuth: " + azimuth + " degrees" + endl +
"Pitch: " + pitch + " degrees" + endl +
"Roll: " + roll + " degrees",
Toast.LENGTH_LONG).show();
} /*else
Toast.makeText(getBaseContext(),
"Get Rotation Matrix Failed", Toast.LENGTH_LONG).show();*/
}
}
}
}
我看了sensorManager类的文档,但是并没有帮助解决这个问题.如果有人可以帮助我从中获得意义,我将不胜感激.我正在运行Android 2.1的Nexus One上进行测试
I've looked at the documentation on the sensorManager class, but it hasn't helped solve this. If anyone could help me get meaning out of the this I would really appreciate it. I'm testing on a Nexus One running Android 2.1
推荐答案
因为我是android的新手,所以我在用Toast在屏幕上显示信息.我将其更改为仅更新视图上的文本,这似乎可以解决问题.我还发现我假设的orientVals实际上是正确的.对于我所需要的,不使用卷.还没有意识到有一种方法可以将rad转换为内置的deg,所以我只是使用了此方法.
Because I was new to android I was using toast to display the information on the screen. I changed it to just update text on a view and that seemed to fix it. I also figured out that what I assumed the orientVals actually were is correct. For what I need the roll is not used. Also didnt realize there was a way to convert from rad to deg built in so I just used that.
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