從橫向模式或翻轉方向後的傳感器獲取方向

Question

我試圖在Android中獲取相機的方向。我有一些代碼可以在肖像中完美運行（我通過慢慢轉圈並相互更新1秒來測試它），但它在風景中根本不起作用 - 數字似乎隨機變化。從肖像切換到風景後，它也完全不適用。這是我的代碼

public void onSensorChanged(SensorEvent event) { 

    switch (event.sensor.getType()) { 
    case Sensor.TYPE_ACCELEROMETER: 
     accelerometerValues = event.values.clone(); 

     break; 
    case Sensor.TYPE_MAGNETIC_FIELD: 
     geomagneticMatrix = event.values.clone(); 
     break; 
    default: 
     break; 
    } 

    if (geomagneticMatrix != null && accelerometerValues != null) { 

     float[] R = new float[16]; 
     float[] I = new float[16]; 
     float[] outR = new float[16]; 

     //Get the rotation matrix, then remap it from camera surface to world coordinates 
     SensorManager.getRotationMatrix(R, I, accelerometerValues, geomagneticMatrix); 
     SensorManager.remapCoordinateSystem(R, SensorManager.AXIS_X, SensorManager.AXIS_Z, outR); 
     float values[] = new float[4]; 
     SensorManager.getOrientation(outR,values); 
     float direction = normalizeDegrees((float) Math.toDegrees(values[0])); 
     float pitch = normalizeDegrees((float) Math.toDegrees(values[1])); 
     float roll = normalizeDegrees((float) Math.toDegrees(values[2])); 

     if((int)direction != (int)lastDirection){ 
      lastDirection = direction; 
      for(CompassListener listener: listeners){ 
       listener.onDirectionChanged(lastDirection, pitch, roll); 
      } 
     } 
    } 
} 

任何想法我做錯了什麼？我坦率地承認，我不會100％明白這一點。我也不知道Google爲什麼棄用定位傳感器 - 這似乎是一種普遍的想法。

Answer 1

您是否考慮過，當您從縱向更改爲橫向時，加速計軸會發生變化？像Y軸變成Z軸等等。這可能是奇怪行爲的一個來源。

Answer 2

我似乎已經解決了它，或者至少改進了它，直到我知道什麼是問題。我加入了一個濾波器，以便不用傳遞單個傳感器讀數，而是記住最後的讀數並對其應用增量。每個新的傳感器點允許添加最多5度。這完全濾除了奇怪的跳躍，並強制它收斂到一個值。我感到偶爾會有奇怪的跳躍，但我認爲我需要的是更復雜的過濾器。新代碼：

public void onSensorChanged(SensorEvent event) { 
    if (event.accuracy == SensorManager.SENSOR_STATUS_UNRELIABLE) 
     return; 

    switch (event.sensor.getType()) { 
    case Sensor.TYPE_ACCELEROMETER: 
     accelerometerValues = event.values.clone(); 

     break; 
    case Sensor.TYPE_MAGNETIC_FIELD: 
     geomagneticMatrix = event.values.clone(); 
     break; 
    } 

    if (geomagneticMatrix != null && accelerometerValues != null) { 

     float[] R = new float[16]; 
     float[] I = new float[16]; 
     float[] outR = new float[16]; 

     //Get the rotation matrix, then remap it from camera surface to world coordinates 
     SensorManager.getRotationMatrix(R, I, accelerometerValues, geomagneticMatrix); 
     SensorManager.remapCoordinateSystem(R, SensorManager.AXIS_X, SensorManager.AXIS_Z, outR); 
     float values[] = new float[4]; 
     SensorManager.getOrientation(outR,values); 

     int direction = filterChange(normalizeDegrees(Math.toDegrees(values[0]))); 
     int pitch = normalizeDegrees(Math.toDegrees(values[1])); 
     int roll = normalizeDegrees(Math.toDegrees(values[2])); 
     if((int)direction != (int)lastDirection){ 
      lastDirection = (int)direction; 
      lastPitch = (int)pitch; 
      lastRoll = (int)roll; 
      for(CompassListener listener: listeners){ 
       listener.onDirectionChanged(lastDirection, pitch, roll); 
      } 
     } 
    } 
} 

//Normalize a degree from 0 to 360 instead of -180 to 180 
private int normalizeDegrees(double rads){ 
    return (int)((rads+360)%360); 
} 

//We want to ignore large bumps in individual readings. So we're going to cap the number of degrees we can change per report 
private int filterChange(int newDir){ 
    int change = newDir - lastDirection; 
    int circularChange = newDir-(lastDirection+360); 
    int smallestChange; 
    if(Math.abs(change) < Math.abs(circularChange)){ 
     smallestChange = change; 
    } 
    else{ 
     smallestChange = circularChange; 
    } 
    smallestChange = Math.max(Math.min(change,5),-5); 
    return lastDirection+smallestChange; 
}