Question

您好我正在尝试对加速度计数据使用低通滤波器，这将进一步用于更新对象的位置。最初我将加速度计数据存储在arraylist中，即sensordata。然后使用检索到的加速度计数据执行一些简单的数学计算，结果将存储在accelsum arraylist中。结果在accelsum中我想执行低通滤波并将其存储在低通道arraylist中，因此我实现了低通滤波方法。

现在的问题是，当我打印arraylist即低通量值时，输出是一个空列表。有人可以帮助我。感谢。

以下是代码

    /*Implemented to do some action upon sensor changed*/
    @Override
    public void onSensorChanged(SensorEvent event) {

        if (event.sensor.getType() == Sensor.TYPE_GYROSCOPE) {


            gyro_x = event.values[0];
            gyro_y = event.values[1];
            gyro_z = event.values[2];


        } else if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {

            double x = event.values[0];
            double y = event.values[1];
            double z = event.values[2];
            long timestamp = System.currentTimeMillis();
            AccelData data = new AccelData(timestamp, x, y, z);
            sensorData = new ArrayList();
            sensorData.add(data);//sensordata arraylist contains the x,y,z values of accelerometer

            for(int k=0;k<sensorData.size();k++){
                accelsum.add((float) data.sum(x, y, z));//accelsum arraylist contains the power of x,y and z accelerometer values
                for (int i = 0; i < accelsum.size(); i++) {
                    System.out.println("sum: " + accelsum.get(i));


                }
                for (int i = 0; accelsum.size() > 10; i++) {
                    lowPassVals = lowPass(accelsum, lowPassVals);

                }
                for(int i=0;i<10;i++){
                    System.out.println("lowpassvals: " +lowPassVals);
                }

            }
}
    }

    protected List<Float> lowPass(List<Float> input, List<Float> output) {

        for (int i = 0; i < input.size(); i++) {
            if (output.isEmpty()) {
                return input;
            }
            output.set(i, output.get(i) + ALPHA * (input.get(i) - output.get(i)));


        }
        return output;
    }

这是处理加速度计数据的acceldata类。

public class AccelData {
    private long timestamp;
    private double x;
    private double y;
    private double z;

    /*  public AccelData(SensorEvent event) {
        this.timestamp = timestamp;
        this.x = x;
        this.y = y;
        this.z = z;

        this.x=event.values[0];
        this.y=event.values[1];
        this.z=event.values[2];
        this.timestamp=event.timestamp;

    }*/

    public AccelData(long timestamp, double x, double y, double z) {
        this.timestamp = timestamp;
        this.x = x;
        this.y = y;
        this.z = z;

    }

    public long getTimestamp() {
        return timestamp;
    }

    public void setTimestamp(long timestamp) {
        this.timestamp = timestamp;
    }

    public double getX() {
        return x;
    }

    public void setX(double x) {
        this.x = x;
    }

    public double getY() {
        return y;
    }

    public void setY(double y) {
        this.y = y;
    }

    public double getZ() {
        return z;
    }

    public void setZ(double z) {
        this.z = z;
    }

    public double sum(double x,double y,double z){
        double acc_x=Math.pow(x,2);
        double acc_y=Math.pow(y,2);
        double acc_z=Math.pow(z,2);
        double accsum = acc_x+acc_y+acc_z;
        return accsum;

    }

    public String toString() {

        return "t="+timestamp+", x="+x+", y="+y+", z="+z;
    }
}






    }

Answer 1

原因是这一行

 for (int i = 0; accelsum.size() > 10; i++)

您永远不会进入此循环，因为条件永远不会有效。

android中的低通滤波加速度计数据

1 个答案: