如何使用Android加速度计检测步行 [英] How to detect walking with Android accelerometer

问题描述

我正在编写一个应用程序，我的目标是检测用户何时走路.我正在使用这样的卡尔曼滤波器:

I'm writing an application and my aim is to detect when a user is walking. I'm using a Kalman filter like this:

float kFilteringFactor=0.6f;

        gravity[0] = (accelerometer_values[0] * kFilteringFactor) + (gravity[0] * (1.0f - kFilteringFactor));
        gravity[1] = (accelerometer_values[1] * kFilteringFactor) + (gravity[1] * (1.0f - kFilteringFactor));
        gravity[2] = (accelerometer_values[2] * kFilteringFactor) + (gravity[2] * (1.0f - kFilteringFactor));

        linear_acceleration[0] = (accelerometer_values[0] - gravity[0]);
        linear_acceleration[1] = (accelerometer_values[1] - gravity[1]);
        linear_acceleration[2] = (accelerometer_values[2] - gravity[2]);

        float magnitude = 0.0f;
        magnitude = (float)Math.sqrt(linear_acceleration[0]*linear_acceleration[0]+linear_acceleration[1]*linear_acceleration[1]+linear_acceleration[2]*linear_acceleration[2]);
        magnitude = Math.abs(magnitude);
if(magnitude>0.2)
  //walking

数组gravity[]初始化为0s.

The array gravity[] is initialized with 0s.

我可以检测到用户是否在走路(查看加速度矢量的大小)，但我的问题是当用户没有走路并且他移动手机时，他似乎在走路.

I can detect when a user is walking or not (looking at the value of the magnitude of the acceleration vector), but my problem is that when a user is not walking and he moves the phones, it seems that he is walking.

我是否使用了正确的过滤器?

Am I using the right filter?

是只看向量的大小还是我看单个值是正确的??

Is it right to watch only the magnitude of the vector or have I to look at the single values ??

推荐答案

Google 为此提供了一个名为 DetectedActivity 的 API，可以使用 ActivityRecognitionApi 获取该 API.可以在此处和此处.

Google provides an API for this called DetectedActivity that can be obtained using the ActivityRecognitionApi. Those docs can be accessed here and here.

DetectedActivity 有方法 public int getType() 来获取用户的当前活动，还有 public int getConfidence() 返回一个从 0 到 100 的值.getConfidence() 返回的值越高，API 就越确定用户正在执行返回的活动.

DetectedActivity has the method public int getType() to get the current activity of the user and also public int getConfidence() which returns a value from 0 to 100. The higher the value returned by getConfidence(), the more certain the API is that the user is performing the returned activity.

以下是 getType() 返回的内容的不断总结:

Here is a constant summary of what is returned by getType():

• int IN_VEHICLE 设备在车辆中，例如汽车.
• int ON_BICYCLE 设备在自行车上.
• int ON_FOOT 设备在步行或跑步的用户身上.
• int RUNNING 设备位于正在运行的用户身上.
• int STILL 设备静止(不移动).
• int TILTING 设备相对于重力的角度发生了显着变化.
• int UNKNOWN 无法检测到当前活动.
• int WALKING 设备在步行的用户身上.

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