如何区分 iPhone 中的运动加速度与振动和噪音
stackoverflow 上的大家好。
简短版本:)
我需要使用仅与 iPhone 的移动相关的 (x,y,z) 加速度值。需要明确的是，想象一个像汽车这样的环境。 iPhone 的加速计非常灵敏。如果我以 100Hz 的频率记录加速度值，就会发现有很多与噪声、汽车振动和其他加速度矢量相关的值，这些值不像 iPhone 运动那样定向（例如，阻尼器振荡导致沿 z 轴定向的加速度矢量）。
换句话说，我需要以能够隔离方向与运动方向相同（在一定偏移范围内）的加速度的方式过滤加速度检测。
更深层次的考虑：'（
显然，我可以固定iphone的位置，使其y轴与移动方向重叠（在以前的汽车环境中，这意味着将iphone的y轴固定为与前方平行）。问题是我需要我无法确定 iPhone 的位置。
首先，我分析了噪声和振动产生的值，我发现它们的幅度通常比普通汽车加速度高很多。缓解了这个问题，但这不是一个解决方案：一方面，许多不需要的噪声加速度没有被过滤，因为它们的大小落在范围内，另一方面，许多想要的运动加速度被过滤，因为它们超出了范围，
在 iPhone 3GS 上我可以。使用磁力计测量相对于磁北的航向度数我可以使用它来查找运动方向，但问题仍然存在：磁航向值始终是相对于设备顶部测量的。所以iPhone应该沿着正面方向固定。
我想不出任何其他解决方案。 有想法吗？ 坦克你！
Hi everybody on stackoverflow.
SHORT VERSION :)
I need to use (x,y,z) acceleration values related only to the movement of the iPhone. Just to be clear, think an environment like a car. The iPhone's accelerometer is very sensitive. If I log acceleration values with a frequency of 100Hz, there are so many values related to noise, car vibrations and other acceleration vectors which are not directed like the iPhone motion (for example, dampers oscillations cause acceleration vectors directed along z-axis).
In other words, I need to filter accelerations detection in a way capable to isolate accelerations whose direction is the same (within a certain offset) of the motion direction.
DEEPER CONSIDERATIONS :'(
Obviously, I could fix the iphone position so that its y axis overlaps the movement direction (in the previous car environment, this means fixing the iphone y axis parallel to the front direction). The problem is that I need to allow iphone's relative moments. I can't fix the iphone position.
First of all I analyzed values produced by noise and oscillations, and I figured out that their magnitude is often very higher than normal car accelerations. Filtering the magnitude is a good idea to ease the problem but it's not a solution: on one side many unwanted noise accelerations are not filtered because their magnitude falls within the range, on the other side many wanted motion accelerations are filtered because they falls outside the range.
On the iPhone 3GS I can use the magnetometer to measure degrees heading relative to magnetic North. I could use this to find the direction of motion but the problem is still there: magneticHeading value is always measured relative to the top of the device. So the iPhone should be fixed along the front direction.
I can't think any other solution.
Ideas?
Tank you!
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SDK 中有一个名为“AccelerometerGraph”的示例，具有高通滤波功能。你看过那个吗？
There is a sample named 'AccelerometerGraph' in the SDK that has high pass filtering. Did you look at that?