CMMotionManager deviceMotion态度值中的过度“闪烁”

Question

我在一个CMMotionManager deviceMotion回调中记录从CADisplayLink获得的“态度”值(我需要基于设备旋转来执行动画)。

这些值似乎每隔几毫秒就“抽动”一次(高达30%)。这看起来很不稳定，让我怀疑我是做错了什么，还是设备出了什么问题。

请在下面找到原木。印刷的“角度”是“态度”的“滚动”部分，转换为学位：

2013-04-10 00:07:12.683 MyApp[450:707] Angle: -92.91

2013-04-10 00:07:12.712 MyApp[450:707] Angle: -70.52

2013-04-10 00:07:12.714 MyApp[450:707] Angle: -92.25

2013-04-10 00:07:12.745 MyApp[450:707] Angle: -70.03

2013-04-10 00:07:12.747 MyApp[450:707] Angle: -91.74

2013-04-10 00:07:12.779 MyApp[450:707] Angle: -69.67

2013-04-10 00:07:12.784 MyApp[450:707] Angle: -91.23

2013-04-10 00:07:12.812 MyApp[450:707] Angle: -69.43

2013-04-10 00:07:12.815 MyApp[450:707] Angle: -91.19

2013-04-10 00:07:12.846 MyApp[450:707] Angle: -69.53

2013-04-10 00:07:12.849 MyApp[450:707] Angle: -91.33

2013-04-10 00:07:12.879 MyApp[450:707] Angle: -69.74

2013-04-10 00:07:12.881 MyApp[450:707] Angle: -91.57

2013-04-10 00:07:12.912 MyApp[450:707] Angle: -70.01

2013-04-10 00:07:12.915 MyApp[450:707] Angle: -91.85

2013-04-10 00:07:12.945 MyApp[450:707] Angle: -70.13

2013-04-10 00:07:12.949 MyApp[450:707] Angle: -91.99

2013-04-10 00:07:12.979 MyApp[450:707] Angle: -70.03

2013-04-10 00:07:12.983 MyApp[450:707] Angle: -91.93

2013-04-10 00:07:13.012 MyApp[450:707] Angle: -69.76

2013-04-10 00:07:13.016 MyApp[450:707] Angle: -91.71

2013-04-10 00:07:13.046 MyApp[450:707] Angle: -69.34

2013-04-10 00:07:13.051 MyApp[450:707] Angle: -91.19

2013-04-10 00:07:13.079 MyApp[450:707] Angle: -68.89

2013-04-10 00:07:13.082 MyApp[450:707] Angle: -90.94

2013-04-10 00:07:13.112 MyApp[450:707] Angle: -68.52

2013-04-10 00:07:13.114 MyApp[450:707] Angle: -90.66

2013-04-10 00:07:13.151 MyApp[450:707] Angle: -67.85

2013-04-10 00:07:13.156 MyApp[450:707] Angle: -89.47

2013-04-10 00:07:13.179 MyApp[450:707] Angle: -65.66

2013-04-10 00:07:13.181 MyApp[450:707] Angle: -88.10

2013-04-10 00:07:13.212 MyApp[450:707] Angle: -63.81

2013-04-10 00:07:13.216 MyApp[450:707] Angle: -86.33

2013-04-10 00:07:13.245 MyApp[450:707] Angle: -61.07

2013-04-10 00:07:13.248 MyApp[450:707] Angle: -83.63

2013-04-10 00:07:13.279 MyApp[450:707] Angle: -58.95

2013-04-10 00:07:13.282 MyApp[450:707] Angle: -81.46

2013-04-10 00:07:13.312 MyApp[450:707] Angle: -56.71

2013-04-10 00:07:13.314 MyApp[450:707] Angle: -79.06

2013-04-10 00:07:13.346 MyApp[450:707] Angle: -53.29

2013-04-10 00:07:13.350 MyApp[450:707] Angle: -75.23

2013-04-10 00:07:13.380 MyApp[450:707] Angle: -51.63

2013-04-10 00:07:13.383 MyApp[450:707] Angle: -73.37

2013-04-10 00:07:13.414 MyApp[450:707] Angle: -50.35

2013-04-10 00:07:13.418 MyApp[450:707] Angle: -72.11

2013-04-10 00:07:13.446 MyApp[450:707] Angle: -50.08

2013-04-10 00:07:13.450 MyApp[450:707] Angle: -72.01

2013-04-10 00:07:13.479 MyApp[450:707] Angle: -50.50

2013-04-10 00:07:13.488 MyApp[450:707] Angle: -73.51

2013-04-10 00:07:13.512 MyApp[450:707] Angle: -51.25

2013-04-10 00:07:13.514 MyApp[450:707] Angle: -74.14

2013-04-10 00:07:13.545 MyApp[450:707] Angle: -49.98

2013-04-10 00:07:13.547 MyApp[450:707] Angle: -72.96

2013-04-10 00:07:13.579 MyApp[450:707] Angle: -46.99

2013-04-10 00:07:13.582 MyApp[450:707] Angle: -68.58

2013-04-10 00:07:13.612 MyApp[450:707] Angle: -43.01

2013-04-10 00:07:13.616 MyApp[450:707] Angle: -65.32

2013-04-10 00:07:13.645 MyApp[450:707] Angle: -40.92

2013-04-10 00:07:13.647 MyApp[450:707] Angle: -62.80

2013-04-10 00:07:13.680 MyApp[450:707] Angle: -39.70

2013-04-10 00:07:13.683 MyApp[450:707] Angle: -61.30

2013-04-10 00:07:13.712 MyApp[450:707] Angle: -40.74

2013-04-10 00:07:13.714 MyApp[450:707] Angle: -63.06

2013-04-10 00:07:13.745 MyApp[450:707] Angle: -42.29

2013-04-10 00:07:13.747 MyApp[450:707] Angle: -65.68

2013-04-10 00:07:13.779 MyApp[450:707] Angle: -43.18

2013-04-10 00:07:13.780 MyApp[450:707] Angle: -67.58

2013-04-10 00:07:13.812 MyApp[450:707] Angle: -42.13

2013-04-10 00:07:13.815 MyApp[450:707] Angle: -66.35

2013-04-10 00:07:13.845 MyApp[450:707] Angle: -40.95

2013-04-10 00:07:13.848 MyApp[450:707] Angle: -64.67

2013-04-10 00:07:13.879 MyApp[450:707] Angle: -39.73

2013-04-10 00:07:13.881 MyApp[450:707] Angle: -62.90

2013-04-10 00:07:13.913 MyApp[450:707] Angle: -40.06

2013-04-10 00:07:13.916 MyApp[450:707] Angle: -63.12

2013-04-10 00:07:13.947 MyApp[450:707] Angle: -40.78

2013-04-10 00:07:13.949 MyApp[450:707] Angle: -63.39

2013-04-10 00:07:13.979 MyApp[450:707] Angle: -41.51

2013-04-10 00:07:13.981 MyApp[450:707] Angle: -62.78

2013-04-10 00:07:14.012 MyApp[450:707] Angle: -42.06

2013-04-10 00:07:14.014 MyApp[450:707] Angle: -61.77

2013-04-10 00:07:14.045 MyApp[450:707] Angle: -43.89

2013-04-10 00:07:14.047 MyApp[450:707] Angle: -61.02

2013-04-10 00:07:14.079 MyApp[450:707] Angle: -45.41

2013-04-10 00:07:14.080 MyApp[450:707] Angle: -61.20

2013-04-10 00:07:14.112 MyApp[450:707] Angle: -46.93

2013-04-10 00:07:14.114 MyApp[450:707] Angle: -61.53

2013-04-10 00:07:14.146 MyApp[450:707] Angle: -49.21

2013-04-10 00:07:14.147 MyApp[450:707] Angle: -62.76

2013-04-10 00:07:14.179 MyApp[450:707] Angle: -51.34

2013-04-10 00:07:14.182 MyApp[450:707] Angle: -64.51

2013-04-10 00:07:14.212 MyApp[450:707] Angle: -53.39

2013-04-10 00:07:14.214 MyApp[450:707] Angle: -66.41

2013-04-10 00:07:14.245 MyApp[450:707] Angle: -56.29

2013-04-10 00:07:14.248 MyApp[450:707] Angle: -69.30

2013-04-10 00:07:14.279 MyApp[450:707] Angle: -57.85

2013-04-10 00:07:14.280 MyApp[450:707] Angle: -70.88

2013-04-10 00:07:14.312 MyApp[450:707] Angle: -60.23

测量到的角度是“闪烁”几乎每几毫秒20度。根据我到目前为止所读到的关于CoreMotion的内容，我期待错误，但不是这个范围的错误。

我可能做错了什么--我没有测量正确的东西吗？

编辑:下面的代码-不好意思格式化。“代码”和“区块引号”似乎都不能正常工作。

//我让用户在启动运动更新之前稍微放松一下。 //目前，这是一个天真的空闲计时器的形式，这个计时器是在 //启动应用程序的前9秒(正当原因)

• (void)didFireIdleTimer:(id)theTimer { [mReferenceAttitude release]; mReferenceAttitude = [[[sSharedMotionManager deviceMotion] attitude] retain]; [self stopIdleTimer]; }

//sSharedMotionManager是CMMotionManager //的一个实例，我正在设置一个显示链接回调，其中“当前”deviceMotion //每次检索与当前“态度”之间的差异 //和参照“态度”计算。正是这种不同 //转换为学位并打印//这是显示链接回调，名为延迟。：:)

• (Void)didRefreshScreen：(Id)发件人{ CMAttitude \*thisAttitude = [[sSharedMotionManager deviceMotion] attitude]; [thisAttitude multiplyByInverseOfAttitude:mReferenceAttitude]; NSLog(@"Angle: %0.2f", thisAttitude.roll \* 180 / 3.14159); //Rest of the code //.... }

Answer 1

几个小时的测试证实，出现此问题是因为deviceMotionUpdateInterval没有在CMMotionManager实例上设置。将其设置为1.0/60.0 (或任何其他有效值)将修复此“闪烁”，并导致值的平稳变化。

Answer 2

看看这些值，我注意到，每秒钟的测量序列似乎都是正常的。意思是1，3，5，7，.和2，4，6，8 .都是膨胀稳定的序列。在大多数情况下，这意味着有2个实例正在运行，或者参考态度被切换。

Answer 3

下面是我的代码，以避免在五月应用程序中闪烁：

float xAxis,yAxis, zAxis;
xAxis = self.manager.accelerometerData.acceleration.x;
yAxis = self.manager.accelerometerData.acceleration.y;
zAxis = self.manager.accelerometerData.acceleration.z;

// returns if the phone is lying on the table:
if (zAxis < -0.8 || zAxis > 0.8) return;

CGFloat angle =  atan2f(xAxis, yAxis ); // The angle!!!

float noise = 0.011; // Flicker noise (the noise you want to filter)

// max and min are global variables
if (angle > max){
    max = angle;
    min = max - noise;
}
if (angle < min){
    min = angle;
    max = min + noise;
}

// Average: (no flickering):
angle = min + (max - min) / 2.0;