2011-11-16 53 views
23

我是R的新手,喜欢它,但是我对完全缺乏用于分析运动捕捉数据的固体软件包感到惊讶。R软件包用于运动捕捉数据分析和可视化

最简单的动作捕捉文件只是一张巨大的表格,其中每个连接到记录主体的点的“XYZ”坐标以及捕获的每个帧都是如此。我知道我可以在R中找到单独的方法和函数来执行复杂的操作(如主分量分析),也可以绘制所有点的时间序列。但是当我在寻找可以统计地分析人类运动的例子,并提供用于数据视觉表示的漂亮工具箱时,R原来是一片冷漠的沙漠。另一方面,MATLAB有Motion capture toolboxMoCap Toolbox,特别是后者有非常好的绘图和分析捕获的选项。但说实话 - MATLAB有相当难看可视化引擎比较R.

对于R动作捕捉包中的一些具体要求将包括:

  • 阅读,编辑,可视化和转换动作捕捉数据
  • 动能和运动分析
  • 时间序列和主成分分析
  • 动画数据

我在这里错过了什么(在我的谷歌搜索中)还是真的没有mocap包装R?有没有人试图在R中使用动作捕捉数据?你能给我一些指导吗?

+2

您可能没有缺少什么。我的favo(u)礼仪解决方案,库(sos); findFn(“{动作捕捉}”),没有提出任何有用的东西。有文化方面的问题:用R做很酷的东西是可能的,但是如果所有从事运动捕捉的酷酷的孩子都使用MATLAB或者Python,那么这就是事情将要完成的地方。我肯定会看一下,看看Python中已经做了什么,以及将R与Python进行接口以用于任何尚未在R中实现的统计繁重工作... –

+1

您可以使用包“forecast”和“ftsa”主成分分析。 – power

回答

1

通过快速搜索RSeek来判断,R没有可用的动作捕捉包。它看起来像需要为每个函数找到等价物。更一般的应该很容易找到(插值,子集,转换/投影,时间序列分析,pca,矩阵分析等),编写自己的自定义函数用于估计瞬时动能等特定事情的过程可能很可能学习的最佳方式!

您可能会发现plyr有助于将数据敲入形状并使用animation包进行运动可视化。

1

我使用包rgl从动作手势数据集创建动画。虽然它不是专门用于手势数据的包,但您可以使用它。

在下面的例子中,我们在上身有8个点的手势数据:脊柱,肩中心,头部,左肩,左手腕,右肩和右手腕。受试者的双手向下,右臂向上移动。

我将数据集限制为6个时间观察值(如果您愿意的话),因为否则它会变大以在此处发布。

原始数据集中的每一行对应于一次时间观察,并且每个身体点的坐标以4组(每四列为一个身体点)定义。所以在每一条线上,我们都有“x”,“y”,“z”,“br”为脊椎,然后是“x”,“y”,“z”,“br”为肩中心,依此类推。 “br”始终为1,以便分隔每个身体部位的三个坐标(x,y,z)。

原来这里是(限制)数据集:

DATA.time.obs<-rbind(c(-0.06431,0.101546,2.990067,1,-0.091378,0.165703,3.029513,1,-0.090019,0.518603,3.022399,1,-0.042211,0.687271,2.987086,1,-0.231384,0.419869,2.953286,1,-0.299824,0.173991,2.882627,1,0.063367,0.399478,3.136306,1,0.134907,0.176191,3.159998,1), 
       c(-0.067185,0.102249,2.990185,1,-0.095083,0.166589,3.028688,1,-0.093098,0.519146,3.019775,1,-0.043808,0.687041,2.987671,1,-0.234622,0.417481,2.94581,1,-0.300324,0.169313,2.869782,1,0.056816,0.398384,3.135578,1,0.134536,0.180875,3.162843,1), 
       c(-0.069282,0.102964,2.989943,1,-0.098594,0.167465,3.027638,1,-0.097184,0.52169,3.019556,1,-0.046626,0.695406,2.989244,1,-0.23478,0.417057,2.943475,1,-0.300101,0.168628,2.860515,1,0.053793,0.395444,3.143226,1,0.134175,0.182816,3.172053,1), 
       c(-0.070924,0.102948,2.989369,1,-0.101156,0.167554,3.026474,1,-0.100244,0.522901,3.018919,1,-0.049834,0.696996,2.987933,1,-0.235301,0.416329,2.939331,1,-0.301339,0.170203,2.85497,1,0.04762,0.390872,3.142792,1,0.14041,0.186844,3.182172,1), 
       c(-0.071973,0.103372,2.988788,1,-0.103215,0.16776,3.025409,1,-0.102334,0.52281,3.019341,1,-0.051298,0.697003,2.991192,1,-0.235497,0.414859,2.935161,1,-0.297678,0.15788,2.833734,1,0.045973,0.386249,3.147609,1,0.14408,0.1916,3.204443,1), 
       c(-0.073223,0.104598,2.988132,1,-0.106597,0.168971,3.022554,1,-0.106778,0.522688,3.015138,1,-0.051867,0.697781,2.990767,1,-0.236137,0.414773,2.931317,1,-0.297552,0.153462,2.827027,1,0.039316,0.39146,3.166831,1,0.175061,0.214336,3.207459,1)) 

对于每个时间点,我们可以创建一个矩阵,其中的每一行都将是一个体穴,列将坐标:

# Single time point for analysis 
time.point<-1 
# Number of coordinates 
coordinates<-4 
# Number of body points 
body.points<-dim(DATA.time.obs)[2]/coordinates 

# Total time of gesture 
total.time<-dim(DATA.time.obs)[1] 

# Transform data for a single time. observation into a matrix 
DATA.matrix<-matrix(DATA.time.obs[1,],c(body.points,coordinates),byrow = TRUE) 
colnames(DATA.matrix)<-c("x","y","z","br") 
rownames(DATA.matrix)<-c("hip_center","spine","shoulder_center","head", 
         "left_shoulder","left_wrist","right_shoulder", 
         "right_wrist") 

所以,我们必须在每个时间点,像这样的矩阵:

     x  y  z br 
hip_center  -0.064310 0.101546 2.990067 1 
spine   -0.091378 0.165703 3.029513 1 
shoulder_center -0.090019 0.518603 3.022399 1 
head   -0.042211 0.687271 2.987086 1 
left_shoulder -0.231384 0.419869 2.953286 1 
left_wrist  -0.299824 0.173991 2.882627 1 
right_shoulder 0.063367 0.399478 3.136306 1 
right_wrist  0.134907 0.176191 3.159998 1 

而现在摆在我们Ërgl从这个矩阵图中的数据:

#install.packages("rgl") 
library(rgl) 

# INITIAL PLOT 

x<-unlist(DATA.matrix[,1]) 
y<-unlist(DATA.matrix[,2]) 
z<-unlist(DATA.matrix[,3]) 

# OPEN A BLANK 3D PLOT AND SET INITIAL NEUTRAL VIEWPOINT 
open3d() 
rgl.viewpoint(userMatrix=rotationMatrix(0,0,0,0)) 

# SET FIGURE POSITION 
# This is variable. It will depend on your dataset 
# I've found that for this specific dataset a rotation 
# of -0.7*pi on the Y axis works 

# You can also plot and select the best view with 
# your mouse. This selected view will be passed on 
# to the animation. 
U <- par3d("userMatrix") 
par3d(userMatrix = rotate3d(U, -0.7*pi, 0,1,0)) 

# PLOT POINTS 
points3d(x=x,y=y,z=z,size=6,col="blue") 
text3d(x=x,y=y,z=z,texts=1:8,adj=c(-0.1,1.5),cex=0.8) 

# You can also plot each body point name. 
# This might be helpful when you don't know the 
# initial orientation of your plot 

# text3d(x=x,y=y,z=z,texts=rownames(DATA.matrix), 
#  cex=0.6,adj=c(-0.1,1.5)) 

# Based on the plotted figure, connect the line segments 
CONNECTOR<-c(1,2,2,3,3,4,3,5,3,7,5,6,7,8) 
segments3d(x=x[CONNECTOR],y=y[CONNECTOR],z=z[CONNECTOR],col="red") 

然后,我们有这样的:

创建一个动画,我们可以把这一切变成一个函数,并使用lapply

movement.points<-function(DATA,time.point,CONNECTOR,body.points,coordinates){ 

    DATA.time<-DATA[time.point,] 

    DATA.time<-matrix(DATA.time,c(body.points,coordinates),byrow = TRUE) 

    x<-unlist(DATA.time[,1]) 
    y<-unlist(DATA.time[,2]) 
    z<-unlist(DATA.time[,3]) 

    # I used next3d instead of open3d because now I want R to plot 
    # several plots on top of our original, creating the animation 

    next3d(reuse=FALSE) 
    points3d(x=x,y=y,z=z,size=6,col="blue") 
    segments3d(x=c(x,x[CONNECTOR]),y=c(y,y[CONNECTOR]),z=c(z,z[CONNECTOR]),col="red") 
# You can control the "velocity" of the animation by changing the 
# parameter below. Smaller = faster 
    Sys.sleep(0.5) 
} 

我知道这个解决方案并不优雅,但它的工作原理。

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