VideoMapTimeSeries
ImageMeasurements
FindPeaks

Creative Arts
Image Processing
Video Processing
Signal Processing

Find the Period of the Gait of an Animated Woolly Mammoth

Find the period of the gait of an animated mammoth

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In this example, we will use a video of a wooly mammoth to track its location. The centroid of its mass will be used to estimate the period of the mammoth's gait.

Import the video and acquire important information:

In[1]:=

video=Video["https://cdn.pixabay.com/video/2016/11/15/6426-191723691_large.mp4"]

Out[1]=

In[2]:=

{samplingrate,framecount,duration}=Information[video,{"FrameRate","FrameCount","Duration"}]/.a_Associationa[1]

Out[2]=

{

frames/s

,717,

23.9

}

Binarize the video and extract the intensity centroid of the wooly mammoth:

In[3]:=

ts=VideoMapTimeSeries[ImageMeasurements[Binarize[#Image,.01],"IntensityCentroid"]&,video]

Out[3]=

TimeSeries

Time: 0.0167 to 23.9
Data points: 717



In[4]:=

centroids=ts["Values"];

Plot the position of the centroid of the moving mammoth:

In[5]:=

ListLinePlot[centroids,PlotRange{{0,1920},{240,246}},FrameTrue]

Out[5]=

Compute the peaks of y coordinates of the centroids:

In[6]:=

heights=centroids〚All,2〛;

In[7]:=

peaks=FindPeaksheights,

QuantityMagnitude[samplingrate]

;

Show the centroid heights as well as the detected peaks:

In[8]:=

ListLinePlot[heights,Epilog{Red,Point[peaks]}]

Out[8]=

Compute the mean difference between peaks as a measure of time period:

In[9]:=

Mean[Quantity[Differences[peaks〚All,1〛],"Frames"]/samplingrate]//N

Out[9]=

2.30333

Related Symbols

VideoMapTimeSeries
ImageMeasurements
FindPeaks

Publisher Information

Contributed by: Ali Hashmi