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sift:dynamic_time_warping:dynamic_time_warping [2024/07/12 13:58] – created sgrangersift:dynamic_time_warping:dynamic_time_warping [2024/11/15 20:13] (current) – [Dynamic Time Warping] wikisysop
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-====== Dynamic_Time_Warping ======+====== Dynamic Time Warping ======
  
-Dynamic Time warping is a distance based algorithm that allows you to compare and measure similarity between two time based sequences, by minimizing the Euclidean distance between points. Essentially, it aligns each point of one trace to a corresponding point on the other trace that require the least distance. All distances are added together to make the total cost function of the trace. The large the cost function, the less similar the two traces are. This can be useful when trying to identify a singular trace or to find outliers. To review supporting literature, see [[[https://ieeexplore.ieee.org/document/7023364%7Chere|[1]]]]. +Dynamic Time warping is a distance based algorithm that allows you to compare and measure similarity between two time based sequences, by minimizing the Euclidean distance between points. Essentially, it aligns each point of one trace to a corresponding point on the other trace that require the least distance. All distances are added together to make the total cost function of the trace. The larger the cost function, the less similar the two traces are. This can be useful when trying to identify a singular trace or to find outliers. To review supporting literature, see [[https://ieeexplore.ieee.org/document/7023364|[1]]].
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-{{DTWAlign.png}} +
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-==== Contents ==== +
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-  * [[#Mathematics_of_Dynamic_Time_Warping|1 Mathematics of Dynamic Time Warping]] +
-  * [[#Computing_Dynamic_Time_Warping_in_Sift|2 Computing Dynamic Time Warping in Sift]] +
-    * [[#Exporting_Results|2.1 Exporting Results]] +
-  * [[#References|3 References]]+
  
 +{{:DTWAlign.png}}
  
 ==== Mathematics of Dynamic Time Warping ==== ==== Mathematics of Dynamic Time Warping ====
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 Say you had a trace x of size N, and a trace y of size M, this is how you would calculate the cost matrix: Say you had a trace x of size N, and a trace y of size M, this is how you would calculate the cost matrix:
  
-{{DTWeq.png}}+{{:DTWeq.png}}
  
 where d() is equal to the absolute distance. where d() is equal to the absolute distance.
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 In this example we have used Dynamic Time Warping to find anomalies within all workspaces of AnkleAngleX. The results have given us a list of the traces identified as anomalies and their corresponding cost function. If we have the group plotted, these traces will also be selected. After a quick visual check we can press the **Exclude Anomalies** button and they will be exclude from the group. In this example we have used Dynamic Time Warping to find anomalies within all workspaces of AnkleAngleX. The results have given us a list of the traces identified as anomalies and their corresponding cost function. If we have the group plotted, these traces will also be selected. After a quick visual check we can press the **Exclude Anomalies** button and they will be exclude from the group.
  
-{{DTWAnomalies.png}}+{{:DTWAnomalies.png}}
  
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 In this example we found that the trace - AnkleAngleX/Sub02Workspace/TM_LKrunT2_2.c3d/LAnkleAngle/frames_439,546 is most similar to AnkleAngleX/Sub01Workspace/OG_LA_run02.c3d/frames_454,578. In this example we found that the trace - AnkleAngleX/Sub02Workspace/TM_LKrunT2_2.c3d/LAnkleAngle/frames_439,546 is most similar to AnkleAngleX/Sub01Workspace/OG_LA_run02.c3d/frames_454,578.
  
-{{DTWTrace.png}}+{{:DTWTrace.png}}
  
 === Exporting Results === === Exporting Results ===
  
-Results for each dynamic time warping test can be exported in the {{sift_export_results.png}} [[Sift:Export:Export_Results_Dialog|Export Results Dialog]].+Results for each dynamic time warping test can be exported in the {{:sift_export_results.png}} [[Sift:Export:Export_Results_Dialog|Export Results Dialog]].
  
 ==== References ==== ==== References ====
sift/dynamic_time_warping/dynamic_time_warping.1720792720.txt.gz · Last modified: 2024/07/12 13:58 by sgranger