diff --git a/tex/chapters/filtering.tex b/tex/chapters/filtering.tex index adabfca..5b5ddf3 100644 --- a/tex/chapters/filtering.tex +++ b/tex/chapters/filtering.tex @@ -140,6 +140,7 @@ \subsection{Activity-Detection} + Additionally we perform a simple activity detection for the pedestrian, able to distinguish between standing, walking, walking stairs upwards and downwards. Likewise, this knowledge is evaluated when walking the grid: Edges $\mEdgeAB$ matching the currently detected @@ -159,3 +160,18 @@ + % Activity Recognition + % Naives Bayes als Klassifikator + % Features -> 1: Variance of mean 2: Differenz zwischen Barometer + % Zeitintervall für das die Merkmale berechnet werden + + The transition model includes a simple recognizer of different locomotion modes like normal walking or ascending/descending stairs. The reasoning behind this is to favour paths that correspond with the detected locomotion mode. + + We use a Naives Bayes classifier with two features. For this, the sensor signals are split in sliding windows. Each window has a length of one second and overlaps 500 ms with its prior window. + The first feature is the variance of the accelerometer's magnitude during a window and the second feature is the difference between the last and first barometer measurement of the particular window. + Based on these features the classifier assigns an activity to each sliding window. + + + \todo{Was passiert wenn ein überlappendes Fenster zwei verschiedene Aktivitäten zugewiesen bekommt? Sliding windows evtl. weglassen?} + +