Fall-Detection Algorithm Using 3-Axis Acceleration: Combination with Simple Threshold and Hidden Markov Model

Algorithm 2

HMM algorithm for fall detection.

(1) Calculate all the values in model matricesmatrices   = ()* of all single parameters for activities of four types of

  ADL and three types of fall by the Baum-Welch learning algorithm [29]

(2) Calculate all the likelihoods of all single parameters for observation sequences using the evaluation algorithm [29]

(3) Find a maximum probability among four types of ADL and three types of fall

(4)  If the activity with the maximum probability is among three types of fall  then fall detection

(5) Else no fall (ADL) detection

, and   denote the state transition probability distribution, observation emission probability distribution, and initial

state distribution for activities, respectively.