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TopIn the last few years, various approaches have been put forward by many researches to improve fall detection solutions. Fall detection methods are subdivided into two classes: computer vision-based methods and non-computer vision method.
In this section, we will review some works proposed for fall detection starting by non-vision category. Many sensors have been exploited. In the work of (Cheng et al., 2013) the authors have attached two accelerometers to chest and thigh of 10 persons. Decision tree was applied to recognize posture transitions with threshold to detect falls. The main disadvantage of this method is to wear the sensor.
Another work was proposed in (Sannino et al. 2015) where a wearable accelerometer and a mobile device were used to monitor the patients in real time, the data recorded by the accelerometer is sent to the mobile device to analyze them. This approach has three phases. First, gather data and make a set of simulated falls with the corresponding class “fall” or “non-fall”. Second, knowledge extraction as a set of IF-THEN rules and the last phase consists in patients monitoring in the decisional layer in real time but this approach still preliminary, the tests were done for just three people.
In the work of (Alwan et al., 2006), a special piezoelectric sensor coupled to the floor is used, a binary fall signal can be generated in case of fall, and however, the main drawbacks can be false alarms.
In (Yazar et al., 2014) fall was detected based on three sensors consisting of a vibration sensor and two PIR sensors. The vibrations were converted into electrical signals and then Feature vectors from the vibration waveforms are extracted using the complex wavelet transform (CWT) and they are classified using support vector machine (SVM). PIR sensors were used as additional sensors to detect the infrared radiation emitted by moving objects in the room and that to eliminate falls alarms generated when the vibration sensor signal energy is concentrated in low-frequency bands such as vibration from door slams and other similar events.
In recent work in (Jokanovic et al., 2016) a new method was proposed based on radar technologies to detect falls, the authors proposed to use time-frequency (TF) which is able to reveal higher order velocity for different part of human body and based on deep learning which learns and captures the properties of the TF signatures without human intervention then it is fed to a classifier achieving 87% success rate.