31-07-2012, 01:25 PM
Application feasibility of accelerometer based gait analysis in clinical orthopaedics
Accelerometer in monitoring sleep apnea.pptx (Size: 101.87 KB / Downloads: 56)
Gesture Recognition
A strategy to measure arm movements using accelerometers for the computer recognition of arm gestures. Gesture recognition is being investigated as an alternative method of computer input for people with severe speech and motor impairment; the emphasis is on the needs of people with athetoid cerebral palsy who have difficulties with existing computer input devices. An initial model-based approach to estimate the kinematic motion of the arm from acceleration measurements is given, followed by the chosen measurement scheme. The current system considers the forearm as a rigid body and uses two data streams derived from four linear accelerometers. By treating these signals as outputs from postulated mechanical models, the data are reduced to two series of step inputs that are appropriate for pattern classification and recognition. Although this does not in any way model the arm, the concepts used are based on the type of driving signals expected in the control of arm gestures. Initial experimental results show that the information content of gestures is preserved by this data parameterization.
Accelerometer in monitoring sleep apnea
This paper presents a body-fixed-sensor-based approach to assess potential sleep apnea patients. A trial involving 15 patients at a sleep unit was undertaken. Vibration sounds were acquired from an accelerometer sensor fixed with a noninvasive mounting on the suprasternal notch of subjects resting in supine position. Respiratory, cardiac, and snoring components were extracted by means of digital signal processing techniques. Mainly, the following biomedical parameters used in new sleep apnea diagnosis strategies were calculated: heart rate, heart rate variability, sympathetic and parasympathetic activity, respiratory rate, snoring rate, pitch associated with snores, and airflow indirect quantification. These parameters were compared to those obtained by means of polysomnography and an accurate microphone. Results demonstrated the feasibility of implementing an accelerometry-based portable device as a simple and cost-effective solution for contributing to the screening of sleep apnea-hypopnea syndrome and other breathing disorders
Other applications of accelerometer
Inertial navigation system An Inertial Navigation System (INS) is a navigation aid that uses a computer and motion sensors (accelerometers) to continuously calculate via dead reckoning the position, orientation, and velocity (direction and speed of movement) of a moving object without the need for external references..
Accelerometers are also being used in Intelligent Compaction rollers. Accelerometers are used
alongside gyroscopes in inertial guidance systems.
One of the most common uses for MEMS accelerometers is in airbag deployment systems for modern automobiles. In this case the accelerometers are used to detect the rapid negative acceleration of the vehicle to determine when a collision has occurred and the severity of the collision. Another common automotive use is in electronic stability control systems, which use a lateral accelerometer to measure cornering forces. The widespread use of accelerometers in the automotive industry has pushed their cost down dramatically. Another automotive application is the monitoring of noise, vibration and harshness (NVH), conditions that cause discomfort for drivers and passengers and may also be indicators of mechanical faults.
Modern electronic accelerometers are used in remote sensing devices intended for the monitoring of active volcanoes to detect the motion of magma.
Automatic Collision Notification (ACN) systems also use accelerometers in a system to call for help in event of a vehicle crash.