Sensory data fusion of pressure mattress and wireless inertial magnetic measurement units.

Head movement of infants is an important parameter for analysing infant motor patterns. Despite its importance, this field has received little sensory-based research in the past years. Therefore, we present a sensory-supported data fusion model for head movement analysis of infants in supine position. The sensory system comprises a pressure mattress and two wireless inertial magnetic measurement units, rendering precise, objective and non-intrusive information on pressure distribution and 3D trunk orientation, respectively. Algorithms first perform pressure data pre-processing and calculate image moments to acquire 2D trunk orientation. Afterwards, unscented Kalman filter is used for sensory data fusion. After additional data processing, head and trunk coordinates are calculated along with head displacement distance. The sensory system was tested on experimental measurements, performed in eight normally developing infants aged from 1 to 5 months. Results of several algorithm combinations were compared to referential video recordings in terms of head lifts. Combination of algorithms, incorporating head tracking and sensory data fusion provides completely accurate results in comparison to normative data. Statistical data analysis and referential optoelectronic measurements were performed to evaluate accuracy of the sensory fusion model. Suitability of the proposed sensory system for head movement analysis of infants in supine position was verified.