Contactless sensors for recording motion parameters and vital functions
Project area A researches different wave and radio-based sensor technologies for the remote detection of motion parameters of the human body. The targeted new sensor concepts achieve a precision, measuring rate, dynamics and fine-grained resolution in all dimensions (6D pose, 3D body surface and 3D speed with the respective time course of all values) that are at least one order of magnitude better than the current state of the art are.
Coherently phase-sensitive, wave-based sensors such as radar, laser or coherent radio location systems are particularly suitable for measuring both macroscopic and microscopic movement processes remotely with maximum precision, as they are able to evaluate Doppler and micro-Doppler signal phases.
The EmpkinS sensor technologies are selected on the basis that as many different motion parameters as possible can be recorded with the highest possible quality. Since a single sensor cannot optimally record all conceivable parameters equally, complementary sensor technologies are being researched. They cover different types of detection areas (e.g. the entire body shell (sub-project A01) or areas of interest such as the face, neck or arm, leg or chest area (A03, A04). Moreover different orders of magnitude of movement (e.g. movements of the limbs (A02) or micro-fasciculations (A05) e.g. on the face) and / or different areas of application (e.g. measuring vital parameters or the mobility of limbs) are recorded. Depending on the required input variables of the biomechanical neuro- and psychomotor models or depending on the diagnostic question, the different sensor technologies are used individually or in combination.
A01 Multimodal 3D Body Imaging Camera
Sub-project A01 explores a novel, multimodal sensor concept for high-precision, non-contact detection of the envelope of the human body and the velocity vector of each point on this envelope. For this purpose, a micro-doppler aperture synthesis radar is combined with an optical depth camera and the strengths of the sensors are combined. The body envelope and its movements are detected with outstanding precision and at a high measuring rate. With these properties, the system is a central basis for the research programme of the CRC EmpkinS.
A02 Holographic 6D Wireless Locating and Motion Tracking
Subproject A02 is researching a radiolocation technique for high-precision tracking of human poses (3D position and 3D orientation of body parts). A novel, holographic extended Kalman filter makes it possible to evaluate the absolute signal phases of 61 GHz radio nodes, although the radio modules to be localized emit unsynchronized/inconsistent signals. This enables low-effort tracking with sub-millimeter measurement uncertainty and a measurement rate of up to 10 kHz, which opens up completely new possibilities for the detection of highly dynamic human movements.
In this subproject, localizable electromyography (EMG) radio transponders are to be designed and realized in order to be able to record surface EMG data synchronously with highly accurate radio localization in real time for the first time. For this purpose, a 61-GHz transceiver in CMOS technology is being designed, which emits the phase-coherent signal required for the holographic radiolocation method and at the same time must be designed to be extremely energy-saving. In a further step, the transceiver is to be integrated into an EMG sensor platform, which is to be evaluated in test series on subjects, e.g. on the face or legs, to analyze facial expressions or gait.
A04 Microwave Interferometer for Cardiovascular and Respiratory Monitoring
The aim of this sub-project is to research a microwave interferometric sensor that enables empathokinesthetic examinations based on the analysis of micro-movements of the body surface. Specifically, the temporal and morphological course of pulse waves, heart sounds and breathing of clothed persons is to be recorded in high resolution via relative distance measurements. The new circuit and algorithmic approaches will enable the recording of cardiovascular activity during simultaneous large-body movements and significantly improve the quality and thus the significance of the measured values.
A05 Electro-optic Microstructure- and Micromotion-Sensor
A novel approach for an electro-optical sensor is being researched that can image the smallest movements and changes (e.g. perspiration) of the skin surface without contact and with particularly high accuracy (< 100 nm) and frame rate (1 kHz) in a range of 1 cm2 in real time. For this purpose, the state of the art is extended to simultaneous observation of all image points of a 2D image plane using digital signal processing and radar technology. The focus is on validating the sensor principle, first in the laboratory with phantoms, then in medical studies with D02–D05 to prove a diagnostic added value, e.g. to detect stress.