Towards muscle sensing by a non-contact optical systemusing photogrammetry

Abstract :

The measurement and analysis of muscle activity has enormous significance for patients suffering fromstroke or other neurological disease who run through rehabilitation. Although the control of assistanceand rehabilitation systems like prostheses and exoskeletons depends on it. This is made possibleprimarily by body-worn measurement systems such as the electromyogram, which provides a preciseoutput of the electrical activity of the measured muscle units. The problem with established systems isthat the patient is impaired by the bulky, often wired systems.Based on the assumption that muscle activity causes skin deformations, a non-contact camera-basedmethod is developed that can capture multiple images of the skin surface of a preferred body part. Byusing a photogrammetry tool and computing a 3D model of the body part, time-varying deformationscan be represented that can be attributed to muscle activity. To do this, a 3D printer and tripod wereused to create a camera mount that can vary in height and also change orientation. For the camerasystem itself, the Raspberry Pi Camera Module 3 Wide with an image resolution of 12 megapixels wasselected according to specially defined evaluation criteria.The first images showed promising results in terms of simultaneous recording and transmission ofimages to a central computer.The next step is to finalize the measurement system. Afterwards, the photogrammetric part can start toenable the measurement of muscle activity. In the future, this stand-alone system will serve as groundtruth for a contactless THz-based system to be developed in the terahertz.NRW initiative. Theenvisioned THz-based approach for muscle sensing will enable reflectance measurements with a THzbeam directly on the skin surface....

Links:

https://www.degruyter.com/document/doi/10.1515/bmte-2023-2001/html