Publisher: PREMO S.A. Authors: Ezequiel Navarro, Antonio Rojas, Claudio Cabeza, Lucía Vera, Juan Esteo, Marcos Martínez, Premo Tech Team. English revision: Rob Pagones and Sergio Lorenzi Agustín. Design and layout: María de Andrés Arranz. Print: Altagrafics Inversiones Gatellco 3 Sl / Avenida de la Aurora 28, 29002 Málaga PUBLISHING HOUSE First edition All rights reversed Málaga, Spain, March 2019 PREMO S.A. Severo Ochoa 47 Parque Tecnológico de Andalucía 29590 Campanillas - Málaga - Spain [email protected] www.grupopremo.com 3dcoil.grupopremo.com +34 951

VR/EM MOTION TRACKING SENSORS & APPLICATIONS Innovative Magnetics have a significant role in sensing and tracking position and motion in immersive Virtual and Augmented Reality systems. Premo is committed to contribute with World Class Innovative components to the Key Enabling Technologies of the 4th Industrial Generation. 4 patents have been filed for VR Tracking sensors in less than 6 months. With this book we start a series of publications on our contribution to a coming better world from our experience, vision and value proposition. This is a recognition and tribute to our team of Innovators...

TRACKING SYSTEMS IN VIRTUAL REALITY: WHICH IS THE BEST CHOICE? VR EM MOTION TRACKING SENSORS & APPLICATIONS II VR EM MOTION TRACKING SENSORS & APPLICATIONS II

01 Tracking Systems in Virtual Reality: which is the best choice? Motion tracking has been present in our lives since the 1970s, when they were used for the first time as a photogrammetric analysis tool in researches related to biomechanics. Some examples of these first systems were developed by the Weber brothers [1] in 1936, who established a model for quantitative studies of human locomotion, Marey in 1873 and Muybridge in 1878, who used photographic techniques to quantify patterns of human movement. In the 1980s, there was a relevant research activity around motion tracking in other fields...

Which devices do we know so far? The following next shows a possible classification of Motion Tracking Systems [4]. OPTICAL SYSTEMS PASSIVE MARKERS ACTIVE MARKERS For a correct operation, at least two cameras must capture the marker at the same time; otherwise, the marker could not be tracked, most of the times due to some occlusion problems. As the markers are all the same, there is no difference between them, so the device provides a set of unlabeled points in a three-dimensional workspace. A post-processing task is required to identify, classify and provide a meaning to those 3D points in...

2. Optical systems with active markers 3. Markerless optical systems These optical systems resemble the previous ones, but the markers are called active markers because they act as a light source instead of being only a reflector. These markers are usually infrared emitting diodes (IREDs). The light emitted by the markers is multiplexed so that the camera speed frequency is divided by the number of sensors that the system need to detect. In these case, the system has a limited measurement frequency, but needs less post-processing time because it is possible to identify each individual marker....

Faraday’s Law states than when a receiver sensor moves inside an alternating (AC) magnetic field B (r,T), a voltage proportional to the vector or cross product of the cross sectional winding area and the intensity of the magnetic field, is induced in every winding and generates N times the total voltage across the coils (being N the number of turns of the winding). This induced voltage immediately gives the measurement of rotation (ɵ)vs the reference emitter coils and the position (as the modulus of the resulting vector) in relation with the modulus of the emitting vector (r). From the information...

For a tracking system, an emitter antenna as base station is required to measure the distance between the object and the base by placing a tracking sensor in each object. Image from www.grupopremo.com This approach offers advantages thanks to its flexibility to locate the sensor because there are no occlusion issues, and the portability of the system depends only on the transmitter. Conversely, the area is limited to a small region around the transmitter (base station) and the location could be distorted if there are metallic objects in the surrounding space. Mechanical systems were among the...

Which is the best choice? The following table provides an overview of tracking systems, their advantages and disadvantages. Tracking System Characteristics Advantages Disadvantages Optical Passive Markers Use of cameras and reflective markers. - Precision <lmm - Wireless - Less burden - Position only - Limited measurement space - Occlusions - Post-processing latency As we can see in this post, there are many types of tracking systems and devices used to track and follow the position of an object. There is not a perfect solution and the best choice depends on the application. According to the...

References and links >>[1] Weber W, Weber E: Mechanik der menschlichen Gehwerkzeuge. Göttingen: Dieterich 1836. >>[2] Muybridge E: Animal locomotion. Philadelphia: J.B. Lippincott Company; 1887 >>[3] Marey E: Animal Mechanism: A Treatise on Terrestrial and Aerial Locomotion. London: Henry S. King & Co.; 1874. >>[4] M. Field D. Stirling F. Naghdy Z. Pan “Motion capture in robotics review” IEEE International Conference on Control and Automation (ICCA), pp. 1697-1702 Dec. 2009 >>[5] Roetenberg. Towards a Real-Time Bayesian Imitation System for a Humanoid Robot. 2007 IEEE International Conference...

USING MAGNETIC SENSING FOR TRACKING MULTIPLE FINGERTIPS 20 VR EM MOTION TRACKING SENSORS & APPLICATIONS II VR EM MOTION TRACKING SENSORS & APPLICATIONS II

COMPUTER VISION TECHNIQUES This technology is related to the use of cameras and image analysis for tracking the user’s hand and finger movements inside the application. In this case, the most common solutions use Infrared (IR) cameras to capture and recognize different hands gestures. Also there are some other alternatives, all of them based on computer vision using different kinds of cameras: Using Magnetic Sensing or Tracking Multiple Fingertips Due to rapid advances in Virtual Reality (VR) and Augmented Reality (AR) and the resurgence of head-mounted displays to enhance the AR/VR experience,...