High-Resolution Ultrasound Sensing for Robotics Using Dense Microphone Arrays

Abstract

State-of-the-art autonomous vehicles use all kinds of sensors based on light, such as a camera or LIDAR (Laser Imaging Detection And Ranging). These sensors tend to fail when exposed to airborne particles. Ultrasonic sensors have the ability to work in these environments since they have longer wavelengths and are based on acoustics, making them able to pass through the mentioned distortions. However, they have a lower angular resolution compared to their optical counterparts. In this paper a 3D in-air sonar sensor is simulated, consisting of a Uniform Rectangular Array similar to the newly developed micro Real Time Imaging Sonar (µRTIS) by CoSys-Lab. Different direction of arrival techniques will be compared for an 8 by 8 uniform rectangular microphone array in a simulation environment to investigate the influence of different parameters in a completely controlled environment. We will investigate the influence of the signal-to-noise ratio and number of snapshots to the angular and spatial resolution in the direction parallel and perpendicular to the direction of the emitted signal, respectively called the angular and range resolution. We will compare these results with real-life imaging results of the µRTIS. The results presented in this paper show that, despite the fact that in-air sonar applications are limited to only one snapshot, more advanced algorithms than Delay-And-Sum beamforming are viable options, which is confirmed with the real-life data captured by the µRTIS. INDEX TERMS Acoustic signal processing, array signal processing, beamforming, microphone arrays, sonar.

HiRIS: An Airborne Sonar Sensor With a 1024 Channel Microphone Array for In-Air Acoustic Imaging

“…For the spatial filtering, we apply a function on X(f, t), depending on the kind of beamforming we want to achieve. We limit the scope of this paper to Minimum Variance Distortionless Response beamforming (MVDR) [6], [17], [28].…”

“…In order for the readers to accurately follow the developments, we encourage them to get familiar with our previous work in which we describe in detail the development of a single 32-channel microphone array [3], [6], as the sensor in this paper consists of a distributed version of that single 32-channel module. However, this paper still stands on its own, allowing the reader to follow the development of the data-acquisition methods and signal processing techniques and understand the performance analysis of the system where we compare it with our previously developed 32-channel microphone array [3], [6].…”

Proximity Perception in Human-Centered Robotics: A Survey on Sensing Systems and Applications

“…An example of a combination with capacitive sensors to overcome detection limitations at short distances is provided in [101]. The group of Prof. Steckel at University Antwerp has a strong focus on 3D A-US for robotic applications, e. g. [102], [103]. The group has achieved remarkable results in areas such as SLAM for the navigation of mobile platforms.…”

Development of an Accurate and Robust Air-Coupled Ultrasonic Time-of-Flight Measurement Technique

“…Ultrasonic time-of-flight (ToF) measurements are a common technique in many research and industrial fields, spanning from ranging applications [ 1 , 2 , 3 , 4 ] to human-computer interaction [ 5 , 6 ] to non-destructive testing (NDT) of materials [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. The basic concept of ultrasonic ToF measurements is that a signal is transmitted from an ultrasonic transducer and received at a later time by the same or a different transducer.…”