Exploring Crossmodal Interaction of Tactile and Visual Cues on Temperature Perception in Virtual Reality: a Preliminary Study

Thanks to the digital revolution, virtual reality (VR) has getting popularity due to its capacity to immerse users into virtual environments (VEs). VEs are typically limited to visual and auditory cues; however, recent results show that multiple sensory modalities increase the user’s immersion. In this study, an experimental protocol is proposed to recreate multiple tactile, in particular thermal, sensations in VR. The aim is twofold: (1) studying the performance of different devices for creating warm and cold sensations with regards to their efficiency and acoustic disturbance; and (2) investigating the interdependency between visual and tactile stimuli in the perception of temperature. 14 participants performed two experimental studies. Our results show no acoustic disturbance of the materials used. Spot projector is more efficient than fan heater to create a warm sensation; fan + water spray is more efficient than fan alone to create cold sensation. Moreover, no significant contribution of visual cue on the thermal perception was found except for the extremely cold simulation (snow visualization and thermal stimulation performed with fan + water spray).

A Minimal Metric for the Characterization of Acoustic Noise Emitted by Underwater Vehicles

Underwater robots emit sound during operations which can deteriorate the quality of acoustic data recorded by on-board sensors or disturb marine fauna during in vivo observations. Notwithstanding this, there have only been a few attempts at characterizing the acoustic emissions of underwater robots in the literature, and the datasheets of commercially available devices do not report information on this topic. This work has a twofold goal. First, we identified a setup consisting of a camera directly mounted on the robot structure to acquire the acoustic data and two indicators (i.e., spectral roll-off point and noise introduced to the environment) to provide a simple and intuitive characterization of the acoustic emissions of underwater robots carrying out specific maneuvers in specific environments. Second, we performed the proposed analysis on three underwater robots belonging to the classes of remotely operated vehicles and underwater legged robots. Our results showed how the legged device produced a clearly different signature compared to remotely operated vehicles which can be an advantage in operations that require low acoustic disturbance. Finally, we argue that the proposed indicators, obtained through a standardized procedure, may be a useful addition to datasheets of existing underwater robots.

Applying Fiber Bragg Grating for Acoustic Sensor

In this work, we interested to utilize Fiber Bragg Grating (FBG) for monitoring sound intensity level. Acoustic disturbance could induce strain and changing the refractive index of FBG. Therefore, light will interfere for the trough of transmission at one specific wavelength satisfied Bragg’s condition. In our demonstrations, FBG sensor was perturbed with sound intensity levels of 60, 80 and 100 dB , the measuring Bragg wavelength were recorded at 1552 nm, 1553 nm and 1555 nm, respectively. It was found that the Bragg wavelength shift has a quite linear variation with sound intensity level. In addition, the sensitivity for sensor was 0.0566 nm/dB. The obtained results are promising for developing acoustic and vibration sensors.