Real-Time Wind Velocity Monitoring Based on Acoustic Tomography

Measurement of indoor air temperature distribution using acoustic travel-time tomography: Optimization of transducers location and sound-ray coverage of the room

“…where ( , ) and ( , ) are the travel-times of the early reflections sound paths corresponding to the th and th paths, respectively. The direct path is used to find the starting point of the received signal at the RIR reflectorgram and it is excluded from (17).…”

“…. If Δ is set to a small value, then smaller number of positions satisfy (17) and for large values it is vice versa. To determine the desired threshold level, it requires to start with a small value (based on the desired time differences between the two sound paths).…”

“…To determine the desired threshold level, it requires to start with a small value (based on the desired time differences between the two sound paths). If no ( , ) satisfies (17), Δ should be increased to the point where at least one position to be found in the set . The (17) aims to separate early reflections as much as possible for having a clear reflectogram.…”

“…If no ( , ) satisfies (17), Δ should be increased to the point where at least one position to be found in the set . The (17) aims to separate early reflections as much as possible for having a clear reflectogram. Otherwise, simultaneous sound paths fit into one analysis time-window for peak detection.…”

“…Subsequently, the spatial distribution of temperature and flow velocity within each voxel can be determined by applying a proper tomographic reconstruction algorithm [9,10,11,12,13]. The reconstruction of the air temperature distribution is a scalar tomographic problem, meaning that the scalar temperature influences the sound velocity independently of the direction of sound propagation [14,15,16,17]. Unlike air temperature, calculation of the air flow must be described as a vector field tomographic problem.…”