Beyond content information, sound carries with itself a significant amount of information regarding its location, and the environment it has traveled through. An acoustic wave traveling from a source has the property of being able to reflect from surfaces, bend around objects, and often returns carrying valuable information. Processing methods can be used to extract characteristic information about the environment acoustic waves have passed through.
This research study aims at using acoustic measurements in order to develop a method for extracting the general characteristics of geometric spaces, including size, shape, volume, and detecting motion inside of this space.

Acoustic reflectometry (APR) is a non-invasive, time-domain method of identifying the geometry of an acoustical space from its impulse response. The impulse response can provide details about the length, cross-sectional area, and scattering junction of each segment of the cavity. The specific details of the cavity can be obtained from the temporal cues, magnitude, and contour of each reflection. Spaces investigated using APR are typically a series of narrow tubes, commonly musical instruments. While the works have been successful in characterizing numerous features, our research involves utilizing APR to characterize particular features in rooms or hallways. If the research achieves its aims, a room or hallway can be defined solely by its impulse response.

Scattering Junction Comparisons

Our early work relied on methodologies similar to previous studies, while obtaining information that would be beneficial while reconstructing larger spaces: the length of each segment, junction type between two segments (known as scattering junctions), and how the cavity is terminated. Later work created a more versatile identification algorithm that incorporated computer-learning methodologies to identify scattering junctions. This advancement will be beneficial as the cavities become more complex.
Currently, we have focused our efforts on characterizing rooms. Preliminary experiments have been successful in calculating the dimensions of these spaces.
Our progress will be detailed at the 124th Audio Engineering Society Convention in Amsterdam and at the 2nd ASA-EAA joint conference in Paris later this year.