In
signal processing
Signal processing is an electrical engineering subfield that focuses on analyzing, modifying and synthesizing ''signals'', such as audio signal processing, sound, image processing, images, Scalar potential, potential fields, Seismic tomograph ...
, the high frequency content measure is a simple measure, taken across a signal
spectrum
A spectrum (: spectra or spectrums) is a set of related ideas, objects, or properties whose features overlap such that they blend to form a continuum. The word ''spectrum'' was first used scientifically in optics to describe the rainbow of co ...
(usually a
STFT spectrum), that can be used to characterize the amount of high-frequency content in the signal. The magnitudes of the spectral bins are added together, but multiplying each magnitude by the bin "position" (proportional to the frequency). Thus if ''X''(''k'') is a discrete spectrum with ''N'' unique points, its high frequency content measure is:
:
In contrast to perceptual measures, this is not based on any evidence about its relevance to
human hearing
Hearing, or auditory perception, is the ability to perceive sounds through an organ, such as an ear, by detecting vibrations as periodic changes in the pressure of a surrounding medium. The academic field concerned with hearing is auditory sc ...
. Despite that, it can be useful for some applications, such as
onset detection.
The measure has close similarities to the
spectral centroid The spectral centroid is a measure used in digital signal processing to characterise a spectrum. It indicates where the center of mass
In physics, the center of mass of a distribution of mass in space (sometimes referred to as the barycenter o ...
measure, being essentially the same calculation but without normalization according to overall magnitude.
References
* P. Brossier, J. P. Bello and M. D. Plumbley.
Real-time temporal segmentation of note objects in music signals', in Proceedings of the International Computer Music Conference (ICMC 2004), Miami, Florida, USA, November 1–6, 2004.
* Masri, P. (1996). ''Computer modeling of Sound for Transformation and Synthesis of Musical Signal.'' PhD dissertation, University of Bristol.
Digital signal processing
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