Spectrogram: Difference between revisions

Revision as of 22:58, 12 February 2023

Revision as of 01:54, 15 February 2023

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[[Image:Scaleogram.png|thumb|250px|Scaleograms from the [[discrete wavelet transform|DWT]] and [[continuous wavelet transform|CWT]] for an audio sample]]

A spectrogram is usually depicted as a [[heat map]], i.e., as an image with the intensity shown by varying the [[colour]] or [[brightness]].

A spectrogram is usually depicted as a [[heat map]], i.e., as an image with the intensity shown by varying the [[colour]] or [[brightness]]. However, there are spectrograms in which multiple information are displayed as different colors, i.e., the phase information are represented as hue in addition to magnitude represented as luminescence of the [[HSL and HSV|HSL/HSV]] image,<ref>{{cite journal |last1=Wedekind |first1=Stephen |last2=Fraundorf |first2=P. |title=Log Complex Color for Visual Pattern Recognition of Total Sound |journal=Audio Engineering Society Convention |date=23 July 2019 |doi=10.48550/arXiv.1907.09936 |url=https://arxiv.org/pdf/1907.09936 |access-date=12 February 2023}}</ref> or the different colors for each channels are superimposed into a single spectrogram image.<ref>{{cite web |title=FFmpeg Filters Documentation |url=https://ffmpeg.org/ffmpeg-filters.html#showcqt |website=ffmpeg.org |access-date=12 February 2023}}</ref>

==Format==

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|File:PAL-I.png|Spectrum above and waterfall (Spectrogram) below of an 8MHz wide [[PAL]]-I Television signal.

|File:Parus major sonagram.jpg|Spectrogram of [[media:Parus major 15mars2011.ogg|great tit song]].

|File:GW170817 Gravitational Wave Chirp Spectrogram.jpg|alt8=|[[Constant-Q transform|Constant-Q]] spectrogramSpectrogram of a gravitational wave ([[GW170817]]).

|File:Waterfall_plot_of_a_whistle.png|alt9=|Spectrogram and waterfalls of 3 whistled notes.

|File:Mount Rainier soundscape.jpg|Spectrogram of the [[soundscape ecology]] of [[Mount Rainier National Park]], with the sounds of different creatures and aircraft highlighted

|File:SonogramVisibleSpeech.png|Spectrogram (generated with the freeware [https://github.com/Christoph-Lauer/Sonogram Sonogram visible Speech]).

|File:CQT-piano-chord.png|[[Variable-Q transform]] spectrogram of a piano chord (generated using [[FFmpeg]]'s showcqt filter).

}}[[File:Sound spectrography of infrasound recording 30301.webm|thumb|Sound spectrography of infrasound recording 30301]]