Echolocation, also called bio sonar, is the biological sonar used by several kinds of animals Echolocating animals emit calls out to the environment and listen to the echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects. Echolocation is used for navigation and for foraging (or hunting) in various environments. Some blind humans have learned to find their way using clicks produced by a device or by mouth.
Echolocating animals include some mammals and a few birds; most notably microchiropteran bats and odontocetes (toothed whales and dolphins), but also in simpler form in other groups such as shrews, one genus of megachiropteran bats (Rousettus) and two cave dwelling bird groups, the so-called cave swiftlets in the genus Aerodramus (formerly Collocalia) and the unrelated Oilbird Steatornis caripensis.
蜜蜂舞蹈（英語：waggle dance，蜜蜂八字形搖擺舞）為用於表達蜜蜂養殖行為中之蜜蜂特定八字形舞蹈(figure-eight dance)的一個術語。通過進行這個舞蹈，成功覓食者可以與群體的其他成員分享有關產生花蜜和花粉的花，水源，或以新的巢址位置的方向和距離的信息。出自於奧地利生物學家和諾貝爾獎得主卡爾·馮·弗里希在1940年代的研究翻譯其意義，工蜂在採完花蜜回到蜂巢之後，會進行兩種特別的移動方式。研究對象是一種西方蜜蜂、為卡尼鄂拉蜂。當一隻工蜂回到巢中，其他工蜂會面向她，並以她為中心，就像在觀看這隻蜜蜂跳舞一樣。在發現提出之後經過多年的爭議，最後被大多數生物學家接受，並且成為當代生物學教科書中有關動物行為的經典教材。
蜜 蜂跳舞的移動路徑會形成一個8字形。外圍環狀部分稱做回歸區（return phase）；中間直線部分稱做搖臀區（waggle phase），搖臀舞（Waggle dance）因此得名。蜜蜂會一邊搖動臀部一邊走過這條直線，搖臀的持續時間表示食物的距離，搖臀時間愈長，表示食物距離愈遠，以75毫秒代表100公尺。而這段直線與地心引力的方向之夾角，代表食物方向與太陽方向的夾角。之後更發現，蜜蜂會因太陽位置的相對移動而修正直線的角度。
Sonification is the use of non-speech audio to convey information or perceptualize data. Auditory perception has advantages in temporal, spatial, amplitude, and frequency resolution that open possibilities as an alternative or complement to visualization techniques.
For example, the rate of clicking of a Geiger counter conveys the level of radiation in the immediate vicinity of the device.
Though many experiments with data sonification have been explored in forums such as the International Community for Auditory Display (ICAD), sonification faces many challenges to widespread use for presenting and analyzing data. For example, studies show it is difficult, but essential, to provide adequate context for interpreting sonifications of data. Many sonification attempts are coded from scratch due to the lack of a flexible tool for sonification research and data exploration
The Geiger counter, invented in 1908, is one of the earliest and most successful applications of sonification. A Geiger counter has a tube of low-pressure gas; each particle detected produces a pulse of current when it ionizes the gas, producing an audio click. The original version was only capable of detecting alpha particles. In 1928, Geiger and Walther Müller (a PhD student of Geiger) improved the counter so that it could detect more types of ionizing radiation.
In 1913, Dr. Edmund Fournier d’Albe of University of Birmingham invented the optophone, which used selenium photosensors to detect black print and convert it into an audible output. A blind reader could hold a book up to the device and hold an apparatus to the area she wanted to read. The optophone played a set group of notes: g c’ d’ e’ g’ b’ c” e”. Each note corresponded with a position on the optophone’s reading area, and that note was silenced if black ink was sensed. Thus, the missing notes indicated the positions where black ink was on the page and could be used to read.
Pollack and Ficks published the first perceptual experiments on the transmission of information via auditory display in 1954. They experimented with combining sound dimensions such as timing, frequency, loudness, duration, and spacialization and found that they could get subjects to register changes in multiple dimensions at once. These experiments did not get into much more detail than that, since each dimension had only two possible values.
John M. Chambers, Max Mathews, and F.R. Moore at Bell Laboratories did the earliest work on auditory graphing in their “Auditory Data Inspection” technical memorandum in 1974. They augmented a scatterplot using sounds that varied along frequency, spectral content, and amplitude modulation dimensions to use in classification. They did not do any formal assessment of the effectivenes of these experiments.
In the 1980s, pulse oximeters came into widespread use. Pulse oximeters can sonify oxygen concentration of blood by emitting higher pitches for higher concentrations. However, in practice this particular feature of pulse oximeters may not be widely utilized by medical professionals because of the risk of too many audio stimuli in medical environments.
In 1992, the International Community for Auditory Display (ICAD) was founded by Gregory Kramer as a forum for research on auditory display which includes data sonification. ICAD has since become a home for researchers from many different disciplines interested in the use of sound to convey information through its conference and peer-reviewed proceedings.
an extensive open-source Python framework
In this exercise notebook, we will segment, feature extract, and analyze audio files. Goals:
- Detect onsets in an audio signal.
- Segment the audio signal at each onset.
- Compute features for each segment.
- Gain intuition into the features by listening to each segment separately.