BACKGROUND Videographic material of animals can contain inapparent signals, such as color changes or motion that hold information about physiological functions, such as heart and respiration rate, pulse wave velocity, and vocalization. Eulerian video magnification allows the enhancement of such signals to enable their detection. The purpose of this study is to demonstrate how signals relevant to experimental physiology can be extracted from non-contact videographic material of animals. RESULTS We applied Eulerian video magnification to detect physiological signals in a range of experimental models and in captive and free ranging wildlife. Neotenic Mexican axolotls were studied to demonstrate the extraction of heart rate signal of non-embryonic animals from dedicated videographic material. Heart rate could be acquired both in single and multiple animal setups of leucistic and normally colored animals under different physiological conditions (resting, exercised, or anesthetized) using a wide range of video qualities. Pulse wave velocity could also be measured in the low blood pressure system of the axolotl as well as in the high-pressure system of the human being. Heart rate extraction was also possible from videos of conscious, unconstrained zebrafish and from non-dedicated videographic material of sand lizard and giraffe. This technique also allowed for heart rate detection in embryonic chickens in ovo through the eggshell and in embryonic mice in utero and could be used as a gating signal to acquire two-phase volumetric micro-CT data of the beating embryonic chicken heart. Additionally, Eulerian video magnification was used to demonstrate how vocalization-induced vibrations can be detected in infrasound-producing Asian elephants. CONCLUSIONS Eulerian video magnification provides a technique to extract inapparent temporal signals from videographic material of animals. This can be applied in experimental and comparative physiology where contact-based recordings (e.g., heart rate) cannot be acquired.

中文翻译：

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通过欧拉视频放大倍数提取实验生物学中的生理信息。

背景技术动物的视频照相材料可以包含不透明的信号，例如颜色变化或运动，该不透明的信号保持关于生理功能的信息，例如心脏和呼吸频率，脉搏波速度和发声。欧拉视频放大功能可以增强此类信号，以便对其进行检测。这项研究的目的是演示如何从动物的非接触式影像材料中提取与实验生理相关的信号。结果我们将欧拉视频放大倍数用于检测各种实验模型以及圈养和自由放养野生动物中的生理信号。研究了墨西哥新血管瘤，以证明从专用的录像材料中提取了非胚胎动物的心率信号。使用广泛的视频质量，可以在不同的生理条件（休息，锻炼或麻醉）下，在单腿和多头白血病和正常着色动物的单人或多人动物环境中获得心率。脉搏波速度还可以在in的低血压系统以及人的高压系统中测量。还可以从有意识的，不受约束的斑马鱼的录像带中以及从蜥蜴和长颈鹿的非专用录像材料中提取心率。该技术还可以通过卵壳检测卵内卵内的雏鸡和子宫内的胚胎小鼠的心率，并且可以用作门控信号来获取跳动的鸡胚心脏的两相体积微CT数据。此外，欧拉视频放大倍数用于演示如何在产生次声的亚洲大象中检测到发声引起的振动。结论欧拉视频放大技术提供了一种从动物的视频材料中提取不明显的时间信号的技术。这可以应用于无法获得基于接触的记录（例如心率）的实验和比较生理学。