Article

A waveform is the shape of a signal as it varies with time, distance, phase, or another independent variable. It may represent sound pressure, voltage, current, light intensity, displacement, or any other changing quantity.

Common periodic waveforms include sine, square, triangle, sawtooth, and pulse waves. Each has a characteristic harmonic spectrum and time-domain shape.

A waveform is described using properties such as amplitude, frequency, period, wavelength, phase, duty cycle, rise time, and offset. Complex waveforms can often be represented as combinations of simpler sinusoidal components using Fourier analysis.

Waveforms are central to acoustics, electronics, communications, seismology, music, imaging, control systems, and computer graphics. Oscilloscopes and digital signal-processing tools are commonly used to display and analyse them.

Source details and credits

• Source / publisher: Wikipedia
• URL type: WWW
• Credits: Wikipedia
• URL: https://en.wikipedia.org/wiki/Waveform

Article

White noise is a random signal whose power is distributed equally across frequency when measured over equal-width frequency bands. The name is analogous to white light, which contains a broad mixture of visible frequencies.

An ideal white-noise process has no preferred frequency and successive values are uncorrelated. In practice, real systems can produce only band-limited approximations because unlimited frequency range and power are physically impossible.

White noise is used to test audio equipment, communication systems, filters, control systems, and statistical methods. It can also mask other sounds and is sometimes used in sleep, privacy, and tinnitus-management applications.

Other noise colours describe different spectral shapes. Pink noise has equal power per octave, brown noise emphasises lower frequencies more strongly, and blue or violet noise emphasises higher frequencies.

Source details and credits

• Source / publisher: Wikipedia
• URL type: WWW
• Credits: Wikipedia
• URL: https://en.wikipedia.org/wiki/White_noise

Article

The visible spectrum is the portion of the electromagnetic spectrum that can be detected by the human eye. It is commonly taken to extend from wavelengths of about 380 nanometres at the violet end to about 750 nanometres at the red end.

When white light is dispersed by a prism or diffraction grating, it separates into a continuous range of spectral colours. The familiar sequence is violet, blue, cyan, green, yellow, orange, and red, although the boundaries are gradual rather than sharply defined.

Human vision is most sensitive near the green-yellow part of the spectrum under bright conditions. Sensitivity changes at low light levels, and the exact limits of visible perception vary among individuals and with intensity.

The visible range is important because Earth's atmosphere transmits much of it and sunlight contains substantial energy within it. Visible-spectrum analysis is used in vision, photography, astronomy, spectroscopy, lighting, displays, and remote sensing.

Source details and credits

• Source / publisher: Wikipedia
• URL type: WWW
• Credits: Wikipedia
• URL: https://en.wikipedia.org/wiki/Visible_spectrum

Article

Hue is an attribute of visual perception associated with categories such as red, yellow, green, blue, and violet. It distinguishes one basic colour family from another independently of variations in brightness or saturation.

Hue is often represented as an angle around a colour wheel. Colours with nearby angles appear similar, while those on opposite sides are commonly described as complementary.

A single spectral wavelength may produce a particular hue, but many hues can also result from mixtures of wavelengths. Purple and magenta, for example, do not correspond to a single wavelength in the visible spectrum.

Hue is used in colour models for art, printing, photography, video, computer graphics, and image processing. Its numerical representation depends on the colour space, illumination, and assumptions about human visual perception.

Source details and credits

• Source / publisher: Wikipedia
• URL type: WWW
• Credits: Wikipedia
• URL: https://en.wikipedia.org/wiki/Hue

Article

Colour is the visual perception produced when light stimulates the cone cells of the eye and is interpreted by the brain. Perceived colour depends on the spectrum of the light, the properties of the viewed object, surrounding illumination, and the observer's visual system.

Visible light contains wavelengths that humans commonly perceive from violet through blue, green, yellow, orange, and red. However, colour is not determined by wavelength alone because many different spectral mixtures can produce the same perceived colour.

Colour can be described using attributes such as hue, saturation, brightness, lightness, and chroma. Additive colour systems combine light, commonly using red, green, and blue, while subtractive systems combine pigments or filters, commonly using cyan, magenta, yellow, and black.

Colour science is used in imaging, displays, printing, lighting, art, design, astronomy, medicine, remote sensing, and computer graphics. Accurate colour reproduction requires models of human vision, illumination, materials, and device calibration.

Source details and credits

• Source / publisher: Wikipedia
• URL type: WWW
• Credits: Wikipedia
• URL: https://en.wikipedia.org/wiki/Color

Article

A black body is an idealised physical object that absorbs all electromagnetic radiation incident upon it, regardless of frequency or angle. Because it reflects and transmits none of the incoming radiation, it is considered a perfect absorber.

A black body also emits thermal radiation with a spectrum determined only by its temperature. As the temperature rises, the total emitted energy increases and the peak of the spectrum moves towards shorter wavelengths.

The spectral distribution is described by Planck's law, while the total radiated power follows the Stefan–Boltzmann law and the peak wavelength follows Wien's displacement law. These relationships were central to the development of quantum theory.

Real objects approximate black-body behaviour to varying degrees. Stars, furnaces, heated cavities, planets, and laboratory sources are often analysed using black-body models to estimate temperature and radiation output.

Source details and credits

• Source / publisher: Wikipedia
• URL type: WWW
• Credits: Wikipedia
• URL: https://en.wikipedia.org/wiki/Black_body

First published: 2004

Brief summary

CRI page using images and animations to represent wave structures of matter.

Article

The work of Gabriel La Freniere

Please note that these are actually 2-dimensional representations of the real 3-dimensional wave structures in nature.

The sum of inward and outward concentric waves makes a standing wave.

When the centre is moving, then the inward and outward waves are displaced in opposite directions.

Additional summary

The page is image-heavy and is relevant to animation, rendering and visual explanation of waves and standing-wave structures.

Source details and credits

• Source / publisher: Cycles Research Institute
• Source type: Webpage
• URL type: WWW
• Credits: Cycles Research Institute
• URL: https://cyclesresearchinstitute.org/subjects/wave-structure/la-freniere/

First published: 2018

Brief summary

Geospatial visualisation for animated spatial data.

Article

Kepler.gl is covered by the linked source. Geospatial visualisation for animated spatial data.

The documentation from Kepler.gl describes the main objects, functions and supported visual output.

The tool can create charts, animations, interactive graphics, maps or three-dimensional scenes, depending on the package. Reproducible output requires code, data and version details.

Visual quality does not establish analytical validity. Scales, units, sampling, perspective and aggregation must accurately represent the underlying data or model.

Source details and credits

• Source / publisher: Kepler.gl
• Source type: Software docs
• URL type: WWW
• Credits: Kepler.gl
• URL: https://kepler.gl/

First published: 2010

Brief summary

NASA interactive visualisation tools.

Article

NASA Eyes is covered by the linked source. NASA interactive visualisation tools.

The documentation from NASA describes the main objects, functions and supported visual output.

The tool can create charts, animations, interactive graphics, maps or three-dimensional scenes, depending on the package. Reproducible output requires code, data and version details.

Visual quality does not establish analytical validity. Scales, units, sampling, perspective and aggregation must accurately represent the underlying data or model.

Source details and credits

• Source / publisher: NASA
• Source type: Interactive tool
• URL type: WWW
• Credits: NASA
• URL: https://eyes.nasa.gov/

First published: 2010

Brief summary

Browser-based 3D library.

Article

Three.js is covered by the linked source. Browser-based 3D library.

The documentation from Three.js describes the main objects, functions and supported visual output.

The tool can create charts, animations, interactive graphics, maps or three-dimensional scenes, depending on the package. Reproducible output requires code, data and version details.

Visual quality does not establish analytical validity. Scales, units, sampling, perspective and aggregation must accurately represent the underlying data or model.

Source details and credits

• Source / publisher: Three.js
• Source type: Software docs
• URL type: WWW
• Credits: Three.js
• URL: https://threejs.org/