Aspect ratio
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The aspect ratio of a
The aspect ratio is most often expressed as two integer numbers separated by a colon (x:y), less commonly as a simple or decimal
In objects of more than two dimensions, such as hyperrectangles, the aspect ratio can still be defined as the ratio of the longest side to the shortest side.
Applications and uses
The term is most commonly used with reference to:
- Graphic / image
- Image aspect ratio
- Display aspect ratio
- Paper size
- Standard photographic print sizes
- Motion picture film formats
- Standard ad size
- Pixel aspect ratio
- Photolithography: the aspect ratio of an etched, or deposited structure is the ratio of the height of its vertical side wall to its width.
- HARMST High Aspect Ratios allow the construction of tall microstructures without slant
- Tire code
- Tire sizing
- Turbocharger impeller sizing
- Wing aspect ratioof an aircraft or bird
- optical lens
- Nanorod dimensions
- Shape factor (image analysis and microscopy)
- Finite Element Analysis
Aspect ratios of simple shapes
Rectangles
For a rectangle, the aspect ratio denotes the ratio of the width to the height of the rectangle. A square has the smallest possible aspect ratio of 1:1.
Examples:
- 4:3 = 1.3: Some (not all) 20th century computer monitors (XGA, etc.), standard-definition television
- : international paper sizes (ISO 216)
- 3:2 = 1.5: 35mm still camera film, iPhone (until iPhone 5) displays
- WXGA)
- Φ:1 = 1.618...: golden ratio, close to 16:10
- 5:3 = 1.6: super 16 mm, a standard film gaugein many European countries
- 16:9 = 1.7: widescreen TV and most laptops
- 2:1 = 2: dominoes
- 64:27 = 2.370: ultra-widescreen, 21:9
- 32:9 = 3.5: super ultra-widescreen
Ellipses
For an ellipse, the aspect ratio denotes the ratio of the
Aspect ratios of general shapes
In
- The diameter-width aspect ratio (DWAR) of a compact set is the ratio of its diameter to its width. A circle has the minimal DWAR which is 1. A square has a DWAR of .
- The cube-volume aspect ratio (CVAR) of a compact set is the d-th root of the ratio of the d-volume of the smallest enclosing axes-parallel d-cube, to the set's own d-volume. A square has the minimal CVAR which is 1. A circle has a CVAR of . An axis-parallel rectangle of width W and height H, where W>H, has a CVAR of .
If the dimension d is fixed, then all reasonable definitions of aspect ratio are equivalent to within constant factors.
Notations
Aspect ratios are mathematically expressed as x:y (pronounced "x-to-y").
Cinematographic aspect ratios are usually denoted as a (rounded) decimal multiple of width vs unit height, while photographic and videographic aspect ratios are usually defined and denoted by whole number ratios of width to height. In
See also
- Axial ratio
- Ratio
- Equidimensional ratios in 3D
- List of film formats
- Squeeze mapping
- Scale (ratio)
- Vertical orientation
References
- ^ Rouse, Margaret (September 2005). "What is aspect ratio?". WhatIs?. TechTarget. Retrieved 3 February 2013.
- ^ Rouse, Margaret (September 2002). "Wide aspect ratio display". display. E3displays. Retrieved 18 February 2020.
- S2CID 17962961.