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Visual angle is the angle a viewed object subtends at the eye, usually stated in degrees of arc. It also is called the object's angular size.
The visual angle also depends on the object's size -- larger objects lead to larger visual angles. Calculated size and distance are in the same unit of measurement as the input. E.g. if you enter the size in cm, the calculated distance will be in centimeters.
The visual angle is influenced by two things -- the size of the object and the distance of the object from the eye. Bigger objects cast larger images on the retina than smaller objects. Thus, the larger the object is, the larger its visual angle will be.
3 paź 2024 · The visual angle (\(VA\)) is calculated using the formula: \[ VA = \tan^{-1}\left(\frac{S}{D}\right) \] where: \(VA\) is the Visual Angle in degrees, \(S\) is the visual size, and \(D\) is the distance from the observer to the object. Example Calculation
Visual angles are everywhere in eye tracking. Researchers may want to ensure that their screen fits within the “trackable range” of their system – where the trackable range is 32 degrees horizontally and 25 degrees vertically for example.
When asked to guess the size of the circle, your brain did a quick calculation of the visual angle of the spot and the distance to the monitor and came up with an estimate of about 2.5 cm (yes, your visual system can do trigonometry without a calculator!).
Visual Angle. Vision scientists usually express the size of an image on the retina in terms of visual angle. They use this measure instead of the size of the object or square millimeters of retina covered because it is consistent regardless of the distance from the viewer or the size of the eye.
