Search results
Results from the WOW.Com Content Network
A comparison between a typical normalized M cone's spectral sensitivity and the CIE 1931 luminosity function for a standard observer in photopic vision. In the CIE 1931 model, Y is the luminance, Z is quasi-equal to blue (of CIE RGB), and X is a mix of the three CIE RGB curves chosen to be nonnegative (see § Definition of the CIE XYZ color space).
The random sequences are presented to the subject several times. The strength of the stimulus, perceived in more than half of the presentations, will be taken as the threshold. Adaptive method: Stimulation starts with a surely supra-threshold stimulus; then further stimuli are given with an intensity decreased in previously-defined steps.
Dark adaptation – the participants were completely dark adapted (a process lasting forty minutes) to optimise their visual sensitivity. Location – the stimulus was presented to an area of the right eye where there is a high density of rod cells , 20 degrees to the left of the point of focus (i.e. 20 degrees to the right of the fovea ).
Photopic relative brightness sensitivity of the human visual system as a function of wavelength (luminosity function) The visible light spectrum ranges from about 380 to 740 nanometers. Spectral colors (colors that are produced by a narrow band of wavelengths) such as red, orange, yellow, green, cyan, blue, and violet can be found in this range ...
The Stiles–Crawford Effect is quantified as a function of distance (d) away from the center of the pupil using the following equation: () =,where η is the relative luminance efficiency, and d is defined as positive on the temporal side of the pupil and negative on the nasal side of the pupil.
The minimum brightness required for the detection of a light stimulus is called the "threshold" sensitivity level of that location. [3] This procedure is then repeated at several other locations, until the entire visual field is tested. [3] Threshold static perimetry is generally done using automated equipment.
The basis of the idea of range fractionation is that each stimulus (for example, touch) has a range of intensities that can be sensed (light-touch to deep/hard-touch). For an organism to be able to sense a range of stimulus intensities, sensory neurons are tuned to fractions of the entire range.
Alternately, the difference in sensitivity may be due to a difference in the cerebral functions or ability of the left and right hemisphere. [20] Tests have also shown that deaf children have a greater degree of tactile sensitivity than that of children with normal hearing ability, and that girls generally have a greater degree of sensitivity ...