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Broca-Sulzer Effect
The Broca-Sulzer effect or Broca-Sulzer phenomenon is an experimental observation related to the psychophysics of vision. It has two parts, temporal and spatial. In the temporal effect, the perceived brightness of a single flash of light first increases with the flash duration, then reaches a maximum, and decreases for a longer pulse. The maximum is more pronounced and is observed at shorter durations for a stronger illumination; it is reached at approximately 0.1 for a 100 lux flash. Similarly, in the spatial Broca-Sulzer effect, the perceived brightness increases with increasing angular size of the flashing object until it reaches approximately 2.5 arcminutes, and then decreases for a larger object. The Broca-Sulzer effect was reported by André Broca and David Émile Sulzer in 1902. It conflicted with the 1885 report by Adolphe-Moïse Bloch who believed that the perceived brightness monotonously increases with the flash duration. Later research showed that while the Bloch's law ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Broca-Sulzer Effect
The Broca-Sulzer effect or Broca-Sulzer phenomenon is an experimental observation related to the psychophysics of vision. It has two parts, temporal and spatial. In the temporal effect, the perceived brightness of a single flash of light first increases with the flash duration, then reaches a maximum, and decreases for a longer pulse. The maximum is more pronounced and is observed at shorter durations for a stronger illumination; it is reached at approximately 0.1 for a 100 lux flash. Similarly, in the spatial Broca-Sulzer effect, the perceived brightness increases with increasing angular size of the flashing object until it reaches approximately 2.5 arcminutes, and then decreases for a larger object. The Broca-Sulzer effect was reported by André Broca and David Émile Sulzer in 1902. It conflicted with the 1885 report by Adolphe-Moïse Bloch who believed that the perceived brightness monotonously increases with the flash duration. Later research showed that while the Bloch's law ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psychophysics
Psychophysics quantitatively investigates the relationship between physical stimuli and the sensations and perceptions they produce. Psychophysics has been described as "the scientific study of the relation between stimulus and sensation" or, more completely, as "the analysis of perceptual processes by studying the effect on a subject's experience or behaviour of systematically varying the properties of a stimulus along one or more physical dimensions". ''Psychophysics'' also refers to a general class of methods that can be applied to study a perceptual system. Modern applications rely heavily on threshold measurement, ideal observer analysis, and signal detection theory. Psychophysics has widespread and important practical applications. For example, in the study of digital signal processing, psychophysics has informed the development of models and methods of lossy compression. These models explain why humans perceive very little loss of signal quality when audio and video sign ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Perception
Visual perception is the ability to interpret the surrounding environment through photopic vision (daytime vision), color vision, scotopic vision (night vision), and mesopic vision (twilight vision), using light in the visible spectrum reflected by objects in the environment. This is different from visual acuity, which refers to how clearly a person sees (for example "20/20 vision"). A person can have problems with visual perceptual processing even if they have 20/20 vision. The resulting perception is also known as vision, sight, or eyesight (adjectives ''visual'', ''optical'', and ''ocular'', respectively). The various physiological components involved in vision are referred to collectively as the visual system, and are the focus of much research in linguistics, psychology, cognitive science, neuroscience, and molecular biology, collectively referred to as vision science. Visual system In humans and a number of other mammals, light enters the eye through the cornea and is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angular Diameter
The angular diameter, angular size, apparent diameter, or apparent size is an angular distance describing how large a sphere or circle appears from a given point of view. In the vision sciences, it is called the visual angle, and in optics, it is the angular aperture (of a lens). The angular diameter can alternatively be thought of as the angular displacement through which an eye or camera must rotate to look from one side of an apparent circle to the opposite side. Humans can resolve with their naked eyes diameters of up to about 1 arcminute (approximately 0.017° or 0.0003 radians). This corresponds to 0.3 m at a 1 km distance, or to perceiving Venus as a disk under optimal conditions. Formula The angular diameter of a circle whose plane is perpendicular to the displacement vector between the point of view and the center of said circle can be calculated using the formula :\delta = 2\arctan \left(\frac\right), in which \delta is the angular diameter, and d is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minute And Second Of Arc
A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The nautical mile (nmi) was originally defined as the arc length of a minute of latitude on a spherical Earth, so the actual Earth circumference is very near . A minute of arc is of a radian. A second of arc, arcsecond (arcsec), or arc second, denoted by the symbol , is of an arcminute, of a degree, of a turn, and (about ) of a radian. These units originated in Babylonian astronomy as sexagesimal subdivisions of the degree; they are used in fields that involve very small angles, such as astronomy, optometry, ophthalmology, optics, navigation, land surveying, and marksmanship. To express even smaller angles, standard SI prefixes can be employed; the milliarcsecond (mas) and microarcsecond (μas), for instance, are commonly used in astr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Talbot-Plateau Law
The Talbot-Plateau law is an experimental observation related to the psychophysics of vision. If a light flickers so rapidly that it appears as continuous, then its perceived brightness will be determined by the relative periods of light and darkness: the longer the darkness, the weaker the light. The law was first reported in a 1830 article by the Belgian scientist Joseph Plateau. This article stimulated the English photography pioneer Henry Fox Talbot William Henry Fox Talbot FRS FRSE FRAS (; 11 February 180017 September 1877) was an English scientist, inventor, and photography pioneer who invented the salted paper and calotype processes, precursors to photographic processes of the later ... to publish, in 1834, his own observations on this topic made back in the 1820s. While both scientists have followed each other's experiments, they maintained that they conceived the original idea independently. In 1863, the experiments of A. Fick suggested that the Talbot-Plateau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
