|
Zöllner Illusion
The Zöllner illusion is an optical illusion named after its discoverer, German astrophysicist Johann Karl Friedrich Zöllner. In 1860, Zöllner sent his discovery in a letter to physicist and scholar Johann Christian Poggendorff, editor of ''Annalen der Physik und Chemie'', who subsequently discovered the related Poggendorff illusion in Zöllner's original drawing. One depiction of the illusion consists of a series of parallel, black diagonal lines which are crossed with short, repeating lines, the direction of the crossing lines alternating between horizontal and vertical. This creates the illusion that the black lines are not parallel. The shorter lines are on an angle to the longer lines, and this angle helps to create the impression that one end of the longer lines is nearer to the viewer than the other end. This is similar to the way the Wundt illusion appears. It may be that the Zöllner illusion is caused by this impression of depth. This illusion is similar to the Hering ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Illusion
Within visual perception, an optical illusion (also called a visual illusion) is an illusion caused by the visual system and characterized by a visual perception, percept that arguably appears to differ from reality. Illusions come in a wide variety; their categorization is difficult because the underlying cause is often not clear but a classification proposed by Richard Gregory is useful as an orientation. According to that, there are three main classes: physical, physiological, and cognitive illusions, and in each class there are four kinds: Ambiguities, distortions, paradoxes, and fictions. A classical example for a physical distortion would be the apparent bending of a stick half immerged in water; an example for a physiological paradox is the motion aftereffect (where, despite movement, position remains unchanged). An example for a physiological fiction is an afterimage. Three typical cognitive distortions are the Ponzo illusion, Ponzo, Poggendorff illusion, Poggendorff, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Karl Friedrich Zöllner
Johann Karl Friedrich Zöllner (8 November 1834, Berlin25 April 1882, Leipzig) was a German astrophysicist who studied optical illusions. He was also an early psychical investigator. Biography From 1872 he held the chair of astrophysics at Leipzig University. He wrote numerous papers on photometry and spectrum analysis in Poggendorff's '' Annalen'' and ''Berichte der k. sächsischen Gesellschaft der Wissenschaften'', two works on celestial photometry (''Grundzüge einer allgemeinen Photometrie des Himmels'', Berlin, 1861, 4to, and ''Photometrische Untersuchungen'', Leipzig, 1865, 8vo), and a curious book, ''Ueber die Natur der Cometen'' (Leipzig, 1872, 3rd ed. 1883). He discovered the Zöllner illusion where lines that are parallel appear diagonal. He also successfully proved Christian Doppler's theory on the effect of motion of the color of stars, and the resulting shift of absorption lines, via the invention of a very sensitive spectroscope which he named "Reversionspectros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Christian Poggendorff
Johann Christian Poggendorff (29 December 1796 – 24 January 1877), was a German physicist born in Hamburg. By far the greater and more important part of his work related to electricity and magnetism. Poggendorff is known for his electrostatic motor which is analogous to Wilhelm Holtz's electrostatic machine. In 1841 he described the use of the potentiometer for measurement of electrical potentials without current draw. Biography Poggendorf had apprenticed himself to an apothecary in Hamburg, and when twenty-two began to earn his living as an apothecary's assistant at Itzehoe. Ambition and a strong inclination towards a scientific career led him to throw up his business and move to Berlin, where he entered Humboldt University in 1820. Here his abilities were speedily recognized, and in 1823 he was appointed meteorological observer to the Academy of Sciences. Even at this early period he had conceived the idea of founding a physical and chemical scientific journal, and the rea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annalen Der Physik
''Annalen der Physik'' (English: ''Annals of Physics'') is one of the oldest scientific journals on physics; it has been published since 1799. The journal publishes original, peer-reviewed papers on experimental, theoretical, applied, and mathematical physics and related areas. The editor-in-chief is Stefan Hildebrandt. Prior to 2008, its ISO 4 abbreviation was ''Ann. Phys. (Leipzig)'', after 2008 it became ''Ann. Phys. (Berl.)''. The journal is the successor to , published from 1790 until 1794, and ', published from 1795 until 1797. The journal has been published under a variety of names (', ', ', ''Wiedemann's Annalen der Physik und Chemie'') during its history. History Originally, was published in German, then a leading scientific language. From the 1950s to the 1980s, the journal published in both German and English. Initially, only foreign authors contributed articles in English but from the 1970s German-speaking authors increasingly wrote in English in order to reach an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wundt Illusion
The Wundt illusion is an optical illusion that was first described by the German psychologist Wilhelm Wundt in the 19th century. The two red vertical lines are both straight, but they may look as if they are bowed inwards to some observers. The distortion is induced by the crooked lines on the background, as in the Orbison illusion. The Hering illusion The Hering illusion is one of the geometrical-optical illusions and was discovered by the German physiologist Ewald Hering in 1861. When two straight and parallel lines are presented in front of radial background (like the spokes of a bicycle), t ... produces a similar, but inverted effect. Vertical-horizontal illusion Another variant of the Wundt illusion is the '' Horizontal–Vertical Illusion'', introduced by Wundt in 1858. The two intersecting lines are equal in length although the vertical line appears to be much longer. The horizontal line needs to be extended up to 30% to match the perceptual length of the vertical lin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hering Illusion
The Hering illusion is one of the geometrical-optical illusions and was discovered by the German physiologist Ewald Hering in 1861. When two straight and parallel lines are presented in front of radial background (like the spokes of a bicycle), the lines appear as if they were bowed outwards. The Orbison illusion is one of its variants, while the Wundt illusion produces a similar, but inverted effect. There are several possible explanations for why perceptual distortion produced by the radiating pattern. The illusion was ascribed by Hering to an overestimation of the angle made at the points of intersection. If true, then the straightness of the parallel lines yields to that of the radiating lines, implying that there is a hierarchical ordering among components of such illusion. Others have suggested that angle overestimation results from lateral inhibition in visual cortex, while others have postulated a bias inherent in extrapolating 3D angle information from 2D projections. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Müller-Lyer Illusion
The Müller-Lyer illusion is an optical illusion consisting of three stylized arrows. When viewers are asked to place a mark on the figure at the midpoint, they tend to place it more towards the "tail" end. The illusion was devised by Franz Carl Müller-Lyer (1857–1916), a German sociologist, in 1889. A variation of the same effect (and the most common form in which it is seen today) consists of a set of arrow-like figures. Straight line segments of equal length comprise the "shafts" of the arrows, while shorter line segments (called the fins) protrude from the ends of the shaft. The fins can point inwards to form an arrow "head" or outwards to form an arrow "tail". The line segment forming the shaft of the arrow with two tails is perceived to be longer than that forming the shaft of the arrow with two heads. Variation in perception Research has shown that sensation of the Müller-Lyer illusion can vary. Around the turn of the 20th century, W. H. R. Rivers noted that indige ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Café Wall Illusion
The café wall illusion is a geometrical-optical illusion in which the parallel straight dividing lines between staggered rows with alternating dark and light "bricks" appear to be sloped, not parallel as they really are. It was first described under the name Kindergarten illusion in 1898, and re-discovered in 1973 by Richard Gregory. According to Gregory, this effect was observed by a member of his laboratory, Steve Simpson, in the tiles of the wall of a café at the bottom of St Michael's Hill, Bristol. It is a variant of the shifted-chessboard illusion originated by Hugo Münsterberg. In the construction of the optical illusion often each "brick" is surrounded by a layer of "mortar" intermediate between the dark and light colours of the "bricks". In the first attempt at its deconstruction, the illusion was ascribed largely to the irradiation illusion (apparent greater size of a white area than of a black one), and the image disappears when black and white are replaced by di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
