Carl P. Pulfrich (September 24, 1858 in

Burscheid Burscheid is a town in the Rheinisch-Bergischer district, in North Rhine-Westphalia, Germany. The town is known for its sub-communities (somewhat equivalent to the American concept of neighborhoods) and the town centre with its marketplace and c ...

Rhine Province The Rhine Province (german: Rheinprovinz), also known as Rhenish Prussia () or synonymous with the Rhineland (), was the westernmost province of the Kingdom of Prussia and the Free State of Prussia, within the German Reich, from 1822 to 1946. It ...

– August 12, 1927 in Baltic Sea, drowned when his canoe capsized) was a German

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate caus ...

, noted for advancements in

optics Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviole ...

made as a researcher for the

Carl Zeiss Carl Zeiss (; 11 September 1816 – 3 December 1888) was a German scientific instrument maker, optician and businessman. In 1846 he founded his workshop, which is still in business as Carl Zeiss AG. Zeiss gathered a group of gifted practica ...

company in

Jena Jena () is a German city and the second largest city in Thuringia. Together with the nearby cities of Erfurt and Weimar, it forms the central metropolitan area of Thuringia with approximately 500,000 inhabitants, while the city itself has a popu ...

around 1880, and for documenting the

Pulfrich effect The Pulfrich effect is a psychophysical percept wherein lateral motion of an object in the field of view is interpreted by the visual cortex as having a depth component, due to a relative difference in signal timings between the two eyes. Overvie ...

, a psycho-optical phenomenon that can be used to create a type of 3-D visual effect. Carl Pulfrich was the brother-in-law of

Heinrich Hertz Heinrich Rudolf Hertz ( ; ; 22 February 1857 – 1 January 1894) was a German physicist who first conclusively proved the existence of the electromagnetic waves predicted by James Clerk Maxwell's Maxwell's equations, equations of electrom ...

Advances in optics

Pulfrich was employed to develop

stereoscopy Stereoscopy (also called stereoscopics, or stereo imaging) is a technique for creating or enhancing the illusion of depth in an image by means of stereopsis for binocular vision. The word ''stereoscopy'' derives . Any stereoscopic image is ...

from being pure entertainment to a powerful quantitative technique. His apparatus to measure distances stereoscopically was first presented in Munich in 1899. This was further developed to a stereo-comparator which was presented in Hamburg in 1901. Stereoscopy was used for

topographic mapping In modern mapping, a topographic map or topographic sheet is a type of map characterized by large- scale detail and quantitative representation of relief features, usually using contour lines (connecting points of equal elevation), but historic ...

, astronomy and oceanography because everything could be done quickly and precisely. He pioneered the use of

aerial photography Aerial photography (or airborne imagery) is the taking of photographs from an aircraft or other airborne platforms. When taking motion pictures, it is also known as aerial videography. Platforms for aerial photography include fixed-wing aircra ...

surveys. He introduced in 1909 a "Vacation Course in

Stereophotogrammetry Photogrammetry is the science and technology of obtaining reliable information about physical objects and the environment through the process of recording, measuring and interpreting photographic images and patterns of electromagnetic radiant ima ...

", that gave rise to the annual "Photogrammetry Week" running for more than a century.

Leica Geosystems Leica Geosystems (formerly known as Wild Heerbrugg or just Wild) based in eastern Switzerland produces products and systems for surveying and geographical measurement (geomatics). Its products employ a variety of technologies including GPS sat ...

sponsors the "Carl Pulfrich Award", to honour advancements in the fields of

photogrammetry Photogrammetry is the science and technology of obtaining reliable information about physical objects and the environment through the process of recording, measuring and interpreting photographic images and patterns of electromagnetic radiant ima ...

remote sensing Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object, in contrast to in situ or on-site observation. The term is applied especially to acquiring information about Earth ...

, and

earth imaging Satellite images (also Earth observation imagery, spaceborne photography, or simply satellite photo) are images of Earth collected by imaging satellites operated by governments and businesses around the world. Satellite imaging companies sell ima ...

. Pulfrich had realised that people in whom visual function differed between both eyes perceived the stereo-effect: Pulfrich's comment implies a list of diseases in which the stereo-effect can occur. He wondered why the stereo-effect was not noted earlier because of the abundance of swinging clock pendulums:

Pulfrich refractometer

A Pulfrich refractometer measures refractive index of a sample by measuring the

critical angle Critical angle may refer to: *Critical angle (optics), the angle of incidence above which total internal reflection occurs *Critical angle of attack In fluid dynamics, angle of attack (AOA, α, or \alpha) is the angle between a reference lin ...

of the sample with a well characterized prism. Pulfrich and Max Wolz invented it at the Zeiss factory.

References

External links

* 1858 births 1927 deaths People from Burscheid 19th-century German physicists Photogrammetrists People from the Rhine Province Carl Zeiss AG people 20th-century German physicists {{Germany-physicist-stub

Advances in optics

Pulfrich refractometer

See also

References

External links