Raster Scan - History

History

A set of lines forming a musical staff was formed by a tool known as a rastrum as early as 1833. The use of raster scanning in television was proposed in 1880 by French engineer Maurice Leblanc. The concept of raster scanning was inherent in the original mechanical disc-scanning television patent of Paul Nipkow in 1884. The term raster was used for a halftone printing screen pattern as early as 1894. Similar terminology was used in German at least from 1897; Eder writes of "die Herstellung von Rasternegativen fur Zwecke der Autotypie" (the production of raster negatives for halftones).Max Dieckmann and Gustav Glage were the first to produce actual raster images on a cathode-ray tube (CRT); they patented their techniques in Germany in 1906. It has not been determined whether they used the word raster in their patent or other writings.

An early use of the term raster with respect to image scanning via a rotating drum is Arthur Korn's 1907 book which says (in German): "...als Rasterbild auf Metall in solcher Weise aufgetragen, dass die hellen Töne metallisch rein sind, oder umgekehrt" (...as a raster image laid out on metal in such way that the bright tones are metallically pure, and vice versa). Korn was applying the terminology and techniques of halftone printing, where a "Rasterbild" was a halftone-screened printing plate.There were more scanning-relevant uses of Raster by German authors Eichhorn in 1926: "die Tönung der Bildelemente bei diesen Rasterbildern" and "Die Bildpunkte des Rasterbildes" ("the tone of the picture elements of this raster image" and "the picture points of the raster image"); and Schröter in 1932: "Rasterelementen," "Rasterzahl," and "Zellenraster" ("raster elements," "raster count," and "cell raster").

The first use of raster specifically for a television scanning pattern is often credited to Baron Manfred von Ardenne who wrote in 1933: "In einem Vortrag im Januar 1930 konnte durch Vorführungen nachgewiesen werden, daß die Braunsche Röhre hinsichtlich Punktschärfe und Punkthelligkeit zur Herstellung eines präzisen, lichtstarken Rasters laboratoriumsmäßig durchgebildet war" (In a lecture in January 1930 it was proven by demonstrations that the Braun tube was prototyped in the laboratory with point sharpness and point brightness for the production of a precise, bright raster). Raster was adopted into English television literature at least by 1936, in the title of an article in Electrician. The mathematical theory of image scanning was developed in detail using Fourier transform techniques in a classic paper by Mertz and Gray of Bell Labs in 1934.