Before the Dawn of the Century of Moving Image
The latter half of the 19th century experienced a new media boom similar in significance to the one being experienced now. Pioneers in all fields of science devoted themselves in the realization of mankind’s dreams.
One important discovery related to basic television imaging technology, was the discovery of the element selenium in 1817. Selenium’s photoelectric phenomenon, discovered in 1873 by Willoughby Smith and Joseph May of Great Britain, laid the foundation for the development of television.

Image Scanning, Division, and Reproduction
The most significant development was that of image division/scanning. This made it “possible to reconstruct an image that had been divided/scanned for transmission as a signal. Regarding the transmission of such images, the scanning concept of Great Britain’s Alexander Bain in 1843 is considered to be the first in television technology. Bain’s scanning concept, however, was only for still picture transmission and was not capable of transmitting moving pictures. The transmission method of current TV makes the picture appear to be moving by sending images from a scene successively, each image sent within the persistence of vision of the previous picture. For example, in a movie, the images printed on a piece of film are displayed at the rate of 24 still pictures per second, a rate for which human visual characteristics make the brain interpret what is being viewed as continuous movement.

Principle of Current TV System
Knowing the theory and principles involved does not necessarily make it easier to develop a practical model, or even to popularize it.
It was G.R. Carey of the United States, in 1875, who first proposed a television system using the photoelectric phenomenon. This system used multiple photoelectric transducers, which convert light into electricity, and luminous devices, which convert electricity into light in a display, connecting these in pairs (parallel connection).
The idea that led to the principle used in present TV systems was first proposed by W.E. Sawyer of Great Britain in 1877. He proposed a system called serial TV, which transmits the individual pixel signals making up an image in sequence at high speed instead of transmitting all the pixel signals from a camera at the same time. The pixel signals transmitted in sequence to a receiver via a single transmission line are then reconstructed by reversing the transmission procedure.
In 1884, Bain’s scanning concept was realized mechanically using the “Nipkow disk,” developed by Paul Nipkow of Germany. In 1925, John Logie Baird of Great Britain fabricated a mechanical television. However, this mechanical system was limited in its image resolution.
With regard to the receiver, Karl Ferdinand Braun of Germany invented the Braun tube (cathode-ray tube) in 1897. Louis Lumiere, along with his brother Auguste, of France developed “cinematography” in 1895, combining a camera, cineprojector, and developing machine. About the same time, the motion picture business began with Edison in the United States and others seeing the potential of the new medium.
It was not until the 20th century that these methods of image recording and reproduction of the film medium developed into the shooting and transmission of images by using electricity.

1. Video division/scanning
2. Fundamental difficulties with TV technology