We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
1949
FILMS IN TELEVISION
377
obtain the frame-speed conversion and interlacing required, with continuous film motion and mechanical simplicity. In the specially printed film one frame is used for each television field scanning. Thus it is obtained from the original film by printing its odd-numbered frames twice in succession, and its even-numbered frames three times in succession; two successive frames of the original thus occupying five frames in the print. This enabled the television signal to follow the then current 441-iriterlaced-line, 30-frame-per-second standards. The blanking period was adjusted from the film standard to the television standard by a slight compensating vertical sweep in the imagedissector tube. The light source used was a 1000-watt incandescent lamp.
The sound track was printed specially on the film also, ' "stretched" in the direction of motion in the ratio of 2.5 to 1. Aside from this, the sound pickup was standard.
COLOR-TELEVISION SYSTEMS
An early system of color-film scanning is also attributed to Ives (1931). This made use of 16-mm Kodacolor film of that time. Film motion was continuous and the scanning mechanical with a Nipkow disk. The colors were led separately by lenses and mirrors to three phototubes (so that the system was of the simultaneous type). Because of the nature of the Kodacolor film, with its lenticular markings on the film surface, the color separation was already obtained geometrically, and no filters were necessary. The television standards were 50 lines, 18 frames per second, which previously had been used with black-and-white. The received signal was reproduced on three lamps, superposed optically on a Nipkow scanning disk, and viewed monocularly through an eyepiece by a single observer.
The Columbia Broadcasting System for some years has been intensively developing a color system. On September 27, 1946, this was proposed in a petition to the Federal Communications Commission as the basis for a commercial broadcast service in color television. After an extensive hearing on the subject, however, the petition was denied on March 18, 1947.
The Columbia system, in so far as it used film, has principally used 16-mm film because it was expected that the major available material would be in that size, but a 35-mm machine using the same principles has also 'been in preparation. The film in each case is standard and operates at 24 frames per second. The film is driven continuously