Early History
Richard Howland Ranger received United States patent 1790723 for his invention, "Facsimile system." The patent, which issued in 1931, describes a system for transmitting images over telephone or telegraph lines, or by radio. Ranger's invention permitted continuous tone photographs to be converted first into black and white, then transmitted to remote locations, which had a pen moving over a piece of paper. To render black, the pen was lowered to the paper; to produce white, the pen was raised. Shades of gray were rendered by intermittently raising and lowering the pen, depending upon the luminance of the gray desired.
Ranger's invention used capacitors to store charges, and vacuum tube comparators to determine when the present luminance, plus any accumulated error, was above a threshold (causing the pen to be raised) or below (causing the pen to be lowered). In this sense, it was an analog version of error diffusion.
Read more about this topic: Error Diffusion
Famous quotes containing the words early and/or history:
“Love is the hardest thing in the world to write about. So simple. You’ve got to catch it through details, like the early morning sunlight hitting the gray tin of the rain spout in front of her house. The ringing of a telephone that sounds like Beethoven’s “Pastoral.” A letter scribbled on her office stationery that you carry around in your pocket because it smells of all the lilacs in Ohio.”
—Billy Wilder (b. 1906)
“This is the greatest week in the history of the world since the Creation, because as a result of what happened in this week, the world is bigger, infinitely.”
—Richard M. Nixon (1913–1995)