Color Cameras
Early color cameras used the obvious technique of using separate red, green and blue image tubes in conjunction with a color separator, a technique still in use with 3CCD solid state cameras today. It was also possible to construct a color camera that used a single image tube. One technique has already been described (Trinicon above). A more common technique and a simpler one from the tube construction standpoint was to overlay the photosensitive target with a color striped filter having a fine pattern of vertical stripes of green, cyan and clear filters (i.e. Green; Green+Blue & Green+Blue+Red) repeating across the target. The advantage of this arrangement was that for virtually every color, the video level of the green component was always less than the cyan, and similarly the cyan was always less than the white. Thus the contributing images could be separated without any reference electrodes in the tube. If the three levels were the same, then that part of the scene was green. This method suffered from the disadvantage that the light levels under the three filters were almost certain to be different, with the green filter passing not more than one third of the available light.
Variations on this scheme exist, the principal one being to use two filters with color stripes overlaid such that the colors form vertically oriented lozenge shapes overlaying the target. The method of extracting the color is similar however.
Read more about this topic: Video Camera Tube
Famous quotes containing the words color and/or cameras:
“Rain falls into the open eyes of the dead
Again again with its pointless sound
When the moon finds them they are the color of everything”
—William Stanley Merwin (b. 1927)
“While the music is performed, the cameras linger savagely over the faces of the audience. What a bottomless chasm of vacuity they reveal! Those who flock round the Beatles, who scream themselves into hysteria, whose vacant faces flicker over the TV screen, are the least fortunate of their generation, the dull, the idle, the failures . . .”
—Paul Johnson (b. 1928)