2.1 The eye
All television signals ultimately excite some response in the eye and the viewer can only describe the result subjectively. Familiarity with the operation and limitations of the eye is essential to an understanding of television principles.
The simple representation of Figure 2.1 shows that the eyeball is nearly spherical and is swivelled by muscles so that it can track movement. This has a large bearing on the way moving pictures are reproduced. The space between the cornea and the lens is filled with transparent fluid known as aqueous humour. The remainder of the eyeball is filled with a transparent jelly known as vitreous humour. Light enters the cornea, and the the amount of light admitted is controlled ...