초록 ▼

A system for producing a default signal for an auto focus system whenever the scene being viewed has too low a contrast for the system to operate correctly. The default signal is produced as a function of the out of focus condition of the system so that default occurs when the low contrast value is

A system for producing a default signal for an auto focus system whenever the scene being viewed has too low a contrast for the system to operate correctly. The default signal is produced as a function of the out of focus condition of the system so that default occurs when the low contrast value is below a first magnitude when the lens is near a proper focus position but occurs near a magnitude less than the first magnitude when the lens is further away from the proper focus position.

대표청구항 ▼

Apparatus for producing a low contrast default signal for an auto focus system which system produces a first signal which varies with contrast conditions and a second signal which varies with out-of-focus conditions comprising: first means producing a third signal of predetermined magnitude; signal

Apparatus for producing a low contrast default signal for an auto focus system which system produces a first signal which varies with contrast conditions and a second signal which varies with out-of-focus conditions comprising: first means producing a third signal of predetermined magnitude; signal processing means connected to receive the first, second and third signals, the signal processing means operably to modify one of the first and third signals in accordance with the second signal to produce a fourth signal which varies with the second signal and to compare the fourth signal with the other of the first and third signals to produce the low contrast default signal.