Image definition detector

Abstract

Abstract PURPOSE:To prevent the degradation in the detecting capacity of the change in definition by adjusting the operation characteristics of circuits based on the aperture value (stop value) of a photographic lens by the use of a differentiating circuit for detection of the change in illuminance. CONSTITUTION:The distribution in the illuminances of the image formed by a lens 1 is scanned by a line sensor array 2, and is inputted to a differentiating circuit 4 which is an illuminance change detecting means, via a sample holding circuit 3. The differentiation constant of the circuit 4 is so adjusted that it is smaller, that is, a cutoff frequency is higher, as the aperture value of the lens 1 is larger. The output of the circuit 4 is inputted to a meter 9 via a gain variable amplifier circuit 5, a square circuit 6, an integrating circuit 7 and a sample holding circuit 8, whereby the definition of the image is indicated. In this way, the degradation in the detecting capacity for the change in definition owing to the degration in the image definition with an increase in the aperture value is prevented.

Inventors

• 👤 Takashi Kawabata
• 👤 Takao Kinoshita
• 👤 Nobuhiko Shinoda
• 👤 Shinji Sakai
• 👤 Mitsuya Hosoe

Bibliographic Details