Image pickup for endoscope and method for operating image pickup system for endoscope

摘要

There is provided an image pickup system for endoscope including: a light source; an image forming optical system; a focus lens driving section; an image pickup section outputting an image signal; an image signal amplifying section; an image brightness detecting section; a brightness adjusting section adjusting a brightness control condition such as a light quantity of the light source, an image pickup condition of the image pickup section and an amplification factor of the amplifying section so that brightness of an image becomes a predetermined brightness; an auxiliary AF section estimating a temporary focus position based on the brightness control condition; a control section setting a small scanning range including the temporary focus position; and a contrast AF section causing contrast AF to be performed in the scanning range.

主权项

1. An image pickup system for endoscope comprising:
a light source radiating illuminating light to a subject; an image forming optical system forming an optical image of reflected light reflected from the subject out of the illuminating light radiated by the light source; a driving section driving a focus lens, the focus lens being a part of the image forming optical system, within a predetermined movable range; an image pickup section picking up the optical image formed by the image forming optical system and outputting an image signal; an amplifying section signal-amplifying the image signal outputted from the image pickup section according to an amplification factor; a brightness detecting section detecting brightness of the image indicated by the image signal; a brightness adjusting section adjusting a brightness control condition for, if the brightness of the image detected by the brightness detecting section changes, controlling at least one parameter among a condition of a light quantity by the light source, a condition of image pickup by the image pickup section and the amplification factor of the amplifying section so that the brightness of the image becomes a predetermined brightness; an auxiliary autofocus section estimating a subject distance corresponding to when the brightness of the image becomes the predetermined brightness as a temporary focus position of the optical image with respect to a subject distance indicated by a multivariable function of the brightness control condition adjusted by the brightness adjusting section; and determining a range which includes the temporary focus position and is smaller than the predetermined movable range as a scanning range; and a contrast autofocus section causing the driving section to drive the focus lens to perform contrast autofocus based on the scanning range determined by the auxiliary autofocus section.