초록 ▼

Disclosed is an automatic focusing system for optical imaging equipment, such as a camera, which includes a relative image displacement detection system providing first and second digital quantities indicative of the direction in which the focus of the imaging system is to be altered to achieve focu

Disclosed is an automatic focusing system for optical imaging equipment, such as a camera, which includes a relative image displacement detection system providing first and second digital quantities indicative of the direction in which the focus of the imaging system is to be altered to achieve focus and the magnitude of such alterations, respectively, and an image contrast detection system providing a third digital quantity indicative of the change in the contrast of an image formed by the imaging system as the focus thereof is altered. In addition, the apparatus includes a servomotor for altering the focus of the imaging system and a motor control circuit which receives the first, second and third digital quantities and provides motor control signals to the servomotor. The motor control circuit initially responds to the first and second digital quantities from the relative image displacement detector and provides appropriate motor control signals for altering the focus of the imaging system under the control of the relative image displacement detection system until the change in image contrast as indicated by the third digital quantity becomes negative. Thereafter, the motor control circuit responds to the third digital quantity and provides appropriate motor control signals to alter the focus of the imaging system under the control of the image contrast detection system until the magnitude of the third digital quantity becomes less than a predetermined value.

대표청구항 ▼

An automatic focusing apparatus for an optical imaging system, which includes an optical system adapted to form an image of an object at a focal plane, the apparatus comprising: relative image displacement detection means providing a first and a second digital quantity respectively indicative of the

An automatic focusing apparatus for an optical imaging system, which includes an optical system adapted to form an image of an object at a focal plane, the apparatus comprising: relative image displacement detection means providing a first and a second digital quantity respectively indicative of the direction and magnitude of a focus alteration of the imaging system to achieve a state of focus therein; image contrast detection means providing a third digital quantity indicative of the change in the contrast of an image formed by the imaging system as the focus thereof is altered; focus altering means initially responsive to the first and second digital quantities for altering the focus of the imaging system in a direction indicated by the first digital quantity until the third digital quantity indicates a decrease in the contrast of the image with further focus alteration, the focus altering means being subsequently responsive to the third digital quantity for altering the focus of the imaging system until the magnitude of the third digital quantity is less than a first predetermined quantity.