METHOD AND SYSTEM FOR AUTOMATICALLY FOCUSING A CAMERA

摘要

A method for automatically focusing a camera comprising an image sensor, at least one lens configured to project an image onto the sensor and an actuator configured to modify a focusing parameter of the lens, comprises: a first phase of controlling the actuator in an open loop so the focusing parameter successively takes a plurality of predefined values, images being acquired for each value of the focusing parameter and a sharpness indicator being calculated on the basis of each image; and a second phase of controlling the actuator in a closed loop to maximize the sharpness indicator, the second closed-loop control phase being implemented by making use of a control law and starting conditions determined on the basis of the sharpness indicators calculated during the first phase. A system for automatically focusing a camera for implementing the method, and a camera equipped with such a system is provided.

主权项

1. A method for automatically focusing a camera comprising an image sensor, at least one lens configured to project an image onto said image sensor and an actuator configured to modify a focusing parameter of the lens, the method comprising:
a first phase comprising:
performing open-loop control of said actuator, such that said focusing parameter successively takes a plurality of predefined values;acquiring a plurality of images by means of said sensor, each corresponding to one said predefined value of the focusing parameter; andcalculating a sharpness indicator on the basis of each of said images; and a second phase of controlling, in a closed loop, said actuator so as to maximize said sharpness indicator; said second closed-loop control phase being implemented by making use of a control law and starting conditions determined on the basis of the sharpness indicators calculated during said first phase.