A zoom tracking automatic focus control device of an optical zoom camera and a control method thereof

Abstract

The invention discloses a zoom tracking automatic focus control device of an optical zoom camera. The control device comprises an outline determining portion which is used for reading outline data of an illuminated object and which determines whether the outline data increases or decreases, a reference value calculating portion which is used for calculating reference value by using two selected curve data in M preset curves according to the distance between the illuminated object and the camera, a compensation value calculating portion which is used for calculating and updating a first compensation value when the outline data increases and calculating and updating a second compensation value when the outline data decreases, and a movement amount determining portion which is used for determining a final movement amount of a focus lens from a position to a next position by adding the first compensation value to the reference value or adding a value positive number times the second compensation value to reference value. The invention also discloses a corresponding zoom tracking automatic focus control method of the optical zoom camera. The invention may reduce decision error of the distance of the illuminated object when the magnification of a variable-focal-length lens is fast changed in order to achieve accurate focusing.

Description

technical field [0001] The present invention relates to zoom tracking focus control technology for optical zoom cameras, in particular to a zoom tracking automatic focus control device for optical zoom cameras and a control method thereof. The zoom tracking automatic focus control device and control method of the optical zoom camera for controlling the focus and preventing the focus error from the object to be irradiated. Background technique [0002] In an optical zoom camera, expanding the magnification of the optical variable focal length lens from one time to N times is called TELE; reducing the magnification of the optical variable focal length lens from N times to one time is called WIDE. [0003] The zoom tracking control technology is mainly reflected in the TELE direction, and it is not used in the WIDE direction. When performing optical zoom in the TELE direction, the focus of the object to be irradiated is aligned by controlling the zoom motor. This technology is...

AI Technical Summary

Problems solved by technology

But the biggest problem with this solution is that when the variable focal length lens is moved quickly, the judgment of the distance of the irradiated object is prone to errors, which leads to the situation that the optical variable focal length lens cannot be in focus.

That is to say, as the position of the variable focal length lens is different, the focus of the irradiated object will produce errors. The zoom motor moves in the direction of short distance or long distance, and the contour change rate is small. When the variable focal length lens moves, it is difficult to determine Move the position of the soft focus motor, resulting in misalignment of the focus

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