PTZ (pan/tilt/zoom) camera focusing method and system

Abstract

Disclosed is a PTZ (pan / tilt / zoom) camera focusing method and system. The method includes the steps of according to multiple focal length sampling points, multiple object distance sampling points and focal values of the focal length and object distance sampling points, acquiring a value b of a current focal length, b = y - Kx(f), with x(f) referring to the focal value x changing with change of the focal length f, y to an image distance, and K to a constant; according to the image distance y of the current focal length and the value b of the current focal length, calculating the focal value of the current focal length. The technical problem that the prior method of controlling the focal position of a camera by transmitting the focal value applies only to parfocal lens cameras and applies to no verifocal lens cameras is solved. In use of the PTZ camera focusing method and system in focusing, the cameras with two types of lenses both can accurately focus a tracked target to acquire clear target images.

Description

Technical field [0001] The invention relates to the technical field of video surveillance. Specifically, it relates to a PTZ camera focusing method and system. Background technique [0002] PTZ dome (Pan-Ti lt-Zoom), referred to as fast dome, is an important monitoring front end in the monitoring system. PTZ dome camera integrates PTZ system, communication system and camera system, which can realize automatic tracking of moving targets in the scene. [0003] The current focusing method of the automatic tracking system mainly uses the traditional automatic focusing method. This method often fails in low light or the scene texture information is not rich, and because the automatic focusing needs to be adjusted repeatedly according to the image processing to focus clearly. It will be slower. In the automatic tracking application, due to the continuous switching of the target, the image magnification also changes frequently, resulting in the need for continuous automatic focusing, wh...

AI Technical Summary

Problems solved by technology

But this kind of compensation is only an approximate compensation, especially when the object distance is small (for example, the object distance is less than 5m), the error is large. The target image is not clear due to success

In addition, for most dome cameras in real life, they mainly use a zoom plane lens (verifocal lens), and the optical center changes caused by the zoom plane lens at different focal lengths are very different. The change of the focus value caused by the change of is very large, and the algorithm fails completely

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