Automatic focusing method of camera

Abstract

The invention provides an automatic focusing method of a camera. The automatic focusing method is characterized in that respective treatment is provided for selection of focusing windows correspondingly to normal illumination and low illumination, and on the basis without increasing excessive calculation, the inclusion of information at the upper half part, the left side and the right side of a picture in the focusing process is considered. A focus-adjusting search control strategy adopts an improved hill-climbing algorithm and comprises the steps of: firstly carrying out rough adjustment, then finding an extreme point by function fitting, driving a motor to reach near the extreme point, and then adopting a small-step method to carry out fine adjustment near the extreme point by the hill-climbing algorithm so as to enable the focusing to be more accurate. For the evaluation of the image definition, a Brenner function is adopted as an evaluation function of automatic focusing and is suitable for quickly finding the clearest point of the image in a manner of matching with the focusing process.

Description

technical field [0001] The invention relates to a picture imaging method, in particular to a camera automatic focusing method. Background technique [0002] Today, as the concept of safety is becoming more and more important, the importance of security monitoring systems is also becoming more and more prominent, especially in some sensitive places, such as banks, prisons, highways, etc. For the needs of safety and management, people need to know what happened in these places events and monitor these locations. Due to the monitoring needs of these special places, more and more integrated cameras that can automatically zoom and focus are being demanded. In the integrated camera, the automatic focus technology is the core technology of the camera. Whether the automatic focus can be realized quickly and accurately is the key to evaluate the quality of the integrated camera. The focusing speed and effect are good or bad, which directly affect the user's capture and video record...

AI Technical Summary

Problems solved by technology

[0014] However, if the method 1 is used when the main object is not in the center of the screen, there will be a big defect

Although methods 2 and 3 are adapted to the situation where the main scene is offset to a certain extent, both methods are at the cost of increasing the amount of calculation and introducing more backgrounds

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