WAHG Hao, ZHANG Tao, ZHANG Zhen etc. System of aerial camera auto-focus based on defocus estimate by single image[J]. , 2016,31(5): 484-490 DOI: 10.3788/YJYXS20163105.0484.
System of aerial camera auto-focus based on defocus estimate by single image
In order to solve inevitably multimodal issues and real time problems of traditional focus depth method used in aerial camera
a new method for auto-focus is presented. A focus model is established
and the method is verified by modeling and experiments. Firstly
a large number of different defocus degree of natural images
which are used as the overall sample
are collected. The sample patch from the overall sample is analyzed
and the desire template is got by iteration. Secondly
after the cam completes the coarse focus
the current image is acquired. Then
the sample patches are put into the template through sampling the current image
and the current defocus level is got by calculating defocus. Finally
according to the result of the defocus
the displacement of the actuator is converted. Then
the focus motor is driven to make the movement. The results show that the time to calculate defocus is 0.4 s
which has a great improvement compared with the traditional method whose focus time is 4~8 s. A real-time automatic focus method ensuring the focus accuracy is achieved.
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references
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