An Automatic Examining-Focus System to Aerial Cameras with CCD

Abstract:

A system is put forward which can automatically measure focus and estimate whether the aerial camera is off-focus and the situation of the factual image plane is in the focus depth range or not. The principle, the hardware composition and the software design are discussed in detail. The system acquires examining-focus information with the optical collimate system, receives images information with CCD camera which can be regarded as optoelectric conversion apparatus, processes data with the center of gravity method, and realizes the axial flow of the CCD camera translation with the grating displacement sensor and the digital readout together. Then, the optimum image situation and the image size can be fixed on. The optimum image situation can be used to judge whether the camera is off-focus, and the image size can be used to calculate the focus. The accurate rate of examining focus can reach almost99.87% and the estimation of off-focus or not accords with experiment result of flight. Use this system, the focus of the lens and the situation of the actual image plane can be judged to accord with the technical standards or not, so that image of high quality can be get with aerial camera.

• Periodical: Advanced Materials Research (Volume 571)
• Pages: 312-315
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.571.312
• Online since: September 2012
• Authors: Mei Zhao, Ming Quan Yang, Fei Guo, Yu Fang Sha
• Keywords: Aerial Camera, Automatic Detecting-Focus, CCD, Centre of Gravity Method

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