9 December 2005 Self imaging technique for refocusing an aerospace camera
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Proceedings Volume 6024, ICO20: Optical Devices and Instruments; 60241Q (2005); doi: 10.1117/12.666871
Event: ICO20:Optical Devices and Instruments, 2005, Changchun, China
Abstract
A novel auto-focusing technique using a self imaging approach is developed for an aerospace camera having large aperture and long focus. Its optical system consists of an emitting system, receiving system, and two penta-prisms. Emitting system has three parts: a light source, beamsplitter, and aim slit. The receiving system includes a field lens, two separate lenses, and CCD. Using two little penta-prisms instead of a large planar mirror makes the autofocus system simple and compact. CCD was used as photoelectric converting device. A defocused signal is acquired by measuring the change of the two slit self-images position imaged on the CCD. A simple and compact construction of the auto-focusing system was proposed. The algorithm to calculate the moving of the slit-self images position was analyzed in order to achieve subpixel position estimation. The results of the experiments show a ±10μm focusing precision. The system demonstrates high resolution, easy adjustment and high reliability.
© (2005) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Zhaohui Li, Xiaodong Wang, Wei Li, Haipeng Kuang, Changyuan Han, "Self imaging technique for refocusing an aerospace camera", Proc. SPIE 6024, ICO20: Optical Devices and Instruments, 60241Q (9 December 2005); doi: 10.1117/12.666871; https://doi.org/10.1117/12.666871
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KEYWORDS
Cameras

Imaging systems

Charge-coupled devices

Aerospace engineering

Signal to noise ratio

Prisms

Light sources

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