Autofocus method in thermal cameras based on image histogram

Date
2011
Advisor
Instructor
Source Title
Proceedings of the 19th Signal Processing and Communications Applications Conference, SIU 2011
Print ISSN
Electronic ISSN
Publisher
IEEE
Volume
Issue
Pages
462 - 465
Language
Turkish
Type
Conference Paper
Journal Title
Journal ISSN
Volume Title
Abstract

In this paper, a new histogram based auto-focusing method for thermal cameras is proposed. This proposed method is realized by FPGA (Field Programmable Gate Array) and DSP (Digital Signal Processor) working together and simultaneously. HF (High Frequency) component, obtained from real-time image flow by FPGA and DSP is used for auto-focusing process. Proposed method is able to determine the focus direction from the HF component produced in the process of histogram equalization by FPGA, unlike Fourier transform and pixel differenve based methods in the literature. With this superiority, proposed method requires no extra calculation for thermal cameras for which histogram equalization is necessary. Analysis show that proposed method is successful on the simulations and scanning thermal cameras.

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Book Title
Keywords
Auto-focus, Auto-focusing, High frequency, Histogram equalizations, Image histograms, Real-time images, Thermal camera, Digital signal processors, Field programmable gate arrays (FPGA), Fourier transforms, Graphic methods, Signal processing, Cameras
Citation
Published Version (Please cite this version)