Autofocus method in thermal cameras based on image histogram
Author
Turgay, E.
Teke, Oğuzhan
Date
2011Source Title
Proceedings of the 19th Signal Processing and Communications Applications Conference, SIU 2011
Publisher
IEEE
Pages
462 - 465
Language
Turkish
Type
Conference PaperItem Usage Stats
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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.
Keywords
Auto-focusAuto-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