Khoa Vật lý trân trọng kính mời quý vị đến dự Seminar đầu tiên trong tháng 1/2019
Ngày: 10/01/2019 (Thứ 5)
Giờ: từ 3 giờ 30 chiều đến 4 giờ 30 chiều
Địa điểm: Phòng 408F, nhà T1, TrườngĐại học Khoa học Tự nhiên, 334Nguyễn Trãi
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Speaker: Prof. CUONG DANG (Centre for OptoElectronics and Biophotonics (COEB), School of Electrical and Electronic Engineering, The Photonics Institute (TPI), Nanyang Technological University, Singapore)
Title: FROSTED GLASS IS A MULTI-PURPOSE
OPTICAL COMPONENT: LENS, FILTER AND ENCRYPTER
Abstract: The scattering media such as frosted glass or
biological tissue and human skin seems only diffusing light, creating random
speckles, and deteriorating our visual ability as well as imaging capability.
Here, we demonstrate that scattering media not only help us to take photos but
also do optical filtering at the same time. More interestingly, a single piece
of optical diffuser can work as multiple filters for different optical bands,
enabling the simplest single-shot multispectral camera. Our findings are based on
the spatial correlation and spectral decorrelation of speckle pattern generated
by an optical diffuser. The spatial correlation or memory effect of an optical
diffuser allows us to do imaging by deconvolution method while the spectral
decorrelation is utilized for multi-band optical filters. A single shot of
speckle pattern after optical diffuser is enough to capture all spatial and
spectral information to construct the multispectral image of object. The memory
effect of scattering diffusers is small; therefore, the field of view (FOV) is
limited. We then demonstrate a spatial multiplexing technique to extend the FOV
for imaging. Finally, our spatial multiplexing method with scattering media is
utilized to enhance the security of optical encryption technique.
