Half Field Of View Research Articles

Optimum Design of a Composite Optical Receiver by Taguchi and Fuzzy Logic Methods.

This paper investigates a composite optical receiver for an indoor visible light communication (VLC) system. The optical gain, received power, and signal-to-noise ratio (SNR) are considered to be optimized. However, it is difficult to find a balance between them in general design and optimization. We propose the Taguchi and fuzzy logic combination method to improve multiple performance characteristics effectively in the optical receiver. The simulated results indicate that the designed receiver has the characteristics of an optical gain of 10.57, a half field of view (HFOV) of 45°, a received power of 6.4635 dBm, a signal-to-noise ratio (SNR) of 89.8874 dB, and a spot size of 2 mm. The appropriate weights of the three performance characteristics for the inputs of the fuzzy controllers increase the optical gain by 13.601 dB, and the received power and SNR by 11.097 dB and 0.373 dB, respectively. Therefore, the optical receiver optimally designed by the Taguchi and fuzzy logic methods can significantly meet the requirements of an indoor VLC system.

POLARIMETRIC CALIBRATION OF THE SPACEBORNE DIRECTIONAL POLARIMETRIC CAMERA INSTALLED ON THE GF-5 SATELLITE

Abstract. The Spaceborne Directional Polarimetric Camera (SDPC) is dedicated to obtain an accurate information of clouds and microphysical properties of aerosol particles via multi-angle, multi-spectral and multi-polarization observations. It images the Earth with 110° field of view (FOV) in 3 polarimetric spectral bands and 5 non-polarimetric spectral bands from visible to near infrared. Due to its wide FOV telecentric optical system and multi-channels, polarization sensitivity of optical components (PSOC) and non-uniform response of pixels (NURP) are the main uncertainty factors of polarimetric calibration.In this paper, a polarimetric calibration model of SDPC has been constructed for increasing the measurement accuracy. Combined an integrating sphere with a polarization generator as source, PSOC can be measured in high accuracy by using the Fourier series analysis method which reduces the impact form the alignment error of the generator. The sectional viewing field measurement method is used to acquire NURP while the large aperture integrating sphere served as reference source. Subsequently, the data of NURP have been corrected by the relative transmittance of high frequency and low frequency respectively for polarized channels. The result of validation experiment shows that the polarization measurement errors in 0°, 15°, 30°, and 45° half field of view (HFOV) are all less than 0.5% when the degree of linear polarization of reference source is larger than 0.1.

Optical design of reflecting omnidirectional zoom optical system with peripheral half-field of view from 110° to 72° for day and night surveillance

A reflecting omnidirectional zoom optical system (ROZOS) that is simultaneously operative in the visible-light (400 − 700 nm) and long-wave infrared (8 − 12 μm) ranges is designed for day and night unmanned surveillance and security. The half-field of view (HFOV) and F-number for the developed ROZOS are 40 − 110° and 2.4, respectively, enabling omnidirectional vision. In order to expand the concentrated image in the region of the central blocking area on the image sensor, we successfully established a ROZOS by two moving mirrors to play the role of the focator/variator and compensator, respectively. The zoom magnification and maximum lower HFOV vary from 1 to 1.24 and from 110° to 72° during zooming, respectively. During zooming, the modulation transfer function (MTF) exceed 0.30 at Nyquist frequencies of 34 lp/mm and 20 lp/mm, respectively, at all maximum lower HFOVs from 110° to 72° in the visible and long-wave infrared wavelength ranges. No performance issues are encountered as the ray aberration is very small over the entire zooming range. Tolerance analysis show that when the MTF is 0.3, the cumulative probability over the entire zooming range exceed 90 %.

Design and optimization of optical receiving antenna based on compound parabolic concentrator for indoor visible light communication

An advanced optical receiving antenna based on compound parabolic concentrator (CPC) is proposed for indoor visible light communication (VLC). The design of the antenna is conducted into two parts. Firstly, the Taguchi methodology and ANOVA technique are utilized to explore and optimize structural parameters of receiving lens for improving the optical efficiency and matching the channel performance requirements in VLC system. Then, the indoor communication model is established, and the channel performance is analyzed by Matlab software. The results show that: the half field of view (FOV) of the lens can reach 50°, while the optical gain is 11.29. The received power is 6.7496 dBm, and the SNR is 84.9642 dB. The FOV increases by 66.67% when compared to the CPC. The SNR increases by 26.18% when compared with the case of receiving rays directly without any antenna, which is 2.13 times the CPC’s SNR increase. Thus, the optimally designed lens can ensure the high-speed and stable communication of the indoor VLC systems.

Design of 13 mega-pixel mobile phone lens based on code V

In order to meet the unmet commerce needs of high pixel mobile phone, more and more designs come into being. According to the theory of ray optics, a 13 mega-pixel mobile phone lens was designed based on code V, an optical design software. It consists of five aspherical lenses and a filter. The F-number of the lens is 2.2, the half field of view is 35 degrees, the effective focal length is 3.6, and the total length of the lens is 3.6 mm. The MTF(modulation transfer function) of central field of view is greater than 0.6, the high frequency is greater than 0.2 and in the 0.8 field of view the middle frequency is greater than 0.4. In a word, the lens can meet the requirement of the high imaging quality camera.

Design of a gradient-index lens with a compound parabolic concentrator shape as a visible light communication receiving antenna.

We propose a design for a gradient lens that can extend the field of view and receive higher optical power for indoor visible light communication systems. The proposed structure is an axially symmetric lens with a refractive index gradient distribution in the axial direction and a slight gradient in the radial direction, and with a spherical top surface and side surface in a compound parabolic concentrator (CPC) shape. The radius of the outlet of the CPC is 3mm, and the inlet radius is 6.8mm with a 9.04mm radius of curvature. The height of the receiving system is 15.2mm, resulting in the small volume of the structure. Simulation results show that the half field of view (FOV) of the lens can reach 36.2°, while the gain is higher than that of a bare CPC. The designed receiving system has an average receiving gain ∼1.72 times larger than a bare CPC-based system, and is suitable for indoor visible light communication.

Design of a gradient-index photographic objective

A two-element gradient-index photographic objective was designed. It operates at f/2 and has a focal length of 50 mm. The half-field of view is 21.8 degrees . The design is compared to the six-element new double Gauss photographic objective and performs well in comparison.