Experimentally Derived Feasibility of Optical Camera Communications under Turbulence and Fog Conditions

Abstract

Optical camera communications (OCC) research field has grown recently, aided by ubiquitous digital cameras; however, atmospheric conditions can restrict their feasibility in outdoor scenarios. In this work, we studied an experimental OCC system under environmental phenomena emulated in a laboratory chamber. We found that the heat-induced turbulence does not affect our system significantly, while the attenuation caused by fog does decrease the signal quality. For this reason, a novel strategy is proposed, using the camera’s built-in amplifier to overcome the optical power loss and to decrease the quantization noise induced by the analog-digital converter of the camera. The signal quality has been evaluated using the Pearson’s correlation coefficient with respect to a reference template signal, along with the signal-to-noise ratio that has been empirically evaluated. The amplification mechanism introduced allows our system to receive the OCC signal under heavy fog by gradually increasing the camera gain up to 16 dB, for meteorological visibility values down to 10 m, with a correlation coefficient of 0.9 with respect to clear conditions.

Optical Camera Communication as an Enabling Technology for Microalgae Cultivation

“…Consequently, the PDs of the pixels exposed for a shorter time have a lower signal-to-noise ratio (SNR). In previous works, it was shown that the reduced received power due to the extinction along the path or due to low exposure times can be overcome using the analogue amplifier of the CMOS camera by increasing the gain it provides before the analogue-to-digital converter (ADC), ultimately improving the SNR [ 20 , 21 ].…”

Wireless Sensor Networks Using Sub-Pixel Optical Camera Communications: Advances in Experimental Channel Evaluation

“…Nonetheless, these approaches are impractical if it is considered that the FOV of the receiver optics is drastically reduced. As a solution for maintaining the camera’s original FOV, in previous works [ 15 , 16 ] it is demonstrated that the signal attenuation produced by turbulence and fog phenomena can be overcome by increasing the analog gain of the image sensor without the need to alter the camera optics.…”

“…Further experimentation has been carried out, including the effects of heat-induced turbulence and exploiting the camera’s analog gain in [ 15 , 16 ]. Real conditions of a sandstorm were experimentally studied in [ 17 ].…”

Performance of Vehicular Visible Light Communications under the Effects of Atmospheric Turbulence with Aperture Averaging

“…The average BER of the maritime VLC system under oceanic turbulence was evaluated in [ 14 ], and it was found that the BER decreased with increasing aperture size and wavelength, and increased with oceanic turbulence and link span. In [ 15 ], the effects of fog and weak AT on a VLC link with a camera-based optical receiver (Rx) were investigated using Pearson’s correlation coefficient with reference to a template signal. The results obtained showed that under weak AT there was no significant change in the signal quality.…”

“…The results obtained showed that under weak AT there was no significant change in the signal quality. In [ 11 ], we experimentally investigated the effects of higher AT strengths with AA than in [ 15 ], up to of 1.1 × 10 –10 m −2/3 in vehicular VLC (VVLC) with a camera-based Rx for two camera gain factors (i.e., low and high). Results showed that the peak SNR (PSNR) performance (i.e., an image quality metric) of the link was not significantly degraded by AT with AA for both gain factors investigated.…”