# Visible Light Communications through Diffusive Illumination of Sculptures in a Real Museum
## 5 Conclusions  
In this work we report, for the first time, successful VLC data transfer exploiting standard LED illumination of real three-dimensional sculptures in a museum. We present a detailed characterisation of our novel low-cost VLC prototype which uses a diffusive, nLoS channel through the standard LED-based lighting system in the famous Basilica of Santa Maria Novella in Florence, Italy. In particular, our experimental campaign explores the performances of the prototype on two different sculpture masterpieces (the wooden _Crucifix_ by [PERSON] and the marble _Holy Water Font_ by [PERSON]), in their original location. These artworks have been chosen for their different positioning, material and  
Figure 7: Experimental determination of effective RX FoV in terms of PER performances. Data report measured PER values relative to [PERSON]’s _Crucifix_ (panel (**a**)) as a function of the horizontal (**b**) an vertical (**c**) angular orientation of RX axis, at 6 m distance. Panel (**d**) reports the measured PER for side shifts of \(\pm\)2 m, at 6 m (red) and 8 m (cyan) distance from artwork. shape, so as to encompass a comprehensive set of conditions found in actual museums. We perform extensive tests, recording PER and SNR maps as a function of the position of the RX stage, mimicking realistic viewpoints of the observers. Our results show that the system achieves successful VLC data transfer at baudrates up to 28 kBaud for distances of up to 8 m, and in a with angles between the LED source axis and the observer LoS up to 90\({}^{\circ}\). For what concerns the font, which features a white marble surface and a high degree of cylindrical symmetry, we highlight the possibility to establish error-free communications (PER \(<10^{-5}\)) in the whole 180\({}^{\circ}\) angular range, at a realistic distance of 2 m. We show how the three-dimensional nature of the artifact affects the VLC channel, finding a non-trivial shape of the PER lobe as a function of the angular position of the observer which is quite different when compared to plane artworks (paintings, canvas, etc.). In the case of the wooden _Crucifix_ by [PERSON], located inside a dedicated stone chapet where the minimum allowed observation distance is 6 m, we show the feasibility of successful VLC communication up to 8 m, with best observed PER \(\simeq 4\times 10^{-2}\) at 6 m, which could be improved further by introducing proper software Error Correction Coding (ECC) in our prototype. For this artwork, we also provide for a detailed characterization of effective communication FoV of our system. We observe vertical (horizontal) FoV values of 20\({}^{\circ}\) (25\({}^{\circ}\)) for the reference value PER = 0.1, suggesting a minimum separation of \(\sim\)2 m between artworks, in similar illumination and distance conditions, so as to allow effective discrimination of VLC signals received from nearby artworks. This is an essential parameter to assess the capability of VLC diffusive communication systems to provide indoor positioning and position-based services to users. We also quantify the effects of lateral displacements in the observer position on the quality of VLC transmission, showing the effect of side walls in enhancing the SNR level of VLC signal due to phase-insensitive multipath reflection mechanisms. Our results demonstrate, for the first time, the possibility to implement VLC wireless links through three-dimensional artworks in museums by exploiting standard LED illumination infrastructures. This achievement is an essential step towards the full-fledged deployment of VLC technology in the cultural heritage sector, where sculptures and bas-reliefs are widespread, and completes the characterization of VLC links recently performed on two-dimensional artworks (paintings, canvas) [22].