## 5 Smartphone App Development and Evaluation
### Smartphone App Development  
The app was developed using the Flutter application framework ([[https://flutter.dev/](https://flutter.dev/)]([https://flutter.dev/](https://flutter.dev/)), accessed on 11 July 2022), which allows cross-platform development, and so it can be compiled to run in both major mobile operating systems, Android and iOS. The app is supported by an SQLite database containing information about the artworks and their creators, as well as high-resolution images of each artwork, and thus it does not require any network connection to function. It provides the user with the opportunity to browse \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**ViewDistance** & **1 m** & **1.5 m** & **2.5 m** & **Avg** & **1 m** & **1.5 m** & **2.5 m** & **Avg** \\ \hline \multicolumn{8}{c}{**Brightness = 255/255 (Visitor height = 0\%)**} & \multicolumn{8}{c}{**Brightness = 200/255 (Visitor height = 0\%)**} \\ \hline Forward & 100.0\% & 100.0\% & 94.2\% & 98.1\% & 100.0\% & 100.0\% & 93.2\% & 97.8\% \\ Downwards & 100.0\% & 99.9\% & 92.1\% & 97.3\% & 100.0\% & 100.0\% & 91.4\% & 97.1\% \\ Upwards & 100.0\% & 96.1\% & 78.9\% & 91.7\% & 98.1\% & 98.8\% & 77.8\% & 91.5\% \\ Left & 100.0\% & 100.0\% & 90.6\% & 96.9\% & 100.0\% & 100.0\% & 85.4\% & 95.1\% \\ Right & 100.0\% & 100.0\% & 87.8\% & 95.9\% & 100.0\% & 100.0\% & 91.4\% & 97.1\% \\ Avg & 100.0\% & 99.2\% & 88.7\% & 96.0\% & 99.6\% & 99.8\% & 87.8\% & 95.7\% \\ \hline \multicolumn{8}{c}{**Brightness = 150/255 (Visitor height = 0\%)**} & \multicolumn{8}{c}{**Brightness = 100/255 (Visitor height = 0\%)**} \\ \hline Forward & 100.0\% & 100.0\% & 93.0\% & 97.7\% & 100.0\% & 100.0\% & 93.4\% & 97.8\% \\ Downwards & 100.0\% & 100.0\% & 91.0\% & 97.0\% & 100.0\% & 100.0\% & 88.1\% & 96.0\% \\ Upwards & 97.5\% & 97.8\% & 78.1\% & 91.1\% & 99.2\% & 94.2\% & 78.5\% & 90.7\% \\ Left & 100.0\% & 100.0\% & 86.6\% & 95.5\% & 100.0\% & 100.0\% & 91.1\% & 97.0\% \\ Right & 100.0\% & 100.0\% & 93.1\% & 97.7\% & 100.0\% & 99.8\% & 89.8\% & 96.5\% \\ Avg & 99.5\% & 99.5\% & 88.4\% & 95.8\% & 99.8\% & 98.8\% & 88.2\% & 95.6\% \\ \hline \multicolumn{8}{c}{**Brightness = 50/255 (Visitor height = 0\%)**} & \multicolumn{8}{c}{**Visitor height = 50\% (Brightness = 255/255)**} \\ \hline Forward & 89.2\% & 92.6\% & 86.1\% & 89.3\% & 68.1\% & 70.4\% & 49.9\% & 62.8\% \\ Downwards & 98.0\% & 98.8\% & 78.0\% & 91.6\% & 47.6\% & 54.2\% & 25.1\% & 42.3\% \\ Upwards & 87.2\% & 89.1\% & 56.9\% & 77.8\% & 60.5\% & 61.0\% & 33.4\% & 51.6\% \\ Left & 99.9\% & 99.0\% & 85.4\% & 94.8\% & 72.0\% & 72.6\% & 46.4\% & 63.7\% \\ Right & 97.4\% & 98.0\% & 65.2\% & 86.9\% & 56.9\% & 64.4\% & 28.5\% & 49.9\% \\ Avg & 94.4\% & 95.5\% & 74.3\% & 88.1\% & 61.0\% & 64.5\% & 36.7\% & 54.1\% \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Prediction accuracy (%) for all brightness variations and visitor occlusions at 50% height. Figure 9: Misclassifications between artworks 5 and 7: (a) artwork 5; (b) artwork 7; (c,d) taking a photo of artwork 5 under certain angles of view. and view information about artworks and artists, as depicted in Figure 10. The artist page includes links to all the artist's works included in the app. The app's UI is currently available in both Greek and English and can be readily internationalized to any other language if deemed necessary. The MobileNetV2 model can recognize artworks in visual data collected by a camera mounted on the body or held in the user's hands. However, for the app's development, we chose to continue with the latter approach providing the user with the opportunity to select the artwork of their preference for recognition as follows: As soon as the user clicks the \"Identify artwork\" button, the app instructs the user to point their smartphone camera to the artwork they want to identify (Figure 10d) and begins sending individual frames from the camera stream to the CNN for analysis.