Table 1.

The most important features that correspond to the user’s needs.

Feature	Description
Analysis Type	The system needs to provide a fast processing for the exchanged information between the user and sensors. For example, the system that detects the obstacle that is 2 m in front of the user in 10 s cannot be considered as real time system [12]
Coverage	The system needs to provide its services indoors and outdoors to improve the quality of visually-impaired people’s lives
Time	The system should perform as well in day time as at night time
Range	It is the distance between the user and the object to be detected by the system. Ideal minimum range is 0.5 m, whereas the maximum range should be more than 5 m. Further distance is better
Object Type	The system should avoid the sudden appearance objects, which means the system should detect the dynamic objects as the static objects