  Integrated sensing and communications (ISAC) has been deemed as a key
technology for the sixth generation (6G) wireless communications systems. In
this paper, we explore the inherent clustered nature of wireless users and
design a multi-user based environment reconstruction scheme. Specifically, we
first select users based on the estimation precision of channel's multipath,
including the line-of-sight (LOS) and the non-line-of-sight (NLOS) paths, to
enhance the accuracy of environment reconstruction. Then, we develop a fusion
strategy that merges communications signalling with camera image to increase
the accuracy and robustness of environment reconstruction. The simulation
results demonstrate that the proposed algorithm can achieve a remarkable
sensing accuracy of centimeter level, which is about 17 times better than the
scheme without user selection. Meanwhile, the fusion of communications data and
vision data leads to a threefold accuracy improvement over the image only
method, especially under challenging weather conditions like raining and
snowing.
