the protective housing interposes between the imaging device and the region to be imaged thus protecting the imaging device from oil spillage knocks and other hazards preferably the protective housing comprises a transparent region located between the imaging device and the region to be imaged in an embodiment the transparent region comprises laminated glass and in a prototype triplex laminated glass of 22 mm thickness was used preferably the mounting is a floor mounting for mounting the imaging device at floor level in a particularly preferred embodiment the mounting is a flush floor mounting for insertion into a floor cavity reference is now made to fig4 which is a simplified flow chart showing operation of a preferred embodiment of the present invention in fig4 a vehicle is driven onto a rail carrying an imaging device the invention is not however restricted to u201c drive on u201d inspection of vehicles and thus as an alternative it is possible to insert a rail carrying an imaging assembly into any kind of space that it is difficult to access and then to operative the assembly to scan the space in either case the imaging device then scans the space either under control of a program or according to instructions from an operator the output is viewed and the operator decides whether any kind of action is necessary the output may additionally be recorded if desired reference is now made to fig5 which is a flow chart showing operation according to an alternative embodiment of the present invention stages that are identical to those of fig4 are not described again.