How to explain the blind spot of property monitoring?

This explanation refers to the place where the camera can't shoot.

The blind area of property monitoring refers to the place that the camera can't shoot, or the area where the line of sight is blocked or can't be directly observed by itself. These areas can't be imaged on the camera sensor (CCD/CMOS), so they can't be monitored and recorded. In the property monitoring system, some corners, stairs, corridor corners, doorways and other places that are difficult to cover may have blind spots. These places may not be photographed by the camera because of location, angle, line of sight and other reasons.