A solution for monitoring an area including one or more restricted zones is provided. The solution can include one or more monitoring assemblies deployed to acquire image data of the area and independently monitor operations within the area at each monitoring assembly. A monitoring assembly can include one or more local alert components to generate an audible or visual alarm to local personnel. Data regarding static features present in the area can be used to create a registration map of the field of view, which can subsequently enable accurate determination of the three-dimensional location of a target using two-dimensional image data and/or identify an extent of a restricted zone even when one or more of the static features are obscured. Monitoring a target over a series of images can be used to determine whether an alert condition is present.