10. A system for automatically identifying portions of an image of a physical scene as depicting physical objects of predefined types in the physical scene, the system comprising: a digital camera capturing two-dimensional data from the physical scene, the two-dimensional data being in the form of the image of the physical scene; a lidar device capturing three-dimensional data from the physical scene; and a computing device comprising: one or more processing units; and computer-readable media comprising computer-executable instructions, which, when executed by the one or more processing units, cause the computing device to: generate correspondences between subsets of the two-dimensional data and subsets of the three-dimensional data; identify, based on a first subset of the two-dimensional data, a first portion of the image of the physical scene as depicting a physical object of a first predefined type; select a first subset of the three-dimensional data that corresponds to the first subset of the two-dimensional data based on the generated correspondences; and determine, based on the first subset of the three-dimensional data, that the identified first portion of the image does not actually depict a physical object of the first predefined type.
12. The system of claim 10 , wherein the computer-executable instructions that cause the computing device to determine, based on the first subset of the three-dimensional data, that the identified first portion of the image does not actually depict a physical object of the first predefined type comprise computer-executable instructions, which, when executed by the one or more processing units, cause the computing device to: determine, based on the first subset of the three-dimensional data, that the identified first portion of the image depicts a physical object whose physical size, physical shape or physical location are inconsistent with physical objects of the first predefined type.