1. A method performed by a computing system having one or more processors and a memory, the method comprising: causing a plurality of projectors that are fixedly posed in an environment to each provide, onto a respective area of the environment, a predetermined respective distinct pattern; determining respective poses of the plurality of projectors; determining a map of the environment that identifies, for each distinct pattern, respective locations on one or more surfaces in the environment on which the distinct pattern is detectable; based on sensor data from at least one sensor, identifying a portion of a particular distinct pattern in the environment; using the map and the determined respective pose of a particular projector of the plurality that is providing the particular distinct pattern to make a determination that the portion is located in the environment at a new location different from the respective location identified by the map for the particular distinct pattern; and transmitting an output signal indicating the determination that the portion is located in the environment at the new location different from the respective location identified by the map for the particular distinct pattern.