US Patent 10571591 RF in-wall image registration using optically-sensed markers

A radio frequency (RF) imaging device comprises an optical position sensor, an RF sensor assembly, a processor, and a memory. The optical position sensor captures an optical image of a field of view and outputs data representing the optical image. The RF sensor assembly is disposed at a first position and receives an RF signal for capturing an RF image of a portion of a space disposed behind a surface at the first position and outputs data representing the RF signal. The processor receives the data representing the optical image and the RF signal, and determines that an optical signature of a reference marker is present in the optical image. If the optical signature is present in the optical image, the processor defines the first position of the RF assembly as a reference position. The memory stores the data representing the RF signal in association with the reference position.