A radio frequency (RF) imaging device comprises a position sensor, an optical sensor, a processor, and an output. The position sensor determines a position of the RF imaging device relative to a surface. The optical sensor captures optical image data representing an optical image of an area of the surface. The optical image data is associated with position data representing a position relative to the surface derived from the determined position of the RF imaging device. The derived position data corresponds to the area of the surface imaged by the optical sensor. The processor produces a composite image in which one or more portions of the optical image data are simultaneously viewable with RF image data representing an RF image of a space behind the surface at the same position as the optical image data. The output displays the composite image. The output may be a projector.