An apparatus includes a shaft, an imaging head, and a processor. The shaft includes a distal end sized to fit through a human nostril into a human nasal cavity. The imaging head includes an image sensor assembly, a plurality of light sources, and a plurality of collimators. At least some of the light sources are positioned adjacent to the image sensor assembly. Each collimator is positioned over a corresponding light source of the plurality of light sources. The processor is configured to activate the light sources in a predetermined sequence. The image sensor assembly is configured to capture images of a surface illuminated by the light sources as the light sources are activated in the predetermined sequence.