An imaging device incorporated in an omnidirectional video capturing system including an imager, a memory, and a transmitter. The imager includes imaging lenses to capture images from a plurality of directions. The memory stores projective transformation data. The projective transformation data includes photographing direction data representing the plurality of directions and projection data representing image heights of the images associated with angles at which light rays enter the imaging lens. The transmitter reads the projective transformation data stored in the memory, and transmits frame data of the images and the projective transformation information to an image processing device of the omnidirectional video capturing system.