A computer-based 3D imaging method is for a wireless endoscope unit, equipped with a camera, of the size of a capsule that can be swallowed by the patient. When the notebook computer is used, the keyboard and the screen can be in the state of being separated from each other in use, so that the screen and the keyboard of the notebook computer are used separately. Pulse width varying circuitry varies the pulse width of the clock signal based on the result of comparing the first signal and the second signal.