Patent ID: 7762947

Claim:
A capsule endoscope inserted into a subject and picking up an image inside the subject, comprising: an illuminating unit that illuminates an interior surface of the subject with illuminating light; an imaging unit that generates an electronic signal corresponding to incident light and outputs the electronic signal generated; a noise canceller that eliminates noise charges which are caused by dark current and accumulated in the imaging unit; a timing controller that controls driving starting timing of the noise canceller to lay within a period after the imaging unit finishes an output operation of the electronic signal, the timing controller matching a driving starting timing of the illuminating unit with a driving stopping timing of the noise canceller; a comparing unit that compares a predetermined reference luminance with a luminance of the image picked up by the imaging unit; and a light-emission-amount adjustment unit that adjusts an emission amount of the illuminating light output from the illuminating unit based on a comparison result of the comparing unit wherein the comparing unit derives a magnitude correlation between the image luminance and the reference luminance, and the light-emission-amount adjustment unit adjusts a driving period of the illuminating unit so as to decrease the driving period by a predetermined time when the image luminance exceeds the reference luminance, and adjusts the driving period of the illuminating unit so as to increase the driving period by a predetermined time when the image luminance is below the reference luminance.