1. A noise-removing system comprising: an iris controller configured to control a degree of openness of a lens iris; a noise image analyzer configured to perform an analysis of a noise image that is obtained in a state when the iris controller closes the iris; a normal image analyzer configured to perform an analysis of a normal image that is obtained in a state when the iris controller opens the iris; and a noise remover configured to remove noise from an image, based on a result of the analysis performed by the noise image analyzer and the analysis performed by the normal image analyzer.