Disclosed is a surveillance apparatus such as a surveillance camera and a digital video recorder. The surveillance apparatus includes: an analog-to-digital converter configured to convert an analog video signal, of at least one image of a region captured by an optical system, into digital video data of the region; and a main controller configured to detect a current motion region from the digital video data of the region, remove a high frequency component of the region except the current motion region, and transmit the digital video data of the region, from which the high frequency component is removed, to a target device over a communication network.