IMAGE PROCESSING APPARATUS AND METHOD

An image processing apparatus for adding additional information to an input image so that it cannot be easily identified by the human eye, and a method of operating such an apparatus, are provided. Various functions are described for adding predetermined additional information to the input image in such a way that it cannot be easily identified by the human eye. The apparatus includes a first input device for inputting first additional information by a first data input method; a second input device for inputting second additional information by a second data input method different from the first input method; a selection device for selecting one of the first and the second input device; an addition device for adding the first or second additional information, input from the first or second input device, to the input image data so that it cannot be easily identified by the human eye; and an output device for outputting the image data to which the additional information is added by the addition device.