In accordance with the present invention, there is provided A method for implanting surgical device. To this end, a data processing apparatus of this invention has input means for inputting image data consisting of a plurality of coefficients, and embedding means for embedding digital-watermark information in coefficients having values falling within a predetermined range of the input image data. The number of display panels to be processed in the first step is greater than both the number of display panels having been processed in the second step and the number of display panels to be introduced into the third step.