A method for image processing comprising inputting and reading a combined image that includes a latent image unperceivable by the human eye, a patterned image in the background allowing the latent image to appear clearly on a recording medium when data recorded on a recording medium is copied onto another recording medium, and text and/or image data embedded with a digital watermark. The text and/or image data is extracted from the combined image and the digital watermark extracted from the text and/or image data. A permission code enabling copying of image data composed of a combination of a patterned image and the extracted text and/or image data onto a recording medium is input. The copying is regulated based on the extracted digital watermark and the permission code.