1. An image processing apparatus comprising: an arrangement section, arranged to arrange a code string of additional information to be embedded in an image into a two-dimensional form; a search section, arranged to search the arranged additional information for an area in which a same code consecutively appears for a predetermined number of codes, to find code consecutiveness; a setting section, arranged to set a periodic image pattern used for embedding the arranged additional information based on a search result of the search section, wherein in a case where code consecutiveness is found, a first periodic image pattern is set for a part of code positions in an area having code consecutiveness, and a second periodic image pattern, which has a pattern phase different from a pattern phase of the first periodic image pattern is set for another part of the code positions so as to prevent repetition of the same periodic image pattern; and an embedding section, arranged to embed the arranged additional information in the image in accordance with the periodic image pattern set by the setting section, wherein at least the embedding section is implemented using a processor.