Identification method and identification medium

An identification method for performing authenticity determination on an identification medium having code information and having a variable light pattern portion whose pattern of observed light varies with change in an observation angle and for performing reading of the code information, the method comprising:

• generating, for captured image data of the variable light pattern portion of the identification medium, reference image data corresponding to the observation angle as an angle of an imaging direction of the captured image data with respect to a reference line of an observation target surface of the identification medium by a reference image generation unit;
• obtaining a degree of similarity between the captured image data and the reference image data;
• and
• performing, based on whether the degree of similarity exceeds a preset threshold, the authenticity determination about whether the identification medium is authentic and reading the code information,
• wherein an available image selection unit is further provided, the available image selection unit being configured to determine whether the observation angle for the captured image data is within a range available for the authenticity determination on the variable light pattern portion of the identification medium so that to determine whether the captured image data can be compared with the reference image data, thereby selecting captured image data available for the authenticity determination from the captured image data to output the selected captured image data as available captured image data.