Money identifying method and device

A money identifying device, comprising:

• image obtaining means for obtaining a surface image of a coin;
• extracting means for determining center coordinates and radius of the coin on the basis of the surface image of the coin obtained by the image obtaining means and extracting from the surface image a previously set particular threshold calculation range containing a feature area of the coin subject to judgment and not containing a background, on the basis of the determined center coordinates the radius;
• binary threshold calculation means for determining a density histogram of an image of the threshold calculation range extracted by the extracting means and calculating a binary threshold value for binarizing from the determined density histogram by applying a discriminating analysis;
• binarizing means for binarizing the surface image obtained by the image obtaining means using the binary threshold value calculated by the binary threshold calculation means;
• and
• identifying means for identifying the coin on the basis of the binary image binarized by the binarizing means.