A method for detecting an image corresponding to at least a monetary banknote is provided. The method includes selecting a detection procedure from a plurality of different detection procedures, and verifying the image according to the selected detection procedure. A method for performing a currency type analysis operation on an image corresponding to at least a monetary banknote is provided. The method includes respectively assigning a plurality of bit values to a plurality of currency types to create a currency type definition table, performing a color analysis operation on the image to generate a color analysis operation result, and determining a currency type of the monetary banknote according to the color analysis operation result and the currency type definition table.