1. A method for performing a color analysis operation on an image corresponding to at least a monetary banknote, the method comprising: dividing the image into a plurality of blocks; performing a block analysis operation on each block of the image to generate a block analysis result of each block; performing a super-block analysis operation on each super-block of the image to generate a super-block analysis result of each super-block by a hardware imaging device, wherein each super-block includes more than one block; and performing a global analysis operation on the image to identify a currency type of the monetary banknote according to super-block analysis results of super-blocks of the image; wherein the step of performing the super-block analysis operation on each super-block of the image comprises: for each super-block: when detecting that most of blocks in the super-block correspond to a specific currency type, determining that the super-block has the specific currency type.