Abstract: An image classifying method includes the following operations: reducing an order of a color of a first image to generate a first order reduction image, wherein the first order reduction image includes several first image blocks; obtaining a second order reduction image from a database, wherein the second order reduction image includes several second image blocks; calculating several block color difference values between the first order reduction image and the second order reduction image respectively according to differences between a color value of each of the first image blocks and a color value of each of the second image blocks; and determining whether or not the first image belongs to a same category as the second order reduction image according to the block color difference values between the first order reduction image and the second order reduction image.

Abstract: An image classifying method includes the following operations: reducing an order of a color of a first image to generate a first order reduction image, wherein the first order reduction image includes several first image blocks; obtaining a second order reduction image from a database, wherein the second order reduction image includes several second image blocks; calculating several block color difference values between the first order reduction image and the second order reduction image respectively according to differences between a color value of each of the first image blocks and a color value of each of the second image blocks; and determining whether or not the first image belongs to a same category as the second order reduction image according to the block color difference values between the first order reduction image and the second order reduction image.

Abstract: A character string recognition method includes: selecting a keyword database, which corresponds to content of a character string, from a number of keyword databases, wherein the selected keyword database comprises at least one prefix keyword, comparing the content of the character string with the at least one prefix keyword, when the content of the character string corresponds to one of the at least one prefix keyword, updating the content of the character string based on a definition of the prefix keyword which corresponds to the content of the character string, and when the content of the character string does not correspond to any of the at least one prefix keyword, selectively ending the character string recognition method, and outputting the content of the character string.