1. An image processing apparatus comprising: a memory that stores plural kinds of feature information for identifying an object and a period of time, set for each kind of the feature information, for which the feature information is effective in connection with each other; an extraction unit that extracts a feature from image data; and a matching unit that compares the feature extracted by said extraction unit with the feature information, which is within the set period of time, among the feature information stored in said memory and recognizes an object.