13. A method executed in an image processing apparatus, comprising: converting input image data to a bitmap data format; extracting, from the input image data, feature information of an object of interest in the input image data of the bitmap data format; referring to a dictionary and determining a similarity between feature information of an object registered in the dictionary and the feature information of the object of interest extracted in the extraction step, wherein in the dictionary, feature information of a plurality of objects are stored, each feature information is classified into one of a plurality of object-groups, and each feature information is associated with the image data in which an object represented by the feature information is included; registering, in the dictionary, the feature information of the object of interest extracted from the input image; determining whether a number of common images between an object-group of interest in the plurality of object-groups and object-groups other than the object-group of interest satisfies a predetermined criterion; and if the number of common images does not satisfy the predetermined criterion, updating the dictionary so that the feature information included in the object-group of interest is unusable when the dictionary is used for determining.
13. A method executed in an image processing apparatus, comprising: converting input image data to a bitmap data format; extracting, from the input image data, feature information of an object of interest in the input image data of the bitmap data format; referring to a dictionary and determining a similarity between feature information of an object registered in the dictionary and the feature information of the object of interest extracted in the extraction step, wherein in the dictionary, feature information of a plurality of objects are stored, each feature information is classified into one of a plurality of object-groups, and each feature information is associated with the image data in which an object represented by the feature information is included; registering, in the dictionary, the feature information of the object of interest extracted from the input image; determining whether a number of common images between an object-group of interest in the plurality of object-groups and object-groups other than the object-group of interest satisfies a predetermined criterion; and if the number of common images does not satisfy the predetermined criterion, updating the dictionary so that the feature information included in the object-group of interest is unusable when the dictionary is used for determining. 16. The method according to claim 13 , wherein the dictionary is used for identifying a person.