17. The system of claim 11 , wherein each word image is assigned to a word cluster based on its feature vector, by: calculating a distance between each one of the multiple word images and every other one of the multiple word images, based on feature vectors associated with those word images; selecting, from among the multiple word images, two of the word images that are closest in distance to each other; and assigning the two of the word images to the word cluster.
18. The system of claim 17 , wherein the stored instructions further configure the system to: select, from among the multiple word images other than the assigned word images, an additional one of the multiple word images that is closest to the representative word image; assign the additional one of the word images to the word cluster; and repeat the foregoing elements until a predetermined number of the multiple word images have been assigned to the word cluster.