1. A computer-implemented method, comprising: classifying clip images defined in a received OCR output of a document processed by an optical character recognition (OCR) process into a plurality of clusters of clip images, each cluster including clip images that are assigned the same one or more character codes by the OCR process, wherein the OCR process performed on one or more computers generates the received OCR output; processing clip images in each of the plurality of clusters to generate exactly one cluster image for each cluster; classifying a first cluster in the plurality of clusters as a suspect cluster; identifying a nearest cluster to the suspect cluster, the nearest cluster being nearest based on a shape distance between the cluster image for the nearest cluster and the cluster image for the suspect cluster; and replacing the one or more character codes assigned to the suspect cluster with character codes assigned to the nearest cluster at each occurrence of one of the clip images of the suspect cluster in the OCR output to produce a modified OCR output.