Abstract: A method of identifying a match for a model string in an image includes performing optical character recognition on the image to identify a candidate string including a plurality of candidate characters. A minimum edit cost is determined between the candidate string and the model string, the model string including a plurality of model characters. The minimum edit cost represents a cost of edit operations performed on the candidate string to satisfy characteristics of the model string. If there is a missing or invalid candidate character in the candidate string, the minimum edit cost includes a special cost of an edit operation for identifying the missing or invalid candidate character. If based on the minimum edit cost the candidate string is a match for the model string, a partial string corresponding to the candidate string including a label representing the missing or invalid character is returned as the output string.