It learns right? – The misconception about recognition learning

by Ilya Evdokimov | Dec 21, 2009 | data capture

OCR and ICR arguably learn everytime it's used

Because of the way the market has come to understand OCR ( typographic recognition ) and ICR ( hand-print recognition ) there is no surprise when some of the most common questions and expectations about the technology appear to be fact from a tarot card. Before I talked about one of these questions “How accurate is it” and how the basis of this question is completely off and can come to no good, here is a similar “It learns right?” which is quite a loaded question, so lets explore.

Learning is the process of retaining knowledge for a subsequent use. Learning is based in the realm of fact, following the same exact steps creates the same exact results. OCR and ICR arguably learn everytime it’s used, for example engines will do one read and go back and re-read characters with low confidence values using patterns and similarities they identified on a single page. This is on a page level, and after that page is processed this knowledge is gone. This is where the common question comes in. What people expect happens is that the OCR engine will make an error on a degraded character that is later corrected, now that it’s been corrected once that character will never have an error again, assuming this is true then you would believe that at some point the solution will be 100% accurate when all the possible errors are seen.

WRONG! Because the technology does not remember sessions, this is also the reason it works so well. Can you imagine if for example a forms processing system was processing all surveys generated by a single individual ( this is true for OCR as well ), the processing happened enough that in learned all possible errors and was 100%. Then you start processing a from generated by a new individual, your results on the first form type and the new will likely be horrendous, not because of the recognition capability, all because of supposed “learning”. In this case learning killed your accuracy as soon as any variation was introduced.

What most people don’t realize is that characters change, they change based on paper, printer, humidity, handling conditions, etc. In the area of ICR it’s exaggerated as characters for a single individual change by the minute, based on mood and fatigue. So learning is a misnomer as what you are learning is only one page, one printer, one time, one paper who will likely never repeat again. A successful production environment allows as much variation that is possible at the highest accuracy and this is not done with this type of learning.

Things that can be learned: Like I said before a single pass of a page, can have a second pass of low confident characters with learned patters on that page. In the world of Data Capture field locations can be learned, field types also can be learned. In the world of classification documents based on content are learned, this in fact is what classification is.

While the idea of errors never repeating again is attractive, people need to understand this technology is so powerful because of the huge range of document types and text that can be processed, and this is only possible by allowing variance.

Chris Riley – Sr. Solutions Architect