Shared Questionnaire System

Hello,
When I use sqs-reader ,I find sqs-reader generates RESULT directory and config.xml in the directory.
Firstly, can you tell me the meaning of the markRecognition(doubleMarkIgnoranceThreshold,resolutionScale,horizontalMargin,verticalMargin) in config.xml ?
And why is verticalMargin value negative number? What is the meaning of the resolutionScale?
Secondly,I find the "getGrayscaleDensityWithFilter" method is the core of the recognition algorithm,but the method is hard to understand for me .Can you elaborate the getGrayscaleDensityWithFilter method ? And I know you are very busy and hope that my questions don't waste your too much time.
Thanks very much! Hope for your answers.