Techniques to Enhance Images for Mokkan Interpretation

In this study, we investigate several methods for enhancing scanned mokkan images to aid archeologists and historians in the interpretation of mokkans. Mokkans are wooden tablets with handwritten characters used in 8th century Japan. Due to damages and natural deterioration, the interpretation of the text on mokkans is difficult even for archeologists and historians. The automatic interpretation of mokkan text is unrealistic due to drastic deterioration. Our aim is to realize an image processing software system for archeologists, specific to the processing of mokkans. This paper evaluates noise reduction and contrast enhancement techniques for inclusion in the system. Several operations such as thresholding and Gaussian blurring are shown to be effective, when used in conjunction with contrast enhancement in the HSV space. We also identified several techniques that allow convenient selection of character strokes in of mokkan images. The selection can then be used as input for character recognition.