Abstract. In the paper, a portable off-line OCR and bi-linguistic translation system (Chinese to English, English to Chinese)—Electronic Reading Pen (ERPen) is designed and implemented. The constitution of ERPen hardware is designed and several modules, including CCD line array acquisition, wheel driven unit, FLASH management and USB interface are implemented. Moreover, the embedded software, consisting of image preprocessing, character segmentation and recognition, and corpus based postprocessing, is also discussed and implemented. A novel segmentation approach, central growth algorithm, is proposed and applied in ERPen system. Experimental results have shown that ERPen is effective to tackle printed character recognition and translation.