A image processing apparatus includes a scanner scanning data from both document sheets and Optical Mark Reader (OMR) data sheets thereon, a converter converting data scanned by the scanner to digital multi-valued coded data, a multiplexer selecting a suitable threshold level for recognizing the digital...http://www.google.com.au/patents/US6128419?utm_source=gb-gplus-sharePatent US6128419 - Image processing apparatus having scanner and method for sharing the scanner with an optical mark reader
