Optical mark recognition can read scanned OMR sheets which are clearly scanned in black and white using a quality image scanner, preferably a document scanner, with an automatic paper feed tray
, for easy scanning. The scanned images of the forms that will be detected with optical mark recognition
must be sharp and clear and should be scanned at a fairly high resolution, around 300 dpi, unless you have a high end scanner which can scan particularly clearly at a lower resolution. This is because page identifying barcodes must be accurately detected for the omr sheets to be recognized by optical mark recognition and the filled in checkboxes must be accurately detected to capture analysis data which is free from error.
How to Scan OMR Sheets
OMR sheets being scanned with a document scanner.
Scanned OMR sheet images must be clear and sharp for page identifying barcodes to be free from imperfections so they can be read by and accepted by the optical mark recognition.
Barcode Detection: This is a clearly scanned barcode but if there were imperfections in the scanned image of this barcode (such as white dots on the black) the omr sheet would be unrecognized by optical mark recognition and the omr sheet wouldn’t be processed. The page would have to be re-scanned and uploaded again.
Requirements for Scanning OMR Sheets
Flatbed scanners and document scanners are image scanners and are used for scanning OMR sheets for optical mark recognition form processing. A decent quality document scanner with an automatic paper feeding tray is recommended for fast easy scanning of OMR sheets, where as Flat bed scanners are used if not many OMR sheets are being scanned.A TWAIN compliant scanner is desirable for one click scanning.OMR software requires clearly scanned images of the OMR sheets to accurately detected the barcodes and the checkboxes. A resolution setting of between 200 and 300dpi is recommended for scanning OMR sheets but this will depend on the quality of the scanner that is being used. If the image produced isn’t clear or has imperfections a higher resolution setting should be tried. The OMR sheet images are saved as PNG, GIF OR TIFF files, but they are not photographs so don’t save as JPEG files.
Recommended Scanners for Optical Mark Recognition
Optical mark recognition captures the value of checkboxes which have been detected as filled and converts this information to readable checkbox value data(A,B,C,D) . Optical mark recognition is fast and accurate and captures and processes the checkbox responses into readable information from OMR sheet forms at a rate of around 30 pages per minute, saving much valuable time and producing faster analysis data from multiple choice response forms used for exams, tests, surveys, checklists, order forms and ballot forms.
Tips for OMR sheet Scanning
- Place the OMR sheets in the paper feeding tray, without overloading, and align the paper guides.
- If you don’t have a TWAIN compliant scanner, scan omr sheets at 300 dpi black and white and save as Tiff image files.
- Don’t fold omr sheets as fold line will often show up as black lines on the scanned images which could interfere with detection of the checkboxes.
- Clean the scan head regularly to avoid black marks appearing on the scanned images.
A clearly scanned OMR sheet image. Checkboxes that have been fully shaded with a dark pen or pencil are accurately detected and the value data is captured by optical mark recognition.
Clearly scanned omr checkboxes. The filled checkboxes are accurately detected and the checkbox values are captured. Unclearly scanned OMR sheets can cause all sorts of imperfections with the checkbox images such as broken borders and black where there should be white. Imperfections can cause distortion of the number of black pixels detected inside checkboxes which causes errors with the captured mark data.