Optical Data Capture Optical Mark Recognition OMR UNSD

Optical Data Capture: Optical Mark Recognition (OMR) UNSD Regional Workshop on Census Data Processing for the English speaking African Countries: Contemporary technologies for data capture, methodology and practice of data editing Dar es Salaam, Tanzania, 9 -13 June 2008

Summary o o o o Concept/Definition Forms Design Scanners & Software Storage Accuracy OMR Advantages and Disadvantages Commercial Suppliers UNSD Regional Workshop on Census Data Processing for the English speaking African Countries: Contemporary technologies for data capture, methodology and practice of data editing Dar es Salaam, Tanzania, 9 -13 June 2008

Definition/Concept of OMR o A technology that allows an input device (e. g. imaging scanner) to read hand-drawn marks such as small circles or rectangles on specially designed paper. n Often used for test, survey, or questionnaire answer sheets. UNSD Regional Workshop on Census Data Processing for the English speaking African Countries: Contemporary technologies for data capture, methodology and practice of data editing Dar es Salaam, Tanzania, 9 -13 June 2008

Definition/Concept of OMR o The process of capturing data by contrasting reflectivity at predetermined positions on a page n Sometimes Referred to as Optical Mark Reader UNSD Regional Workshop on Census Data Processing for the English speaking African Countries: Contemporary technologies for data capture, methodology and practice of data editing Dar es Salaam, Tanzania, 9 -13 June 2008

OMR Forms p “Reads” mark information in the form of numbers or letters and put it into the computer. p The marks have to be precisely located UNSD Regional Workshop on Census Data Processing for the English speaking African Countries: Contemporary technologies for data capture, methodology and practice of data editing Dar es Salaam, Tanzania, 9 -13 June 2008

OMR Forms n An OMR works with a specialized document and contains timing tracks along one edge of the form to indicate scanner where to read for marks which look like black boxes on the top or bottom of a form. UNSD Regional Workshop on Census Data Processing for the English speaking African Countries: Contemporary technologies for data capture, methodology and practice of data editing Dar es Salaam, Tanzania, 9 -13 June 2008

OMR Forms o Timing tracks indicate where to read for marks and indicate where to clip images UNSD Regional Workshop on Census Data Processing for the English speaking African Countries: Contemporary technologies for data capture, methodology and practice of data editing Dar es Salaam, Tanzania, 9 -13 June 2008

OMR Scanners and Software o Have specifically placed LEDs (Light-emitting diodes) o LEDs sense marks in certain columns once a timing track is detected o Software interprets the output from the scan and translates it to the desired format (e. g. ASCII) UNSD Regional Workshop on Census Data Processing for the English speaking African Countries: Contemporary technologies for data capture, methodology and practice of data editing Dar es Salaam, Tanzania, 9 -13 June 2008

OMR Scanners and Software o Scanner Characteristics: n ~85 pages per minute Kodak 3000 Series) (e. g Axiome AXM 980 or n ~130 pages per minute (e. g. Kodak i 830) o Software Characteristics: n performing specific imaging functions such as: - image acquisition, - file conversion, - data extraction, and - file read/write commands (e. g. ISIS) UNSD Regional Workshop on Census Data Processing for the English speaking African Countries: Contemporary technologies for data capture, methodology and practice of data editing Dar es Salaam, Tanzania, 9 -13 June 2008

OMR Storage Characteristics o Storage n Barcodes: Identification of forms n OMR Marks and Barcodes are read and moved directly into a database management system (e. g. SQL) then to a census database n Images are not normally scanned and stored n However, The capability of saving the scanned image is there! UNSD Regional Workshop on Census Data Processing for the English speaking African Countries: Contemporary technologies for data capture, methodology and practice of data editing Dar es Salaam, Tanzania, 9 -13 June 2008

OMR Storage Characteristics o Storage of Scanned Images (Recent Mainstream Capability) n Increasingly critical for validating results n Images can be used for correcting poorly filled out forms n Images can be used for validating results n Comprehensive image database of forms UNSD Regional Workshop on Census Data Processing for the English speaking African Countries: Contemporary technologies for data capture, methodology and practice of data editing Dar es Salaam, Tanzania, 9 -13 June 2008

OMR Accuracy o Accuracy n To achieve high accuracy, well structured design and good quality printing of these forms is critical. n If the timing track and the bubbles on the form are not in the exact columns where the LEDs in the read head can detect them (Skew), there is no way for the scanner to read the marks (Float) o This is referred to as skew and float UNSD Regional Workshop on Census Data Processing for the English speaking African Countries: Contemporary technologies for data capture, methodology and practice of data editing Dar es Salaam, Tanzania, 9 -13 June 2008

OMR Advantages o OMR is a data collection technology that does not require a recognition engine. Therefore: n It is fast, using minimum processing power to process forms n Costs are predictable and defined n OMR capture speeds range around 4000 forms per hr UNSD Regional Workshop on Census Data Processing for the English speaking African Countries: Contemporary technologies for data capture, methodology and practice of data editing Dar es Salaam, Tanzania, 9 -13 June 2008

OMR Disadvantages o Disadvantages n OMR cannot recognize hand-printed or machineprinted characters. n With OMR, images of forms are not captured by scanners so electronic retrieval is not possible. n Tick boxes may not be suitable for all types of questions UNSD Regional Workshop on Census Data Processing for the English speaking African Countries: Contemporary technologies for data capture, methodology and practice of data editing Dar es Salaam, Tanzania, 9 -13 June 2008

OMR Challenges/Issues o The entire process must be tested n Information Capture n Recognizing n Verifying Results o Questionnaire Design and Preparation is Critical n Forms must be readable to the scanner when collected o Field Operators must take particular care in filling out questionnaires n Completeness and consistency checks must be in place n Careful care must be taken for the condition of the Questionnaire (dust, humidity, transportation, etc) UNSD Regional Workshop on Census Data Processing for the English speaking African Countries: Contemporary technologies for data capture, methodology and practice of data editing Dar es Salaam, Tanzania, 9 -13 June 2008

Major Commercial Suppliers o Pearson NCS - UK Company with US manufacturing base (http: //www. ncspearson. com) o Scantron - US Company with US manufacturing base (http: //www. scantron. com) o Sekonic - Japanese Company with Japanese manufacturing base (http: //www. sekonic. co. jp) o Axiome - Swiss Company with Swiss Manufacturing base (http: //www. axiome. ch) UNSD Regional Workshop on Census Data Processing for the English speaking African Countries: Contemporary technologies for data capture, methodology and practice of data editing Dar es Salaam, Tanzania, 9 -13 June 2008

THANK YOU! UNSD Regional Workshop on Census Data Processing for the English speaking African Countries: Contemporary technologies for data capture, methodology and practice of data editing Dar es Salaam, Tanzania, 9 -13 June 2008