You need to specify threshold values to distinguish unchecked from checked areas. Complete the following steps If the engine cannot decide whether the OMR zone is checked, such as for all degrees of blackness outside the ranges specified, it returns a question mark, similar to the behavior of OCR engines with unrecognized characters. Ensure that the OMR zone is not smaller than the specified zone, and that there is only one rectangle in the specified zone. In particular, if your OMR zones are filled in manually, do not choose too high values for the upper limit of checked OMR zones. A very high degree of blackness may rather indicate that a manual entry has been corrected. If this can be safely excluded, you can also configure the OMR recognition to never return question marks.
- Switch to Definition Mode.
- In the left pane, on the Classes tab, select a class.
- In the left pane, select the Fields tab.
- In the right pane, on the Field tab, click the OCR Settings button.
- In the Field OCR Settings Properties dialog box, under Recognition Type, select OMR.
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Optional. On the
General tab, modify the following settings.
- Unchecked - Lower [%]. Lower limit for degree of blackness in percent.
- Unchecked - Upper [%] Upper limit for degree of blackness in percent.
- Unchecked - Returnvalue A number or a character string. This value is returned if the measured degree of blackness is between the lower and the upper value for Unchecked. In this case, it can reliably be assumed that the OMR zone is unchecked.
- Checked - Lower [%] Lower limit for degree of blackness in percent. The value should of course exceed the upper limit for Unchecked.
- Checked - Upper [%] Upper limit for degree of blackness in percent.
- Checked - Returnvalue A number or a character string. The engine returns the value if the measured degree of blackness is between the lower and the upper value for Checked. In this case, it can reliably be assumed that the OMR zone is checked.
- Search For OMR Box An algorithm searches for a black square box within the defined zone. For better recognition results, the recognition is then applied for this square box zone. If nothing was found, the engine searches for a check mark within the originally defined zone. If an OMR box was found, the returned value corresponds to the specified Returnvalue. The returned value is “?” if no OMR box was found.