Welcome to Kofax Capture Help > Administration > User Interface > Windows (Dialog Boxes) > Create Index Zone Window - General Tab > Create Index Zone Window - OMR Tab

Create Index Zone Window - OMR Tab

Use this window to select OMR options for an index zone.

Related Tab

Pixel Percentage Threshold

Override default

Select this check box if you want to use the settings from this window instead of the default settings for the recognition profile. The default settings are the values specified in the Recognition Profile window.

Auto Set Threshold button

Click this button if you want the Administration module to automatically calculate an appropriate threshold value for you. This function works by calculating the ratio of black to white pixels within the zone box you have drawn around the OMR shape. If that threshold value is exceeded, the OMR engine determines that the item has been marked. This button should only be used on unmarked OMR shapes on your sample page.

You can use this button as a calculator to determine a starting point for setting the threshold. Since the Auto Set Threshold button does not display in the Recognition Profile window, you can take advantage of it here and use the same value for the profile.

To use the Auto Set Threshold button as a calculator:

  • On the sample page, size your index zone so that there is only a small amount of space around the item.

  • Only use Auto Set Threshold on items that are not marked.

  • Make a note of the automatically determined threshold value for a typical unmarked zone; you will need it later.

  • Try to make all the other OMR index zone boxes the same size as the one used for determining the threshold.

  • In the Recognition Profile window, manually set the threshold for the other OMR index zones to the automatically determined threshold value that you noted above.

Follow the preceding points to ensure that a check mark cause the pixels to exceed the threshold.

Use the slider to manually select the pixel percentage threshold. If the percentage of black pixels (compared to total pixels in the zone) is above this limit, the zone returns a marked value (the default is 1). Otherwise, it returns an unmarked value (the default is 0).

See Advanced OMR Settings window for more information on pixel percentage threshold calculations.

Note Do not confuse threshold with confidence. One method of calculating confidence involves the percentage of black pixels, which for an empty OMR zone may equal or be close to the threshold. Threshold and confidence are two different numbers used for different purposes. Threshold is the percentage of black pixels above which Kofax Capture determines the zone has been marked. Confidence is a measure of certainty about that determination, and controls the border color of zones in the Validation and Verification modules.

Return Values

Override default

Check this box if you want to use these settings instead of the default settings. The default settings are the values specified in the Recognition Profile window.

Value for marked zone

This field specifies the value that the zone returns if the OMR engine decides the zone is marked. By default, the return value is 1, but you can specify any combination of letters and numbers up to a maximum of 254.

Value for unmarked zone

This field specifies the value the zone returns if the OMR engine decides the zone is not marked. By default, the return value is 0, but you can specify any combination of letters and numbers up to a maximum of 254. When using SmartGroups, make sure that his field is blank for all OMR zones in the group if you set minimum and maximum return values.

Note If you are concatenating multiple results (especially with a delimiting character), keep your return values short enough that all of them concatenated together, along with the delimiting character, do not exceed the size allowed for the Associated field. If the field length is exceeded, the result is truncated.