IOcrOmrOptions Interface

Summary

The OMR (Optical Mark Recognition) settings currently used by the engine.

Syntax

Objective-C

C++/CLI

Java

Python

public interface IOcrOmrOptions

@interface LTOcrOmrOptions : NSObject

public class OcrOmrOptions

public interface class IOcrOmrOptions

class IOcrOmrOptions:

Remarks

Use of OMR in LEADTOOLS requires a special key to unlock OMR capabilities. For more information, refer to Unlocking Special LEAD Features.

To get the instance of the IOcrOmrOptions interface currently used in the engine call the IOcrSpellCheckManager.OmrOptions property.

Use the IOcrOmrOptions interface to change the following OMR settings:

Change the frame detection method using the IOcrOmrOptions.FrameDetectionMethod property. Frames stand for the checkboxes that may exist around OMR fields.
Change the sensitivity of the OMR detection engine using the IOcrOmrOptions.Sensitivity property.
Change which characters are used to replace unfilled and filled OMR marks in the output document (for example, in a PDF file) by calling the IOcrOmrOptions.GetStateRecognitionCharacter and IOcrOmrOptions.SetStateRecognitionCharacter methods.
Note that the native engine formats do not support outputting OMR characters in the final document.

The OMR zones of a page are zones that have the OcrZone.ZoneType set to OcrZoneType.Omr.

All LEADTOOLS OCR engines support OMR. However, only the LEADTOOLS OCR Module - LEAD Engine supports auto-detection of OMR zones during auto-zoning of the OCR page. To set up OMR zone auto-detection, make sure that the "Detect Checkbox" is one of the Recognition.Zoning.Options setting flags included before calling IOcrPage.AutoZone or IOcrPage.Recognize. The rest of the OCR engines require that the OMR zones be manually added to the page by setting their boundaries through OcrZone.Bounds and zone type as described above. Then add the zones to the page using the IOcrPage.Zones collection before calling IOcrPage.Recognize.

For more information refer to Using OMR in LEADTOOLS .NET OCR.

Example

This example will load a TIF image, create OMR zones and recognize them.

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Ocr; 
using Leadtools.Forms.Common; 
using Leadtools.Document.Writer; 
using Leadtools.WinForms; 
 
public void OcrOmrExample() 
{ 
   // Create an instance of the engine 
   using (IOcrEngine ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.LEAD)) 
   { 
      // Start the engine using default parameters 
      ocrEngine.Startup(null, null, null, LEAD_VARS.OcrLEADRuntimeDir); 
 
      // We will use Mixed.tif shipped with LEADTOOLS in the Images folder. This image has 3 OMR check marks 
      string tifFileName = Path.Combine(LEAD_VARS.ImagesDir, "Mixed.tif"); 
 
      // Create an OCR document 
      using (IOcrDocument ocrDocument = ocrEngine.DocumentManager.CreateDocument()) 
      { 
         // Add a page to the document 
         IOcrPage ocrPage = ocrDocument.Pages.AddPage(tifFileName, null); 
 
         // Add the OMR zones. We calculated the 3 OMR zone boundaries for this image perviously 
         LeadRect[] omrBounds = 
         { 
            new LeadRect(484, 98, 84, 78), 
            new LeadRect(494, 184, 70, 54), 
            new LeadRect(498, 244, 76, 76) 
         }; 
 
         foreach (LeadRect omrBound in omrBounds) 
         { 
            // Create a new OMR zone and add it to the page 
            OcrZone zone = new OcrZone(); 
            zone.ZoneType = OcrZoneType.Omr; 
            zone.Bounds = omrBound; 
            ocrPage.Zones.Add(zone); 
         } 
 
         // Show how many zones we have and they properties 
         Console.WriteLine("Page has {0} zones:", ocrPage.Zones.Count); 
         for (int i = 0; i < ocrPage.Zones.Count; i++) 
         { 
            OcrZone zone = ocrPage.Zones[i]; 
            Console.WriteLine("{0}: Type: {1}", i + 1, zone.ZoneType); 
         } 
 
         // Change the OMR options (Auto detection of frames with highest sensitivity) 
         IOcrOmrOptions omrOptions = ocrEngine.ZoneManager.OmrOptions; 
         omrOptions.FrameDetectionMethod = OcrOmrFrameDetectionMethod.Auto; 
         omrOptions.Sensitivity = OcrOmrSensitivity.Highest; 
 
         // Get the character we are using in the engine to represent the filled/unfilled states 
         char filledCode = omrOptions.GetStateRecognitionCharacter(OcrOmrZoneState.Filled); 
         char unfilledCode = omrOptions.GetStateRecognitionCharacter(OcrOmrZoneState.Unfilled); 
 
         // Recognize the page 
         Console.WriteLine("Recognizing..."); 
         ocrPage.Recognize(null); 
 
         IOcrPageCharacters pageCharacters = ocrPage.GetRecognizedCharacters(); 
         foreach (IOcrZoneCharacters zoneCharacters in pageCharacters) 
         { 
            // We must have one character (the state for each OMR zone) 
            Debug.Assert(zoneCharacters.Count == 1); 
            OcrCharacter character = zoneCharacters[0]; 
            Debug.Assert(character.Code == filledCode || character.Code == unfilledCode); 
            Console.WriteLine("{0}: State: {1}, Confidence: {2}", zoneCharacters.ZoneIndex, character.Code == filledCode ? "Filled" : "Unfilled", character.Confidence); 
         } 
 
         // Now save the result as PDF using the default characters representation for OMR states (0 for unfilled, 1 for filled) 
         string pdfFileName1 = Path.Combine(LEAD_VARS.ImagesDir, "Omr_Results1.pdf"); 
         Console.WriteLine("Saving to {0}...", pdfFileName1); 
         ocrDocument.Save(pdfFileName1, DocumentFormat.Pdf, null); 
 
         // Change the character representation for the OMR states to Y for unfilled, and X for filled 
         omrOptions.SetStateRecognitionCharacter(OcrOmrZoneState.Unfilled, 'Y'); 
         omrOptions.SetStateRecognitionCharacter(OcrOmrZoneState.Filled, 'X'); 
 
         string pdfFileName2 = Path.Combine(LEAD_VARS.ImagesDir, "Omr_Results2.pdf"); 
         Console.WriteLine("Saving to {0}...", pdfFileName2); 
         ocrDocument.Save(pdfFileName2, DocumentFormat.Pdf, null); 
      } 
 
      // Shutdown the engine 
      // Note: calling Dispose will also automatically shutdown the engine if it has been started 
      ocrEngine.Shutdown(); 
   } 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS22\Resources\Images"; 
   public const string OcrLEADRuntimeDir = @"C:\LEADTOOLS22\Bin\Common\OcrLEADRuntime"; 
}