[SerializableAttribute()]
public enum OcrOmrFrameDetectionMethod
Value | Member | Description |
---|---|---|
0 | Auto | Automatically detect whether there is a printed frame (e.g. check box). |
1 | WithoutFrame | The OMR zone is inside the printed frame, so the printed frame is not visible. |
2 | WithFrame | The OMR zone is outside the printed frame, so the printed frame is visible. |
OMR stands for Optical Mark Recognition. For more information refer to Using OMR in LEADTOOLS .NET OCR.
Frames stand for the check boxes that may exist around OMR fields. You can set the LEADTOOLS OCR engine to automatically detect these frames and take them into consideration when recognizing OMR fields. If you know whether the OMR fields contain frames, set the IOcrOmrOptions.FrameDetectionMethod accordingly to increase recognition performance and accuracy.
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:\LEADTOOLS23\Resources\Images";
public const string OcrLEADRuntimeDir = @"C:\LEADTOOLS23\Bin\Common\OcrLEADRuntime";
}