OCR Zone Problem

Hi, I am just trying to integrate Leadtools OCR engine to my project. I get a piece of code from CodeProject tells me how to integrate OCR engine to .net projects.

But somehow it doesn't work. I try the same process from the demo program, it read me the number which I need. But when I try to process it with my application. It returns me empty string. I dont know why. Below is the code part shows how I process the image in my application with OCR engine. Is that anyone can tell me whats wrong with it?

        {
            // *** Step 3: Create an OCR document with one or more pages.
            IOcrDocument ocrDocument = _ocrEngine.DocumentManager.CreateDocument();

            var rasterImage = RasterImageConverter.ConvertFromImage(image, ConvertFromImageOptions.None);
            // Add all the pages of a multi-page TIF image to the document
            ocrDocument.Pages.AddPages(rasterImage, 1, -1, null);

            // *** Step 4: Establish zones on the page(s), either manually or automatically
            // Automatic zoning
            LogicalRectangle rect = new LogicalRectangle(0, 0, image.Width, image.Height, LogicalUnit.Pixel);
            OcrZone zone = new OcrZone();
            zone.Bounds = RestrictZoneBoundsToPage(ocrDocument.Pages[0], rect);
            ocrDocument.Pages[0].Zones.Add(zone);

            // *** Step 7: (Optional) Set any special recognition module options
            // Change the fill method for the first zone in the first page to be default
            OcrZone ocrZone = ocrDocument.Pages[0].Zones[0];
            ocrZone.FillMethod = OcrZoneFillMethod.Default;
            ocrDocument.Pages[0].Zones[0] = ocrZone;

            // *** Step 8: Recognize
            ocrDocument.Pages.Recognize(null);

            // *** Step 9: Save recognition results
            // Save the results to a PDF file
            var result = ocrDocument.Pages[0].RecognizeText(null);
            ocrDocument.Dispose();

            return result;
        }

        private static LogicalRectangle RestrictZoneBoundsToPage(IOcrPage ocrPage, LogicalRectangle bounds)
        {
            RasterImage image = ocrPage.GetRasterImage();
            LeadRect pageBounds = new LeadRect(0, 0, image.ImageWidth, image.ImageHeight);
            LeadRect rc = bounds.ToRectangle(ocrPage.DpiX, ocrPage.DpiY);

            rc = LeadRect.Intersect(pageBounds, rc);
            return LogicalRectangle.FromRectangle(rc);
        }

BTW I initialised my engine out side the class passed in as a parameter. Thanks a lot.

Using LeadTools V17

The following forum post contains a simplified v16.5 .NET OCR demo. Please try it and if it doesn't work, tell me what errors you are getting when you try it.
http://support.leadtools.com/SupportPortal/CS/forums/24675/ShowPost.aspx

The same demo can be used with LEADTOOLS v17 .NET assemblies.