--- title: "Choosing a zone to OCR in VB.NET" canonical_url: "https://www.nutrient.io/guides/dotnet/samples/select-ocr-zone-vbnet/" md_url: "https://www.nutrient.io/guides/dotnet/samples/select-ocr-zone-vbnet.md" last_updated: "2026-06-15T15:43:43.655Z" description: "Learn how to set the right OCR context to accurately extract specific text from documents, improving your data processing efficiency." --- # Choosing the appropriate OCR zone in VB.NET This example shows how to choose the appropriate OCR context. OCR context is easy to set and use, and it’s important in the OCR process. Often on your forms, you don’t want to recognize all the text in the document, but only small parts of it — whether it’s a column in a table, a name on a forum, or an additional notes area. You have to inform the OCR engine of the layout type of the data you want to process using OCR. [Get Started](https://www.nutrient.io/sdk/dotnet/getting-started.md) [All Samples](https://www.nutrient.io/guides/dotnet/samples.md) [Download](https://www.nutrient.io/guides/dotnet/downloads.md) [Launch Demo](https://www.nutrient.io/demo/) --- ### C# [C#](https://www.nutrient.io/guides/dotnet/samples/select-ocr-zone-cs.md) ### VB.NET [VB.NET](https://www.nutrient.io/guides/dotnet/samples/select-ocr-zone-vbnet.md) ```vb 'We assume that GdPicture has been correctly installed and unlocked. 'We assume a GdViewer object called GdViewer1 has been created and painted on the form. Dim oGdPictureImaging As New GdPictureImaging() 'Loading the image from a file. Dim imageId As Integer = oGdPictureImaging.CreateGdPictureImageFromFile("image.tif") 'Checking if the image has been loaded correctly. If oGdPictureImaging.GetStat() <> GdPictureStatus.OK Then MessageBox.Show("The image can't be loaded. Error: " + oGdPictureImaging.GetStat().ToString(), "OCR Context Example", MessageBoxButtons.OK, MessageBoxIcon.Error) Else 'Displaying the image in the GdViewer. GdViewer1.DisplayFromGdPictureImage(imageId) oGdPictureImaging.ReleaseGdPictureImage(imageId) End If oGdPictureImaging.Dispose() 'On the Mouse UP event on the GdViewer, set the ROI based on the rectangle of selection of the GdViewer. 'If a rectangle of selection is painted on the GdViewer, the area will be OCRed with a single line OCR context. Public Sub OCR_ROI_MouseUP(eventSender As System.Object, eventArgs As System.EventArgs) Dim oGdPictureOCR As GdPictureOCR = New GdPictureOCR() 'Initializing variables to hold the position of the rectangle of selection on the document. Dim leftArea As Integer = 0 Dim topArea As Integer = 0 Dim widthArea As Integer = 0 Dim heightArea As Integer = 0 'Checking if a rectangle of selection has been painted on the GdViewer. If GdViewer1.IsRect() Then 'Getting the location of the selection on the document. GdViewer1.GetRectCoordinatesOnDocument(leftArea, topArea, widthArea, heightArea) 'Setting the ROI on the document. oGdPictureOCR.SetROI(leftArea, topArea, widthArea, heightArea) Else oGdPictureOCR.ResetROI() End If 'Processing the OCR: 'Selecting the OCR context, here we will use it to recognize a single line on our form. oGdPictureOCR.Context = OCRContext.OCRContextSingleLine 'Setting up the required parameters for the OCR engine. oGdPictureOCR.ResourceFolder = "Redist\OCR" If (oGdPictureOCR.AddLanguage(OCRLanguage.English) = GdPictureStatus.OK) AndAlso (oGdPictureOCR.SetImage(imageId) = GdPictureStatus.OK) Then 'Running the OCR. Dim resID As String = oGdPictureOCR.RunOCR() 'Checking the status. If oGdPictureOCR.GetStat() <> GdPictureStatus.OK Then MessageBox.Show("The OCR has failed with the status: " + oGdPictureOCR.GetStat().ToString(), "OCR Context Example", MessageBoxButtons.OK, MessageBoxIcon.Error) Else 'Checking the results. For i As Integer = 1 To oGdPictureOCR.GetCharacterCount(resID) oGdPictureImaging.DrawRectangle(imageId, oGdPictureOCR.GetCharacterLeft(resID, i) + leftArea, oGdPictureOCR.GetCharacterTop(resID, i) + topArea, oGdPictureOCR.GetCharacterRight(resID, i) - oGdPictureOCR.GetCharacterLeft(resID, i), oGdPictureOCR.GetCharacterBottom(resID, i) - oGdPictureOCR.GetCharacterTop(resID, i), 1, Color.Red, False) Next End If End If oGdPictureOCR.Dispose() End Sub ``` This code sample is an example that illustrates how to use our SDK. Please adapt it to your specific use case. --- ## Related pages - [Automatically rotate pages of a multipage TIFF file using OCR and C#](/guides/dotnet/samples/auto-rotate-tiff-cs.md) - [Saving images into folders based on their barcode](/guides/dotnet/samples/barcode-auto-sorting-cs.md) - [Saving images into folders based on their barcode](/guides/dotnet/samples/barcode-auto-sorting-vbnet.md) - [Automatically rotate pages of a multipage TIFF file using OCR and VB.NET](/guides/dotnet/samples/auto-rotate-tiff-vbnet.md) - [Convert PDFs, MS Office, and images to TIFF in C#](/guides/dotnet/samples/convert-to-tiff-cs.md) - [Generate a multipage TIFF file using a compression mode per page in C#](/guides/dotnet/samples/create-multipage-tiff-cs.md) - [Converting a Microsoft Word binary file document (DOC) to a Microsoft Word OpenXML document (DOCX) in C#](/guides/dotnet/samples/doc-to-docx-cs.md) - [Using an external OCR engine during PDF/OCR generation](/guides/dotnet/samples/integrate-omnipage-ocr-cs.md) - [Merging two PDF documents by alternating pages from both files in VB.NET](/guides/dotnet/samples/merge-pdf-alternate-pages-vbnet.md) - [Converting a multipage PDF to a multipage TIFF using color detection in VB.NET](/guides/dotnet/samples/pdf-to-tiff-color-detection-vbnet.md) - [Converting a multipage PDF to a multipage TIFF using color detection in C#](/guides/dotnet/samples/pdf-to-tiff-color-detection-cs.md) - [Merging two PDF documents by alternating pages from both files in C#](/guides/dotnet/samples/merge-pdf-alternate-pages-cs.md) - [Recompress an existing PDF using color detection in C#](/guides/dotnet/samples/recompress-pdf-cs.md) - [Recompress existing PDFs using MRC compression in C#](/guides/dotnet/samples/recompress-pdf-mrc-cs.md) - [Recompress existing PDFs using MRC compression in VB.NET](/guides/dotnet/samples/recompress-pdf-mrc-vbnet.md) - [Recompress an existing PDF using color detection in VB.NET](/guides/dotnet/samples/recompress-pdf-vbnet.md) - [Highlight and crop an image in C#](/guides/dotnet/samples/select-image-crop-area-cs.md) - [Choosing the appropriate OCR zone in C#](/guides/dotnet/samples/select-ocr-zone-cs.md) - [Highlight a region in a PDF or an image in C#](/guides/dotnet/samples/select-pdf-image-region-cs.md) - [Highlight a region in PDF or an image in VB.NET](/guides/dotnet/samples/select-pdf-image-region-vbnet.md) - [Save bitonal TIFF images with C# and CCITT4](/guides/dotnet/samples/tiff-photometric-cs.md) - [Highlight and crop an image in VB.NET](/guides/dotnet/samples/select-image-crop-area-vbnet.md) - [Convert a multipage TIFF to a multipage JBIG2 in C#](/guides/dotnet/samples/tiff-to-jbig2-cs.md) - [Save bitonal TIFFs with VB.NET using photometric 0](/guides/dotnet/samples/tiff-photometric-vbnet.md) - [Convert a multipage TIFF to a multipage JBIG2 in VB.NET](/guides/dotnet/samples/tiff-to-jbig2-vbnet.md)