Technical FAQs

Question

When using OCR in ImageGear .NET, is there any way to distinguish between a capital/uppercase letter O and the number 0?

Answer

Not without context or a font that makes the difference clear (such as one with a slashed 0). ImageGear will properly recognize Oliver and 1530 as containing O and 0, respectively, but cannot reliably distinguish it when letters and numbers are mixed. That is, ImageGear may not reliably distinguish between 1ABO0F3 and 1AB0OF3.

Question

The logging for ImageGear C & C++ Deployment Packaging Wizard (DPW) is showing different output for some components since v19.3, why is this?

In ImageGear C & C++ v19.2 and prior, the DPW had additional logging information for the ARTX component in its deployment.log:

Deploying an application that uses the ARTXGUI library of ImageGear
ARTX Component requires the following merge modules to be installed:

Microsoft_VC90_CRT_x86_x64.msm

Microsoft_VC90_MFC_x86_x64.msm

But since v19.3, the logs are no longer telling me to install these modules. Is this a mistake, or are they no longer necessary?

Answer

This was an intentional change on our end, and the Deployment Packaging Wizard (DPW) is working as intended. We made some updates to the DPW in the latest release; one update is that the CRM requirements for CORE (which is required in every project) now also covers the ARTX component. If the DPW is not saying you need additional components to use the ARTX component, then you’ll be fine.

Question

Why do I get a “File Format Unrecognized” exception when trying to load a PDF document in ImageGear .NET?

Answer

You will need to set up your project to include PDF support if you want to work with PDF documents. Add a reference to ImageGear24.Formats.Pdf (if you’re using another version of ImageGear, make sure you’re adding the correct reference). Add the following line of code where you specify other resources:

using ImageGear.Formats.PDF;

Add the following lines of code before you begin working with PDFs:

ImGearFileFormats.Filters.Insert(0, ImGearPDF.CreatePDFFormat());
ImGearPDF.Initialize();

The documentation page linked here shows how to add PDF support to a project.

Question

How do I use a Network Drive path for Image and ART storage in my ImageGear .NET web application?

Answer

In an ImageGear .NET web application, you have to define the location of the images and annotations directory in the storageRootPath and artStorageRootPath configuration property.
In the current version of ImageGear .NET, the storageRootPath and artStorageRootPath do not work with a network drive path \\SERVER-NAME\sharefilename.

The workaround for this would be to create a Symbolic link from a local directory to the network drive directory.

  • To create a symbolic link: Open “Command Prompt” as Administrator and type in > mklink /d "local path" \\SERVER-NAME\sharefilename
  • Pass in the path of the symbolic link as image or art storage root path in your web.config: storageRootPath="local path" artStorageRootPath="local path"
Question

Why do I get a “File Format Unrecognized” exception when trying to load a PDF document in ImageGear .NET?

Answer

You will need to set up your project to include PDF support if you want to work with PDF documents. Add a reference to ImageGear24.Formats.Pdf (if you’re using another version of ImageGear, make sure you’re adding the correct reference). Add the following line of code where you specify other resources:

using ImageGear.Formats.PDF;

Add the following lines of code before you begin working with PDFs:

ImGearFileFormats.Filters.Insert(0, ImGearPDF.CreatePDFFormat());
ImGearPDF.Initialize();

The documentation page linked here shows how to add PDF support to a project.

Accusoft’s ImageGear for .NET has established a reputation over the years as one of the most comprehensive imaging tools available to developers. It gives applications across many industries valuable functionality, enabling engineers, physicians and various other professionals to handle image viewing and processing (tasks like file capture, file conversion and optical character recognition) with ease.

But it also has features that its name – ImageGear – might lead some to overlook. Prominent among these is the power and versatility of an embedded HTML5 viewer, which helps ensure that ImageGear for .NET can do as much for text-based content as it does for images.

The viewer integration offers several advantages for application development, such as unmatched flexibility. The viewer itself has zero footprint and operates on any platform, language or device. So whether your end users are running Linux or Windows, on desktops or mobile devices, the viewer can handle your needs. It also supports over 100 file formats, ranging from the very common (PDFs and Microsoft Word documents) to industry-specific types (like the DICOM image files prevalent in radiology).

And the most recent release of ImageGear for .NET takes things a step for further, incorporating annotation into the HTML5 viewer. This allows multiple end users to collaborate on their work, highlighting or commenting on specific passages or emphasizing important areas of images. These markups are saved as separate layers, meaning they can easily be updated or deleted over the course of collaborating on the files.

Accusoft customers have noted the usefulness of similar annotations in PrizmDoc, our suite of REST APIs that also features an HTML5 document viewer, and we saw value in integrating that functionality into ImageGear for .NET. Now your applications can count on one SDK to facilitate collaboration on virtually any type of work file, whether a simple text document, spreadsheet, architectural rendering or highly intricate medical image.

In the example above, multiple users are collaborating on an image of an X-ray, using ImageGear for .NET’s HTML5 viewer to zoom, as well as its annotation functionality to offer feedback and recommended courses of treatment. And as mentioned, since all markup is handled in separate layers from the image itself, the original file is not altered.

It’s easy to get caught up in the many other document and imaging functions that ImageGear provides, but annotation is another valuable feature that can make a real difference for applications of various kinds. Try our online demo here or contact us to learn more about our products and how they can help you.

Question

ImageGear .NET v24.6 added support for viewing PDF documents with XFA content. I’m using v24.8, and upon trying to open an XFA PDF, I get a SEHException for some reason…

SEHException

Why might this be happening?

Answer

One reason could be because you need to execute the following lines after initializing the PDF component, and prior to loading an XFA PDF:

// Allow opening of PDF documents that contain XFA form data.
IImGearFormat pdfFormat = ImGearFileFormats.Filters.Get(ImGearFormats.PDF);
pdfFormat.Parameters.GetByName("XFAAllowed").Value = true;

This will enable XFA PDFs to be opened by the ImageGear .NET toolkit.

Question

I encounter an Unhandled Exception error, as shown below, in ImageGear when trying to load a page into the recognition engine.

Error Message: An unhandled exception of type
‘ImageGear.Core.ImGearException’ occurred in ImageGear22.Core.dll

Additional information: IMG_DPI_WARN (0x4C711): Non-supported
resolution. Value1:0x4C711

What is causing this and how can I fix it?

Answer

This is probably because the original image used to create the page didn’t have a Resolution Unit set.

Resolution unit not set in original image

To fix this, check if the page has a Resolution Unit set. If it does not, set it to inches. You should also set the DPI of the image as those values were probably not carried over from the original image since the Resolution Unit wasn’t set. The following code demonstrates how to do this.

// Open file and load page.
using (var inStream = new FileStream(@"C:\Path\To\InputImage.jpg", FileMode.Open, FileAccess.Read, FileShare.Read))
{
    // Load first page.
    ImGearPage igPage = ImGearFileFormats.LoadPage(inStream, firstPage);

    if (igPage.DIB.ImageResolution.Units == ImGearResolutionUnits.NO_ABS)
    {
        igPage.DIB.ImageResolution.Units = ImGearResolutionUnits.INCHES;
        igPage.DIB.ImageResolution.XNumerator = 300;
        igPage.DIB.ImageResolution.XDenominator = 1;
        igPage.DIB.ImageResolution.YNumerator = 300;
        igPage.DIB.ImageResolution.YDenominator = 1;
    }

    using (var outStream = new FileStream(@"C:\Path\To\OutputImage.jpg", FileMode.OpenOrCreate, FileAccess.ReadWrite))
    {
        // Import the page into the recognition engine.
        using (ImGearRecPage recognitionPage = recognitionEngine.ImportPage((ImGearRasterPage)igPage))
        {
            // Preprocess the page.
            recognitionPage.Image.Preprocess();

            // Perform recognition.
            recognitionPage.Recognize();

            // Write the page to the output file.
            recognitionEngine.OutputManager.DirectTextFormat = ImGearRecDirectTextFormat.SimpleText;
            recognitionEngine.OutputManager.WriteDirectText(recognitionPage, outStream);
        }
    }
}
Question

How do I remove XMP Data from my image using ImageGear .NET?

Answer

When removing XMP data in ImageGear, the simplest way to do this is to set the XMP Metadata node to null, like so:

ImGearSimplifiedMetadata.Initialize(); 
doc.Metadata.XMP = new ImGearXMPMetadataRoot();

Or, you can traverse through the metadata tree and remove each node from the tree:

// Example code. Not thoroughly tested
private static void RemoveXmp(ImGearMetadataTree tree)
{
ArrayList toRemove = new ArrayList();
foreach (ImGearMetadataNode node in tree.Children)
{
    if (node is ImGearMetadataTree)
        RemoveXmp((ImGearMetadataTree)node);

    if (node.Format != ImGearMetadataFormats.XMP)
        continue;

    toRemove.Add(node);
}

foreach (ImGearMetadataNode node in toRemove)
    tree.Children.Remove(node);
}