Image Redaction

Image Redaction in C#

GroupDocs.Redaction(which is a part of Conholdate.Total for .NET) supports two ways of redacting images (since version 21.3), both in separate image files and embedded images:

• Allows to put a colored box over a given area, such as header, footer, or an area, where customer’s data are expected to appear.
• Allows any 3-rd party OCR engine to process the image, search it for text and redact sensitive data within the image.

GroupDocs.Redaction for .NET also allows you to change image metadata (e.g. edit EXIF data of an image or act as an “EXIF eraser”).

Redact image area

In order to redact image area, you have to use ImageAreaRedaction class:

C#

using (Redactor redactor = new Redactor("D:\\test.jpg"))
{
   System.Drawing.Point samplePoint = new System.Drawing.Point(516, 311);
   System.Drawing.Size sampleSize = new System.Drawing.Size(170, 35);
   RedactorChangeLog result = redactor.Apply(new ImageAreaRedaction(samplePoint,
                new RegionReplacementOptions(System.Drawing.Color.Blue, sampleSize)));
   if (result.Status != RedactionStatus.Failed)
   {
      redactor.Save();
   };
}

If the redaction cannot be applied to this type of files, e.g. MS Word document without embedded images, RedactorChangeLog.Status will be RedactionStatus.Skipped.

Redact recognized text from an image

To enable OCR-processing and search for a text using regular expressions, you have to implement IOcrConnector interface and pass the instance to RedactorSettings constructor. .

C#

using (Redactor redactor = new Redactor("D:\\test.jpg", new LoadOptions(), new RedactorSettings(new MyCustomOcrConnector())))
{
   RedactorChangeLog result = redactor.Apply(new RegexRedaction("\\d{4}", new ReplacementOptions(System.Drawing.Color.Blue)));
   if (result.Status != RedactionStatus.Failed)
   {
      redactor.Save();
   };
}

In the example above MyCustomOcrConnector class implements IOcrConnector interface.

Clean image metadata

The following example demonstrates how to edit exif data (erase them) from a photo or any other image:

C#

using (Redactor redactor = new Redactor("D:\\photo.jpg"))
{
    redactor.Apply(new EraseMetadataRedaction(MetadataFilters.All));
    // Save the document to "*_Redacted.*" file in original format
    redactor.Save(new SaveOptions() { AddSuffix = true, RasterizeToPDF = false });
}

If the redaction cannot be applied to this type of files, e.g. BMP image, RedactorChangeLog.Status will be RedactionStatus.Skipped.

Redact embedded images

You can redact image area within all kinds of embedded images inside a document. You can both use ImageAreaRedaction class and any type of TextRedaction (regular expression, exact phrase), if the OCR is enabled in RedactorSettings.

The following example demonstrates how to redact all embedded images within a Microsoft Word document:

C#

using (Redactor redactor = new Redactor("D:\\sample.docx"))
{
   System.Drawing.Point samplePoint = new System.Drawing.Point(516, 311);
   System.Drawing.Size sampleSize = new System.Drawing.Size(170, 35);
   RedactorChangeLog result = redactor.Apply(new ImageAreaRedaction(samplePoint,
                new RegionReplacementOptions(System.Drawing.Color.Blue, sampleSize)));
   if (result.Status != RedactionStatus.Failed)
   {
      redactor.Save();
   };
}

If the redaction cannot be applied to this type of files, e.g. a spreadsheet document, RedactorChangeLog.Status will be RedactionStatus.Skipped.