Advanced and OCR

The Advanced settings enable you to adjust the processing limits and preferences Secure Web Gateway uses.

The OCR settings determine how Secure Web Gateway extracts and scans text from images, optionally including QR codes and barcodes, for analysis.

The OCR feature requires a license. If you have not purchased the license for this feature, these settings will not be displayed in the user interface. The QR and barcode scanning is an extended functionality of the OCR feature to enhance the lexical analysis Secure Web Gateway performs. If you have the OCR license, you will be able to use the QR and barcode scanning functionality.

Configure Advanced and OCR settings

1. Navigate to System > Gateway Settings > Policy Engine Settings. The Policy Engine Settings page is displayed.
2. In a panel showing the Advanced and OCR settings, click Click here to change these settings.
3. Adjust the settings as required:

Advanced

• Maximum recursion depth

  In an attempt to search for hidden threats, Secure Web Gateway decomposes complex data formats into their component parts. Decomposed components may need even further disassembly, if they are archives, or encoded or compressed files. This process is complete when each component is recognized as a raw data type, such as a bitmap, text file, binary file, or application executable file.

  Maximum recursion depth specifies the number (level) of this decomposition. The default is 50.

  When this limit is exceeded, Secure Web Gateway abandons processing.

  We recommend that you do not change this setting from the default value.

• Child node limit

  Child node limit specifies the maximum number of immediate child nodes in a container to be processed. The range is between 100,000 and 2,147,483,647, and the default is 1,000,000.

• PDF image extraction

  PDF image extraction allows you to choose whether images are extracted from PDF documents.

  Select Enabled or Disabled from the drop-down menu. The default is Disabled.

OCR

• Minimum image size

  Minimum image size specifies the smallest image size, in pixels, that can be scanned when Secure Web Gateway is extracting text to be processed.

  The default is 200, representing a 200 x 200 pixel square. You are not able to enter a value lower than 16.

  If either the height or width of an image is smaller than the Minimum image size, scanning will not be carried out.

  We recommend that you set both Minimum image size and Maximum image size to be meaningful values. For the minimum value, consider the image size that might contain sensitive information. Depending on a number of images Secure Web Gateway needs to process, the image size settings can affect performance.

• Maximum image size

  Maximum image size specifies the largest image size, in pixels, that can be scanned when Secure Web Gateway is extracting text to be processed.

  The default is 8,400, representing a 8,400 x 8,400 pixel square. You are not able to enter a value greater than this.

  If either the height or width of an image is larger than the Maximum image size, scanning will not be carried out.

  We recommend that you set both Minimum image size and Maximum image size to be meaningful values. Depending on a number of images Secure Web Gateway needs to process, the image size settings can affect performance.

• QR and barcode scanning

  QR and barcode scanning allows you to choose whether Secure Web Gateway extracts text from QR codes and barcodes.

  Select Enabled or Disabled from the drop-down menu. The default is Disabled.

• Languages enabled

  Languages enabled specifies languages used in the OCR feature. Secure Web Gateway supports the detection of a large number of available languages.

  Select a language from the drop-down menu. Alternatively, type a language and matching suggestions will be displayed.

  Secure Web Gateway can apply the OCR feature to a selection of languages. English, French, German, and Spanish are enabled when you first upgrade or install. We, however, recommend that you use as few languages as possible, as this can help Secure Web Gateway reduce processing time and increase accuracy of processing results.

4. Click Save.
5. Apply the configuration.

If you change any configuration or policy settings, you must Apply Configuration for the new settings to take effect. You can do this either from the Changes Made panel, or System > Configuration > Apply Configuration. See Apply new configuration for more information. If you use Peer Gateways (i.e. when multiple Gateways are peered), any configuration changes from a local Gateway can then be applied to all the peers at the same time. See Configure Peer Gateways for more information.