Enforce console Alert: 4803 OCR request was not successful - Image Size Error

Products

• Data Loss Prevention Network Monitor and Prevent for Email and Web
• Data Loss Prevention
• Data Loss Prevention Cloud Package

Issue/Introduction

You have successfully implemented Optical Character Recognition (OCR) in your DLP environment

However in the Enforce console, you notice a significant number of alerts with the code 4803 - OCR Request was not successful

Clicking on the details of the alerts shows the subcategory: Image Size Error or Bits Per Pixel error

For Example, you can find the coinciding errors in the ocrworker-OCRWORKER log from the OCR server.

Error while loading page: Image error: [8004c70e]: IMG_SIZE_ERR - *2363063181216,3924 (0)

Received OCR request ID [0e2159ef-b05f-4a58-8e9e-9ff369d681b8], image size [620] bytes

Another example, regardless of the size of the image, if the color resolution (Bits Per Pixel) is too low, grayscale, for example, dlp may not be able to distinguish any characters.

03/13/23 12:10:00 | WARN  | ocrEngine | NuanceEngine | Error while loading page: Image error: [8004c708]: IMG_BITSPERPIXEL_ERR - *2618016796576,329332 (0)

When using OCR with Email Prevent, many times the images in Signatures are too small or not enough color resolution for detection and will cause these errors.

Environment

Release : 15.x

Component : OCR

Cause

These alerts are because the OCR pre-filter on the detection server is passing images to the OCR servers that have sizes or color resolutions that are unsupported, either too big, too small, or too fuzzy and are unsuitable for OCR extraction.

The OCR server then drops that file and posts the alert to the Enforce.

Resolution

Alerts of this type can be safely ignored, no extractable data was available in those images, so OCR detection is not failing.

 

Additional Information

Refer to article Image Quality and Resolution for OCR results for image specifications for OCR results.