Processing PDF Files (Standard)

Limina supports scanning PDF files for PII and creating de-identified or redacted copies. Limina’s supported entity types function across each file type, with localized variants of different PII (Personally Identifiable Information) entities, PHI (Protected Health Information) entities, and PCI (Payment Card Industry) entities being detected. Our Supported Languages and Supported Entity Types page provides a more detailed look.

If you’d like to try it yourself, please sign up for an account to get a free API key.

How PDFs Are Processed

PDFs are processed as follows:

First, each page in the PDF is rendered as an image. The result is similar to a PDF created by a photocopier scan. This is done to ensure that all PII is properly captured - PDF is a complicated format.
Each page in the PDF is processed as an image.
A new PDF is created using the redacted/de-identified images produced in the previous step.
If specified, an invisible, de-identified text layer is created using the OCR system output. This ensures that the resulting PDF is searchable and allows for text to be copy & pasted.

You can configure the OCR System by setting it as an Environment Variable or sending it in the request object. Check out our OCR Guide to further understand the OCR modes and their usage.

Constraints

Any attachments in a PDF file are removed.
If the PDF document to be de-identified already has an invisible text layer, it will be discarded and replaced with a new text-layer created through the use of OCR.

Parameters

Below are the parameters that control the behaviour of the PDF De-identifier. These parameters shall be specified under pdf_options.

Parameter	Explanation	Default
`approach`	This parameter changes which PDF approach is used.	”standard”
`density`	PDFs are converted into images using this DPI value. Smaller values result in images with smaller resolutions, which will take up less storage space and process faster, at the cost of output quality & redaction accuracy.	200
`max_resolution`	PDFs are converted into images using the `density` DPI value. Any resulting images with maximum size length larger than this will be resized to this value, while preserving aspect ratio.	3000

PDF Approaches shows the differences between Standard and Enhanced PDF processing.

Support Matrix

	CPU Container	GPU Container	Community API	Professional API
Supported	Yes	Yes	Up to 10 MiB	No

Sample Request

Connect with one of our privacy experts to run this code.

{
  "file": {
    "data": "<file_content_base64>",
    "content_type": "application/pdf"
  },
  "entity_detection": {
    "return_entity": true
  },
  "pdf_options": {
    "approach":"standard"
  }
}

echo '{
          "file": {"data": "'$(base64 -w 0 sample.pdf)'", 
          "content_type": "application/pdf"}, 
          "entity_detection": {"return_entity": "True"},
          "pdf_options": {"approach": "standard"},
      }' \
| curl --request POST --url 'https://api.getlimina.ai/community/v4/process/files/base64' \
       -H 'Content-Type: application/json' \
       -H 'x-api-key: <YOUR KEY HERE>' \
       -d @- \
       | jq -r .processed_file \
       | base64 -d > 'sample.redacted.pdf'

import requests
import base64

file_url = "https://paidocumentation.blob.core.windows.net/$web/sample.pdf"
filename_out = "/path/to/output/sample.redacted.pdf"
file_content = requests.get(file_url).content
file_content_base64 = base64.b64encode(file_content).decode()

url = "https://api.getlimina.ai/community/v4/process/files/base64"

headers = {"Content-Type": "application/json", "x-api-key": "<INSERT API KEY>"}

payload = {
  "file":{
    "data": file_content_base64,
    "content_type": "application/pdf",
  },
  "entity_detection": {
    "return_entity": True
  },
  "pdf_options": {
    "approach": "standard"
  }
}

response = requests.post(url, json=payload, headers=headers)
with open(filename_out, "wb") as f:
    f.write(base64.b64decode(response.json()["processed_file"]))

from privateai_client import PAIClient
from privateai_client.objects import request_objects
import base64

filename_in = "sample.pdf"
filename_out = "sample.redacted.pdf"

file_type= "application/pdf"
client = PAIClient(url="https://api.getlimina.ai/community/v4/", api_key="<YOUR API KEY>")

with open(filename_in, "rb") as b64_file:
    file_data = base64.b64encode(b64_file.read())
    file_data = file_data.decode("ascii")

file_obj = request_objects.file_obj(data=file_data, content_type=file_type)
request_obj = request_objects.file_base64_obj(file=file_obj)
resp = client.process_files_base64(request_object=request_obj)

with open(filename_out, 'wb') as redacted_file:
    processed_file = resp.processed_file.encode("ascii")
    processed_file = base64.b64decode(processed_file, validate=True)
    redacted_file.write(processed_file)

Sample Response

Response

{
  "processed_file": "Base64 Encoded File Content of the Redacted File",
  "processed_text": "string",
  "entities": "List[Entity]",
  "entities_present": true,
  "languages_detected": {"lang_1": 0.67, "lang_2": 0.74}
}

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Processing PDF Files (Standard)

How PDFs Are Processed

Constraints

Parameters

Support Matrix

Sample Request

Sample Response

​How PDFs Are Processed

​Constraints

​Parameters

​Support Matrix

​Sample Request

​Sample Response

How PDFs Are Processed

Constraints

Parameters

Support Matrix

Sample Request

Sample Response