Fingerprints test for matching text in a document to determine whether it's a good fit for a config or not. There are two types of fingerprints:

• one for optimizing extraction performance for standalone documents
• one for segmenting portfolio files into separate documents.

If you use a config for both portfolio and standalone versions of the same document, Sensible automatically converts between the two and uses the appropriate fingerprint.

Standalone documents

Parameters

A fingerprint consists of an array of tests, where each test is a string, a Match object, or array of Match objects. For more information, see Match object.

Behind the scenes, Sensible automatically expands this simple syntax to syntax for portfolio fingerprints using "page" : "any".

Examples

The following fingerprint tests a vendor-specific config "anyco_life_insurance_quote" in a document type "life insurance quotes". This fingerprint tests that a document is a life insurance quote from Anyco by looking for three known key phrases.

{
  "fingerprint": {
    "tests": [
      {
        "type": "startsWith",
        "text": "anyco"
      },
      "[email protected]",
      "life insurance quote"
    ]
  },
  "fields": []
}

The config preferentially runs if the fingerprint finds the phrases.

Portfolios

Parameters

A fingerprint consists of an array of tests, where each test contains a Page parameter and a Match parameter:

"fingerprint": {
    "tests": [
      {
        "page": "every",
        "match": [
          {
            "text": "this text always shows up on every page of the document",
            "type": "includes"
          }
        ]
      },
      {
        "page": "last",
        "match": [
          {
            "text": "this text always shows up on the last page of the document",
            "type": "startsWith"
          }
        ]
      }
    ]
  }

The following table shows parameters for each test for portfolio documents:

Tips

Use the following tips when you define fingerprints for portfolios:

test criteria

Portfolio fingerprints differ from single-file document fingerprints in the following behaviors:

• If you specify a Match array in a test, then Sensible must find all the matches in the array on the same page in the portfolio for the test to pass and for Sensible to identify a page as "first", "last", or another type. In single-file documents, matches can occur anywhere in a document.
• Sensible must find 100% of all matches in all tests to segment a document in a portfolio. In single-file documents, Sensible must find 50% of all matches anywhere in the document by default to give the document a "passing" score.

page types

• Only use "page": "first" and "page": "last" if you're confident that these pages will never be omitted from the document.
• If using "page": "first" always pair it with another test type such as "page": "every" or "page": "last".
• If the first page doesn't contain unique text and the last page does, Sensible recommends specifying a last page test and an every page test.
• Avoid specifying an any page test unless other page types fail to segment the document.
• If you want to specify fallback matches for the same page type, specify the matches in separate tests. For example, a form has revisions 1 and 2 that have slightly different wordings on the first page. Specify one test with a first page type and wording A, and specify a second test with a first page type and wording B.

text matches

• Sensible runs fingerprints before any preprocessors. Because of this, make sure to comment out any preprocessors before writing fingerprints so that the document in the editor displays the lines of text exactly as they will be recognized when the fingerprints tests are ran.

• Unless the document contains a highly unusual and characteristic string or match object, always use an array of match objects, rather than an array of single-match tests. In other words, don't write the following:

// AVOID THIS SYNTAX
"fingerprint": {
    "tests": [
      {
        "page": "every"
        "match": [
          {
            "text": "NARS",
            "type": "includes",
            "isCaseSensitive": true
          }
        ]
      },
      {
        "page": "every"
        "match": [
          {
            "text": "Name of Insured",
            "type": "includes",
            "isCaseSensitive": true
          }
        ]
      },
    ]
  }

Instead, write the following:

// PREFER THIS SYNTAX
"fingerprint": {
    "tests": [
      {
        "page": "every"
        "match": [
					[
          {
            "text": "NARS",
            "type": "includes",
            "isCaseSensitive": true
          },
          {
            "text": "Name of Insured",
            "type": "includes",
            "isCaseSensitive": true
          },
		  ]
        ]
      }
    ]
  }

Examples

For an example of using fingerprints to extract multiple documents from a portfolio file, see Multi-document extraction.

Notes

For information about configuring fingerprint strictness for standalone documents, see Fingerprint mode.