---
Source: https://docs.microblink.com/verify/glossary
Title: Glossary
Description: Glossary of terms and concepts used in BlinkID Verify documentation
---

# Glossary

## APCER

Attack Presentation Classification Error Rate.
See [FAR](#far).

## BPCER

Bona Fide Presentation Classification Error Rate.
See [FRR](#frr).

## (Document) Liveness

A "live" document is one that's physically present with the person presenting it, in its original form (not printed, photocopied, and so on).
The term liveness is used both as a property of documents, and for the act of checking for this property.

## Extraction

Extraction is the process of extracting personal data from a document.
We also sometimes use it as a noun, and "an extraction" is a single transaction performed on one or more images of one document that extracts the data from it from various sources (VIZ, MRZ, barcodes, images, etc).

Every verification requires at least some degree of extraction.

## FAR

False acceptance rate, or FAR, is the rate at which a verification solution incorrectly accepts fraudulent documents as legitimate.

FAR is sometimes also known as [APCER](#apcer) (Attack Presentation Classification Error Rate).

## Fraud

In the context of BlinkID Verify, by default, fraud is the act of presenting a document that is not genuine or live.
Verify's job is to detect this, but it also provides flexibility for you to define fraud for your company's or client's use cases.
For example, you can disable liveness checks, and only check for the document being genuine.

## Front and back images

Most identity documents are double sided, and have a front and back side.
For BlinkID Verify, "front image" typically refers to a full frame with context that contains a document's front side.
"Back image" typically refers to a full frame with context that contains a document's back side.

For single sided documents, or documents like passports, the relevant image is referred to as the "front image".

## FRR

False rejection rate, or FRR, is the rate at which a verification solution incorrectly rejects legitimate documents as fraudulent.

FRR is sometimes also known as [BPCER](#bpcer) (Bona Fide Presentation Classification Error Rate).

## Manual review

Manual review is the act of a human expert or worker reviewing a document.
This review can be detailed, and check for fraud, but it can also be a simple check due to inconsistencies, or minor issues.

## MRZ

Machine Readable Zone, or MRZ, is the standardized text area found at the bottom of many identity documents, such as passports and ID cards.
It contains encoded personal data that can be read by machines.

## TAR

True acceptance rate, or TAR, is the rate at which a verification solution correctly accepts legitimate documents as legitimate.
For a solution that only has a boolean output, this is equivalent to `1-FRR`.
However, if the solution has outputs other than PASS/FAIL (which BlinkID Verify does), it's its own metric.

## TRR

True rejection rate, or TRR, is the rate at which a verification solution correctly rejects fraudulent documents as fraudulent.
For a solution that only has a boolean output, this is equivalent to `1-FAR`.
However, if the solution has outputs other than PASS/FAIL (which BlinkID Verify does), it's its own metric.

## Verification

A verification is a single transaction that determines whether a document is genuine and live.
It can be performed on one or multiple images depending on the document, capture conditions, and your desired options.

## VIZ

Visual Inspection Zone, or VIZ, is the human-readable area of a document containing personal data such as name, date of birth, and document number.
It is typically the main printed area of the document's front side.


Last updated on May 13, 2026