What are false negatives?

False negatives - definition

False negatives occur when an image analysis system fails to detect an object or attribute that should be anonymized, such as a face or license plate, resulting in those elements not being anonymized.

Causes of false negatives

They may arise due to poor image quality, difficult lighting conditions, objects occluded by other elements, or limitations in detection algorithms which cannot capture every instance.

Impact of false negatives on anonymization

Failure to detect sensitive data leads to personal data leaks, violating privacy laws and increasing legal risks for organizations processing the data.

Minimizing false negatives

To reduce false negatives, advanced machine learning models, continuously learning systems, and manual review in critical applications are employed.

Examples of false negatives

  • Missing detection of a face in a crowd during live broadcast
  • Failing to anonymize a vehicle's license plate due to partial occlusion in the image

See also

  • False positives
  • Balancing false positives and negatives
  • Object detection
  • Video anonymization

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False Negatives

Definition

False negatives are cases where an image or video analysis system fails to detect an object that is actually present in the visual data. In the context of visual data anonymization, a false negative refers to a failure to identify an element requiring masking, such as a face, license plate, or person.

As a result, the object is not anonymized, potentially exposing personal data and violating privacy laws such as the GDPR.

Causes of false negatives

Cause

Description

Occlusion

Object partially blocked or hidden behind another item

Poor lighting conditions

Low image quality or low contrast preventing accurate detection

Unusual orientation

Object presented at an unexpected angle or posture

AI model limitations

Poor training data diversity, weak architecture, misconfigured hyperparameters

High detection threshold

A strict confidence score may discard valid detections

Impact on anonymization processes

  • Privacy breaches under GDPR – missed detection may expose personal data
  • Loss of user trust – insufficient anonymization can reveal identities
  • Non-compliance with Privacy by Design – systems prone to false negatives fail to meet legal standards
  • Workflow disruption – requires manual review or reprocessing of affected material

Minimizing false negatives

Method

Description

Advanced AI architectures (e.g. CNNs, transformers)

Better generalization and detection in diverse scenarios

Diverse training datasets

Include varied lighting, angles, environments

Model ensembles

Combine results from multiple models to improve reliability

Threshold tuning

Adjusting confidence score to optimize recall

Manual validation

Human-in-the-loop review in sensitive use cases

Examples

  • A face turned away in a crowd goes undetected and remains unblurred
  • A license plate missed at night due to glare from headlights
  • A person in deep shadow not recognized by the detection model