Internal investigation footage - definition
Internal investigation footage is image or video material reviewed as part of an employer’s, organization’s, or compliance function’s inquiry into a workplace incident, alleged misconduct, safety event, policy breach, or regulatory concern. It may come from closed-circuit television (CCTV), access-control cameras, vehicle cameras, mobile devices, interview recordings, or other visual sources.
For image and video anonymization, the central task is to preserve information relevant to the investigation while redacting people who are not connected to the matter. These people can include bystanders, visitors, customers, employees in adjacent work areas, or passersby captured by a camera with a broad field of view. Face blurring and license plate blurring can reduce unnecessary disclosure when footage is shared with investigators, management, outside counsel, regulators, witnesses, or other authorized recipients.
Internal investigation footage is not automatically anonymous after face blurring. A person may still be identifiable through clothing, location, role, voice, context, or other visual details. Redaction decisions should therefore be based on the intended recipient, the investigation purpose, and the minimum information required for that recipient to perform their role.
Why unrelated people should be redacted
Investigation footage often contains more people than the individuals involved in the reported event. Providing an unedited copy can expose personal information that is not needed to establish facts, evaluate allegations, or make a decision. A redacted derivative can limit access to unrelated people while retaining the evidentiary sequence of the event.
- Witness protection: A bystander may be a witness and may have no reason to appear in material distributed during the inquiry.
- Purpose limitation: Recipients should receive only the visual information needed for the defined investigation task.
- Access control: A manager, investigator, external reviewer, and witness may require different versions of the same footage.
- Disclosure control: A redacted copy can be used for routine review, while the original is retained under restricted access for evidence preservation.
Redaction scope for internal investigation footage
The redaction scope should distinguish people relevant to the matter from people who are only present in the recording. This assessment should be documented before editing begins. The table shows a practical approach for defining the scope.
Visual element | Typical treatment in a shared investigation copy | Reason for review
|
|---|---|---|
Subject of the allegation | Usually retained where identity and conduct are relevant | The person may be necessary to establish the event. |
Complainant or directly affected person | Retain or redact according to the recipient and investigation need | Identity may be relevant, but unnecessary disclosure can create additional risk. |
Material witness | Retain only if visual identity is necessary | Presence, position, and actions may matter more than identity. |
Unrelated employee, visitor, or customer | Blur the face and assess other identifying details | The person is outside the defined investigation scope. |
Vehicle license plate | Blur unless the vehicle is relevant to the matter | A plate can identify or help identify a vehicle owner or user. |
Video anonymization workflow
A defensible workflow separates preservation of the original footage from creation of redacted working copies. The original should not be overwritten by an edited file. ISO/IEC 27037:2012 describes principles for identifying, collecting, acquiring, and preserving digital evidence, including maintaining integrity and documenting handling.
- Define the investigation question, authorized recipients, and required time range.
- Preserve the source file, including available metadata, in restricted storage.
- Create a working copy for review and redaction.
- Identify relevant subjects, witnesses, and unrelated people scene by scene.
- Apply face blurring to unrelated people and license plate blurring where plates are not relevant.
- Review every blurred track for missed detections, incorrect masks, and frames where a person re-enters the scene.
- Record the redaction rationale, software version, editor, review date, export settings, and recipient group.
Key quality parameters
Face detection supports efficient review, but it does not replace human verification. Detection performance can vary with camera angle, motion blur, occlusion, compression artifacts, low light, and small faces. The review team should measure quality on the actual footage type rather than rely on a general performance statement.
Useful operational metrics include the following:
- Face detection recall: the proportion of visible faces that received a mask. It can be expressed as recall = true positive detections / all visible faces requiring redaction.
- False negative count: the number of faces or license plates requiring redaction that remain visible after export.
- Track continuity: whether the mask remains correctly positioned across consecutive frames.
- Mask coverage: whether the blur covers the identifiable facial region or license plate throughout movement.
- Export integrity: whether the output preserves the required frame rate, duration, sequence, and audio track.
Technical limits and manual redaction
Automatic face detection and license plate detection address only those two categories. They do not automatically detect company logos, tattoos, name badges, documents, computer monitors, or other visual content that may identify a person or reveal confidential information. These elements require a case-specific review and, where needed, manual masking.
Gallio PRO can automatically blur faces and license plates in imported images and video. It does not perform real-time anonymization or video-stream anonymization. Other visual elements can be blurred manually with the built-in editor. Audio also requires separate assessment because spoken names, voices, and background conversations can identify people even when faces are masked.
Standards and references
Internal investigation footage combines evidence handling, access control, and image-processing quality assurance. The following sources provide a technical basis for building and documenting the process.
- ISO/IEC 27037:2012, Information technology - Security techniques - Guidelines for identification, collection, acquisition and preservation of digital evidence.
- ISO/IEC 27001:2022, Information security, cybersecurity and privacy protection - Information security management systems - Requirements.
- National Institute of Standards and Technology (NIST) Special Publication 800-86, Guide to Integrating Forensic Techniques into Incident Response, 2006.
- NIST Special Publication 800-53 Revision 5, Security and Privacy Controls for Information Systems and Organizations, 2020, including access control and audit-related control families.