Privacy Masking

What is privacy masking?

Privacy masking enables users to obscure specific sections of a camera's video feed, protecting individual privacy when footage is displayed on viewing platforms. For instance, a surveillance system monitoring a public street may employ privacy masks to conceal portions of private property, such as windows and doors, in compliance with privacy laws.

These privacy masks can either completely block out an area with a solid color or blur it. This feature affects live footage, recordings, and video exports equally.

Once set, privacy masks remain fixed to a particular section of the video image, regardless of any camera movements such as pan, tilt, or zoom, ensuring the same area remains concealed at all times. Some PTZ (pan-tilt-zoom) cameras even offer dedicated privacy masking functions.

Privacy masks come in two varieties:

1. Permanent privacy mask: This type covers designated areas continuously, ideal for sections of the video that either don't require surveillance or where recording is prohibited. These zones are also excluded from any motion detection functionality.

2. Liftable privacy mask: Unlike permanent masks, these can be disabled temporarily by users with the necessary clearance in XProtect Smart Client. If a user without those privileges attempts to disable a mask, the system will request authorization from an approved user.

The masks will stay inactive for a set duration or until a user reactivates them. Note that once a mask is lifted by an authorized user, all video feeds accessible to that user will have their privacy masks removed.

How does masking work?

Pixel Alteration

At its heart, both images and videos are composed of numerous pixels. Each pixel's color is defined by its assigned value. Masking changes the pixel values in a specific area to conceal parts of the image or video.

Pixel Alteration Methods: Two common pixel alteration techniques are blackout and blur.

• Blackout: This approach changes pixel values to a single solid color, such as black, effectively hiding what's underneath.

• Blur: Alternatively, blur manipulation averages a pixel's value with those of its surrounding pixels, creating a diffuse look.

Defining Regions

Effective masking requires identifying which areas to obscure. This is achieved through methods like manual input, system algorithms, or layering.

• Manual Methods: Users directly mark the regions to be masked on the video system's interface.

• Automatic Recognition: Some systems intelligently detect and respond to particular parameters, such as motion or facial recognition, to mask areas.

• Layering Technique: Advanced setups add a masking layer atop the original media; this layer can be mixed with the base to achieve the masked effect while preserving the initial content for potential later access

Implementation Timing

Masking in video surveillance can be persistent or activated through certain conditions.

• Always-On Masking: Some regions are perpetually obscured.

• Conditional Masking: Masking activates when certain criteria, such as detected movements within set boundaries, are met.

• Adaptive Masking: In sophisticated systems, the mask can track and adjust to cover moving subjects or items within the video frame.

• Encryption Masking: Rather than modifying pixels, this technique encrypts the area intended for masking. Only individuals with the decryption key can view these zones, ensuring robust protection, albeit with increased processing demands.

Data Storage

There are two primary methods for saving masked video content: permanently or in a reversible manner.

• Permanent Method: The video is saved with the masks in place, which means the concealed information is lost or overwritten.

• Reversible Method: The original video is saved along with the masking details, allowing the possibility of reverting to the video's unmasked version.

Broadcasting and Distribution

Masking is applied to video content before broadcasting or streaming to ensure confidentiality: end-users do not view the secured content.

Where are privacy masks applied?

Video Surveillance/CCTV (Closed-Circuit Television)

• To obscure private residences or windows that fall into the camera's range to comply with privacy laws.

• In areas where personal privacy is a concern, such as changing rooms, toilets, or other sensitive areas.

• To hide pin entry on ATM machines to secure user information.

• In institutions like schools or care facilities, to prevent unauthorized identification of minors or vulnerable individuals.

Video Conferencing

• To blur or block out the background for participants who might not want to disclose their location or sensitive information visible within their environment.

• To hide other individuals who may unintentionally pass by the camera’s field of vision during a call.

Drones and Body Cams

• On drones that might capture individuals in residential or private areas.

• On body-worn cameras by law enforcement to mask faces or sensitive items at a scene.