How to blur every face so nobody can be identified
Tell Vizard Agent that nobody in the video may be recognisable and that nothing else may change. That is a pass-or-fail standard rather than a setting: a face missed for ten frames because it turned sideways defeats the whole purpose, so the tuning is done against the hardest face in the clip.
What do you type into Vizard Agent?
State the standard rather than the effect. "Blur the faces" describes an operation that can be done badly and still count as done, while "impossible to tell who anyone is" describes the result you'll be judged on. Both halves matter: without the second, cropping a face out of frame would count. Warn Vizard Agent about a child partly behind an adult, since small, partly hidden faces are where detection fails.
Blur every face in this video completely, so it is impossible to tell who anyone is. Do not change anything else about the video.
What does Vizard Agent actually do?
It gets the detection right before it blurs anything. Several detectors are tried on sample frames, the results are drawn as boxes and looked at, and the model that finds the difficult faces is the one that gets used, not the first one that returns something. In the session behind this article it:
- Found the video's rotation lived in metadata, so the detector was seeing sideways frames and finding nothing, and prepared a correctly oriented working copy without changing the visible frame.
- Compared detection models and switched to one that handles small and side-on faces.
- Built per-frame face coordinates rather than one moving box, so there were no gaps between detections.
- Tuned the threshold so real faces were masked but the water, the netting and a bucket were not, keeping stable face trajectories and discarding brief spurious detections.
- Went through the doubtful frames one at a time at full size with the boxes drawn, including the child's smallest, earliest appearance.
When does this not work well?
When someone is identifiable without their face. A distinctive uniform, a name on a shirt, a tattoo or a car registration all identify a person, and a face blur touches none of them, so say if the requirement is anonymity. And this is obfuscation, not redaction: if the requirement is legal, a solid opaque box is the safer instrument, and Vizard Agent will use one if you ask.
Common questions
How do I know it did not miss one? Review the frames with the boxes drawn. Vizard Agent produces them for exactly that check.
Why did it blur a bucket? A low threshold catches false positives. Vizard Agent rejects unstable tracks instead.
What about names on shirts? A face blur doesn't cover them. Tell Vizard Agent and it masks those too.