Concepts
How face search works, concept by concept
How the technology works, from a photo to a match, and where it fails.
- Step 1
Photo
One image, any source. Metadata is stripped by most engines.
- Step 2
Detect and align
Find the face, rotate and crop it to a standard frame.
- Step 3
Embed
Turn the face into a vector of numbers that describes its shape.
- Step 4
Match
Compare the vector with millions indexed from public pages; rank by similarity.
Introductory
- Deepfakes and synthetic faces How deepfakes and AI-generated faces are made, why a face search cannot find a face that never existed, the tells that still work, and the laws that now apply. 4 min read
- Face detection and alignment What face detection and alignment do before a face is compared, how detectors work, why small or turned faces fail, and the photo properties that matter. 4 min read
- How a face search works The face search pipeline step by step: detection, alignment, embedding, index lookup, ranking and source pages, with the limits at each stage. 5 min read
- Image provenance and metadata What EXIF metadata, platform identifiers and C2PA content credentials reveal about a photo, who strips them, and how provenance helps or fails when tracing an image. 4 min read
- Opt-outs, removal, and the limits of both Opting out of a face search engine, de-listing from Google and removing a photo from its host: the legal bases, routes, timelines and limits of each. 4 min read
Intermediate
- Accuracy, bias and testing How face recognition accuracy is measured, what NIST FRTE reports found on error rates and demographic differences, and why marketing claims cannot be checked. 4 min read
- Building a web-scale face index How face search engines crawl the public web, store billions of embeddings for nearest-neighbour lookup, keep the index fresh, and decide what counts as public. 4 min read
- Embeddings and similarity What a face embedding is, how networks place the same face close together, how cosine similarity becomes a score, and why a high score is not proof of identity. 4 min read