What Amazon Rekognition does
Amazon Rekognition is a set of pretrained image and video analysis APIs inside AWS. For faces it covers detection and attributes (DetectFaces), one-to-one comparison of two images (CompareFaces), and one-to-many search: you add faces to a collection with IndexFaces, optionally group them into users, then query with SearchFacesByImage or SearchUsersByImage. Face Liveness checks a short selfie video for spoofs such as printed photos or masks. The same service also does labels, text, moderation, celebrity recognition and stored or streaming video.
You call it through the AWS SDKs or CLI with an AWS account and IAM permissions; there is nothing to host. Collections hold face vectors that you control, not the images themselves. Under the AWS Service Terms (section 50), AWS keeps a moratorium on police use of face comparison in criminal investigations, bars sustained surveillance of a specific person without independent review such as a court order, and applies separate Biometric Notice and Consent terms.
