If the source image contains multiple faces, the service detects the largest face and uses it to compare with each face detected in the target image.
In response, the operation returns an array of face matches ordered by similarity score with the highest similarity scores first. For each face match, the response provides a bounding box of the face and confidence
value (indicating the level of confidence that the bounding box contains a face). The response also provides a similarity
score, which indicates how closely the faces match.
By default, only faces with the similarity score of greater than or equal to 80% are returned in the response. You can change this value.
In addition to the face matches, the response returns information about the face in the source image, including the bounding box of the face and confidence value.
This is a stateless API operation. That is, the operation does not persist any data.
For an example, see get-started-exercise-compare-faces
This operation requires permissions to perform the rekognition:CompareFaces
action.