Face Recognition Operations - Find Similar

Service:

Azure AI Services

API Version:

v1.2-preview.1

Given query face's faceId, to search the similar-looking faces from a faceId array. A faceId array contains the faces created by Detect.
Depending on the input the returned similar faces list contains faceIds or persistedFaceIds ranked by similarity.

Find similar has two working modes, "matchPerson" and "matchFace". "matchPerson" is the default mode that it tries to find faces of the same person as possible by using internal same-person thresholds. It is useful to find a known person's other photos. Note that an empty list will be returned if no faces pass the internal thresholds. "matchFace" mode ignores same-person thresholds and returns ranked similar faces anyway, even the similarity is low. It can be used in the cases like searching celebrity-looking faces.

The 'recognitionModel' associated with the query faceId should be the same as the 'recognitionModel' used by the target faceId array.

POST {endpoint}/face/{apiVersion}/findsimilars

URI Parameters

Name	In	Required	Type	Description
apiVersion	path	True	string	API Version
endpoint	path	True	string uri	Supported Cognitive Services endpoints (protocol and hostname, for example: https://{resource-name}.cognitiveservices.azure.com).

Request Body

Name	Required	Type	Description
faceId	True	string	faceId of the query face. User needs to call "Detect" first to get a valid faceId. Note that this faceId is not persisted and will expire 24 hours after the detection call.
faceIds	True	string[]	An array of candidate faceIds. All of them are created by "Detect" and the faceIds will expire 24 hours after the detection call. The number of faceIds is limited to 1000.
maxNumOfCandidatesReturned		integer	The number of top similar faces returned. The valid range is [1, 1000]. Default value is 20.
mode		FindSimilarMatchMode	Similar face searching mode. It can be 'matchPerson' or 'matchFace'. Default value is 'matchPerson'.

Responses

Name	Type	Description
200 OK	FindSimilarResult[]	A successful call returns an array of the most similar faces represented in faceId if the input parameter is faceIds or persistedFaceId if the input parameter is faceListId or largeFaceListId.
Other Status Codes	FaceErrorResponse	An unexpected error response. Headers x-ms-error-code: string

Security

Ocp-Apim-Subscription-Key

The secret key for your Azure AI Face subscription.

Type: apiKey
In: header

AADToken

The Azure Active Directory OAuth2 Flow

Type: oauth2
Flow: accessCode
Authorization URL: https://api.example.com/oauth2/authorize
Token URL: https://api.example.com/oauth2/token

Scopes

Name	Description
https://cognitiveservices.azure.com/.default

Examples

Find Similar among Face IDs

Sample request

HTTP

POST {endpoint}/face/v1.2-preview.1/findsimilars

{
  "faceId": "c5c24a82-6845-4031-9d5d-978df9175426",
  "maxNumOfCandidatesReturned": 3,
  "mode": "matchPerson",
  "faceIds": [
    "015839fb-fbd9-4f79-ace9-7675fc2f1dd9",
    "be386ab3-af91-4104-9e6d-4dae4c9fddb7"
  ]
}

Sample response

Status code:

200

[
  {
    "confidence": 0.9,
    "faceId": "015839fb-fbd9-4f79-ace9-7675fc2f1dd9"
  }
]

Definitions

Name	Description
FaceError	The error object. For comprehensive details on error codes and messages returned by the Face Service, please refer to the following link: https://aka.ms/face-error-codes-and-messages.
FaceErrorResponse	A response containing error details.
FindSimilarResult	Response body for find similar face operation.

FaceError

The error object. For comprehensive details on error codes and messages returned by the Face Service, please refer to the following link: https://aka.ms/face-error-codes-and-messages.

Name	Type	Description
code	string	One of a server-defined set of error codes.
message	string	A human-readable representation of the error.

FaceErrorResponse

A response containing error details.

Name	Type	Description
error	FaceError	The error object.

FindSimilarResult

Response body for find similar face operation.

Name	Type	Description
confidence	number	Confidence value of the candidate. The higher confidence, the more similar. Range between [0,1].
faceId	string	faceId of candidate face when find by faceIds. faceId is created by "Detect" and will expire 24 hours after the detection call.
persistedFaceId	string	persistedFaceId of candidate face when find by faceListId or largeFaceListId. persistedFaceId in face list/large face list is persisted and will not expire.