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Face Recognition Operations - Find Similar From Large Face List

  • Reference
Service:
Azure AI Services
API Version:
v1.1-preview.1

Given query face's faceId, to search the similar-looking faces from a Large Face List. A 'largeFaceListId' is created by Create Large Face List.
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 Large Face List.

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.
largeFaceListId True

string

An existing user-specified unique candidate Large Face List, created in "Create Large Face List". Large Face List contains a set of persistedFaceIds which are persisted and will never expire.
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 from LargeFaceList

Sample request

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

{
  "faceId": "c5c24a82-6845-4031-9d5d-978df9175426",
  "maxNumOfCandidatesReturned": 3,
  "mode": "matchPerson",
  "largeFaceListId": "your_large_face_list_id"
}

Sample response

Status code:
200 
[
  {
    "confidence": 0.8,
    "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.