Face Recognition Operations - Identify From Large Person Group

Service:

Azure AI Services

API Version:

v1.2-preview.1

1-to-many identification to find the closest matches of the specific query person face from a Large Person Group.
For each face in the faceIds array, Face Identify will compute similarities between the query face and all the faces in the Large Person Group (given by largePersonGroupId), and return candidate person(s) for that face ranked by similarity confidence. The Large Person Group should be trained to make it ready for identification. See more in "Train Large Person Group".

Note

• • The algorithm allows more than one face to be identified independently at the same request, but no more than 10 faces.
  • Each person could have more than one face, but no more than 248 faces.
  • Higher face image quality means better identification precision. Please consider high-quality faces: frontal, clear, and face size is 200x200 pixels (100 pixels between eyes) or bigger.
  • Number of candidates returned is restricted by maxNumOfCandidatesReturned and confidenceThreshold. If no person is identified, the returned candidates will be an empty array.
  • Try "Find Similar" when you need to find similar faces from a Face List/Large Face List instead of a Person Group/Large Person Group.
  • The 'recognitionModel' associated with the query faces' faceIds should be the same as the 'recognitionModel' used by the target Person Group or Large Person Group.

POST {endpoint}/face/{apiVersion}/identify

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
faceIds	True	string[]	Array of query faces faceIds, created by the "Detect". Each of the faces are identified independently. The valid number of faceIds is between [1, 10].
largePersonGroupId	True	string	largePersonGroupId of the target Large Person Group, created by "Create Large Person Group". Parameter personGroupId and largePersonGroupId should not be provided at the same time.
confidenceThreshold		number	Customized identification confidence threshold, in the range of [0, 1]. Advanced user can tweak this value to override default internal threshold for better precision on their scenario data. Note there is no guarantee of this threshold value working on other data and after algorithm updates.
maxNumOfCandidatesReturned		integer	The range of maxNumOfCandidatesReturned is between 1 and 100. Default value is 10.

Responses

Name	Type	Description
200 OK	IdentificationResult[]	A successful call returns the identified candidate person(s) for each query face.
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

Identify from LargePersonGroup

Sample request

HTTP

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

{
  "faceIds": [
    "c5c24a82-6845-4031-9d5d-978df9175426"
  ],
  "largePersonGroupId": "your_large_person_group_id",
  "maxNumOfCandidatesReturned": 9,
  "confidenceThreshold": 0.7
}

Sample response

Status code:

200

[
  {
    "faceId": "c5c24a82-6845-4031-9d5d-978df9175426",
    "candidates": [
      {
        "personId": "85c0c630-c9c9-40f8-8a4e-f9ae4f926ea5",
        "confidence": 0.8
      }
    ]
  }
]

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.
IdentificationCandidate	Candidate for identify call.
IdentificationResult	Identify result.

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.

IdentificationCandidate

Candidate for identify call.

Name	Type	Description
confidence	number	Confidence value of the candidate. The higher confidence, the more similar. Range between [0,1].
personId	string	personId of candidate person.

IdentificationResult

Identify result.

Name	Type	Description
candidates	IdentificationCandidate[]	Identified person candidates for that face (ranked by confidence). Array size should be no larger than input maxNumOfCandidatesReturned. If no person is identified, will return an empty array.
faceId	string	faceId of the query face.