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Version 1

POST https://okaylivefacedemo.innov8tif.com/api/check_liveness

Request Body

NameTypeDescription

apiKey*

string

To be assigned by Innov8tif

data*

object

The binary image data uploaded as a file

Meta

string

The JSON string with device information

X-Meta

string

The JSON string with any additional information

{    
    "probability": 0.99,    
    "score": 9.0,    
    "quality": 1.0 
}, 

"Meta" parameter is not required but it can significantly decrease overall error rate. The current version of API supports mobile OS setting.

Meta KeyMeta ValueRequired

OS

"IOS", "ANDROID" or "UNKNOWN"

True

MANUFACTURE

"UNKNOWN"

False

MODEL

"UNKNOWN"

False

If you're not sure about the device meta, please set 'UNKNOWN' value or just not to pass 'Meta' in the header.

Interpretation of Result

KeyValue

probability

Probability of liveness

score

Linear liveness score: bigger value means more alive,

(not suggested as a threshold to detect the liveness.)

quality

The quality score of the selfie image ranges from 0 (bad) to 1 (good). If the quality score is less than 0.5, the image should be rejected in most cases. The "quality" refers to the eligibility of the image as input for the liveness check. Please refer to the "Image Requirement" section to get the best result for each API return.

error

Error message from the server

The response of "score" and "quality" is NOT suggested to be used for the decision making for detection result.

  • Probability of liveness is a main response of the system.

  • The image is accepted as "live" when a probability is bigger than 0.5.

  • Linear liveness score can be used for BPCER / APCER tuning. The range of score is (ln 1e-7, -ln 1e-7).

  • Quality value is a probability of "appropriate image".

  • Probability can be lower than 0.5 by the reasons below.

    • Face minimal side is less than 180 pix or distance between eyes is less than 90 pix.

    • Face out-of-plane rotation is bigger than 20 degrees.

    • The distance between face and camera is very small, so the face can be significantly distorted.

    • The luminous power is insufficient.

    • High motion or gaussian blur rate or light shot.

We highly advise to analyze quality value and reject inappropriate images.

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