About OneShotLiveness estimation#
OneShotLiveness is an algorithm for determining whether a person in one or more images is "real" or a fraudster using a fake ID (printed face photo, video, paper, or 3D mask).
OneShotLiveness is used as a pre-check before performing face detection.
To perform the OneShotLiveness estimation, LUNA ID sends a request to the LUNA PLATFORM 5 /liveness endpoint. For more details about LUNA ID and LUNA PLATFORM 5 interaction, see the Interaction of LUNA ID with LUNA PLATFORM 5 section of LUNA ID overview.
Image requirements#
An image that LUNA ID takes as input must be a source image and meet the following requirements:
| Parameters | Requirements |
|---|---|
| File format | PNG, RGB color model |
| Resolution | FullHD Minimum acceptable dimensions: 720x960 pixels Maximum acceptable dimensions: 1080x1920 pixels |
| Compression | No |
| Image cropping | No |
| Effects overlay | No |
| Number of faces in the frame | 1 |
| Face detection bounding box size | More than 200 pixels |
| Frame edges offset | More than 10 pixels |
| Head pose | -20 to +20 degrees for head pitch, yaw, and roll |
| Image quality | The face in the frame should not be overexposed, underexposed, or blurred. |
OneShotLiveness thresholds#
By default, two thresholds are used for OneShotLiveness estimation:
Quality threshold#
Quality threshold estimates the input image by the following parameters:
- Lightness (overexposure)
- Darkness (underexposure)
- Blurriness
- Illumination
- Specularity
The table below has the default threshold values. These values are set to optimal:
| Threshold | Value |
|---|---|
| blurThreshold | 0.61 |
| darknessThreshold | 0.50 |
| lightThreshold | 0.57 |
| illuminationThreshold | 0.1 |
| specularityThreshold | 0.1 |
For details on image quality estimation, see Image Quality Estimation and Quality estimator settings.
Liveness threshold#
Liveness threshold is the threshold lower which the system will consider the result as a presentation attack.
For images received from mobile devices, the default liveness threshold value is 0.5. For details, see Liveness threshold.