Yoti FCM Face detection

Face detection for the face capture module. It takes an image and returns a validated image or a validation error describing the issue in the image.

Dependencies

The package uses C++ libraries so the machines that run the face detector will need to install the Microsoft Visual C++ Redistributable packages.

Usage

1. Install the Yoti.FCM.FaceDetection nuget package.

2. Create an face detector instance instance and call Detect that expects an System.Drawing.Image:

   var faceDetector = FaceDetectorFactory.NewInstance();
   
   var imagePath = "<image_path>";
   var image = Image.FromFile(imagePath);
   var result = await faceDetector.DetectAsync(image);
   

The face detector implements the interface IFaceDetector:

/// <summary>
/// Face detector entity.
/// </summary>
public interface IFaceDetector : IDisposable
{
    /// <summary>
    /// Detects a face in the image provided.
    /// </summary>
    /// <param name="image">Image with a face.</param>
    /// <param name="crop">
    /// If the crop option is used. This new crop image will contain a single-face optimized
    /// to be sent to Yoti AI service.
    /// <see href="https://developers.yoti.com/age-estimation/integration-guide"/>.
    /// </param>
    /// <param name="cancellationToken">The token to cancel the detection method.</param>
    /// <returns>The <see cref="FaceDetectorResult"/> as an asynchronous operation.</returns>
    Task<FaceDetectorResult> DetectAsync(Image image, bool crop = false, CancellationToken cancellationToken = default);
}

Response

The DetectAsync method returns a FaceDetectorResult that contains the image (ResultB64 property) to be sent to Yoti AI service with the .NET Yoti SDK or any other Yoti SDK if the image is propagated to a back-end first.

Error codes

The FaceDetectorResult also provides an Error property in case the face detection fails:

Exceptions

The face detector can throw the following exceptions:

• Yoti.FCM.FaceDetection.Exceptions.ConfigurationException: Invalid configuration.
• System.Exception: Unexpected exceptions.

Options

The integrators can provide the custom options to the face detector. See DefaultConfig class for more details:

var options = new DefaultConfig();
var faceDetector = FaceDetectorFactory.NewInstance(options);

Note: Package integrators can provide their own custom configuration instance if they implement the interface IConfig.

Configuration fields:

Note: Set NumberStableFrames to 1 to check a single image and ignore StabilityConfidenceThreshold configuration. If NumberStableFrames value is different than 1, the Face detector will expect multiple consecutive different images of the same face with minimum differences.