AWS SDK Version 3 for .NET
API Reference

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Container for the parameters to the CompareFaces operation. Compares a face in the source input image with each face detected in the target input image.

If the source image contains multiple faces, the service detects the largest face and compares it with each face detected in the target image.

In response, the operation returns an array of face matches ordered by similarity score in descending order. For each face match, the response provides a bounding box of the face, facial landmarks, pose details (pitch, role, and yaw), quality (brightness and sharpness), and confidence value (indicating the level of confidence that the bounding box contains a face). The response also provides a similarity score, which indicates how closely the faces match.

By default, only faces with a similarity score of greater than or equal to 80% are returned in the response. You can change this value by specifying the SimilarityThreshold parameter.

CompareFaces also returns an array of faces that don't match the source image. For each face, it returns a bounding box, confidence value, landmarks, pose details, and quality. The response also returns information about the face in the source image, including the bounding box of the face and confidence value.

If the image doesn't contain Exif metadata, CompareFaces returns orientation information for the source and target images. Use these values to display the images with the correct image orientation.

This is a stateless API operation. That is, data returned by this operation doesn't persist.

For an example, see get-started-exercise-compare-faces.

This operation requires permissions to perform the rekognition:CompareFaces action.

Inheritance Hierarchy


Namespace: Amazon.Rekognition.Model
Assembly: AWSSDK.Rekognition.dll
Version: 3.x.y.z


public class CompareFacesRequest : AmazonRekognitionRequest

The CompareFacesRequest type exposes the following members


Public Method CompareFacesRequest()


Public Property SimilarityThreshold System.Single

Gets and sets the property SimilarityThreshold.

The minimum level of confidence in the face matches that a match must meet to be included in the FaceMatches array.

Public Property SourceImage Amazon.Rekognition.Model.Image

Gets and sets the property SourceImage.

The source image, either as bytes or as an S3 object.

Public Property TargetImage Amazon.Rekognition.Model.Image

Gets and sets the property TargetImage.

The target image, either as bytes or as an S3 object.


This operation compares the largest face detected in the source image with each face detected in the target image.

To compare two images

var response = client.CompareFaces(new CompareFacesRequest 
    SimilarityThreshold = 90,
    SourceImage = new Image { S3Object = new S3Object {
        Bucket = "mybucket",
        Name = "mysourceimage"
    } },
    TargetImage = new Image { S3Object = new S3Object {
        Bucket = "mybucket",
        Name = "mytargetimage"
    } }

List faceMatches = response.FaceMatches;
ComparedSourceImageFace sourceImageFace = response.SourceImageFace;


Version Information

.NET Standard:
Supported in: 1.3

.NET Framework:
Supported in: 4.5, 4.0, 3.5

Portable Class Library:
Supported in: Windows Store Apps
Supported in: Windows Phone 8.1
Supported in: Xamarin Android
Supported in: Xamarin iOS (Unified)
Supported in: Xamarin.Forms