This activity facilitates measuring the degree of possibility that faces in two images are of
the same person. Here it uses a similarity score to verify if it is the same person by comparing
it against a reference photo in real time.

Technical Reference

	INPUT	SimilarityThreshold: Specifies the percentage of similarity threshold to be applied to the comparative images.
		SourceImagePath: Specify the path of the source image to be compared.
		TargetImagePath: Specify the path of the target image path to be compared to.
	MISC	Display Name: Displays the name of the activity. You can also customize the activity name to help troubleshoot issues faster. This name will be used for logging purposes.
		SkipOnError: It specifies whether to continue executing the workflow even if it throws an error. This supports only Boolean value “True or False”. By default, it is set to “False” True: Continues the workflow to the next step False: Stops the workflow and throws an error.
		Version: It specifies the version of the AmazonRekognition feature in use
	OUTPUT	Output: This is not a mandatory field. However, to see the output of the match percentage declare a variable here.
		Result: Declare a variable here to validate the activity. It accepts only Boolean value. This is not a mandatory field.

*Mandatory fields to execute the workflow

Use Case

The following steps illustrates on how we can use the compare faces activity to
derive the percentage of similarity by comparing two faces, the source image, and
the target image. 

Steps to execute a bot

1.     Drag and drop an amazon scope activity.

2.     Enter the access key ID,region end point and the secret access key.

3.     Drag and drop a compare faces activity from the Amazon Rekognition feature within the
amazon scope.

4.     Click on the activity.

5.     Enter the similarity threshold percentage that you would like to apply for the images.
By default, it is at 70%.

6.     Enter the declared variable in the output box

7.     Drag and drop a writelog activity below the amazon scope.

8.     Enter the log level as “info”.

9.     Execute the activity.

The bot executes the activity and gives the percentage of similarity in the output box.