Core Components of Amazon A2I

Review the following terms to familiarize yourself with the core components of Amazon A2I.

Task Types

The AI/ML workflow into which you integrate Amazon A2I defines an Amazon A2I task type.

Amazon A2I supports:

Select a tab in the following table to see diagrams that illustrate how Amazon A2I works with each task type. Select the task type page using the links in the preceding list to learn more about that task type.

Amazon Textract – Key-value pair extraction

This image depicts the Amazon A2I built-in workflow with Amazon Textract. On the left, the resources that are required to create an Amazon Textract human review workflow are depicted: an Amazon S3 bucket, activation conditions, a worker task template, and a work team. These resources are used to create a human review workflow, or flow definition. An arrow points right to the next step in the workflow: using Amazon Textract to configure a human loop with the human review workflow. A second arrow points right from this step to the step in which activation conditions specified in the human review workflow are met. This initiates the creation of a human loop. On the right of the image, the human loop is depicted in three steps: 1) the worker UI and tools are generated and the task is made available to workers, 2) workers review input data, and finally, 3) results are saved in Amazon S3.

Amazon Rekognition – Image moderation

This image depicts the Amazon A2I built-in workflow with Amazon Rekognition. On the left, the resources that are required to create an Amazon Rekognition human review workflow are depicted: an Amazon S3 bucket, activation conditions, a worker task template, and a work team. These resources are used to create a human review workflow, or flow definition. An arrow points right to the next step in the workflow: using Amazon Rekognition to configure a human loop with the human review workflow. A second arrow points right from this step to the step in which activation conditions specified in the human review workflow are met. This initiates the creation of a human loop. On the right of the image, the human loop is depicted in three steps: 1) the worker UI and tools are generated and the task is made available to workers, 2) workers review input data, and finally, 3) results are saved in Amazon S3.

Custom Task Type

The following image depicts the Amazon A2I custom workflow. A custom ML model is used to generate predictions. The client application filters these predictions using user-defined criteria and determines if a human review is required. If so, these predictions are sent to Amazon A2I for human review. Amazon A2I collects the results of human review in Amazon S3, which can access by the client application. If the filter determines that no human review is needed, predictions can be fed directly to the client application.

Human Review Workflow (Flow Definition)

You use a human review workflow to specify your human work team, to set up your worker UI using a worker task template, and to provide information about how workers should complete the review task.

For built-in task types, you also use the human review workflow to identify the conditions under which a human loop is initiated. For example, Amazon Rekognition can perform image content moderation using machine learning. You can use the human review workflow to specify that an image is sent to a human for content moderation review if Amazon Rekognition's confidence is too low.

You can use a human review workflow to create multiple human loops.

You can create a flow definition in the SageMaker console or with the SageMaker API. To learn more about both of these options, see Create a Human Review Workflow.

Work Team

A work team is a group of human workers to whom you send your human review tasks.

When you create a human review workflow, you specify a single work team.

Your work team can come from the Amazon Mechanical Turk workforce, a vendor-managed workforce, or your own private workforce. When you use the private workforce, you can create multiple work teams. Each work team can be used in multiple human review workflows. To learn how to create a workforce and work teams, see Workforces.

Worker Task Template and Human Task UI

You use a worker task template to create a worker UI (a human task UI) for your human review tasks.

The human task UI displays your input data, such as documents or images, and instructions to workers. It also provides interactive tools that the worker uses to complete your tasks.

For built-in task types, you must use the Amazon A2I worker task template provided for that task type.

Human Loops

A human loop is used to create a single human review job. For each human review job, you can choose the number of workers that are sent a task to review a single data object. For example, if you set the number of workers per object to 3 for an image classification labeling job, three workers classify each input image. Increasing the number of workers per object can improve label accuracy.

A human loop is created using a human review workflow as follows:

When do human loops get created?

When you use one of the built-in task types, the corresponding AWS service creates and starts a human loop on your behalf when the conditions specified in your human review workflow are met. For example:

When using a custom task type, you start a human loop using the Amazon Augmented AI Runtime API. When you call StartHumanLoop in your custom application, a task is sent to human reviewers.

To learn how to create and start a human loop, see Create and Start a Human Loop.

To generate these resources and create a human review workflow, Amazon A2I integrates multiple APIs, including the Amazon Augmented AI Runtime Model, the SageMaker APIs, and APIs associated with your task type. To learn more, see Use APIs in Amazon Augmented AI.