Image Recognition module

Digital asset management Bundled: DX Core

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The Magnolia Image Recognition module searches for untagged images, recognizes and tags them via either a local pre-trained neural network or an external image recognition solution. The module also provides the integration of the image recognition feature with content tags.

Module structure

artifactID Description


Parent reactor.


Provides functionality to integrate content tags and the image recognition service using decorations.


Provides an API to recognize images.


Provides the image recognition module and service.


Provides functionality to recognize images via Amazon Rekognition.


Provides functionality to recognize images locally via a pre-trained neural network.

Installing with Maven

Bundled modules are automatically installed for you.

If the module is unbundled, add the following to your bundle including your project’s <dependencyManagement> section and your webapp’s <dependencies> section. If the module is unbundled but the parent POM manages the version, add the following to your webapp’s <dependencies> section.

  <version>1.2.5</version> (1)
1 Should you need to specify the module version, do it using <version>.
  <version>1.2.5</version> (1)
1 Should you need to specify the module version, do it using <version>.
  <version>1.2.5</version> (1)
1 Should you need to specify the module version, do it using <version>.
  <version>1.2.5</version> (1)
1 Should you need to specify the module version, do it using <version>.
  <version>1.2.5</version> (1)
1 Should you need to specify the module version, do it using <version>.

General configuration

In the module configuration you:

  • Choose between the local image recognition service and Amazon Rekognition service.

  • Adjust the minConfidence property.

  • Fine-tune the performance of parallel image recognition.

Choosing a service provider

Choose which image recognition solution you want to use: the local image recognition service provided by Magnolia or the Amazon Rekognition service.

You can configure the service provider in /image-recognition/config.yaml.



Property Description


required, default is`.image.ImageRecogniser$Noop`

The class name of the service to be used.

Can be:



If you want to use the Amazon Rekognition service, you must change the currentService property and see the Amazon-specific configuration below.

Recognition confidence

For the Amazon Rekognition service, see Amazon Rekognition configuration options.

For the local image recognizer, set it with the minConfidence property under /local-image-recognition/config.yaml.

Property Description


optional, default is `5`

The confidence score of recognition.

An integer value between 0-100. The filter drops the tags with a confidence score lower than the value of this property.

Setting the value higher usually results in fewer tags being attached to an image asset. A higher confidence score means that the tag more correctly describes the image or its components.

Parallel recognition threads

Image recognition can be a very intensive process in terms of CPU resources. One of the functions of our implementation of image recognition is that the recognition process can be delegated to several parallel threads. With more threads working you can obtain the results faster.

You can specify the number of parallel image recognition threads for the image recognition service provided by the image-recognition-api submodule. Set the number in the configuration file through a Magnolia property called magnolia.image.recognition.numberOfThreads.

For example, magnolia.image.recognition.numberOfThreads=3 enables three recognition threads. If the property is not set in the file, the default number of threads used by the system is one.

Amazon Rekognition service configuration


This section lists the prerequisites for using Magnolia with Amazon Rekognition Image recognition service.

To use Amazon Rekognition, you must configure the currentService property as described in Choosing a service provider.

AWS service permissions

First, make sure that you have acquired appropriate permissions for the service in the Amazon IAM Management Console:

AWS users summary page

Access keys

You need an AWS secret access key to access the service. Access keys consist of two parts:

  • Access Key ID

  • Secret Access Key

Generate the key in the security credentials section of the Amazon IAM Management Console. (In the navigation bar on the upper right, choose your user name, and then choose My Security Credentials.)

Add the two parts of the key to your Magnolia instance in the Passwords app using the following names:


Padlock icon aws_access_key_id

Padlock icon aws_secret_access_key

For more information about the keys, see Understanding and Getting Your Security Credentials.

Region name

You need to know a region name to configure the Amazon Rekognition Image service in Magnolia. To reduce data latency, AWS offers several regional endpoints. Each of the endpoints can be referred to in service configurations by a region name, for example eu-west-1.

For more information see Amazon’s AWS Regions and Endpoints page. Please note that if you pick a region that does not support this service, you may get erratic results.

Configuration options

In version 1.1 of this module, the configuration was JCR-based. From version 1.2+, we have completely removed JCR-based configuration and any existing configuration will not be taken into account.

Make sure you replace your configuration with the config.yaml file.

Under /amazon-image-recognition/config.yaml, you must configure the following properties for the recognition service:

  name: your_aws_region_name
maxLabels: 10
minConfidence: 50
  png: png
  jpg: jpg
  jpeg: jpeg


Property Description

region name


Label designating a regional endpoint to which the image recognition service connects, such as eu-west-1.

For a list of available regions and labels, see


required, default is 10

The maximum number of tags you want the recognition service to return.

An integer value. Minimum value is 0. If 0 is used, no tag would be assigned to an image asset.


required, default is `50`

The confidence score of recognition.

The Amazon Rekognition service returns a confidence score for each image tag. Image tags with a recognition confidence lower than the value of the minConfidence property are dropped.


required, default is png, jpg, `jpeg`

A list of image formats defining which image types are automatically recognized by the image recognition service.

The Amazon Rekognition service currently supports only two image formats: JPEG/JPG and PNG.

Be aware that the Amazon Rekognition service has several service limits which may influence the performance of the recognition process. For more information see Amazon Rekognition Limits.

Using other image recognition solutions

You can implement another image recognition solution or integrate your app with another third-party image recognition solution using the interface provided by the image-recognition-api submodule:

     * Takes image bytes as parameter and returns a {@link Collection collection}
     * of {@link ImageLabel Image label}s as output.
     * <p>
     * Returns empty collection for the cases below:
     * <li>Upon exception</li>
     * <li>Image couldn't be recognized</li>
     * </p>
    Collection<ImageLabel> recognise(byte[] imageBytes);

Recognizing images

The image recognition and tagging action is executed during the startup of the author instance and every time you upload a new image asset.

You can also trigger the action manually in the Assets app by selecting one or more assets and clicking the Run recognition action.

Images that have already been tagged are marked as such using a JCR property called lastTaggingAttemptDate. Executing the manual Run recognition action forces a new tag to be set even if the image was previously tagged.

The image recognition feature is available only on author instances.

Removing tags

Once an image has been tagged, you can remove some or all of the tags by selecting the asset and clicking the Modify tags action in the Assets app.

In the dialog box that opens, you can remove individual tags or click Remove all tags.


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