What is Custom Vision?

Azure Custom Vision is an image recognition service that lets you build, deploy, and improve your own image identifier models. An image identifier applies labels (which represent classifications or objects) to images, according to their detected visual characteristics. Unlike the Computer Vision service, Custom Vision allows you to specify your own labels and train custom models to detect them.

This documentation contains the following types of articles:

  • The quickstarts are step-by-step instructions that let you make calls to the service and get results in a short period of time.
  • The how-to guides contain instructions for using the service in more specific or customized ways.
  • The tutorials are longer guides that show you how to use this service as a component in broader business solutions.

What it does

The Custom Vision service uses a machine learning algorithm to analyze images. You, the developer, submit groups of images that feature and lack the characteristics in question. You label the images yourself at the time of submission. Then, the algorithm trains to this data and calculates its own accuracy by testing itself on those same images. Once you've trained the algorithm, you can test, retrain, and eventually use it in your image recognition app to classify images. You can also export the model itself for offline use.

Classification and object detection

Custom Vision functionality can be divided into two features. Image classification applies one or more labels to an image. Object detection is similar, but it also returns the coordinates in the image where the applied label(s) can be found.


The Custom Vision service is optimized to quickly recognize major differences between images, so you can start prototyping your model with a small amount of data. 50 images per label are generally a good start. However, the service is not optimal for detecting subtle differences in images (for example, detecting minor cracks or dents in quality assurance scenarios).

Additionally, you can choose from several variations of the Custom Vision algorithm that are optimized for images with certain subject material—for example, landmarks or retail items. See Select a domain for more information.

What it includes

The Custom Vision Service is available as a set of native SDKs as well as through a web-based interface on the Custom Vision website. You can create, test, and train a model through either interface or use both together.

Custom Vision website in a Chrome browser window

Data privacy and security

As with all of the Cognitive Services, developers using the Custom Vision service should be aware of Microsoft's policies on customer data. See the Cognitive Services page on the Microsoft Trust Center to learn more.

Next steps

Follow the Build a classifier guide to get started using Custom Vision on the web portal, or complete a quickstart to implement the basic scenarios in code.