Google has unveiled a new tool which lets developers build applications that understand the content of images.

The tool, Google Cloud Vision API, encloses powerful machine learning models in an easy to use REST API.

It classifies images into several categories, detects individual objects and faces within images, and identifies as well as reads printed words contained in the images.

Developers can build metadata on their image catalog, moderate offensive content, and make new marketing scenarios via image sentiment analysis.

The company said that in future phases it will add support for integrating with Google Cloud Storage. The tool allows users to request one or more annotation types per image.

Sony Mobile Communications’ subsidiary Aerosense has been testing Google Cloud Vision API in its drones.

Aerosense general manager Tomoaki Kobayakawa said: "We have drones that take thousands of photos per flight. We find that Google Cloud Vision API as the best way to turn those huge number of photos, automatically produced, into meaningful insights."

Last month, Google announced the open source release of TensorFlow, its second-generation machine learning system.

TensorFlow is a followup to the company’s original DistBelief engine, which was used to make speech recognition work better and build image search into Google Photos.