Google Measure: During the last WWDC, Apple announced that it would add a measuring app called Measure to every iPhone. But Google also has a metering app, also called Measure.
In fact, Google seems to have overtaken Apple, as the Measure app was briefly added to Tango devices. For the first time, Google seems to trust enough AR technology to launch the app on all Android devices.
The Google Measure app will work with any phone compatible with Google's AR Core platform. How; Very simple: check with your phone a scene, and then drag a virtual bar over the item you want to measure.
See the presentation video
The application appears to be fairly accurate, but it should not be used professionally for the time being at least.
These types of measurements were used by specialized cameras to detect the depth. Today, the editing seems to be good enough to be able to get functional results from a simple old camera.
Of course, improvements are expected.