CamRuler

CamRuler lets you measure (almost) anything that you can take a photo of. Now you don't need to carry a ruler around just to get a measurement - your phone's got you covered.

CamRuler produces measurements by utilizing a reference object of known dimensions in the image you wish to measure. The app comes pre-loaded with common objects such as:

-Coins and paper currency (US, CAN, UK, EU, AUS, MEX)
-Common paper sizes (8.5x11, Legal size, business card, index card)

All you need to do is take a photo (or have someone send you one) with your chosen reference object in it.

You can also create your own custom objects of known dimensions (so if your country's currency isn't pre-loaded, you can add it).

Another measurement option is using a custom reference length, which can be used to get distance measurements from maps with scale bars, as well as length measurements on microscope photos (micrographs and electron micrographs) given a length reference. CamRuler's custom reference length mode also works well if there is an image of a ruler in the photo.

CamRuler allows users to choose between many common units of measurement, both metric and imperial:

-Metric: nanometers, micrometers, millimeters, centimeters, meters, kilometers
-Imperial: inches, feet, yards, miles, nautical miles

You can also set a custom scale (architectural scale) for whatever you are measuring - things such as blueprints, designs, scale models and get the relevant measurement. CamRuler comes pre-loaded with common scales and also allows you to set your own.

CamRuler allows you to set a label for your measurements and save them as a screenshot to your phone's camera roll. You can also save images for future measurement.

CamRuler allows you to take new photos or use images in your phone's camera roll. This makes it easy to ask someone to send you a photo from a remote location - then you can measure it on the fly. Pretty useful!

Limitations: The measurements you make must be in the same plane (or as close as possible) as the reference object you select. Also, measurements will be more accurate when the reference object takes up more space in the image.

The accuracy of the measurements provided by CamRuler depend on the user's ability to correctly target the reference object. While it's possible to get accurate measurements with CamRuler, the measurements should be considered an estimate only, and should not be used where precision is required. Using a quarter as a reference object, accuracies within a millimeter can be achieved.