Drawing app corrects errant strokes - but leaves your style intact

Researchers at Carnegie Mellon University have put together an iOS app, DrawAFriend, where what you draw is subtly corrected in real time, making your art better, yet still your own. It's free to try, and the more people who use it, the better it gets.

Drawing on a smartphone or tablet isn't particularly easy. They're small to begin with, a bit pixelated, and instead of a precise pencil or pen, you have your fat finger, and you can't even really see where it's touching!

A team from the university and Microsoft Research decided to look into this problem and ended up making an app that corrects your drawing as you go, by adjusting it to be more like drawings of the same thing — better ones, of course.

The team did it by having thousands of users draw celebrities and friends, each of their drawings analyzed stroke by stroke by a computer program and averaged into a larger database. That way, when you do an eyebrow and it goes a bit too high, the app can compare it to its collection of drawings and determine how it's off, correcting it while your finger is still on the screen.

CMU draw
Photos of Kristin Stewart, President Barack Obama and other celebrities were used in the app. From left: the original picture, an average of many drawings, a "vector field" comprising the tiny corrections the app makes, and another way of visualizing that field.

Yet despite tweaking your lines, your original style (such as it may be) is retained, because strokes it doesn't have on record are left as is. If you're skeptical, you can switch between the corrected version and your original — but be warned, you may not be quite the artist you thought you were.

The team did it to improve how computers analyze and interpret art. Such basic research could improve everything from touchscreen software to handwriting analysis. For instance, if the computer "understands" that someone has a habit of touching the screen left of where others do, it can accommodate that, resulting in more accurate touches.

You can download the app for free and try it yourself, or read the paper (PDF) that explains the primary findings and methods. The team is showing it off at this year's SIGGRAPH computer graphics expo.

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Devin Coldewey is a contributing writer for NBC News Digital. His personal website is