visualization: Thatcherizer


Photobooth version of the classic Thatcher illusion from cognitive psychology. Developed for Brain Awareness Week open house.

Alterations to local facial features (e.g. eyes, mouth) are rendered less conspicuous by inverting the entire image. This photobooth allowed individuals to Thatcherize a self-portrait, and print a copy to take home.


In the original example (Thompson, 1980) an image of Margaret Thatcher was manipulated such that the eyes and mouth were flipped relative to the rest of the face. The result is obvious and jarring. However, by simply inverting the image, the manipulation becomes all but unoticeable -- even when compared alongside the untouched original image.

Here, the goal was to develop a photobooth that would allow visitors to the Brain Awareness Week Open House to create a "Thatcherized" self-portrait of themselves (and learn about how the brain processes faces).


  • built on a Raspberry Pi, with Pi Camera module and 7" touchscreen; 3D printed stand

  • Pygame front end, with automatic face/eye/mouth detection via OpenCV classifiers (download code)

  • original and Thatcherized images assembled into Brain Awareness Week template, with option to print via connected Canon CP910 photoprinter


mouseover to invert