Researchers at Northwestern University have developed a drone, dubbed the Phantom Twist, that is nearly invisible to the naked eye. By spinning up to 25 times per second and having its propeller and body rotate in opposite directions, the drone exploits human vision's limitations, creating an optical illusion of near-invisibility. This design makes it approximately 10 times less visible than standard quadcopters.

The development process involved an AI-driven computational model that generated and optimized thousands of drone designs to minimize visibility. Researchers simulated flight and used perception models to mimic human vision. The final design separates components at different heights and ensures no synchronized rotations, making it difficult for the human eye to focus on any specific part. Michael Rubenstein, a lead researcher, explained the focus was on designing the drone around human perception of motion, rather than just camouflage.

While the Phantom Twist achieves a "ghostly smudge" effect, it is not fully invisible. It still emits an audible whirring sound and some components, like wires, remain visible. Potential civilian applications include wildlife surveying and infrastructure inspection, where minimizing disruption is key. However, the advancement also highlights potential military and surveillance uses, aligning with the rapid development in drone warfare. The research was partly funded by the National Science Foundation and presented at the Robotics: Science and Systems conference.