The Leap Motion vs. the Xbox Kinect
The Leap Motion and the Xbox Kinect are both exciting devices that provide new ways of interacting with computers. Both allow the user to wirelessly interact with a computer by moving their body in 3D space, though there are significant differences in both use cases and the internal workings of each.
The Xbox Kinect was developed at Microsoft for use with its Xbox 360 game console, and was released in early November 2010. It was designed to be placed in front of the TV, pointing at the user. Microsoft’s APIs allow game designers to access information about the position and speed of different body parts. This allows for Minority Report style user interfaces, where the user interacts with a program using physical metaphors (i.e. “picking up” some virtual object and “moving” it).
The Kinect was the first cheap 3D motion-tracking device, and as such, a community of “hackers” grew around it. These people developed alternative libraries to communicate with the Kinect, as well as programs that use the Kinect in unexpected ways. The Kinect has been used to map caves, build lightsaber-duelling robots, perform 3D scanning of objects, and map terrain for walking robots.
The Kinect works by projecting a grid of infrared laser dots outwards and determining the distance to each dot by measuring how long it takes for the light to bounce off a surface and return to its camera sensor. Most of the “magic” lies in Microsoft’s algorithms for depth-finding (partially explained here). To make the Kinect a functional product, Microsoft had to be able to quickly and accurately analyze image data, a feat which likely could not have occurred without the high computing power of modern processors or intense research efforts.
The Leap Motion is another 3D controller device, though it is quite different from the Xbox Kinect. Leap Motion had announced this sensor in 2010, though it did not start shipping until July 2013.
The Leap Motion is meant for use much closer to the user than the Kinect. While the Kinect has a usable range from about 1.2 m to 3.5 m from the sensor, the Leap Motion has a range of about 1 to 20 inches (though it has a 150 degree field of view). It also has a much higher precision than the Kinect, with the ability to resolve movements of 1/100 mm (vs. the Kinect’s 1.3 mm resolution). This means it is more suited to the role of a computer input device than the Kinect, as it has a range that is more conducive to use at desk-range. Its high resolution allows for the possibility of handwriting recognition, virtual keyboards, and more precise gesture-based controls. However, it cannot track the entire body, like the Kinect does; rather, it (more precisely) tracks a smaller portion of the body (usually the hands and arms).
The Leap works in a different way than the Kinect does. Inside the Leap, there are 3 infrared LED lights and two infrared cameras. The LEDs illuminate the objects being tracked, and proprietary software translates the images from the cameras into 3D points. The hardware itself is quite simple and does not require any new technology; the “magic” happens in software.
The Leap was developed by a startup called Leap Motion. This company is working to include their sensor in laptops and mobile devices, as well as selling the sensor as a peripheral. The sensor is $80 currently, and can be bought at physical stores like Best Buy as well as online.
The availability of many different 3D input devices represents a shift in the way humans interact with computers. In conjunction with wearable computing, this technology could act as a step towards the seamless integration of computers and humans.