Cameras

How does the HoloLens know its location? If you look at the device and take a closer look at its front, you will see five tiny cameras. These are the eyes of the device; these are what make the device aware of its surroundings.

The camera you see in the middle is a normal, 2 megapixel RGB style camera, like the ones you will find in your mobile phone. The four cameras to the sides, two to the right and two to the left, are the environment cameras. They look at the area around you and are partially responsible to produce the knowledge the device needs to know what the room you are in looks like. I said partially, because there is another camera in the middle and front of the device. You cannot really see it since it is hidden behind the see-through visor. This camera is the IR camera. The device emits infrared light that is detected by this piece of hardware. By calculating the time it takes for the light to return, the HoloLens can measure depth and thus create a 3D image of your room. If you are familiar with Microsoft Kinect, you will recognize this; essentially, you will be wearing a tiny Kinect controller on your head. If you are not familiar with that amazing device, I suggest you look at https://developer.microsoft.com/en-us/windows/kinect for more information. It is worth getting to know the background of a lot of the principles described in this book.