ABSTRACT
In its broadest sense, an image is a spatial map of one or more physical properties of a sub-
ject where the pixel intensity represents the value of a physical property of the subject at that point.
Imaging the subject is a way to record spatial information, structure, and context information. In this
context, the subject could be almost anything: your family sitting for a family photo taken with your
smartphone, the constellations of orion’s belt viewed from a telescope, the roads of your neighbor-
hood imaged from a satellite, a child growing inside of its mother viewed using an ultrasound probe.
The list of possible subjects is endless, and the list of possible imaging methods is long and ever-
expanding. But the idea of imaging is simple and straightforward: convert some scene of the world
into some sort of array of pixels that represents that scene and that can be stored on a computer.
