A.2 Image Representation

Now that you’ve seen how colors and images in the real world are perceived by your visual and cognitive systems, we’ll discuss how they’re represented on the computer.

Discretization

Although it seems counterintuitive, all images are represented discretely, rather than continuously. This is referred to as discretization. Images are composed of a large number of tiny, discrete dots, all very close to each other. Because they’re so small and so close, we can’t distinguish these dots, and so they create the illusion of a continuous image. Consider the following image representations:

  • A visual image: When an image is focused in our eye, the wavelength and intensity of light are sensed by the rod and cone cells in the retina. ...

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