DigitalVideoAndHDTVAlgorithmsAndInterfaces.pdf

Raster images 1
This chapter introduces the basic features of the pixel
array. I explain how the pixel array is digitized from the
image plane, how pixel values are related to brightness
and color, and why most imaging systems use pixel
values that are nonlinearly related to light intensity.
Imaging
In human vision, the three-dimensional world is imaged
by the lens of the eye onto the retina, which is populated
with photoreceptor cells that respond to light
having wavelengths ranging from about 400 nm to
700 nm. In video and in film, we build a camera having
a lens and a photosensitive device, to mimic how the
world is perceived by vision. Although the shape of the
retina is roughly a section of a sphere, it is topologically
two dimensional. In a camera, for practical
reasons, we employ a flat image plane, sketched in
Figure 1.1 below, instead of a section of a sphere. Image
science concerns analyzing the continuous distribution
of optical power that is incident on the image plane.
Figure 1.1 Scene,
lens, image plane
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