For images of distant objects (normal photography), the field of view is measured as an angle. For planar objects (scanner), the field of view is measure as a distance.
Combination of scale and field of view gives the number of pixels in the image.
Scale (pixels/per unit length) may be different horizontally than vertically (anamorphic)
Orientation tells us what direction the camera is pointing (optic axis)
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Perspective is a change in magnification as a function of distance from the camera.
Rectangles transform into trapezoids
Magnification varies as a function of distance from the center of the image.
Maintained by John Loomis, last updated May 20, 1997