VISUALIZATION OF 3D GRAY-TONE IMAGES - Fundamentals of Three-Dimensional Digital Image Processing - page 227

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Fig. 7.12. General frame of computer graphics.

7.7 Photorealistic rendering and rendering for
visualization

Mathematical models presented in Sections 7.4 7.6 were developed to gen-

erate images that arouse feelings similar to the ones we have when we see the
scene in the real world. In this sense, they are tools of what we call photore-
alistic rendering , or tools for designing industrial products utilized in the real
world. The whole of a basic idea common to them is presented in Fig. 7.12.
Light is irradiated by a light source and shines on objects. Then part of
a light reflected by objects or passed through objects reaches the position of
eye located at a viewpoint . An image plane that corresponds to a screen of a
display device exists somewhere on the way of this light path. The above model
for rendering is a modeling that realizes all such phenomena concerning the
image generation process within acceptable image quality and computation
cost.
Major factors in image generation by this model are a light source, a space
through which light propagates, interaction among light and objects, posi-
tional relation among an image plane, a viewpoint and an object, and optical
properties of objects. All of them and many other factors relating to image
generation have been studied extensively in the field of computer graphics.
Ray tracing and radiosity methods following this remarkably contributed to

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