lecture13-2

Lecture13 2

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Unformatted text preview: CS 445 / 645 Introduction to Computer Graphics Lecture 13 Color Assignment 3 Due March 23 • Fourth years plan for thesis collision • We’ll provide lots of details to keep the assignment doable Morphing algorithm Last Class We discussed vision physiology and perception of gradients Today: Color perception Color representations Specifying Color Color perception usually involves three quantities: • Hue: Distinguishes between colors like red, green, blue, etc • Saturation: How far the color is from a gray of equal intensity • Lightness: The perceived intensity of a reflecting object Sometimes lightness is called brightness if the object is Sometimes emitting light instead of reflecting it. emitting In order to use color precisely in computer graphics, we In need to be able to specify and measure colors. need Combining Colors Additive (RGB) Shining colored lights on a white ball Subtractive (CMYK) Mixing paint colors and illuminating with white light How Do Artists Do It? Artists often specify color as tints, shades, and tones Artists of saturated (pure) pigments of • Tint: Gotten by adding white to a pure pigment, decreasing saturation decreasing • Shade: Gotten by adding black to a pure pigment, decreasing lightness decreasing • Tone: Gotten by adding white and black to a pure pigment pigment White Grays Black Tin ts Tones de s Sha Pure Color HSV Color Space Computer scientists frequently use an intuitive Computer color space that corresponds to tint, shade, and tone: tone: • Hue - The color we see (red, green, purple) • Saturation - How far is the color from gray (pink is less saturated than red, sky blue is less saturated than royal blue) saturated • Brightness (Luminance) - How bright is the color (how bright are the lights i...
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This note was uploaded on 01/23/2012 for the course CS 445 taught by Professor Bloomfield,a during the Spring '08 term at UVA.

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