Page 196 - DCAP504_Computer Graphics

Unit 12: Color and Shading Model

2. Fill in the blanks:
(a) The hue of light can be used to differentiate a ...................... from a red or green light.
(b) The tri-chromaticity theory is a contribution of ……………… and ………………. researchers.
(c) Brightness is similar to physical property of light called ………………...

(d) The ………………….. model requires less memory and has limited color available on
displays.
(e) In …………… reflection, light energy from the light source gets reflected uniformly in all
directions.

3. Select a suitable option for every question:
(a) In NTSC YIQ color model, what does Y indicate?
(i) Luminosity
(ii) Intensity
(iii) Saturation
(iv) Hue

(b) According to Phong model, what is the mathematical equation for the total reflected energy,
Intensity I?
(i) I=Iaka+Ip (kscos(θ) + kd cosk(φ))
(ii) I=Iaka+Ip (kd cos(φ) + kscosk(θ))
(iii) I=Iaka+Ip (kd cos(θ) + kscosk(φ))

(iv) I=Iaks+Ip (kd cos(θ) + kacosk(φ))
(c) What is the other name for constant shading?
(i) Faceted shading
(ii) Gouraud shading
(iii) Phong shading
(iv) Intensity interpolation
(d) What is the correct expression of tri-stimulus generalization theory?
(i) S=r+g+b

(ii) r=S+g+b
(iii) b=S-r+g
(iv) g=S-r-b

λ
(e) In CIE XYZ color model, one of the primaries can be calculated as Y= k P(λ) y(λ) d(λ).
∫
What is k?
(i) Variable based on wavelength of the light
(ii) Constant based on yellow color of the light
(iii) Variable based on light source
(iv) Constant based on light source

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