television 1 jess role @ ueab2006 principles of color television
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Television 1 Jess Role @ UEAB2006
Principles of Color Television
Television 1 Jess Role @ UEAB2006
Three Basic Colors of Television
• Blue
• Red
• Green
11 %
30%
59 %
Television 1 Jess Role @ UEAB2006
Three Color Characteristics
• Hue – adjusted color sometime called tint control (from green to red)
• Brightness – illumination of the picture that includes sharpness of edges including the contrast control
• Saturation -
Television 1 Jess Role @ UEAB2006
Lights
• 430 Terahertz (430 X 10 Hz) to 750 Terahertz (750 X 10 Hz)
• 430 Terahertz is considered as a wavelength• 750 Terahertz correspond to the color red and
the higher frequency• 400 nm seen deep blue• Some colors do not correspond to any one given
wavelength of light (example brown and purple)
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Television 1 Jess Role @ UEAB2006
Electromagnetic Spectrum
Television 1 Jess Role @ UEAB2006
Color Mixing
• When sunlight passes through a glass prism will separate into multitude of color components. The display is called saturation
Television 1 Jess Role @ UEAB2006
Subtractive color mixing
• Subtractive mixing – make use of filtering action that dyes pigments and inks. Ex: pictures, photographs, color movies.
• Additive mixing – superior to subtractive mixing. Using the primary colors as the base.
Television 1 Jess Role @ UEAB2006
Spectrum of White light
Television 1 Jess Role @ UEAB2006
Additive Mixing
Television 1 Jess Role @ UEAB2006
Result of Additive Mixing
Television 1 Jess Role @ UEAB2006
Result of 3 color additive mixing
WhitePale
yellowGray pink
Pale green
BluishGreen
100%White
50%White
50 %Saturated
red
50%Saturated
Yellow
Television 1 Jess Role @ UEAB2006
Luminance Level
• Dark yellow producing a shade of gray approaching black
• Y= 0.59G + 0.39R + 0.11B
• For equal Energy• Y = 0.59(1) + 0.30(1) + 0.11(1)
» =1.00
• For 50 % red 100% blue 100% green• Y = 0.59G + 0.30R + 0.11B
» = 0.59(1) + 0.30(1) + 0.11(1)
» = 0.59 + 0.15 + 0.11
» =0.85
Television 1 Jess Role @ UEAB2006
Object size and color
• A 23 in television picture tube can show a video signal of 0.5 MHz or less correspond to horizontal picture tube object sizer ranging from 0.34 in or more.
• Object sizes ranging from 0.34 in to a minimum of 0.12 in corresponding to the half cycle of video frequency of 1.5 MHz.
• Only two colors orange and cyan can provide complete color reprodution
Television 1 Jess Role @ UEAB2006
continuation
• Luminance signal information has required bandpass from 0 to 4.2 MHZ
• The narrower the bandwidth of the color information the less complex the color tv system need be.
Television 1 Jess Role @ UEAB2006
Color Television Transmission
Television 1 Jess Role @ UEAB2006
Matrix Y Color Transmitter
Television 1 Jess Role @ UEAB2006
G-Y Matrix
• (R –Y) + Y = R
• (B – Y) +Y = B
• (G – Y) + Y = G
Television 1 Jess Role @ UEAB2006
Y color Receiver
Television 1 Jess Role @ UEAB2006
Balance Modulator
Television 1 Jess Role @ UEAB2006
Color Burst color synchronizing
Television 1 Jess Role @ UEAB2006
Phase relationship
• The amplitude of the composite chrominance signal represents the color Saturation information and its phase corresponds to the actual color of hue information of the picture being transmitted
• Phasor – a sine and cosine waves can be represented by a straight line.
Television 1 Jess Role @ UEAB2006
Three phasors properties
• Length
• Speed of counter clockwise rotation
• Relative angular position
Television 1 Jess Role @ UEAB2006
Performance of the chrominance signal
• Y =0.59G + 0.30R + 0.11B=0.599(0) +0.30(0) + 0.11(0) = 0.41
• R –Y = 0.70R – 0.11B– 0.59G=0.70(1) – 0.11(1) – 0.59(1) = 0.59
• B – Y 0.89B – 0.30R – 0.59G=0.89(1) – 0.30(1) – 0.59(0) = 0.59
Television 1 Jess Role @ UEAB2006
COLOR PHASE ANGLE
Television 1 Jess Role @ UEAB2006
Television 1 Jess Role @ UEAB2006
Misconvergence
Television 1 Jess Role @ UEAB2006
Television 1 Jess Role @ UEAB2006
Low green adjustment
Television 1 Jess Role @ UEAB2006
High adjustment of blue
Television 1 Jess Role @ UEAB2006
Dominant Red missing green
Television 1 Jess Role @ UEAB2006
Dominant Blue Missing Green
Television 1 Jess Role @ UEAB2006
Missing Red
Television 1 Jess Role @ UEAB2006
Too much Blue adjustment
Television 1 Jess Role @ UEAB2006
Low red adjustment
Television 1 Jess Role @ UEAB2006
Low green and blue adjustment
Television 1 Jess Role @ UEAB2006
Low red and green color adjustment