LG RD-JT30 Service Manual page 80

A2. BRIGHTNESS UNIFORMITY
Brightness Uniformity = Minimum (L10,L11,L12,L13)/ Average (L1,L2,L3,L4,L5,L6,L7,L8,L9)
A3. JBMA UNIFORMITY
JBMA Uniformity = Average (L1,L3,L7,L9)/ L5
A4. ANSI CONTRAST
ANSI Contrast = Average lux value of the white rectangles/Average lux value of the black
rectangles
Contrast Ratio shall be determined from illuminance values obtained from a
black-and-white "chessboard" pattern consisting of 16 equal rectangles. The white rectangles shall
be at 100% gray and the black rectangles at 0% gray. Illuminance measurements shall be made at the
center of each of the rectangles.
A5. FOFO CONTRAST
FOFO Contrast = Lux value at the center of a solid white screen/the lux value at the center of a solid
black screen
A6. JBMA CONTRAST
JBMA Contrast = Average (L1,L2,L3,L4,L5,L6,L7,L8,L9) under solid white / Average
(L1,L2,L3,L4,L5,L6,L7,L8,L9) under solid black
A7. LIGHT LEAKAGE
Leakage = The maximum light leakage under a solid black pattern in or outside of the projected
image
A8. IMAGE DISTORTION
Keystone = (W2-W1)/ (W1+W2) x 100%
Vertical TV dist = (H1+H2-2xH3)/2H2 x100%
Horizontal TV dist = (W1+W2-2xW3)/2W1 x100%
W1: image width at image bottom
W2: image width at image top
W3: image width at the half image height.
H1: image height at image left
H2: image height at image right
H3: image height at half image
Note:
1. Keystone and Vertical TV Distortion are recommended for Front Projection Display
2. Vertical and Horizontal TV Distortion are recommended for Rear Projection Display
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