Flashcards in Contrast Deck (13):
What is transduction
A transformation of physical quantity into perceptual experience
What are the three ways of measuring contrast?
What is webers contrast?
-each square has array of own luminance
- each square has own luminance and each square has own weber contrast
- to calculate webers contrasts you need the background contrast
c = L1 -LB /LB
What are the units for webers contrast?
What do grey levels display?
Darkest pixels display close to grey level 0
Brightest pixel display white level -=1
What is rms contrast?
root mean squared difference between each squares grey levels and sample
What is the difference between rms and webers contrast?
Webers contrasts quantify each square modulation of luminance
rms contrasts quantify entire array modulation of luminance
What is the equation of rms contrasts ?
same as standard deviation with no bessels correction
what is the range of rms contrasts?
cannot be negative and no greater than -1 and has to be less than 1
What is Michelson contrasts?
uses luminance instead of grey scale
what is the equation of Michelson contrast?
C=Lmax - Lmin / Lmax +Lmin
What is the range of Michelson contrast?
cannot be negative and be high as 1.