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Flashcards in Contrast Deck (13):
1

What is transduction

A transformation of physical quantity into perceptual experience

2

What are the three ways of measuring contrast?

Webers contrast
rms contrast
Michelson contrast

3

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

4

What are the units for webers contrast?

No units

5

What do grey levels display?

Darkest pixels display close to grey level 0
Brightest pixel display white level -=1

6

What is rms contrast?

root mean squared difference between each squares grey levels and sample

7

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

8

What is the equation of rms contrasts ?

same as standard deviation with no bessels correction

9

what is the range of rms contrasts?

cannot be negative and no greater than -1 and has to be less than 1

10

What is Michelson contrasts?

uses luminance instead of grey scale

11

what is the equation of Michelson contrast?

C=Lmax - Lmin / Lmax +Lmin

12

What is the range of Michelson contrast?

cannot be negative and be high as 1.

13

What is the contrast of sinusoidal gratings?

Contrast of sinusoidal gratings is proportional to amplitude of the sinusoidal that describes the luminance. Proportion to vertical separation between peaks and troughs