Contrast

Question 1

What is transduction

Answer 1

A transformation of physical quantity into perceptual experience

Question 2

What are the three ways of measuring contrast?

Answer 2

Webers contrast
rms contrast
Michelson contrast

Question 3

What is webers contrast?

Answer 3

-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

Question 4

What are the units for webers contrast?

Answer 4

No units

Question 5

What do grey levels display?

Answer 5

Darkest pixels display close to grey level 0

Brightest pixel display white level -=1

Question 6

What is rms contrast?

Answer 6

root mean squared difference between each squares grey levels and sample

Question 7

What is the difference between rms and webers contrast?

Answer 7

Webers contrasts quantify each square modulation of luminance
rms contrasts quantify entire array modulation of luminance

Question 8

What is the equation of rms contrasts ?

Answer 8

same as standard deviation with no bessels correction

Question 9

what is the range of rms contrasts?

Answer 9

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

Question 10

What is Michelson contrasts?

Answer 10

uses luminance instead of grey scale

Question 11

what is the equation of Michelson contrast?

Answer 11

C=Lmax - Lmin / Lmax +Lmin

Question 12

What is the range of Michelson contrast?

Answer 12

cannot be negative and be high as 1.

Question 13

What is the contrast of sinusoidal gratings?

Answer 13

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