Light Adaptation

Question 1

What are the 4 parts of the TVI curve?

Answer 1

1. Dark-Light level
2. Square root law
3. Weber’s law
4. Rod saturation

Question 2

What is the slope for the dark-light level?

Answer 2

0

Question 3

This is when background light must exceed the dark background noise; slope = 1/2

Answer 3

Square root law

Question 4

This states the more intense the stimulus, the more change is needed to notice the difference; slope = 1

Answer 4

Weber’s law

Question 5

What are the constants for Scotopic and photopic vision in weber’s law?

Answer 5

Scotopic = 0.14
Photopic = .015

Question 6

Which system (photopic/scotopic) is more sensitive to VA? Contrast? Absolute sensitivity?

Answer 6

1. VA = Photopic
2. Contrast = Photopic
3. Absolute = Scotopic

Question 7

The area within Ricco’s law that holds true is called?

Answer 7

Critical Area ~ 10’ of arc (varies with eccentricity)

Question 8

This law describes the reciprocal relation between threshold luminance and stimulus area

Answer 8

Ricco’s law (L x A = C)

Question 9

This describes the reciprocal relationship between threshold luminance and time

Answer 9

Bloch’s law (L x T = C)

Question 10

What law is used if the stimulus area is larger than 10’ (the critical area)?

Answer 10

Pipers law!

Question 11

According to Ricco’s law, if luminance is halved, what happens to the area?

Answer 11

Area = doubled

Question 12

The scotopic systems has good temporal ______ but poor temporal ______.

Answer 12

Good temporal summation

Poor temporal resolution (100msec)

Question 13

The photopic system has good temporal _____ but poor temporal ____

Answer 13

Good temporal resolution

Poor temporal summation (10msec)