# Lernkarten

Karten 151 Karten 2 Lernende English Universität 01.11.2017 / 27.01.2018
15 Exakte Antworten 59 Text Antworten 77 Multiple Choice Antworten

2: An optical system that demonstrates astigmatism is one whose point spread function is ------ . This means that the system's linespread function will depend on the  ----- .

symmetric --- line orientation

asymmetric --- line orientation

2:

A system is a transformation from one signal—called the input—to another signal—called the output or the response of the system. Assume you have a system f with time-varying input x(t), and time-varying response y(t). Thus:

y(t)=f [x(t) ]

If you your system f was a linear system, its input-output relationship obeys two important properties: homogeneity and additivity. Which of the following statements express the propertiy of additivity mathematically?

f [x_1(t)] * f [x_2(t)] = f [x_1(t) * x_2(t)]

f [x_1(t)] + f [x_2(t)] = f [x_1(t) * x_2(t)]

f [x_1(t)] + f [x_2(t)] = f [x_1(t) + x_2(t)]

f [x_1(t)] + f [x_2(t)] = f [x(t_1 + t_2)]

f [x_1(t)] + f [x_2(t)] = f [x(t_1 * t_2)]

2: In 1966, Campbell and Gubisch estimated the  ---    of the human eye using the ---   method. They found that for  ---  pupil sizes, the retinal image quality was mainly limited by  ---  .

linespread --- double pass -- small --- diffraction

linespread --- double pass -- big --- diffraction

pointspread --- double pass --- big ---- diffraction

2: The pointspread and linespread functions describe the spread (blurring) induced by an optical system on a point and a line respectively. Which statements are true

3: Before reaching the photoreceptors, light passes through the:

cornea -> vitreous humor -> pupil -> lens -> aqueous humor -> retina

sclera -> cornea -> vitreous humor -> pupil -> lens -> aqueous humor -> retina

cornea -> aqueous humor -> pupil -> lens -> vitreous humor -> retina

sclera -> cornea -> aqueous humor -> pupil -> lens -> vitreous humor -> retina

sclera -> aqueous humor -> pupil -> lens -> vitreous humor -> retina

3: Cones and rods are photoreceptors. Cones are mainly responsive in the --- , meaning they have  --- sensitivity to absolute light levels. They are concentrated in the  --- , and there are estimated to be about --- million cones.

day --- low --- fovea --- 5

night --- high --- peripher --- 100

day --- high ---- fovea --- 5

night --- low --- fovea --- 5

day --- high --- peripher --- 100

3: Rods are not found in the  ---  [one word]. They express the photopigment  ---  and are mainly sensitive to  ---  wavelength light. There are estimated to be about  ---  million rods.

fovea --- Rhodopsin --- long (red) --- 5

peripher --- Rhodopsin --- short (blue) --- 100

fovea --- Rhodopsin --- short (blue) --- 100

peripher --- Rhodopsin --- middle (green) --- 5

fovea --- Rhodopsin --- short (blue) --- 5

3: To bring near objects into focus, the ciliary muscles ---  , making the lens of the eye ---  , in a process known as --- . This capacity decreases with age such that by ---   years, accommodation amplitude is less than 2.5 diopters (compared to around ---   diopters for 20-year-olds).

relax --- more thick --- Accomodation --- 40 - 50 --- 10

contract --- more thick --- Accomodation --- 50-60 --- 10

relax --- more thin --- Accomodation --- 50 -60 --- 5

contract --- more thin --- Accomodation --- 40-50 ---10

contract --- more thick ---- Accomodation --- 50-60 --- 5