Optics Lecture 1

Question 1

The illuminate or luminance distribution of the image of a point source of light

Answer 1

PSF

Question 2

In the absence of defocus, aberration and scatter, the PSF is

Answer 2

Diffraction limited PSF

Question 3

Defocus, aberrations and scattered light do what to the PSF

Answer 3

Shorten and broaden

Question 4

The form of PSF depends upon

Answer 4

Shape and diameter of aperture

Question 5

What controls impact of ocular aberrations and diffraction on retinal image quality

Answer 5

Pupil size

Question 6

What size pupil give the best retinal image quality

Answer 6

3mm

Question 7

3 ways that psf. Can be reduced to a single number that specifes the image quality

Answer 7

Rayleigh’s criterion
Half-width
Strehl ratio

Question 8

2 point resolution limit occurs when the first minimum of one pattern coincides with the center max of the other pattern

Answer 8

Rayleighs criterion

Question 9

Diffraction pattern often associated with rayleighs criterion

Answer 9

Airy disk

Question 10

Width of PSF at half the peak heigh

Answer 10

Half-width

Question 11

Half width of diffraction limited psf

Answer 11

3.23

Question 12

What happens to the half-width as you increase aberrations

Answer 12

It increases

Question 13

Measure of the effect of aberrations on reducing the max or peak value of the PSF

Answer 13

Strehl ratio

Question 14

The greater the aberrations, the (higher/lower) the strehl ratio and the (better/poorer) the image quality

Answer 14

Lower the ratio

Poorer the image quality

Question 15

How does the strehl ratio compare to 1

Answer 15

Always less than or equal to

Question 16

What do aberrations do to the PSF and the max peak height

Answer 16

Spread out PSF

Decrease max peak height

Question 17

A good, near to diffraction-limited system is that the strehl intensity ration has a value of

Answer 17

.8

Question 18

Illuminate or luminance distribution in the image of a line source of light

Answer 18

LSF

Question 19

What is the double pass method

Answer 19

Light distribution of a point source at the retina that cannot directly be measure, so the light passing back out of the eye is measured

Question 20

Imaging systems ability to distinguish object detail

Answer 20

Resolution

Question 21

How faithfully the minimum and maximum intensity values are transferred from object plane to image plane

Answer 21

Contrast or modulation

Question 22

What 2 things are important to understand OTF

Answer 22

Resolution and contrast

Question 23

OTF=

Answer 23

MTF + PTF

Question 24

A function of spatial resolution which refers to the smallest line pair the system can resolve

Answer 24

MTF

Question 25

Due to light attenuation, MTF is normalized to

Answer 25

1

Question 26

Decrease in amplitude and causes transverse shift of image position is what aberration

Answer 26

Coma

Question 27

Aberrations that produce a transfer shift produce an effective phase shift in the image known as

Answer 27

Phase transfer function

Question 28

In an on-axis in a rotationally symmetric optical system, what happens with the phase spatial frequency

Answer 28

There is no change

OTF = MTF –> PTF = 0

Question 29

For higher levels of defocus, what happens to MTF

Answer 29

Becomes negative

Question 30

When the MTF is negative, what has happened to the image pattern compared with the object

Answer 30

Reversed contrast

Question 31

The spatial frequency at which the modulation transfer function first goes to zero is

Answer 31

The resolution limit

Question 32

Any resolution of higher frequency patterned is called

Answer 32

Spurious resolution

Question 33

Phenomenon in which the contrast of image of a periodic grating first goes to zero as defocus is increased, them rises at higher levels of defocus

Answer 33

Spurious resolution