Flashcards in Lecture Nine: Optics 2 Deck (10)

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1

## What other practical factors affect resolution and their solutions?

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1) Numerical aperture of lens >NA

2) Resolution and Contrast are linked! >contrast

2) Digitalisation: what size pixel? resolution/2.33) Refractive index of mountant match to oil

4) Depth of focus – keep close to cover slip

5) Coverslip thickness – 170 μm or #1.5

6) Noise e.g. photons , instrumentation - >photons

7) Quality of labelling – use controls e.g. blank

2

## What happens when we under sample?

### We get aliasing

3

## What is nyquist theorem in imaging?

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Nyquist sampling of an image of two points separated by the Rayleigh resolution

Nyquist rate is 2.3 for images unlike voltage

4

## What is a good approximation of an airy disk?

### A gussian function

5

## What can cause spherical abberation?

### Mismatch between emersion medium and mounting medium

6

## What is the optimal coverslip thickness?

### 0.17-0.18mm this has the smallest FWHM for a constant light compared to all others. (look at graph of this)

7

## Should everything be sampled at the diffraction limit?

### Depends on the question

8

## How is photon noise modulated?

### Poisson distribution where mean equals the variance Reduce noise by increasing number of photons e.g. improve labelling, laser intensity, averaging

9

## What are the types of filter averaging to remove noise

###
Mean

Median

Gussian

10