Digital Images Flashcards

1
Q

What is the singular of ‘data’?

A

Datum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What can image analysis be used for?

A

To calculate morphological parameters on a computer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

List the different types of radiation on the electorate-magnetic spectrum from the largest wavelength to the smallest.

A
Radio
Microwave
Infrared
Visible
Ultraviolet
X-ray
Gamma ray
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the wavelength of radio waves?

A

10^3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the wavelength of microwaves?

A

10^-2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the wavelength of infrared?

A

10^-5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the wavelength of visible light?

A

0.5x10^-6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What can image processing and analysis be used for in a biological context?

A
CT-scanner
CT slice
MRI
radiography
Counting objects (e.g. bacteria)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How many bits in a byte?

A

8 bits are in a byte

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How many bytes are in a pixel?

A

A pixel = 1 byte

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a pixel?

A

a sample of light based in that particular position

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How many different combinations are there of 0 and 1 in a single byte?

A

256

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

An image is a sequence of numbers ranging between 0 and _____

A

255 (not 256 because we start at 0)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How many bytes does a greyscale image of size 800x600 occupy on the computer?

A

800x600= 480000 Bytes (480kB)

Because 1 pixel= 1 byte so an image of size MxN pixels occupies M x N Bytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Some images use more than 8 bits for storing grey levels. With 16 bits, how many different values of grey can a pixel assume up to?

A

2^16 = 65536 different values of grey

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How many Bytes does an RGB image of size 800x600 occupy on the computer?

A

800 x 600 x 3 = 1,440,000 Bytes (1.44 MB)

To get MB divide by 1 million

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What three colours are used in colour images?

A

Red, Green, Blue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Image formation means?

A

Object in, image out (on computer)

19
Q

Image processing means?

A

Image in, image out

20
Q

Image analysis means?

A

Image in, features out (for example, area and perimeter)

21
Q

Computer graphics means?

A

Numbers in, image out

22
Q

Computer vision means?

A

Image in, interpretation out

23
Q

Visualisation means?

A

Image in, representation out

24
Q

What does the operation ‘image processing’ do?

A

1) Enhancement and restoration

2) segmentation (thresholding and edge detection)

25
What does the operation 'image analysis' do?
Feature extraction and measuring
26
Define binary image
A digital image that had only two possible values for each pixel
27
Define image segmentation
The process of partitioning a digital image into multiple segments
28
What is the goal of image segmentation?
To simplify/change the representation of an image into something simpler and easier to analyse
29
Define image processing
The analysis and manipulation of a digitised image, especially in order to improve its quality
30
Define image analysis
the extraction of meaningful information from images
31
List some applications of image analysis (not necessarily biological)
1) to see the internal organisation of termite nests 2) co-localisation of markers in microscope images 3) counting trees in an oil palm plantation (via aerial image)
32
What does dilation do?
Adds pixels to the edges of objects in a binary image
33
What does erosion do?
Removes pixels form the edges of objects in a binary image
34
What does watershed do?
Watershed segmentation is a way of automatically separating or cutting apart particles that touch
35
What is a computer program?
A program is simply a sequence of instructions telling a computer what to do
36
What is morphological filtering?
It is used to clean an image after segmenting it (it fills in holes, removes isolated background and foreground pixels etc)
37
What does connected components labelling do?
It allows you to connect together pixels that belong to the same object
38
Name two ways in which a high-level language can be translated into machine language which the computer can execute
You can either compile or interpret the language
39
What does binarisation do?
It converts an image into black and white (background black, foreground white)
40
Define grey level (or grey scale) image
A monochrome image in which pixels typically represent brightness values ranging from 0 to 255.
41
Define restoration
Given a noisy sample of some true data, the goal of restoration is to recover the best possible estimate of the original true data.
42
Define saturation
Reaching the upper limit of a dynamic range. For instance, intensity saturation occurs for an 8- bit monochromatic image when intensities greater than 255 are recorded: any such value is encoded as 255.
43
Define thresholding
Thresholding is the quantization of an image into two values. One example is the conversion of a greyscale image to a binary image.