Image Production > Imaging Processing & Display > Flashcards

Imaging Processing & Display Flashcards

(95 cards)

Study These Flashcards
1
Q

What is pre-processing?

A

Correction to the raw image data due to physical flaws in the image acquisition

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

What is post-processing?

A

Manipulation of the image after corrections have been made for personal preference

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

What is flat field uniformity?

A

Designed to even out brightness across an image field that could be caused by dropped/dead pixels

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

How is flat field uniformity tested?

A

By examining pixels across an exposed field usually in different corners and the center

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

How are dead pixels corrected?

A

Using interpolation

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

What is interpolation?

A

Where an average of the 8 pixels surrounding the dead pixel are utilized to fill it with a more appropriate gray scale

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

What steps occur as part of pre-processing analysis?

A

Segmentation
Partioned pattern recognition
Exposure field recognition
Contruction of initial histogram
Histogram analysis

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

What is segmentation?

A

Identifies areas of noise and densities outside the collimated field

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is partioned pattern recognition?

A

Used on in CR and can separate fields of collimation

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

What is exposure field recognition?

A

Analyzes background densities outside the anatomy by looking at anatomical landmarks

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

What are anatomical landmarks also known as?

A

VOI (value of interest)

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

How is the initial histogram constructed?

A

It identifies all densities on the iamging plate in the form of a graph

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

What is the X-axis of the histogram?

A

The amount of exposure

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

What is the Y-axis of the historgram?

A

The number of pixels per each exposure

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

What do brightness areas on the left of the histogram represent?

A

Bone, contrast or metal

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

What do darker areas on the right of the histogram represent?

A

Air, gas

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

How does raw radiation display on a histogram?

A

A spike at the far right

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

When would raw radiation display on a histogram?

A

When a part doesn’t cover the entire IR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How does a histogram display when the whole part covers the IR?

A

A singular graph with no spikes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does contrast display on a histogram?

A

A spike on the far left

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How is landmark identification done on a histogram?

A

By applying a threshold including a Smin and Smax to remove any unecessary values

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How is grayscale represented in graph form?

A

In a graph where the X axis represents log relative exposure and Y axis represent brightness of pixels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

If there is long grayscale, how will is show graphically?

A

With a shallow slope because there are slow changes in pixel brightness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

If there is a short grayscale, how will it show graphically?

A

Steeper, since there are more drastic changes in pixel brightness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Once a VOI is selected what happens?
Only this range of pixels will be sent/compared to the Look Up Table
26
How can histogram processing errors occur?
If the wrong histogram is chosen or in cases of extreme under/over exposure
27
What is normalization?
An attempt to make the image more like a conventional radiograph by simple alignement to image brightness
28
What are the 3 domains images are processed under?
Spatial domain Intensity domain Frequency domain
29
What is the spatial domain?
Sorting images based on the location of pixels in a space
30
What are the 3 operations of the spatial domain?
Point processing Area processing Global processing
31
What is point processing?
A pixel by pixel specific algorithm, where each pixel is adjusted
32
What is an example of point processing?
Subtraction
33
What is area processing?
Where operations are performed on a set/group of pixels
34
What is an example of area processing?
Magnification
35
What is global processing?
Where operations are performed across the entire image
36
What is an example of global processing?
Flipping the image left to right
37
What is the intensity domain?
Involves processes that are based on the individual values of the pixels, regardless of location
38
What are examples of the intensity domain?
Construction of the initial histogram and windowing/leveling
39
What is the frequency domain?
Where the image is sorted by the objects size/detail
40
What are examples of operations in the frequency domain?
Edge enhancement and smoothing
41
What is gradation processing?
Changes in the scale of contrast which is graphically represented by the slope of a curve
42
What is dynamic range?
The number of brightness values that can be represented by the entire system including software and hardware
43
What is bit depth?
Includes the brightness range of hardware only
44
What is used to save storage when it comes to gray scales?
Dynamic range compression
45
What is gray scale truncation?
When the darkers and lightest densities are cut out, making the image appear grayer
46
What is detail processing?
Allows the system to demonstrate fine details without major changes in image contrast
47
Where is detail processing done?
In the spatial or frequency domains
48
What can a kernal that utilizes multiplication do?
Enhance the edge structures, which increases noise Smooth the edges, which decreases spatial res
49
What is the unsharp mask filter?
Filter used to leave only small structures in the image
50
How does the unsharp mask filter work?
Image is created with only large structures, and structures smaller than the kernal are supressed (resulting image blurry) In the intensity domain, a positive of the unsharp mask is made (pixels inverted) Positive mask is substracted from the original image leaving only smalll structures
51
What is image smoothing?
Reduces noise in images
52
What type of filtering is imaging smoothing?
Low pass filtering
53
What does smoothing lead to in the image?
Loss of spatial resolution
54
In the frequency domain how are pixels look at?
The is broken into itswave components
55
How are the waves represented in the frequency domain?
Gray levels are the height of the wave and the number of pixels is the frequency
56
What do shorter wavelengths represent?
Smaller details
57
What do longer wavelengths represent?
Larger details
58
How does the wavelength relate to pixel size?
Shorter wavelengths represent smaller pixels with higher frequencies Longer wavelengths represent larger picels with lower frequencies
59
How does frequency related to detail?
The higher the frequency the more details
60
What must the number of pixel in a matrix match in a image display?
The number of pixels available on the monitor
61
What adjustments are made by the radiologist or technologist?
Windowing Edge enhancement Adding annotations Flipping the image Zooming
62
What is windowing?
Post porcessing technique that controls the contrast of the image
63
What is leveling?
Post processing technique that controls the brightness/density of the image
64
To demonstrate soft tissue structires what combination of window/level should be used?
Wide/long window width with a low window level
65
When does automatic rescaling occur?
When exposure is grater or less than what is needed to produce an image
66
What is the purpose of automatic rescaling?
To display the pixels for the area of interest
67
What does automatic rescaling do?
Produces images with uniform density and contrast, regardless of the exposure
68
What problem occur with rescaling?
When too little exposure is used, quantum mottle is present - When too much exposure is used, there is a lack of contrast
69
With CR and DR what is the primary control of radiographic contrast?
Look-up tables
70
What is a look-up table (LUT)
A table that maps the image grayscale values in some visible output intensity on a monitor
71
With CR, what is optical density on a film controlled by?
MAs
72
In CR and DR what does MAs have more influence on?
Image noise
73
In digital images how can sharpness be controlled?
By adjusting processing parameters
74
What are the specific changes to parameters that can be adjusted in digital images?
can choose the structure to be enhanced - control the density to reduce image graininess - adjust how much edge enhancement is applied
75
What happens to the signal after it's obtained?
They are averaged to shorten processing time and storage
76
What effect does pixel quantity have on image appearance?
The more pixels involved in averaging the smoother the image appears
77
When does edge enhancement occur?
When fewer pixels in the neighborhood are included in the signal average
78
What is histogram equalization?
A method of image processing of contrast adjusting using the images histogram
79
Why is histogram equalization useful?
It's useful in images with backgrounds and foregrounds that re both bright or dark
80
What is an advantage of histogram equalization?
Better view of bone structures in x-rays
81
What is the disadvantage of histogram equalization?
It is indiscriminate, and may increase the contrast of back ground noise while decreasing the usable signal
82
What is masking in digital imaging processing?
Electronic collimation - act of chasing the color of certain areas of a picture or transferring these areas onto another background
83
What can masking result in?
The loss of small details
84
What is an Analog to Digital Converter?
Takes an analog input signal and converts it, through a mathematically function, into a digital output signal
85
What are the 3 major steps of ADC/
anti-aliasing filter blocks unwanted frequencies - signal is sampled - sample signal is quantified - the quantified signal is digital coded
86
What is the DICOM standard made up of?
16 different parts ranging from image display to medial storage
87
What does PACS stand for?
Picture archival and communication system
88
What is PACS?
A networked group of computers, servers and Archie’s that can be used to manage digital images
89
What can PACS accept?
Any image that is in DICOM format
90
What does PACS serve as?
A file room, reading room, duplicator and courier
91
What does PACS provide?
Access to multiple users at the same time, on demand image viewing, electronic annotation and specialty imaging processing
92
What is the RIS/
Radiology information system
93
What does the RIS hold?
All radiology specific patient data
94
What is the HIS?
Hospital information system from patient scheduling info to radiologists dictated and transcribed reports
95
What does the HIS hold?
Patient's full medical inflation from hospital billing to inpatient ordering system
Image Production
flashcards
Decks in class (13)
# Cards
Brainscape helps you reach your goals faster, through stronger study habits.
© 2026 Bold Learning Solutions. Terms and Conditions