Lesson 6 (Part 1) Flashcards
What are the parts of the image processor? (5)
- Preprocessor
- from the signal processor - Scan converter
- Image memory
- Post processor
- Digital-to-analog converter
- to the display
What is information from the scan lines built into?
Frames for information
- preprocessor
Where are frames stored?
In image memory
- can be pulled out postprocessor
Where are image memories sent to?
The display as an analog signal
Image processor
Converts the digitized, filtered, detected and compressed serial scan line data into images that are stored in image memory, all to prepare for the presentation on the instrument display
What is scan conversion done by?
The scan converter
What does the scan converter do? (2)
- Changes echo information (scan lines) into image form (frames)
- helps to build a frame - Properly locates each echo on the image frame
How do you get real time scanning?
By locating each frame several times a second
How many scan lines are in a frame?
96-256
What is used to determine the proper location in the image memory? (2)
- The direction of each scan line
2. Location of each echoes in depth down each scan line
What does the image processor properly locate?
Each series of echoes corresponding to each scan line for each pulse emitted from the transducer
- filling up the memory with echo information
What does the image process format?
Echo displays into image form for image processing, storage and display
What is each frame made up of?
A matrix of tiny blocks called pixels
How do you get better resolution?
By having more pixels
Volex
3D
What do frames require?
Processing
When does preprocessing start?
Before (while) the echo data is stored in the image memory
- the frame is still being built during this time
What are 8 examples of preprocessing?
- Edge enhancement
- Pixel interpolation
- Persistence
- 3D acquisition
- Spatial compounding
- Panaramic imaging
- 4D imaging
- Elastography
Edge enhancement
Sharpens boundaries to make them more detectable and make more precise measurements
Pixel interpolation
Average the brightness of the adjacent pixels and fill in the missing pixels accordingly
Persistence
Average of sequential frames to reduce noise and random content
What does persistence do to the frame rate?
It decreases it
3D acquisition
Multiple parallel 2D frames obtained and built into 3D volumes
What is 3D acquisition also known as? (2)
- Volume imaging
2. Volumetric scanning
Spatial compounding
Hits the same structure from different angles and averages it out in order to sharpen the borders
Panaramic imaging
Results in an image with a wider field of view
- works the same as your phone camera
4D imaging
3D imaging + real time
Elastography
Is an imaging method that presents qualitative tissue stiffness information on the anatomic display and in some cases, presents quantitative stiffness information
- split screen is used
What does colour indicate?
Compressibility
What does compressibility have a correlation with?
Malignancy potential
When can preprocessing only occur?
Before you hit the freeze button on the US machine
Why might preprocessing be useful? (2)
- Combine 3 mages using different frequencies will give you better penetration
- use 5 and you get better resolution - Over all you get a better quality image
What are the benefits of having high and low frequencies?
Averages the frames created using all of the different frequencies
What are the drawbacks of having high and low frequencies?
Decreases frame rate and temporal resolution
