Flashcards in Imaging Processing and displays Deck (59):
What does the image processor do?
converts or processes the data
(voltages have been changed) in prep for display
What is the Scan Converter?
changes the US format (spokes) into TV format (interlaced) to make an image...now we can see it
What is the role of the scan converter?
image storage or memory
makes gray scale displays and real time imaging possible by **storing the image data**
What reformats echo data into image form for image processing, storage and display?
Before computers what kind of scan converter did you have?
now we have DIGITAL
What is performed on the image as part of the scan conversion?
Preprocessing is done BEFORE....
What happens in the machine before storage in the preprocessing?
finish slide 13
What is pixel interpolation?
assigns a brightness value to a missed pixel
filling in missing pixels before it stores it
What is Persistence (frame averaging)?
averaging of sequential frames from the same view for a smoother appearance and NOISE reduction
***increase signal to noise ratio***
IMPROVES CONTRAST RESOLUTION
not used for rapid structures - heart
What is panoramic imaging?
makes it wider than normal
what is spatial compounding?
a method and an apparatus for **spatially compounding**US frames by using multiple angle views. (averaging at an angle)
successive image frames of a pixel data are processed using a SUM OF ABSOLUTE DIFFERENCE registration algorithm.
When frames are averaged and the anatomy is viewed from different angles, what is this called?
what does edge enhancement do?
sharpens and defines boundaries
What is 3D imaging?
What is elastography?
estimates tissue stiffness
Is TGC a preprocessing thing?
comprises a TGC curve generator and the ability to drive the TGC curve generator to provide digital generation of the TGC curve
What is Write Magnification or Zoom (RES)?
rescans of the region of interest and creates a new image with improved spatial resolution
What is Log compression?
the max dynamic range the eye can see
What is the memory?
image data converted to numbers
numbers stored in memory
numbers processed into an image
What is a pixel?
smallest element of a digital picture
(divide picture into a grid, each square is a pixel)
More pixels = best __________ ____________
What is a matrix?
a board divided into pixels
the more pixels in the matrix the better the spatial resolution of the image
What is a BIT?
smallest amount of digital storage
Binary numbers are based on 2...all numbers consist of what numbers?
0 and 1
If you have 8 bits how many shades of gray?
2 to the 11th power = 254
if you have low bits and low shades of gray which equals high contrast imaging....what kind of imaging are you doing?
cardiac and vascular
if you increase the gray mapping what are you imaging?
^bits and ^shades of gray = low contrast imaging for abd, OB, and superficial
post processing is done AFTER
What is Read magnification?
occurs after the data is stored
number of pixels the same
does not improve resolution just makes it larger
What is black and white inversion?
simply inverting black things to white and white to black
What is the display
the link between the system and the sonographer
makes a visual picture
What are the old kind of displays?
CRT - cathode Ray Tube (like and old TV)
has ELECTRONS sweep across the face of the screen
and those hit the PHOSPHOR
then it glows and turns electrons into light
brightness of the echo is seen on the display
What is a raster scan?
it's the moving of the electrons across the monitor
to make a picture on the old CRT display
The CRT used _______ display
525 closely spaced horizontal lines
odd field and even field are laced together to make a frame
frame rate is 30Hz
What are the three colors for the electron in the CRT?
Red, Blue, Green cathodes
The new displays have what kind of screen?
HIGHER FRAME RATE
less power consumption
less heat generation
What is bistable? (old display)
only two choices - white or black, off or on
high contrast image
narrow dynamic range
What are the controls on the display? (new display)
brightness (determined the brilliance of the signals displayed)
contrast (determines the range of brightness that is displayed)
on the new displays, what is gray scale - gray mapping?
levels of brightness
assignment of different shades of gray for each echo amplitude
low contrast image
how is digital generation of the time gain compensation curve achieved?
by an initial gain and data represented by a series of SLOPES and associated TIME-DEPENDENT break-points
Pixel density =?
pixels per inch
WHat is the ability to observe subtle echo strength difference between adjacent tissue?
What is the operator controlled after the image is stored adjustments called?
What ways can we manipulate the image data after storage?
What is B color?
echoes in various colors rather than gray
improved contrast resolution
What is surface rendering?
Three dimensional imaging (aka 4D when you watch in real time 3D)
What are the differences between analog and digital display?
real world computer world
actual measuring discrete
unlimited choices limited choices
if you change the image display on one monitor does it change another image display on a different monitor?
What are all of parts of the system in order of their job?
master > beam former > receiver > Image processing > scan converter (preprocessing) > digital storage (post processing)>>>display
The beam scanned...analog or digital?
echoes received, converted to numbers...analog or digital?
What are the different ways of recording and archiving?
Paper (what we give for anatomy pics)
What was the problem with magnetic recording and archiving?
disrupted by strong magnetic field
Video tapes, cassette tapes...erased if near magnetic field
what was the problem with chemically media recording and archiving?
wrong temp, contaminated chemicals
way back when sonographers needed to print films of their studies
What is the advantages of magneto-optical recording and archiving?
magnetic and laser technology
huge capacity for storage
time required to locate and mount disk
What are our options for image recording an archiving in a digital world?
JPEG (joint photographic experts group)
TIFF (tagged image file format)(larger but better quality)
MPEG (moving picture experts group)
AVI (audio video interleave)
What is PACS?
picture archiving and communication system (physical network)
What are the pros and cons of PACS?
computer network - digital retraining