chapter 15 ultrasound Physics
PACS
Picture Archiving and Communication System
what is a bit
a binary digit
wgat is a pixel?
a picture element
digital number
accosiated with computer devices. have obly descreat values, limited chioces. 165.
frequency compounding
creates pictures from sub-bands made of different frequencies
brightness
determines the briliance
contrast
determins the range of briliance
types of scan converters
digital or analog
what is pixel depth?
how many shades of grey displayed
limitations of analog converter
image fade, image flicker, notability, and deterioration
analog scan converter
made grey scale possible
edge enhancement
make edges sharper with bright and dark highlights
bistable
only 2 shades. black or white, either on or off, 0 or 1
fill-in interpolation
pedicts the gray value of gaps between scanlines
wgat are the two important pieces of a digital scan converter?
pixel and bit
spatial compounding
scans image from different angles and combines the pictures
temporal compounding
superimposes old pictures onto the current picture
elastography
tests tge stiffness of tissue using shearing force of sound
pixel density
the number of pixels per inch
advatages of a digital scan converter
uniformity, stability, durability, speed abd accuracy
digital scan converter
use computer technology to convert images into numbers, a process called digitizing
coded exitation
uses long complex pulses to improve the S-N ratio and resolution
how many bytes per word?
16 bytes per _________
analog number
1st grey scale image technique. "real world". unlimited and continuous ramge of numbers. 165.96712
how many bits are in a byte
8 bits per ______
DICOM
Digital Imaging and Computers in Medicine
