Physics Chapter 15-US
Terms
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- in the DISPLAY, The ______are fired by the electron gun.
- electrons
- After the electrons are fired by the electron gun, they are sent through the _____
- magnetic field
- After the electrons are sent through magnetic field the phosphors ____
- glow when electrons hit them
- Together the even and odd field are interlaced reducing
- flicker creating a frame
- The Tv screen is made up of ___ closely spaced horizontal lines
- 525; they are swept with line scans
- bi means
-
2
- bistable=
- black and white
- grayscale =
- multiple levels of brightness
- found on the monitor
- display controls
- range of brilliancies within display
- contrast
- black and white images
- high contrast
- many gray shades
- low contrast
- determines the brilliance
- brightness
- what makes grayscale
- scan converters
- a scan converter ____then ___
- stores then displays
- to store is called
- writing
- to display is called
- read
- a scan converter translates info from ____format to ___format
- spoke to video
- what converters do we use today?
- digital scan converters
- real numbers are ___
- analog
- continuous; unlimited
- analog
- used in computers
- digital
- use discrete values; limited choices
- digital
- original scan converter
- analog scan converter
- made grayscale possible
- analog scan converter
- with the analog scan converter...vacuum tube with electron gun, electrons are set to silcon wafer or _____ot be stored in an _____
- dielectric matrix; electron bucket
- with the analog scan converter there is excellent ___resolution
- spatial
- Limitations of analog S. Converters
-
image fade
image flicker
instability
deteriation
- used in computer technology
- digital scan technology
- images converted to ____and ____ with the digital scan converters
- 1's and 0's
- with the digital scan converter, it is ____or digitized for display
- retranslated
- advantages of digital scan converters
-
uniformity
stability
durability
speed
accuracy - 2 elements of digital scan converters
-
pixel
bit - pixel stands for
- picture element
- single shade of gray
- pixel
- number of elements per inch
- pixel density
- smaller pixels, more pixels
- high density
- improves with high density, better detail
- spatial resolution
- binary digit
- bit
- smallest amount of memory assigned to pixel
- bit
- 0 or 1
- bistable
- 8 bits of memory
- byte
- series of 0s and 1s
- binary number
- regular numbers 0-9
- decimal numbers
- 2 bytes or 16 bits
- word
- more bits, improves ___ ____
- contrast resolution
- calculating the number of gray shades
- 2 number of bits
-
A and D Data
During reception.
analog is converted to digital for _____ - storage
- occurs in digtal format before storage (TGC, log compression, write magn)
- preprocessing
- occurs after storage in digital scan converter ( after freeze, black/white inversion, read mag, contrast variation)
- post processing
- Digital signals translated back to analog for display on TV
- digital to analog
- signal on TV monitor is in analog called
- video display
- TGC, log compression, write mag are examples of
- preprocessing
- black/white, read mag, contrast variations are examples of
- postprocessing
- example of both post and pre
- persistence ; frame averaging; edge enhancement; smoothing; fill in interpolation
- region of interest is enlarged
- magnification
- 2 types of zoom
- read and write
- after image is stored or frozed
- read
- same number of pixels lines as original
- read
- larger pixel size
- read
- not rescanned
- read
- spatial res is unchanged
- read
- during data acquistion
- write
- before frozed
- write
- rescans
- write
- number of pixels is greater than original
- write
- pixels stay the same
- write
- digital images stored on a large comp network
- pacs
- advantages of pacs
- instant access; no degradation; transmits images to others
- combo of magnetic laser technology
- magnetooptical storage
- stores large amounts of data
- magneto-optical storage