when a computer takes data from the user and processes it using a machine language of 1s and 0s known as binary code
if the transistor circuit is closed and current passes through it is assigned what value number? and if the circuit is open and current does not pass through, it is assigned a value of what?
What are the 2 major functions of the box are?
- to hold all of the components in a relatively cool, clean and safe environment
- to shield the outside environment from the radio frequencies being emitted by the electronic components of the computer
What is the brain of the computer and what does it do?
the CPU aka microprocessor.. small chip found on the motherboard.. and its main job is to read date from storage, manipulate the date and move the data back to storage or send it to external devices
What does the BIOS do?
it is a basic input/ and output system
- runs the startup diagnostic system
- makes sure all the peripherals are functioning properly
- oversees the basic function of receiving and interpreting signals
- acts as the intermediary between the operating system and hardware
What is the Bus?
it is a series of connections, controllers, and chips that create information highways of the computer
What is temporary memory AKA ? and what is memory measured in?
RAM. memory is measured in bytes
What does CMOS use to retain information about the PC's hardware while the computer is turned off?
small rechargeable or lithium battery
What does a sound card do? and what does it interpret?
it contains all of the circuitry for recording and reproducing sound on the PC.. it interprets many different files types such as the WAV files.. MP3 files and MIDI files
What does the network card do?
it enables the PC to connect to other PCs that are on the same network.. it can come as an expansion card plugged into a slot or part of the motherboard.
When there is a power surge, what takes the blunt force of the power?
the power supply.
How does a DVD compare to a CD when dealing with storage capacity?
DVD hols up to 7 times more data than does a CD.
a DVD holds from 9.4 to 17 GB of data
What are the 3 main types of CD/DVD drives?
ROM- can only write
R- can write 1 time but read a lot
RW- can read and write many times
what is a Land and Pit?
Pit-0- does not reflect
What are the 2 basic types of keyboards?
Soft- no sound
What is a pixel?
is an individual controllable set of dot triads
What is a matrix?
What is dot pitch? and how does it relate to resolution?
Dot pitch is the measurement of how close the dots are located to one another within a pixel.
the smaller the dot pitch of a display, the finer the resolution
what is refresh rate(vertical scanning rate) ? and how does it relate to flicker?
refresh rate is a measure of how fast the monitor rewrites the screen or the number of times that the image is redrawn on the display each second.
refresh rate helps control the flicker is seen by the user... the higher the refresh rate the less flicker seen.
How does CRT create the image?
consists of a cathode and anode within a vacuum tube. cathode boils off a cloud of electrons, and then a potential difference is placed on the tube. a stream of electrons is sent across to the anode, which is the case of the monitor is a sheet of glass coated with a phosphor layer. electrons then strike the phosphor on the glass. causing glass to emit a color based intensity where most electrons strike. .. does this all in a raster scan pattern
How does LCD emit an image?
LCD produces images by shining or reflecting light through a layer of liquid crystal and a series of color filters. when a current is applied to the liquid crystal. it aligns and allows light in varying intensities through to the next layer of glass through color filters. Light forms the colors and images seen on display.
How does plasma screens emit an image?
They are made up of many small fluorescent lights that are illuminated to form the color of the image.
between CRT and LCD how do they compare?
CRT= leaset expensive. Bulky. more luminance than LCD
LCD= more expensive. less of a viewing angle. takes up less space
What are the 3 major operating systems?
Windows by Microsoft
What TYPE of operating system of modern X-ray equipment use?
What is a network?
2 or more objects sharing resources and information.
What is the difference between a LAN and a WAN?
LAN- local area network=least expensive and faster
WAN- wide are network
What are the typical classifications of networks? and do they do?
Peer to Peer- each computer on the network is considered equal.
Server/ Client based - SERVER-centralized computer (SERVER) controls the operations, files, and sometimes the programs= distributes everything
CLIENT- server returns only the results back to the client - only what is needed/requested
What is a sever? Thin Client? and thick Client?
server= computer that manages resources for other computers, servers, and networked devices
Thin Client= a component found on a network that requests services and resources from a server
Thick Client= computer that can work independently from the network
What are the different types of cables?
Coaxial= similar to tv cable center conduction wire surrounded by insulation and grounded shield and braided wire.
Twisted Pair= wire similar to telephone wire. used for LAN
Fiberoptic= uses glass threads to transmit data on a network- easily to damage
Wireless= used infrared or radio freq. no cabled are needed but each device must contain wireless transmitters/receiver.. wall thickness and distance must be taken into account
What is a network interface card? and what does it do?
It provides the interface between the computer and the network medium.. it provides physical connections between the network and computer to establish and manage data
What does a network hub do?
send and receives data to all devices connected to it.(connects several pieces of equip).. does not know what it is or where it goes simply just sends it.
What does a network switch do?
sends data only to those devices to which data is directed to. reads the data and selects the path intended to.
What does a network bridge do?
used in large networks. it is a physical WIRED connection from one network to the other.
What does network router do?
reads portion of the messages and directs them to there intended target. even if target is on a separate network and uses a different network protocol
what is an IP address?
devices used to communicate. the address is made up of 4 octets that range from 0 to 255.. the first sets indicates the network class
What is the OSI a model of?
open systems interconnection model need to understand the basic principles of network connections. bc of this mode different types of networks can be connected and transmit data from one another.
What is unique about a Bus, Ring, token ring, Star, and mesh?
BUS-a network in which all devices are physically attached to and listen for communication on one single wire. if one wire is down everything is down- devices connected in a circle.
RING- devices are connected in a circle. each device goes around in circle always the same direction .. if there is break in the circle it goes down
TOKEN RING- connected in a circle. when computers are ready to send a message the computer send an empty toke and passes it to be filled with the message.. can be ignored.
STAR- connected to a central hub or switch. most common
MESH- multiple passageways. what internet uses
What is the difference between Analog and Digital?
Analog= information values that are continuous varying- can estimate.. film screen
Digital= only can display information in few discrete values.. matrix number.. digital clock
What is spatial location domain?
Numbers that represent shades of gray X and Y
What is spatial Frequency domain?
number of cycles per unit length, or the number of times a signal changes per unit length
How is the Fourier transform used?
its transfers spatial location domain into spatial frequency domain.
Why does we have to transfer from one domain to the other?
BC some operations perform task on one domain and not the other.. they each require a certain domain
What is Image enhancement, image restoration, image analysis and image compression?
Image enhancement- change the image so that it meets the demands of viewers usually it facilitates the diagnoses made by the radiologist.
Image restoration- improves quality of images that have been degraded. filtering a blurred image to make it sharper
Image analysis- allows for measurements and statistic as well as image segmentation
Image compression- reduces the size of the image file which will then reduce transfer time and storage needs
What does matrix pixel and voxel mean?
single pixel. which makes a matrix. which makes a voxel
What happens when matrix size increases?
longer processing time, transfer time and storage requirements
How does matrix size relate to spatial resolution?
as matrix size increases.. resolution increases
how does matrix size, FOV, and spatial resolution relate?