Computer Science - El Camino College

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8 Νοε 2013 (πριν από 3 χρόνια και 9 μήνες)

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Computer Science

Bushong Ch. 24

And

Carter Ch. 2

Objectives


Historical perspectives of computerized imaging



Computer classifications



Components of computer hardware



Define computer terminology



Computers


Are often classified according to size, processing
speed, and storage capacity.



Computers


Supercomputers


are the fastest and highest
-
capacity computers, containing hundreds to
thousands of microprocessors (eg: weather
forecasting)


Mainframe computer


are fast, mid
-
to
-
large

size, large
-
capacity system that has multiple
microprocessors. They can support a few
hundred to thousands of users (eg: ATM’s)


Computers


Workstation


powerful desktop system usually
connecting individual users to a larger computer
system to share and transfer information




Microcomputers


best known as PC’s or palm
pilot.


1946
-

First all electronic, general
purpose digital computer

Anatomy of the Computer


Basic form = input, output, and processing
devices


Input devices: keyboards, mice, microphones,
barcode readers, touch screens, and image
scanners.


Output devices: monitors, printers, and speakers


Processing: central processing unit (CPU)

Computer Language


Computers operate on the
Binary Number
System



It has only two digits, 0 and 1



Computers function by converting all data into
binary values.

Byte


Represents one character, digit, or value.



A bit describes the smallest unit of measure 0 or
1


computers ultimately understand only 0 or 1



Byte are 8 bits

Alphabet in
Binary

Analog vs Digital


Analog refers to a continuously varying quantity



A digital system uses only two values that vary
discretely through coding. Binary Number
System



Analog vs Digital


Analog
-

one value
blends into another


(like a thermometer)



Digital
-

distinct
separation


98.6


exact

0
2 0
4 0
6 0
8 0
1 0 0
1 s t
Q t r
3 r d
Q t r
E a s t
W e s t
N o r t h
Computer Processing


Computer processing is performed by a series of
transistors
.



Transistors are either on or off. If the transistor
circuit is closed and current passes through, it is
assigned a value of 1. If no current passes
because of the circuit being open, then 0.



Computer Processing


Transistors can be switched on and off millions
of times in a second. Each 1 or 0 is a bit.

Memory


One byte is the amount of memory needed to
store one letter.



A kilobyte represents 1024 bytes, megabyte is 1
million bytes, gigabyte is approximately 1 billion
bytes


Memory is talked about in kilo, mega, giga, or
tera.


Anatomy of the Computer


Hardware


the nuts & bolts of the computer



Software


computer programs



Hardware
: Motherboard


the largest circuitry
board inside the computer and it contains many
important small components.


The CPU


Central processing unit, or microprocessor is the
brain of the computer.



It is a small chip found on the motherboard.
(not the “box” as most people refer)



CPU = a series of transistors that manipulate
data received from the software.

CPU


The CPU


Basic tasks are to read data from storage,
manipulate the data, and then move the data
back to storage or send it to external devices,
such as monitors or printers.



CPU’s are named after its manufacturer and the
speed at which it manipulates data.

The BIOS


The basic input/output system.


A simple set of instructions to bring the
computer to life and run diagnostic test to make
sure the peripherals are functioning.


ROM = Read
-
only memory. Contains
information supplied by the manufacturer,
cannot be written on or erased. (how to start the
system)


The BIOS


After start up, BIOS oversees the basic
functions of receiving and interpreting signals
from the keyboard and other ports.



BIOS is the intermediary between the operating
system (OS) and the hardware.


The Bus


The bus provides the connections for the
information to flow within the computer.



There are several: ex. connecting the
microprocessor and the system memory
(graphics port, video adapters, universal serial
bus)

Memory


RAM = Random access memory. Data can be
stored or accessed at random from anywhere in
the main memory. Only temporary storage when
the computer is turned off RAM is wiped clean.
Usually expressed as MB (mega), GB (giga) or
TB (tera)


CMOS = (complementary metal oxide
semiconductor) retains information about the
hardware while the computer is turned off. Ex:
date and time


Ports


Connectors sticking

out of the


back of the PC

Ports


Parallel (printer port) = 8 bits of data through
the connection.



Serial (mouse) = 1 bit of data down a single
wire.



USB (universal serial bus) = multiple devices
may be connected into one port.


Sound Card



Network Card

Power supply


Provides electricity and contains a fan to keep
the computer cool.



Contains a transformer that converts AC from
the wall to DC.

Hard Drive


The main storage for programs and documents.

CD/DVD Drive


DVD’s can hold up to 7 times more than the
CD.


3 types of CD/DVD:


ROM (read
-
only memory)


R (write once
-
read many)


RW (read and write many times)

Information can be “burned”


Starting in the center and spiraling out.



Tiny depression (pit) is laser burned into the
disk to create a series on pits and areas not
burned.



To read, a laser scans the disk if the laser hit a
pit the light reflects back. A diode translates the
impulses into binary.

Storage = archival form of memory


Common type of secondary storage are optical
disks, tape, diskette, Magnetic tape, CD or DVD


Peripherals


Keyboard



Mouse



Scanners



Speakers



Microphones


Operating Systems


The OS takes over just after the computer wakes
up and allows the computer to begin doing
tasks.



Ex: Windows by Microsoft, Macintosh OS,
UNIX/Linux

OS


Early OS’s were command based. To save a file
the user needed to know the word commands.



Now most computers use GUI, graphical user
interface. A picture (icon) based program, where
the mouse is used to point and click on the
function.

Windows


based OS


Is the most commonly used. Some PACS
systems used a proprietary system.



UNIX is usually used on large servers because of
the exceptional multitasking capabilities.

Display


Soft copy = CRT or LCD display


(Plasma screen)


Hardcopy = film

Pixels


Digital images are made of discrete picture
elements, arranged in a matrix. The size of the
image is described in the binary number system



Modern imaging systems are at least 1024 x 1024



4096 x 4096 is being developed for digital
radiography. The number of pixels on a display
determines the resolution.

Pixel


Transmission of Images


PACS

-

Picture Archiving & Communications


System



DICOM

-

Digital Images & Communication


in Medicine



TELERADIOGRAPHY

-
Remote
Transmission of Images

Digital Image Processing

ALGORITHM



a set of mathematical values
used to solve a problem or find an average



A step by step process used to solve a problem


RADIOLOGIC TECHNOLOGY

A

HIGH TECH


HIGH TOUCH

PROFESSION

Questions ?