Introduction to digital image processing, image processing, digital image, analog image, formation of digital image, level of digital image processing, components of a digital image processing system, advantages of digital image processing, limitations of digital image processing, fields of digital image processing, ultrasound imaging, x-ray imaging, SEM, PET, TEM
Digital image processing is the use of computer algorithms to perform image processing on digital images. As a subcategory or field of digital signal processing, digital image processing has many advantages over analog image processing.
Digital image processing is the use of computer algorithms to perform image processing on digital images. As a subcategory or field of digital signal processing, digital image processing has many advantages over analog image processing.
Digital image processing focuses on two major tasks
-Improvement of pictorial information for human interpretation
-Processing of image data for storage, transmission and representation for autonomous machine perception
Presentation on Digital Image ProcessingSalim Hosen
Digital image processing is the use of a digital computer to process digital images through an algorithm. As a subcategory or field of digital signal processing, digital image processing has many advantages over analog image processing.
In computer science, digital image processing is the use of computer algorithms to perform image processing on digital images. As a subcategory or field of digital signal processing, digital image processing has many advantages over analog image processing.It allows a much wider range of algorithms to be applied to the input data and can avoid problems such as the build-up of noise and signal ...
digital image processing pdf
digital image processing books
digital image processing textbook pdf
digital image processing textbook
digital image processing pdf book
digital image processing gonzalez pdf
digital image processing 4th pdf
digital image processing 3rd pdf
digital image processing slides
history of image processing
digital image processing third edition
digital image processing pdf
digital image processing gonzalez ppt
digital image processing 3rd edition pdf
digital image processing third edition pdf
image processing basics
Here in the ppt a detailed description of Image Enhancement Techniques is given which includes topics like Basic Gray level Transformations,Histogram Processing.
Enhancement using Arithmetic/Logic Operations.
image averaging and image averaging methods.
Piecewise-Linear Transformation Functions
Biomedical Image Processing
Topics covered: Biomedical imaging, Need of image processing in medicine, Principles of image processing, Components of image processing, Application of image processing in different medical imaging systems
Digital image processing focuses on two major tasks
-Improvement of pictorial information for human interpretation
-Processing of image data for storage, transmission and representation for autonomous machine perception
Presentation on Digital Image ProcessingSalim Hosen
Digital image processing is the use of a digital computer to process digital images through an algorithm. As a subcategory or field of digital signal processing, digital image processing has many advantages over analog image processing.
In computer science, digital image processing is the use of computer algorithms to perform image processing on digital images. As a subcategory or field of digital signal processing, digital image processing has many advantages over analog image processing.It allows a much wider range of algorithms to be applied to the input data and can avoid problems such as the build-up of noise and signal ...
digital image processing pdf
digital image processing books
digital image processing textbook pdf
digital image processing textbook
digital image processing pdf book
digital image processing gonzalez pdf
digital image processing 4th pdf
digital image processing 3rd pdf
digital image processing slides
history of image processing
digital image processing third edition
digital image processing pdf
digital image processing gonzalez ppt
digital image processing 3rd edition pdf
digital image processing third edition pdf
image processing basics
Here in the ppt a detailed description of Image Enhancement Techniques is given which includes topics like Basic Gray level Transformations,Histogram Processing.
Enhancement using Arithmetic/Logic Operations.
image averaging and image averaging methods.
Piecewise-Linear Transformation Functions
Biomedical Image Processing
Topics covered: Biomedical imaging, Need of image processing in medicine, Principles of image processing, Components of image processing, Application of image processing in different medical imaging systems
Initial Introduction of Image processing is included in these slides which contain 1. Introduction of Image Processing
2.Elements of visual perception
3. Image sensing and Quantization
4.A simple image formation model
5.Basic concept of Sampling and Quantization
Reader will find it easy to understand the topics described here in slides . A detailed description of each topic illustrated here.
Please read and if you like do comments also.... Thanks
Digital image processing is the use of algorithms and mathematical models to process digital images. The goal of digital image processing is to enhance the quality of images, extract meaningful information from images, and automate image-based tasks.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
clinical needs, medical devices, medicalAbdulWahab672
clinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, medical devices, medical devices vs medical instrumentsclinical needs, me
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Discover the fundamentals, Characteristics & types of digital image analysis. Learn about pixels, bit depth, challenges, and AI impacts on image processing.
How to make power point presentation; How to give a successful presentation; how to make a poster; how to present a poster;
Presentation and communication skill development
Introduction to Medical Imaging, Basics of Medical Imaging, Fundamentals of Digital Image Processing, First chapter of Digital Image Processing Book by Rafael C. Gonzalez.
Digital Signature, Electronic Signature, How digital signature works, Confidentiality of digital signature, Authenticity of digital signature, Integrity of digital signature, standard of digital signature, Algorithm of digital signature, Mathematical base of digital signature, parameters of digital signature, key computation of digital signature, key generation of digital signature, verification of of digital signature
History of Computer, History of Computing, Evolution of Computer, Generations of Computer, Past Present and Future of Computer, Abacus, Differential Engine, Analytical Engine
Introduction to Input Devices of Computer System, Introduction to Input Mouse, Introduction to Input Keyboard, How keyboards works, DVORAK Keyboard, QWERTY Keyboard, Ergonomics. Computer Basics
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Francesca Gottschalk - How can education support child empowerment.pptxEduSkills OECD
Francesca Gottschalk from the OECD’s Centre for Educational Research and Innovation presents at the Ask an Expert Webinar: How can education support child empowerment?
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
2. Image
Practically every scene around us involves images or image
processing.
An image can be defined as a two dimensional signal analog or
digital that contains intensity or color information arranged
along x and y spatial axis.
It can be defined as a two dimensional function f(x,y) where
the x and y are spatial co-ordinates. Here the amplitude of
function “ f ” at any pair of co-ordinates (x,y) is called the
intensity or gray level or the color of the image at that point.
2
3. Image Types
There are two types of images, analog and digital.
Simple example, let 1 represent white and 0 represent black
color.
3
4. Analog Image
Analog image is a two dimensional function of f(s,t) considered
in the continuous time domain.
An image can be defined as a two dimensional function f(x,y)
where the x and y are spatial co-ordinates. Here the amplitude
of function “ f ” at any pair of co-ordinates (x,y) is called the
intensity or gray level or the color of the image at that point.
When x, y and the amplitude values of f are continuous
quantities then the image is referred as analog image.
4
5. Analog Image
Analog images are the type of images that we, as humans, look at.
They also include such things as photographs, paintings, TV
images, and all of our medical images recorded on film or
displayed on various display devices.
What we see in an analog image is various levels of brightness (or
film density) and colors. It is generally continuous and not
broken into many small individual pieces.
Analog images are required for human viewing.
5
6. Digital Image
An image can be defined as a two dimensional function f(x,y)
where the x and y are spatial co-ordinates. Here the amplitude
of function “ f ” at any pair of co-ordinates (x,y) is called the
intensity or gray level or the color of the image at that point.
When x, y and the amplitude values of f are all finite and discrete
quantities then the image is referred as digital image. Digital
image processing refers to the processing of digital images by
means of digital computer.
A digital image is composed of a finite number of elements, each
of which has a particular location and value. These elements are
referred to as pels, pixels, picture elements or image elements
6
7. Digital Image
A digital image is a matrix of many small elements, or
pixels.
Each pixel is represented by a numerical value. In general, the
pixel value is related to the brightness or color that we will see
when the digital image is converted into an analog image for
display and viewing.
7
8. Impact Digital Image
Digital images are necessary in all modern medical imaging
methods. Because of the following functions that can be performed
with digital images :
1. Image reconstruction (CT, MRI, SPECT, PET, etc)
2. Image reformatting (Multi-plane, multi-view reconstructions)
3. Wide (dynamic) range image data acquisition (CT, digital
radiography, etc)
4. Image processing (to change contrast and other quality
characteristics)
5. Fast image storage and retrieval
6. Fast and high-quality image distribution (teleradiology)
7. Controlled viewing (windowing, zooming, etc)
8. Image analysis (measurements, calculation of various parameters,
computer aided diagonisis)
8
10. Image Processing
Some people consider that image processing is a discipline in
which both the input and output of a process are images.
According to this definition computing average intensity of an
image would not be considered as image processing task.
However there is no such limitations or boundaries for image
processing.
However, one useful paradigm is to consider three types of
computerized processes in this continuum:
1. low-level image processing
2. mid-level image processing and
3. high-level image processing
10
11. Level of Image Processing
A low-level process is characterized by the fact that both its
inputs and outputs are images such as image preprocessing to
reduce noise, contrast enhancement, and image sharpening.
A mid-level process is characterized by the fact that its inputs
generally are images, but its outputs are attributes extracted
from those images. Such as segmentation (partitioning an image
into regions or objects).
A high-level process is characterized by the fact that its inputs
generally are attributes extracted from images, but its outputs
are images. higher-level processing involves an ensemble of
recognized objects, as in image analysis
11
12. Origins of Digital Image
Processing
One of the first applications of digital images was in the
newspaper industry, when pictures were first sent by submarine
cable between London and New York.
Introduction of the Bartlane cable picture transmission system in
the early 1920s reduced the time required to transport a picture
across the Atlantic from more than a week to less than three
hours.
Specialized printing equipment was used to code pictures for
transmitting it via cable and then reconstruct the image from the
codes at the receiving end.
12
13. Digital Image Processing
Digital image processing can be defined as processing of
digital image in a digital manner meaning that using a
digital device like computer or others.
The digital image processing is getting more and more
importance now a days because of its two major
application areas:
1. Improvement of pictorial information for human
interpretation.
2. Processing of image data for storage, transmission and
representation for autonomous machine perception
13
15. Advantages of DIP
1. It improves the visual quality of an image and the distribution of
intensity.
2. It can easily process an degraded image of uncoverable objects
3. It can process an image in such a way that the result is more
suitable than the original image
4. An image can be easily modified using a number of techniques
5. The image compression technique reduces the amount of data
required to represent a digital image.
6. Mathematical and logical operations can be performed on an
image like addition subtraction, OR etc
7. The image segmentation is used to detect discontinuity, the
presence or absence of specific anomalies like missing
components or broken connection path.
15
16. Limitations of DIP
1. Digital image processing requires so much storage and
processing power. Progress in the field of digital image
processing is dependant on the development of digital
computers and supporting technology including data
storage, display and transmission
2. Effect of environmental conditions may degrade the image
quality
3. It involves various types of redundancy like data
redundancy, interpixel redundancy etc
4. Segmentation of nontrivial image is one of the most difficult
task in digital image processing
16
17. Fields that Use Digital Image
Processing
Unlike humans, who are limited to the visual band of the
electromagnetic (EM) spectrum, imaging machines cover almost
the entire EM spectrum, ranging from gamma to radio waves.
They can operate on images generated by sources that humans
are not accustomed to associating with images.
1. Gamma ray imaging
2. X-ray imaging
3. Imaging in an ultraviolet band
4. Imaging in the visible and infrared bands
5. Imaging in the microwave band
6. Imaging in the radio band
17
18. Gamma ray imaging : imaging based on gamma rays
include nuclear medicine and astronomical observations.
In nuclear medicine the approach is to inject a patient
with a radioactive isotope that emits gamma rays as it
decays. Images are produced from these emissions
collected by gamma ray detectors.
PET : another major modality of nuclear imaging is
positron emission tomography. When a positron meets
an electron both an annihilated and two gamma rays are
given off. These are detected and a tomographic image is
created using the principles of tomography
18
19. X-ray imaging : X-rays are the oldest sources of EM radiation
used for imaging. The best known use of X-ray is medical
diagnostics, but they are used extensively in industry and
others areas like astronomy. In digital radiography, digital
images are obtained by one of the two methods:
1. By digitizing x-ray films
2. By having the x-rays that pass through the patient and
fall onto a device such as phosphor screen that convert x-
rays into light
Imaging in the ultraviolet band : the major application of
imaging in ultraviolet band includes lithography, industrial
inspection, microscopy, lasers, biological imaging and
astronomical observations. Ultraviolet light is used in
fluorescence microscopy, one of the fastest growing areas of
microscopy
19
20. Imaging in the visible and infrared bands : the infrared
band is used in conjunction with visual imaging. Another
major area of visual processing is remote sensing
Imaging in the microwave band : the major application of
imaging in the microwave band is radar. Its unique ability is
to collect data over virtually any region at any time without
regarding the weather or ambient light conditions
Imaging in the radio band : the major application of
imaging in the radio band include medicine and astronomy.
In medicine radio waves are used in MRI(magnetic
resonance imaging). It places a patient in a powerful magnet
and passes radio waves through the body in short pulses
20
21. Ultrasound Image
The ultrasound imaging is used to determine the development
of health and to determine the sex of unborn babies in the
womb. Ultrasound images are generated using the following
procedure:
1. The ultrasound system transmits a high frequency sound pulse
into the body usually 1 to 5 MHz
2. The sound wave travel through the body and hit a boundary
between tissues.
3. Some of the waves are reflected back to the probe and relayed to
the computer.
4. The machine calculates the distance from probe to the tissue
boundaries by using the speed of the sound and the time required
for each echo’s to return.
5. The system displays the distances and intensities of the echoes on
the screen, forming a two dimensional image
21
22. Transmission electron microscopy (TEM) is a microscopy
technique in which a beam of electrons is transmitted through
an ultra-thin specimen, interacting with the specimen as it
passes through.
An image is formed from the interaction of the electrons
transmitted through the specimen.
The image is magnified and focused onto an imaging device, such
as a fluorescent screen, on a layer of photographic film
Or to be detected by a sensor such as a CCD camera.
TEMs are capable of imaging at a significantly higher resolution
than light microscopes. TEMs find application in cancer research,
virology, materials science as well as pollution, nanotechnology,
and semiconductor research.
Transmission Electron
Microscopy
22
24. A scanning electron microscope (SEM) is a type of electron
microscope that produces images of a sample by scanning it with
a focused beam of electrons. The electrons interact with atoms in
the sample, producing various signals that can be detected and
that contain information about the sample's surface topography
and composition
SEM can achieve resolution better than 1 nanometer. Specimens
can be observed in high vacuum, in low vacuum, in wet
conditions (in environmental SEM), and at a wide range of
cryogenic or elevated temperatures.
Scanning electron microscope
24
27. Components of Image Processing
System
Following figure shows the basic components comprising a
typical general-purpose system used for digital image processing.
27
28. Components of the System
Image Sensor: With reference to sensing, two elements are required
to acquire digital images: a sensor and a digitizer. The sensor that
is sensitive to the energy radiated by the object we wish to image.
The second, called a digitizer, is a device for converting the output of
the physical sensing device into digital form. For example, in a digital
video camera, the sensors produce an electrical output proportional
to light intensity. The digitizer converts these outputs to digital data.
Specialized image processing hardware: usually consists of the
digitizer just mentioned, plus hardware that performs other
primitive operations, such as an arithmetic logic unit (ALU). ALU
performs arithmetic and logical operations in parallel on entire
images. ALU is used is in averaging images as quickly as they are
digitized, for the purpose of noise reduction. This type of hardware
sometimes is called a front-end subsystem, and its most
distinguishing characteristic is speed in which they process image.
28
29. Components of the System
Computer: in an image processing system is a general-purpose
computer and can range from a PC to a supercomputer. In
dedicated applications, some times specially designed computers
are used to achieve a required level of performance.
Software: for image processing consists of specialized modules
that perform specific tasks
Mass storage: capability is a must in image processing
applications. Digital storage for image processing applications
falls into three principal categories: (1) short-term storage for use
during processing, (2) on-line storage for relatively fast recall, and
(3) archival storage, characterized by infrequent access.
Image display: it displays images.
Hardcopy devices: used for recording images include laser
printers, film cameras, heat-sensitive devices, inkjet units, and
digital units, such as optical and CD-ROM disks. 29