Digitizing
Encyclopedia
Digitizing or digitization is the representation of an object
, image
, sound
, document
or a signal
(usually an analog signal
) by a discrete set of its points or samples. The result is called digital
representation
or, more specifically, a digital image
, for the object, and digital form, for the signal. Strictly speaking, digitizing means simply capturing an analog signal in digital form. For a document the term means to trace the document image or capture the "corners" where the lines end or change direction.
McQuail identifies the process of digitization having immense significance to the computing ideals as it "allows information of all kinds in all formats to be carried with the same efficiency and also intermingled" (2000:28)
. Digital information exists as one of two digits, either 0 or 1. These are known as bit
s (a contraction of binary digits) and the sequences of 0s and 1s that constitute information are called byte
s.
Analog signals are continuously
variable, both in the number of possible values of the signal at a given time
, as well as in the number of points in the signal in a given period of time. However, digital signals are discrete
in both of those respects – generally a finite sequence of integers – therefore a digitization can, in practical terms, only ever be an approximation
of the signal it represents.
Digitization occurs in two parts:
Discretization: The reading of an analog signal A, and, at regular time intervals (frequency), sampling
the value of the signal at the point. Each such reading is called a sample and may be considered to have infinite precision at this stage;
Quantization: Samples are rounded to a fixed set of numbers (such as integers), a process known as quantization
.
In general, these can occur at the same time, though they are conceptually distinct.
A series of digital integers can be transformed into an analog output that approximates the original analog signal. Such a transformation is called a DA conversion. The sampling rate
and the number of bits used to represent the integers combine to determine how close such an approximation to the analog signal a digitization will be.
of analog sources (such as printed photos or taped video
s) into computers for editing, but it also can refer to audio
(where sampling rate is often measured in kilohertz) and texture map transformations. In this last case, as in normal photos, sampling rate refers to the resolution
of the image, often measured in pixel
s per inch.
Digitizing is the primary way of storing images in a form suitable for transmission
and computer
processing, whether scanned from two-dimensional analog originals or captured using an image sensor
-equipped device such as a digital camera
, tomographical
instrument such as a CAT scanner, or acquiring precise dimensions from a real-world object, such as a car
, using a 3D scanning
device.
Digitizing is central to making a digital representations of geographical features, using raster or vector images, in a geographic information system
, i.e., the creation of electronic maps, either from various geographical and satellite imaging (raster) or by digitizing traditional paper map
s or graphs
(vector).
"Digitization" is also used to describe the process of populating database
s with files or data. While this usage is technically inaccurate, it originates with the previously-proper use of the term to describe that part of the process involving digitization of analog sources such as printed pictures and brochures before uploading to target databases.
Digitizing may also used in the field of apparel, where an image may be recreated with the help of embroidery digitizing software tools and saved as embroidery machine code. This machine code is fed into an embroidery machine and applied to the fabric. The most supported format is DST file.
Nearly all recorded music has been digitized. About 12 percent of the 500,000+ movies listed on the Internet Movie Database
are digitized on DVD
.
Handling of analog signal becomes easy when it is digitized—the signal is digitized before modulation and transmission. The conversion process of analog to digital consists of two processes: sampling and quantizing.
Digitization of personal multimedia such as home movies
, slides, and photographs is a popular method of preserving and sharing older repositories. Slides and photographs may be scanned using an image scanner
, but videos are more difficult. Many companies offer personal video digitization services.
Object (philosophy)
An object in philosophy is a technical term often used in contrast to the term subject. Consciousness is a state of cognition that includes the subject, which can never be doubted as only it can be the one who doubts, and some object or objects that may or may not have real existence without...
, image
Image
An image is an artifact, for example a two-dimensional picture, that has a similar appearance to some subject—usually a physical object or a person.-Characteristics:...
, sound
Sound
Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing and of a level sufficiently strong to be heard, or the sensation stimulated in organs of hearing by such vibrations.-Propagation of...
, document
Document
The term document has multiple meanings in ordinary language and in scholarship. WordNet 3.1. lists four meanings :* document, written document, papers...
or a signal
Signal (electrical engineering)
In the fields of communications, signal processing, and in electrical engineering more generally, a signal is any time-varying or spatial-varying quantity....
(usually an analog signal
Analog signal
An analog or analogue signal is any continuous signal for which the time varying feature of the signal is a representation of some other time varying quantity, i.e., analogous to another time varying signal. It differs from a digital signal in terms of small fluctuations in the signal which are...
) by a discrete set of its points or samples. The result is called digital
Digital
A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...
representation
Group representation
In the mathematical field of representation theory, group representations describe abstract groups in terms of linear transformations of vector spaces; in particular, they can be used to represent group elements as matrices so that the group operation can be represented by matrix multiplication...
or, more specifically, a digital image
Digital image
A digital image is a numeric representation of a two-dimensional image. Depending on whether or not the image resolution is fixed, it may be of vector or raster type...
, for the object, and digital form, for the signal. Strictly speaking, digitizing means simply capturing an analog signal in digital form. For a document the term means to trace the document image or capture the "corners" where the lines end or change direction.
McQuail identifies the process of digitization having immense significance to the computing ideals as it "allows information of all kinds in all formats to be carried with the same efficiency and also intermingled" (2000:28)
Process
The term digitization is often used when diverse forms of information, such as text, sound, image or voice, are converted into a single binary codeBinary code
A binary code is a way of representing text or computer processor instructions by the use of the binary number system's two-binary digits 0 and 1. This is accomplished by assigning a bit string to each particular symbol or instruction...
. Digital information exists as one of two digits, either 0 or 1. These are known as bit
Bit
A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...
s (a contraction of binary digits) and the sequences of 0s and 1s that constitute information are called byte
Byte
The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...
s.
Analog signals are continuously
Continuum (theory)
Continuum theories or models explain variation as involving a gradual quantitative transition without abrupt changes or discontinuities. It can be contrasted with 'categorical' models which propose qualitatively different states.-In physics:...
variable, both in the number of possible values of the signal at a given time
Time
Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....
, as well as in the number of points in the signal in a given period of time. However, digital signals are discrete
Discrete signal
A discrete signal or discrete-time signal is a time series consisting of a sequence of qualities...
in both of those respects – generally a finite sequence of integers – therefore a digitization can, in practical terms, only ever be an approximation
Approximation
An approximation is a representation of something that is not exact, but still close enough to be useful. Although approximation is most often applied to numbers, it is also frequently applied to such things as mathematical functions, shapes, and physical laws.Approximations may be used because...
of the signal it represents.
Digitization occurs in two parts:
Discretization: The reading of an analog signal A, and, at regular time intervals (frequency), sampling
Sampling (signal processing)
In signal processing, sampling is the reduction of a continuous signal to a discrete signal. A common example is the conversion of a sound wave to a sequence of samples ....
the value of the signal at the point. Each such reading is called a sample and may be considered to have infinite precision at this stage;
Quantization: Samples are rounded to a fixed set of numbers (such as integers), a process known as quantization
Quantization (signal processing)
Quantization, in mathematics and digital signal processing, is the process of mapping a large set of input values to a smaller set – such as rounding values to some unit of precision. A device or algorithmic function that performs quantization is called a quantizer. The error introduced by...
.
In general, these can occur at the same time, though they are conceptually distinct.
A series of digital integers can be transformed into an analog output that approximates the original analog signal. Such a transformation is called a DA conversion. The sampling rate
Sampling rate
The sampling rate, sample rate, or sampling frequency defines the number of samples per unit of time taken from a continuous signal to make a discrete signal. For time-domain signals, the unit for sampling rate is hertz , sometimes noted as Sa/s...
and the number of bits used to represent the integers combine to determine how close such an approximation to the analog signal a digitization will be.
Examples
The term is often used to describe the scanningImage scanner
In computing, an image scanner—often abbreviated to just scanner—is a device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image. Common examples found in offices are variations of the desktop scanner where the document is placed on a glass...
of analog sources (such as printed photos or taped video
Video
Video is the technology of electronically capturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images representing scenes in motion.- History :...
s) into computers for editing, but it also can refer to audio
Sound recording and reproduction
Sound recording and reproduction is an electrical or mechanical inscription and re-creation of sound waves, such as spoken voice, singing, instrumental music, or sound effects. The two main classes of sound recording technology are analog recording and digital recording...
(where sampling rate is often measured in kilohertz) and texture map transformations. In this last case, as in normal photos, sampling rate refers to the resolution
Image resolution
Image resolution is an umbrella term that describes the detail an image holds. The term applies to raster digital images, film images, and other types of images. Higher resolution means more image detail....
of the image, often measured in pixel
Pixel
In digital imaging, a pixel, or pel, is a single point in a raster image, or the smallest addressable screen element in a display device; it is the smallest unit of picture that can be represented or controlled....
s per inch.
Digitizing is the primary way of storing images in a form suitable for transmission
Transmission (telecommunications)
Transmission, in telecommunications, is the process of sending, propagating and receiving an analogue or digital information signal over a physical point-to-point or point-to-multipoint transmission medium, either wired, optical fiber or wireless...
and computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
processing, whether scanned from two-dimensional analog originals or captured using an image sensor
Image sensor
An image sensor is a device that converts an optical image into an electronic signal. It is used mostly in digital cameras and other imaging devices...
-equipped device such as a digital camera
Digital camera
A digital camera is a camera that takes video or still photographs, or both, digitally by recording images via an electronic image sensor. It is the main device used in the field of digital photography...
, tomographical
Tomography
Tomography refers to imaging by sections or sectioning, through the use of any kind of penetrating wave. A device used in tomography is called a tomograph, while the image produced is a tomogram. The method is used in radiology, archaeology, biology, geophysics, oceanography, materials science,...
instrument such as a CAT scanner, or acquiring precise dimensions from a real-world object, such as a car
Motor vehicle
A motor vehicle or road vehicle is a self-propelled wheeled vehicle that does not operate on rails, such as trains or trolleys. The vehicle propulsion is provided by an engine or motor, usually by an internal combustion engine, or an electric motor, or some combination of the two, such as hybrid...
, using a 3D scanning
3D scanner
A 3D scanner is a device that analyzes a real-world object or environment to collect data on its shape and possibly its appearance . The collected data can then be used to construct digital, three dimensional models....
device.
Digitizing is central to making a digital representations of geographical features, using raster or vector images, in a geographic information system
Geographic Information System
A geographic information system, geographical information science, or geospatial information studies is a system designed to capture, store, manipulate, analyze, manage, and present all types of geographically referenced data...
, i.e., the creation of electronic maps, either from various geographical and satellite imaging (raster) or by digitizing traditional paper map
Map
A map is a visual representation of an area—a symbolic depiction highlighting relationships between elements of that space such as objects, regions, and themes....
s or graphs
Chart
A chart is a graphical representation of data, in which "the data is represented by symbols, such as bars in a bar chart, lines in a line chart, or slices in a pie chart"...
(vector).
"Digitization" is also used to describe the process of populating database
Database
A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...
s with files or data. While this usage is technically inaccurate, it originates with the previously-proper use of the term to describe that part of the process involving digitization of analog sources such as printed pictures and brochures before uploading to target databases.
Digitizing may also used in the field of apparel, where an image may be recreated with the help of embroidery digitizing software tools and saved as embroidery machine code. This machine code is fed into an embroidery machine and applied to the fabric. The most supported format is DST file.
Analog signals to digital
Analog signals are continuous electrical signals. Digital signals are non-continuous.Analog signal can be converted to digital signal by ADC.Nearly all recorded music has been digitized. About 12 percent of the 500,000+ movies listed on the Internet Movie Database
Internet Movie Database
Internet Movie Database is an online database of information related to movies, television shows, actors, production crew personnel, video games and fictional characters featured in visual entertainment media. It is one of the most popular online entertainment destinations, with over 100 million...
are digitized on DVD
DVD
A DVD is an optical disc storage media format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions....
.
Handling of analog signal becomes easy when it is digitized—the signal is digitized before modulation and transmission. The conversion process of analog to digital consists of two processes: sampling and quantizing.
Digitization of personal multimedia such as home movies
Home movies
A home movie is part of the motion picture filmmaking process made by amateurs, often for viewing by family and friends. When the hobby began, home movies were produced on photographic film, but accessibility of video production with video cameras and low cost data storage devices has made the...
, slides, and photographs is a popular method of preserving and sharing older repositories. Slides and photographs may be scanned using an image scanner
Image scanner
In computing, an image scanner—often abbreviated to just scanner—is a device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image. Common examples found in offices are variations of the desktop scanner where the document is placed on a glass...
, but videos are more difficult. Many companies offer personal video digitization services.