Chapter 24: Digital Image Processing
10 megabyte
A __ _____ disk will store over 10,000,000 bytes of information.
little
A high S/N indicates ___ noise in the image.
high
A high contrast image has a ___ frequency.
smaller
A larger matrix provides ____ pixels.
low
A low contrast image has a ___ frequency.
digital computers
All medical imaging is achieved with which type of computers?
1970s-1990s
Around what time did digital computerization come out for CT and US?
0, 1
Because electrical currents are understood as being either on or off, the binary system consists of information recorded as either a _ for off or a _ for on.
window
Because the range of stored densities is so much wider than the visual range, any digital image is only a small part of the total data obtained - each image is a _____ on the total range of data.
two
Binary systems operate with a ___-symbol language.
expansion or compression
Changes in window width are sometimes called gray scale ____ or ____.
200, 500-1000
Commercial systems often have a S/N of ____ but the HR systems used in digital fluoro have a S/N between ________.
hardware
Computer equipment is called what?
byte
Computer memory is often rated in terms of total ____ memory.
software
Computer programs are called what?
number of values displayed per image side
Computerized digital images are described in terms of what
binary machine
Computers operate from ____ ____ language.
health level 7
DICOM imaging now includes compatibility via a database system that includes linage of the patient images with the patient's EMR. This database system is called what?
numerical values
Density and contrast of the digital image are controlled by varying the ____ ____ of each pixel.
1000+
Digital detectors are capable of producing ______ shades of gray.
reduces
Digitalization of analog information (increases / reduces) the quality and quantity of information?
numerical value
Each box of an image matrix will display a ____ ____ which can be transformed into a visual brightness or density level.
shades of gray
Each pixel is capable of representing a wide range of what?
bus
Electrical connections between the CPU and the other components rung along a system of series or parallel conductors called what?
fine
Extremely wide window width requires the computer to ignore ___ contrast differences in order to display the entire range of data.
electronic sources
Fluoroscopic noise mostly comes from what?
increase
If the window level increases, density will _____.
decrease
If window width increases, image contrast will ____.
voxel
In medical imaging, each pixel value corresponds to a 3-D volume of tissue known as what?
1940s
In what time period did mathematical theory and solid-state electronics come out?
1960s
In what time period did microchip technology come out?
decreased
Increased noise = _____ image contrast.
transverse, sagittal, and coronal
It is important that the radiographer understand anatomy from different perspectives due to the methods of digital processing and image information? What are the 3 perspectives?
analog-to-digital converters
Medical imaging is often achieved from information that has been processed by what?
IR
Modalities differ in bit depth that is available depending on the capabilities of what?
inversely
Noise is ____ related to contrast.
signal-to-noise ratio
Noise is measured as what?
peripherals
Scanners, mouse, keyboard, input memory disk drive, and paper printers are all forms of what?
CPU, Bus
The ____ is the heart of the computer while the ___ is the vessels.
greater
The _____ the matrix size, the better the resolution.
32
The human visual range is ___ or fewer shades of gray.
gray scale bit depth
The number of shades of gray is determined by what?
frequency, contrast, and noise
The quality of the data acquired from the IR is measured by what three data characteristics?
direct
There is a ___ relationship between subject contrast and acquired data contrast.
mathematical theory, solid-state electronics, and microchip technology
What 3 things were required prior to digital computer applications in medical imaging?
Input devices
What are devices such as keyboard, touch screen monitors, and voice-activation that you put into or connect to a computer?
computers
What are devices that process information?
monitors and printers
What are the two most common output devices?
programs and data
What are the two types of information computers use?
scanning or array detection
What are the two ways detectors acquire information?
voltage
What can memory be transferred as?
window level
What changes the pixel value by addition or subtraction and controls image density?
window width
What changes the pixel value by multiplication or division and controls image contrast?
pixel size
What determines resolution?
central processing unit
What directs information to and from various parts of the computer?
digital imaging and communication in medicine
What does DICOM stand for?
off
What does a 0 in binary code stand for?
on
What does a 1 in binary code stand for?
IRs
What input device do radiographers use on a normal basis?
array processors
What is a specialized computer that functions as a peripheral and uses CPU memory to perform mathematical operations at extremely high speed?
matrix
What is a square series of boxes that gives form to the image?
digital image
What is an image that has been converted into numerical values for transmission or processing?
pixel
What is an individual matrix box or picture element?
bus speed
What is critical to how fast the computer system can function?
detector
What is required for collection of input information?
central processing unit
What is the "heart" of every computer?
TV camera
What is the "noisiest" component of a digital system?
RAM
What is the "random-access" memory that usually functions as temporary storage for programming and operating instructions during use and is constantly changed/?
ROM
What is the "read-only" memory that contains basic operating instructions that are almost never changing?
DICOM standard
What is the digital standard for imaging that is designed to ensure that all equipment fro all manufacturers who choose to adhere to the standard are speaking the same computer language?
2^x
What is the equation for determining gray scale bit depth?
memory
What is the information stored as magnetic variations referred to as?
Fourier Transformation
What is the mathematical algorithm used to create all medical images?
contrast
What is the measure of the differences between the data values referred to as?
bit
What is the name for a binary digit?
byte
What is the name for an 8-bit word?
ENIAC
What is the name of the "modern electronic computer"?
noise
What is the random background information that does not contribute to the image quality?
frequency
What is the raw data to which a Fourier Transformation is applied to create the digital image?
bus
What is the system of conductors that connects the various components of a computer system and permits the CPU to accept inputs from any point along the conductor?
CT and MRI
What modalities are array processors useful for?
peripherals
What permit input/output of information to or from the CPU?
software
What provides specific instructions for calculations and sequential steps to be followed?
magnetic tape
What type of memory storage device is inexpensive and the data is stored serially (difficult to access)?
CD or DVD
What type of memory storage devices are required for large amounts of data?
abacus
What was the earliest computer device called?
scanning
When detectors acquire their information by ____ they are receiving info from a specific area.
array detection
When detectors acquire their information through ____ they are receiving all the info at once.
RAM, ROM
When power is turned off, (ROM / RAM) is erased and (ROM / RAM) is maintained
high
When subject contrast is high, the acquired data contrast will be ____.
1945
When was ENIAC invented?
analog computers
Which computers handle data composed of continuously varying electrical currents?
digital computers
Which computers handle data composed of definite quantities of current?
read memory
Which memory can only be extracted without alteration; cannot change?
write memory
Which memory replaces new information with the old; can change?
data
Which type of information consists of collected facts?
program
Which type of information consists of operating instructions?
computer, radiographer
Who or what is responsible for density changes on a digital image? On a manual image
inverse
Window width and contrast have an ____ relationship.
parallel, serial
____ circuits permit simultaneous transmission of information while ____ circuits transmit sequentially.
