Studied by 5 PeopleTags & Description
_________________ is a style of image receptor for digital radiography (flat panel 14x17)
Active matrix array (AMA)
_________________ is a device from video camera to computer
analog to digital converter (ADC)
_________________ is when you tell the computer what view it is you're doing and it adjusts the image according to preset parameters (aka diagnostic specifier)
automatic data recognition
_________________ is the slope of the tangent at any point on the characteristic curve
average gradient
_________________ is the average density on unexposed areas of the film due to development of the AgBr crystals either through manufacturer defect or age plus the blue tint of the base
base/fog
_________________ is an electron beam designed for 2 dimensional signal display
cathode ray tube (CRT)
_________________ is a solid state device that converts visible light into a stored charge
charge-coupled device
_________________ is a graph of optical density versus log relative response
characteristic curve (H and D curve)
_________________ is the degree of difference between the light and dark areas of a radiograph
contrast
_________________ uses photostimulable phosphor as the image receptor and a computer
computed radiography
_________________ converts light into electronic signal
Complementary Metal Oxide Semiconductor (CMOS)
_________________ is the area on a characteristic curve of least density
D min
_________________ is the area on a characteristic curve of highest possible density
D max
_________________ is an instrument that measures the optical density of exposed film
densitometer
_________________ is an area x-ray beam intercepted by phosphor plate or CCD into digital
digital radiography
_________________ is DR that uses selenium as image receptor
direct-capture radiography
_________________ is range of values that can be displayed by an imaging system (gray shades), number of gray shades that can be represented.
-also is written in bit depth
dynamic range
_________________ is the ability to use a wide range of of exposure factors and produce a quality image
exposure latitude
_________________ is the straight line portion of the characteristic curve
film gradient
_________________ is the film's ability to produce a wide range of values or gray scale
film latitude
_________________ is the density produced on a film due to unintended development of the AgBr crystals in the film - may be due to exposure to light or x-rays, age, chemical
fog density
_________________ is the name a computer gives to an x,y graph
Histogram
_________________ is a layout of cells (pixels) in rows and columns. Size of this affects spatial resolution.
-multiply column by rows to find this.
Larger the ___ __the _______ the detail
image matrix, matrix, detail
_________________ is the fact that film is 5 times more sensitive to another exposure after the initial exposure from x-rays
latensification
_________________ is a type of display system for computer monitors/calculators
liquid crystal displays (LCD)
_________________ is a description for something that is straight
linear
_________________ is a process in computerized imaging where the computer processes an image further to mimic the traits desired for a specific view
normalization/automatic rescaling
_________________ - Io/It = light originally hitting film/light transmitted through film
-measures optical density
density
_________________ is the degree of blackening of a radiograph
optical density
_________________ is an aluminum step wedge
penetrometer
_________________ is material that gives off light after x-ray and/or laser stimulation
photostimulable phosphor
_________________ is the study of the response of an image receptor to x-rays/light
sensitometry
_________________ is an optical step wedge that is used to construct a characteristic curve
sensitometer
_________________ is an imaging system's ability to respond to a minimum quantity of x-rays
speed
_________________ is the process where any exposures after maximum film density will actually decrease density due to remigration of the silver away from the sensitivity center
solarization
_________________ is the amount of background electrical noise that obscures the electric signal
signal to noise ratio (SNR)
_________________ is the ability to image small objects that have high subject contrast, computer term for detail
spatial resolution
_________________ is a type of image receptor for digital radiography
thin film transistor (TFT)
_________________ is the location on a digital image number scale where grays are assigned, controls the brightness on a monitor
window level
_________________ is a number of gray levels or digital image number scale determines image contrast
window width
What photographers in 1890 in England created the characteristic or sensitometric curve? (happened before or after the discovery of x-rays?
F. Hurter and VC. Driffield (also called H and D curve), before
_________________ is used as a guideline to correct images by computers
H and D curve
T or F - photographic characteristics of x-ray film and camera film are the same
True
_________________ is a graphic representation of density/blackness
sensitometry
x-axis of H and D curve contains the _________________ while the y-axis shows the _________________
log relative exposures, shade gradient
H and D curve -
H and D curve - x-axis is a scale from _______ to _________ and goes up in increments of . It is labeled _____________.
0-3, .3, log relative exposure
y-axis is a scale from _______ to _______ and it is labeled _________________ with _______ on bottom and ______ on top
0-4, shade gradients, white, black
_________________ on the H and D curve is right before it curves. _________________ is between the toe and shoulder (most useful part because it contains the shades of grey), _________________ is where it plateaus and where D max is located
toe, slope/gradient, shoulder
_________________ is the minimum density possible and why doesn't it start at 0?
D min and because film already being tinted, manufacturing causing silver to blacken, and us needing to process film causing the raising of D min.
_________________ is maximum density possible.
D max
More _________________ means higher D max. If you have a D max higher or lower than normal, it is a _________________ issue.
silver, silver
D min can be lower due to having less ___________. (single emulsion D min is ____________ than double emulsions D min)`
silver, lower
anytime the processor is too strong, D min goes ____________ due to exposing unexposed crystals
up
____________ and ____________ are devices that imparts a gray scale onto film
aluminum step wedge (penetrometer), sensitometer
____________ are steps of Al that are different types of thicknesses that creates a gradient. Need to x-ray it
aluminum step wedge/penetrometer
____________ has a gradient and uses light instead of x-rays to mimic increasing exposure levels
sensitometer
____________ is used to measure the shade the aluminum step wedge/penetrometer and sensitometer created. It measures optical density using ___________ formula.
densitometer, D=log Io/It
D=log Io/It
___________ = light originally hitting film, ___________ = light transmitted through film
Io, It
With the optical density formula, if a lot of light gets through, it means a ___________ number, if little light gets through, it means a ___________ number
smaller, bigger
Why is density expressed as a logarithm?
to express large numbers and make the large number easier to manipulate/handle
When checking base and fog density, what should the measurement be? base is ___________ and fog is ___________
less than .25, blue, extra exposure
if the slope/gradient in an H and D curve is steeper it means ___________ contrast, so a more shallow slope means ___________ contrast, and the closer the slope/gradient is to the y-axis means ___________ sensitivity/speed, so if the slope is farther away from the y-axis it means ___________ speed/sensitivity
more, less, more, less
In x-ray, gradient is always greater than ___________ (45 degree slope = ___________)
1, 1
useful range of density readings are ___________ to ___________ (Dmin to Dmax)
.25-2.5
___________ is how many different gray values a film will have per exposure
film lattitude
___________ latitude is shallow slope which means more exposure values are available to use to get good film
wide
film latitude is ___________ related to contrast which means the steeper the slope, the less latitude a system has.
inversely
___________ = closeness to y-axis
___________ = steepness of slope (more steep means more)
___________ = steepness of slope (shallower slope means more)
speed, contrast, film latitude
When the curve changes on an H and D curve, it means what?
that something happened to the film (like a higher base means film was already darkened)
__________ is the film's ability to respond to a minimum amount of exposure
speed/sensitivity
so a 100 speed image receptor will have a slope ___________ y-axis and a 400 speed image receptor will have a slope ___________ y-axis
farther from, closer to
___________ is related to AgBr size and emulsion thickness
speed/sensitivity
curve uses in the past (only on film)
___________ ___________ ___________ is when using a step wedge, make initial curve, and look for changes over time
___________ ___________ ___________ is when using a test strip to check how the chemistry is in the processor (H and D curve will be affected if chemistry is bad)
evaluate tube output, evaluate processor chemistry
Changes in slope or speed indicate ___________ is getting old or contaminated when evaluating processor chemistry
chemistry
_________________ was a way to analyze if film was working properly by looking at its graphic representation
sensitometry
___________ is used in computerized radiography and ___________ or ___________ is used in digital radiography. These receive remnant and scatter radiation from the patient the same as ___________
europium activated barium fluorohalide (Eu: BaFBr/I), cesium Iodide (CsI) or amorphous selenium (a-Se), film
How does the computer know when the exposure is right in Computerized and Digital radiography? It uses ___________ and ___________ ___________
histograms, automatic rescaling/normalization
___________ is a bar graph showing how many pixels of each shade are present.
histograms
histograms require you to run the x-ray under the right _/_ because histograms differ with different _/_, so the computer will use the right histogram to fix the image.
part type/view, part type/view
_/_ ___________ is when the computer sorts pixels by shade. There are numerical values for each pixel's shade of black-grey-white and there are ___________ different shades a pixel can be
pixel/image sampling, 4096
The computer also fixes radiographs by using ___________ ___________ of perfect radiographs as a reference
H and D curves
___________ _/_ is applying histograms of perfect x-rays to an x-ray to fix an image. Also can be defined as the computer adjusting the bars in an histogram to "fix" or adjust the histogram from the x-ray you took to make the radiograph better
automatic rescaling/normalization
___________ ___________ is a file the computer has of all the perfect histograms of films (computer can't understand pictures - only pixels), so it uses histograms
look-up table (LUT)