What makes up the matrix size?
the total number of pixels in the image
What is the smallest component of the matrix?
the pixel
What is pixel density?
the number of pixels/mm in the image
What determines pixel density?
pixel pitch
What is pixel pitch?
the space from the center of one pixel to the center of an adjacent one
What is a histogram?
a graphic display constructed to show the radiographer the distribution of pixel values
what are values of interest?
computer software that determines the range of histogram values
what is rescaling?
the computer keeps the images at a uniform brightness and contrast regardless of exposure used
What is dead pixel correction?
when the computer fills in information in the image where pixels are not responding
What is subtraction?
the removal of superimposed or unwanted structures from the image
what is contrast enhancement used for?
altering of an image to display varying brightness
What is edge enhancement?
improves the visibility of small high contrast areas
What is image smoothing (low pass filtering)
it removes high frequency noise
What is one con of low pass filtering (image smoothing)
you can lose recorded detail and spatial resolution due to blurring of edges
What process adjusts the brightness throughout the range of densities in postprocessing?
window level
What does window level do to image brightness?
as window level increases, the image brightness increases
as window level decreases, image brightness decreases
AS YOU OPEN THE WINDOW, MORE LIGHT COMES IN
AS YOU CLOSE THE WINDOW, LESS LIGHT COMES IN
What happens when you adjust the window width?
as window width narrows, contrast increases
as window width widens, contrast decreases
What is a look up table and what is it used for?
a histogram of pixel values from image acquisition that can be used to correct or enhance brightness
What indicates the level of x-ray exposure received by the patients?
exposure indicator
Why is over-compression of an image bad?
it may result in a loss of information in the image
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Intro to Image Production24
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Equipment used in the production of x-rays42
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The x-ray tube22
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X-Ray Production31
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Fluoro15
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Quality Control of x-ray producing equipment14
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Digital imaging acquisition CR and DR15
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Digital imaging exposure29
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Grids and scatter related software37
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Spatial resolution9
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Distortion11
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Digital image overview20
