IP
CCD's and CMOS perform the ______?
same job
what is the device used to convert x-rays into light in in-direct DR capture?
the scintillator.
what is a histogram?
graphic representation of optimal densities created during an exposure.
how many gray's are produced from bit depth?
2n (n is the number of bits)
when is edge enhancement used?
when fine details are present but appear blurred.
what does CMOS stand for?
complementary metal oxide semiconductor
what type of system is Direct DR image acquisition?
2-step, non-scintillator system,
how is histogram data obtained?
from data within the collimated area after eliminating scatter
if bit depth is 4, how many gray shades are produced?
24 =16 gray shades
what do high-pass filters do?
increase contrast and edge enhancement by amplifying areas of interest and suppressing others.
what technology does CMOS use?
utilizes active pixel sensor technology. (APS)
what kind of array does Direct DR use?
active matrix array (AMA)
Do histograms vary between patients?
they vary in body region but remain fairly constant from patient to patient.
what is the look-up table (LUT) used for?
as a reference to evaluate raw information and to correct luminance values.
what do low-pass filters do?
accomplishes a smoothing effect by averaging pixel values, which remove high frequency noise
incorporating a CMOS results in _________?
low noise, high dynamic range
what material is used in direct DR image acquisition to convert x-rays?
amorphous selenium (a-Se)
what are values of interest (VOI)?
digital data set of information that is arranged into a histogram distribution. (where the histogram should fall)
is there a look-up table for each body part?
yes.
what is:
a method of image processing using the hisrogram of the image to adjust contrast. allows for demonstration of wide range of anatomical structures without overall loss of image quality
Equalization.
CMOS are used in in-direct DR to convert _______?
convert the image into digital format
what does the amorphous selenium do?
converts x-rays into electrons that are collected by the TFT
what determines the shade of each pixel in a digital image?
bit depth (number of bits per pixel)
when does edge enhancement occur?
when fewer pixels are included in the signal average (smaller neighborhood)
what is the image processing technique that provides contrast/grayscale enhancement in digital imaging?
equalization.