Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
PACS chapter 3
Key terms
| Term | Definition |
|---|---|
| Aliasing | loss of digital information because of fluctuating signal; also known as foldover, biasing, or wraparound |
| Archive query | Software function that allows historical information to be gathered from digital storage, such as multiple examinations, a range of dates, or by pathology |
| Automatic rescaling | Occurs when exposure is greater or less than the optimal amount to produce a diagnostic image; It is the effort of the computer to "fix" exposure errors |
| Contrast manipulation | Conversions of the digital image using contrast enhancement parameters |
| Critical frequency | The frequency of a signal that exactly matches the nyquist frequency, resulting in a zero-amplitude signal caused by phase shifts |
| Edge enhancement | Enhancement occurs when fewer pixels in the neighborhood are included in the signal average; the smaller the neighborhood, the greater the enhancement |
| High-pass filtering | Technique for the enhancement of contrast and edge that amplifies the frequencies of areas of interest that are known and suppresses frequencies outside the area of interest |
| Histogram | Graphic representation of all of the digitally recorded signals of a digital X-ray exposure |
| Image annotation | Software function that allows text or markers to be digitally added to an image |
| Image orientation | identification of the top or side of an image |
| Image stitching | Process of "sewing" together multiple images to form one continuous image |
| Look-up table | reference histogram of the luminance values derived during image acquisition |
| Low-pass filtering | result of averaging each pixels frequency with surrounding pixel values to remove high-frequency noise; the result is a reduction of noise and contrast; useful for viewing small structures such as fine bone |
| Manual send | computer function that allows images to be sent to specified reading stations |
| Nyquist theorem | When sampling a signal such as the conversion from an analog to a digital image, the sampling frequency must be greater than twice the bandwidth of the input signal so that the reconstruction of the original image will be nearly perfect |
| Patient demographics | input information regarding patient age, identifying number, ordering physician, and so on |
| Shuttering | used to blacken out the white collimation borders in a digital image, effectively eliminating veil glare |
| Smoothing | also known as low-pass filtering, the result of averaging each pixel's frequency with surrounding pixel values to remove high-frequency noise |
| Spatial frequency resolution | amount of detail or sharpness in a digital image |
| Window level | Image manipulation parameter that changes screen image brightness, usually through the use of a mouse |
| Window width | image manipulation parameter that changes screen image contrast, usually through the use of a mouse |
Created by:
2304598396295915
Popular Radiology sets