Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
45 Cards in this Set
- Front
- Back
|
what is a soft copy image? |
an image on a display monitor |
|
|
what is a hard copy image |
a physical image you can hold (ie. film) |
|
|
What is a primary monitor? |
one used for diagnostic interpretation, used by the radiologist |
|
|
What is the criteria for a primary monitor? |
o They should be 5 megapixels (2048 x 2560pixels). o The ACR states they should be able to display atleast 2.5 lp/mm. o Minimum luminance should be 171 cd/m2 o Must be at least 8 bits |
|
|
What is a secondary monitor? |
A monitor that is not configured for diagnostic interpretation. Is used by non-radiologists. |
|
|
What are the components of the CRT (cathode ray tube)? |
· Electrongun- fires electrons toward the screen · Control grid,focusing and deflecting coil serve to direct and steer the electrons ontothe fluorescent screen · Fluorescentscreen- curved sheet of glass coated with a phosphor material. Has “pixels’that contain red, blue, and green dots. |
|
|
How do the electrons strike the fluorescent screen? |
in a raster pattern (left to right like reading a book) 2 types: interlaced or progressive |
|
|
What is interlaced scanning? |
scansevery other line, top to bottom, then returns to the top to fill in the gaps |
|
|
What is progressive scanning? |
scanseach line with no gaps |
|
|
What determines horizontal resolution for CRT monitors? |
bandwidth & electron spotsize |
|
|
What determines vertical resolution for CRT monitors? |
line spacing and electron spotsize |
|
|
What is the construction on an LCD monitor? |
· Fluorescentlight source- emits light that is directed toward the first filter. · 2Polarizing filters- The first filterhas bars arranged horizontally, and the second filter has bars arrangedvertically. Each filter serves to allow light through that is traveling in acertain direction, and block light that is traveling in a different direction. · LCD layer-layer of liquid crystal arranged into cells. |
|
|
When a pixel is turned "off" _______ is applied |
current |
|
|
When a pixel is turned "on" ______ _______ is applied. |
no current |
|
|
When current is applied to the LCD layer |
Crystals line up in the same direction and light is unchanged. No light gets through the second filter |
|
|
When NO current is applied to the LCD layer |
Light flows the twist of the crystals and is changed from horizontal to vertical. Light gets through the second layer |
|
|
When a pixel is turned off it displays: |
black |
|
|
When a pixel is turned on it displays |
bright |
|
|
What turns the pixel on and off? |
TFT switch |
|
|
what is Spatial resolution |
ARRT: The sharpness of structural edges recordedon the image. |
|
|
What is the relationship of FOV, pixel size, and matrix size? |
· Pixel size = FOV Matrix Pixel size is inverse to matrix Pixel size is direct to FOV |
|
|
When FOV is the same, decreasing the matrix will |
increase pixel size |
|
|
When FOV is the same, increasing the matrix will |
decrease pixel size |
|
|
what is dot pitch |
thedistance between the 3 dots contained in 1 pixel |
|
|
decreasing dot pitch will |
increase spatial resolution |
|
|
luminescence |
the measurement of light intensityemitted from the surface of a monitor measured in candela per squaremeter (cd/m2 or nits) |
|
|
contrast resolution |
howgood a system is at displaying objects of similar shades of gray as separate. |
|
|
what is bit depth? |
the number of shades of gray available for display |
|
|
What is veiling glare |
amount of ambient light reflected off thescreen. This will reduce image contrast |
|
|
What is ambient light? |
room light |
|
|
Which monitor type can produce a true black? |
CRT |
|
|
Which monitor will display geometric distortion? |
CRT |
|
|
Which monitor has higher spatial resolution? |
LCD |
|
|
Which monitor displays veiling glare? |
CRT |
|
|
Which monitor has a restricted viewing angle? |
LCD |
|
|
Which monitor needs to be warmed up? |
LCD |
|
|
Which monitor is the most expensive? |
LCD |
|
|
Which monitor has an aspect ratio of (4:3) |
CRT |
|
|
Which monitor will not display flicker |
LCD |
|
|
Which monitor has an aspect ratio of 16:9 |
LCD |
|
|
What is aspect ratio |
the ratio of the width of the display monitor comparedto the height of the display monitor. |
|
|
What is response rate |
describes the amount of time taken for a pixel to change from “on” to“off”. a lower number means a new image can be displayed faster with little or no ghosting artifact |
|
|
What is refresh rate |
Is the number of timesan image is drawn on the screen each second. Thehigher the refresh rate, the less “flicker” the viewer will see. |
|
|
What is persistence for a CRT |
howlong it takes the phosphors to glow after they are struck with an electron. Ashort persistence means that an image can be displayed quickly |
|
|
What is persistence for an LCD |
refers to an image being “burned”into the screen. This happens when an image has been displayed for an extendedperiod of time, so the pixels “remember” the old image. The new image may not display with the correct brightness level |
