Allied Guppy, Техническое руководство, Страница: 231 / 238

Glossary
GUPPY Technical Manual V4.0.1
231
USB U niversal S erial B us (USB) provides a serial bus standard for connecting
devices, usually to computers such as PCs, but is also becoming common-
place on digital cameras.
Vertical binning Vertical binning increases the light sensitivity of the camera by a factor
of two by adding together the values of two adjoining vertical pixels out-
put as a single pixel. At the same time this normally improves signal-to-
noise separation by about 2 dB.
See also: full binning and horizontal binning
WDM WDM = W indows D river M odel
In computing, the Windows Driver Model (WDM) - also known (somewhat
misleadingly) at one point as the Win32 Driver Model - is a framework for
device drivers that was introduced with Windows 98 and Windows 2000 to
replace VxD, which was used on older versions of Windows such as Windows
95 and Windows 3.1 and the Windows NT Driver Model.
White balance A function enabling adjustment of the image colors to make the white
objects really appear as white. Thus one can avoid color shifts caused e.g.
by differing illumination conditions.
YUV The YUV model defines a color space in terms of one luminance and two
chrominance components. YUV is used in the PAL and NTSC systems of tele-
vision broadcasting, which are the standards in much of the world.
YUV models human perception of color more closely than the standard RGB
model used in computer graphics hardware, but not as closely as the HSL
color space and HSV color space.
Y stands for the luminance component (the brightness) and U and V are
the chrominance (color) components.
YUV signals are created from an original RGB (red, green and blue) source.
The weighted values of R, G and B are added together to produce a single
Y signal, representing the overall brightness, or luminance, of that spot.
The U signal is then created by subtracting the Y from the blue signal of
the original RGB, and then scaling; and V by subtracting the Y from the
red, and then scaling by a different factor.
An advantage of YUV is that some of the information can be discarded in
order to reduce bandwidth. The human eye has fairly little color sensitivity:
the accuracy of the brightness information of the luminance channel has
far more impact on the image discerned than that of the other two.
(See also 4:2:2 and 4:1:1)