DOCTER DOCTER®nightvision 1x24 - Manual (Page 24)

Halo
Appears as a circularly shaped, brightly lighting area in the tube image around a brightly
lighting object spot (e.g. the corona around a lantern).
Equivalent Brightness (EBI)
This is the minimum brightness required to perceive a luminance change in relation to
the basic brightness of the phosphor screen.
Wave length range and sensitivity
The diagram shows the photo cathode’s course of sensitivity and, thus, also that of the
whole night vision device as long as no filters are used. In the wave length range from
450 to 850nm, the night vision device is most sensitive.
Range of vision
This range measures the maximum distance to an object standardised by type, contrast,
shape, and size in which such object can be detected, allocated, recognised or identified
yet.
The range of vision depends on the ambient brightness. In a full moon night, luminance
equals 250mLux. In a cloudless night (new moon), luminance amounts to 1mLux,
whereas on a cloudy night sky (without extraneous lights) 0.1mLux are reached. For the
standardised information, a luminance of 1mLux is set forth in ISO14490-8 to determine
the range of vision. It needs to be determined at which distance a structure (black/white
pattern) can be detected. Here, the standard distinguishes between four resolution
levels as shown in the table below.
R
ad
ia
tio
n
se
ns
iti
vi
ty
o
f t
he
p
ho
to
c
at
ho
de
[m
A
/W
]
Q
ua
nt
um
e
ffi
ci
en
cy
[%
]
Radiant sensitivity
Wave length [nm]