USL PSA-200U - Manual (Page 15)

Page 15 1st Edition. October, 2004 USL, Inc. PSA-200U Instruction Manual
value for the center zone is displayed and
the rest of the zones show the luminance
value as a percentage of the center value
reading.
It is possible to measure the total light
incident on the screen by switching to the
Lumens mode. To do so, check the box la-
beled “Lumens Mode” and enter the screen
height, width and gain. (See Fig. 12).
(Fig. 13) Luminance Grid 9x5
(Fig. 14) Luminance Grid 3x3
A check box is provided for the choice of
luminance data being displayed rapidly
as measured or after filtering. The filtered
data is updated more slowly and is easier
to read.
Camera
This section sets the measurement range of
the camera and display. It also will adjust
the data to compensate for the vertical
angle-of-view when the camera is positioned
in the projection booth.
The nominal measurement range of the PSA-
200U is three to 30 foot-Lamberts. With the
addition of an optional ND1 neutral density
filter, the range can be changed to 30 to 300
Program
The Program section controls values for
the display and measurement functions
(see Fig. 12).
(Fig. 12) Program Setup
Display
Five shades of gray are used to show bright-
ness differences among the zone squares.
The “foot-Lamberts per gray step” value
sets the number of foot-Lamberts variation
between steps or displayed shades of gray.
A value of one is the default value and is
proper for most applications.
“Fit display contrast to image contrast”:
This asks the software to maximize the
contrast of the display and to have it follow
the camera video closely. This is normally
checked.
Weave and Jitter
If the Weave and Jitter option is included
and such measurements are to be made,
the screen aspect ratio should be inserted
here. Correct calculation of the results is
dependant upon the aspect ratio.
Luminance
This section allows choice of display win-
dow type, either 9x5=45 zones (see Fig. 13)
or 3x3=9 zones (see Fig. 14). In the 9x5 dis-
play, the luminance value is displayed for
each zone. In the 3x3 display, the luminance