Lumagen VisionProHDP - Manual (Page 23)

VisionPro HDP
™ User Manual and Installer Guide
© 2004-2006 Lumagen®, Inc. 20 Rev 1.1
Non-linear Stretch
Non-linear-stretch (NLS) is used to horizontally stretch a 4:3 aspect ratio source to fit a
display that has a wider aspect, such as 16:9. The image is stretched by a constant amount
in the center and by an increasing amount approaching the left and right edges. This
eliminates the black sidebars normally seen when viewing 4:3 material on a 16:9 display.
The goal is to stretch the image to fill the screen in a way that looks as natural as
possible. The Lumagen NLS command is very flexible and allows the image to be
adjusted to user preferences to achieve this goal. The NLS adjustments are center width,
center stretch, top cropping and bottom cropping. The center section of the image is
stretched by a constant amount from 0 to 24% (CENTER STR%). The width of the center
section can be set from 15% to 75% (CENTER SIZ%). By programming the center
section width and stretch amount, the amount of non-linear stretch in the left and right
sections can be optimized. In addition, the top (CROP TOP%) and bottom (CROP
BTM%) cropping can be set from 0 to 12%. Increasing the amount of cropping reduces
the amount of stretch near the left and right edges of the image. When setting the
cropping parameters, it is recommended that the satellite/cable box menu be checked to
assure that critical parameters remain visible.
The NLS feature is off by default, and must be enabled before any of its parameters can
be changed. Also, it is only active when the input aspect ratio is set to 4:3. The command
reports the NLS status as "OFF," "NLS1", "NLS2" or "USER" mode. It is recommended
that NLS2 be used as a starting point before setting user preferences. After selecting
NLS2, or NLS1, changes to any parameter automatically selects USER mode.
Some 4:3 sources fill the entire source image (e.g. DVD 16:9 movies), but other sources
place a 4:3 image in the center of a 16:9 image (e.g. HDTV with up-scaled SD source).
This latter case is seen as a “pillar-boxed” image with black bars on the left and right.
The “PILLARBOXED” parameter must be enabled for this case. The Lumagen will then
crop the pillbox bars and stretch the active 4:3 image.
When enabled, the NLS command is only active when the 4:3 input source aspect ratio is
selected. Since it is often desirable to view 4:3 source as transmitted, without stretching
it, the NLS command allows either the 1.85 (or LBOX), input aspect ratio button to be
reprogrammed to turn off NLS (using the “NLS OFF BTN” parameter). This is global to
all configuration memories which have NLS enabled. Note, the 1.85 (or LBOX), source
aspect button still selects the respective input aspect ratio for configuration memories that
have NLS disabled. When this feature is enabled, a 1.85 (or LBOX), source aspect ratio
can still be selected using the left and right arrows buttons to step through the aspect
ratios while the menu is not visible on the screen.
When NLS is enabled, the image will fill the screen with the 4:3 (1.33) source for any
output aspect ratio up to 1.85. If the output aspect ratio is greater than 1.85, software
limits the maximum width to the equivalent of 1.78 and adds left and right sidebars.
Select the parameter to adjust using the ‡ and ˆ arrows, and change the value of the
selected parameter using the … and † arrows. The command format is:
MENU → IN → CONFIG → ADJ → SIZE → NLS →
[ … , † , ˆ , ‡ ] OK