vds 69871-01 Operation & Maintenance Manual Download Page 51

Page: 51 / 93

Marquee ACON Ultra Installation/Operation Guide

2-28

AU User Controls, Settings and Operation

When

takes a measurement from any test point, the camera is indexed to the established

coordinates, and a routine determines the intersection
that is closest to the center of the captured camera field
of view. If the measurement type is an

Intersection

type,

the

and

position of this intersection is the reported

measure. If the measurement type is a

Linearity

type,

the spacing of the grid line – both horizontal and vertical
– is reported.

Each of the passes of Geometry Correction (Center,
Screen and Edge maintains a separate list of test points from which to make observations as to the
quality of the current projector geometry. Convergence uses the test point set from the third
Geometry pass.

2.3.4.1

Choosing Good Intersections

utilizes the intersection of horizontal and vertical grid lines as measurement centers for all of the

tested observations. The process of correctly positioning test points is not completely automated.
The Auto Setup routine will give a “best guess” as to the location of the Convergence and Center
Geometry test points, but it is necessary to visit the automatically set test points to verify that the
position is optimal. Screen Geometry test points have no automated setup procedure.

When positioning a test point, the intersection should be completely visible on the facet and un-
obstructed by glare.  Generally, a good test point is one whose lines are all at least as long as ½ the
size of a full grid box.  In some irregularly shaped screens, some convergence zones may have an
area of effect that shows up only on one intersection of the test pattern.  Even if this intersection
would otherwise be considered a poor juncture, this point must be chosen to allow

to make

corrections to this zone.

A poor intersection is most at risk of dropping off the facet edge due to drift or otherwise becoming
unrecognizable by the

software. If this happens, the

correction routines may fail to make the

required corrections to the area, or in the worst case, make the errors even worse.

2.3.4.2

The Center Geometry Test Point set

For the Center Geometry Test Point Set (the first pass of
geometry correction), the test points are arranged along the
cardinal points of the compass.  Each test point reports both a
horizontal and a vertical measurement.  There are 15 test points
in the Center Geometry Set: three test points in the center of the
screen, and three in each of the different compass directions:
north, south, west, and east of center.  The test points at the
center of the screen take a linearity measure, and an
intersection measure of the picture (external test pattern), and
an intersection measure of the raster (internal test pattern).  The
name of the test point, as seen in the Maintenance Dialog
Window – and shown in the adjacent diagram – indicates the
type of measurement being taken as well as the position of the
test point.  For example:

Example 1. The

North

Int

test point is located above the center of the raster and an

Intersection

style measurement is being taken.

Example 2. The

West

Lin

test point is located to the left of the center of the raster and a

Linearity

(or