Creating A Seamless Image With Edge Blending - Christie M Series User Manual

Each corner adjustment affects only this quadrant.
c) Repeat for each screen.
11. Repeat steps 7 and 8 and, if necessary, fine-tune the zones so that they all still exhibit a single
color temperature.
Related information
Matching colors across multiple screens (on page 31)

Creating a seamless image with edge blending

To blend overlapping edges together smoothly, use Edge Blending controls to set the precise width,
shape and midpoint.
Edge Blending provides a range of controls for smoothing together the overlapping bright edges of
multiple adjacent projected images to create a single larger seamless image. These controls, which
primarily affect white levels, are typically used in conjunction with mechanical lens blinders (optional),
which are installed on the front of the projector and which primarily affect black levels.
Brightness uniformity adjustment, if required, should be performed first. The Edge Blend or Grid Test
Pattern are useful for the mechanical setup of the projectors. If necessary, adjust Black Level Blending
first with the Black test pattern, then use the White test pattern to blend the white levels on the blend
edges. The final step is to check the blended image with an external source. The Edge Blending test
pattern has a center line (both horizontal and vertical). The intersection of these lines is the true
center of the projector's display area.
In multiple-projector walls, complementary blends between neighboring images can compensate for
the extra brightness or intensity where these edges overlap. By controlling blend width and other
properties, you can achieve uniformity across the group of images. Visible overlaps disappears, as
shown below.
For best results, use the same projector model and type throughout your display wall. In addition,
avoid high-gain screens whenever possible—the optical performance of such screens demands minimal
image offset, thus projectors must be located very close to one another.
• Blend Width—Determines how much area is used for blending along an overlapping edge.
Slide bar values represent the number of pixel steps used for the blend. For example, a setting
of eight creates a blended edge eight pixels wide.
A setting of 0 signifies no blending. For best results in most applications, use a blend width
greater than 10% of the resolution of the projector (192 on a 1920 x 1080 projector). Larger
blend widths can mask uniformity issues between multiple projectors.
Ranges: (Projector number of columns / 2) horizontal, (projector number of lines / 2) vertical.
Example: 1920 / 2 = 960 pixels horizontal, 1080 / 2 = 540 pixels vertical.
• Blend Shape—Determines the rate of roll-off across the blend width, such as, how quickly the
white levels across the blend change from light and dark. Increasing the Blend Shape setting
accelerates the rate of change at both extremes so that less of the region appears mid-grey
(see Figure 3.20). Decreasing the Blend Shape setting slows the rate of change so that more
of the region appears mid-grey. For most applications, this subtle control is best left close to
50.
• Blend Midpoint—Determines the white level at the blend midpoint (the point equidistant
between the beginning and end of the blend). Increasing the Blend Midpoint setting creates
a blend that appears brighter than the rest of the image. Decreasing the Blend Midpoint
setting creates a blend that is darker than the rest of the image. A setting of 50 means the
midpoint is approximately 50% black—for best results in most applications, keep fairly close to
this default.
M Series User Guide
020-101948-02 Rev. 1 (08-2018)
Copyright 2018 Christie Digital Systems USA, Inc. All rights reserved.
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Adjusting the image
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