Operator`s manual

36 BlendPRO – Wide Screen Image Processor Manual # 26-0206000-00 / Revision A
projectors and setting the overlap to 640 pixels. This provides horizontal total of 1920 source pixels, which equals the
native horizontal resolution of HDTV. In this case, an exact one-for-one pixel mapping can be achieved from the
source material through the scaler to the BlendPRO and out to the projectors. Note that generally 56 of the 1080
HDTV input lines are omitted from the displayed image.
Pixel Mapping & Projector Alignment
Blend Pro is designed to support 1:1 pixel mapping of the input sources, minimizing the effects of noise and aliasing
while maintaining the full resolution of the source image. Sample clock phase and horizontal and vertical position
adjustments, similar to those found on most projectors, allow BlendPRO to be set up for accurate capture of the
source image.
As with single projector applications, it will be necessary to adjust the projector's clock phase and properly size and
position the input image. To aid in projector clock phase and image sizing adjustments, BlendPRO provides high-
resolution test patterns (one-pixel On/one-pixel Off and Output Raster Box). Once exact 1:1 pixel mapping has been
set at the projectors, the next step is to use the lens shift of the projectors to move the images together to cover the
overlap region. Registration test patterns are provided (grids and registration lines) and are output to reflect the
proper amount of overlap and projector resolution. Great care is required when setting up the projectors; the exact
distance to the screen, minimum amount of off-axis angle, and correct color calibration are all essential for a quality
wide screen display. Note: to achieve good color matching between projectors, we recommend that all of the
projectors be of the same type. DLP or CRT projectors are preferred. It is also recommended that all projectors have
approximately the same amount of hours on the lamps.
Edge Blending
Once projector alignment as been achieved, the edge feathering can be enabled. BlendPRO has adjustable transfer
function curves that can be applied to the selected overlap regions. Generally, matching the gamma curve to the
projectors gamma achieves the best results. With DLP projectors, the overlap region will have a greater black level
due to the light overlapping from the two projectors. BlendPRO can minimize this effect by adjusting the non-
overlapped brightness level separately from the overall brightness level. The brightness level in the non-overlapped
region is raised to where it equals the intensity of the overlapped region. This helps obscure overlap artifacts
introduced because black output levels are not entirely black. It is recommended, whenever possible, to avoid lower
luminance levels and flat fields when creating source material.
Delay
The maximum delay through BlendPRO is one non-interlaced frame (16.6 msec when using 60hz input sources). If
the input sources are already locked together, the BlendPRO introduces very minimal transport delay (a few hundred
microseconds).
Source Material
Content for the BlendPRO can be created a number of different ways.
For the highest resolution backgrounds available, a multiple-head graphics card, such as a Matrox G200 MMS, can
be used. For example, a quad-head card outputting each channel at 1280x1024 can provide a background image
with maximum resolution of 5120x1024.
An ATI card can feed each input separately and the creation of display material can be done in Power Point or
Macromedia Director. A patch to allow a slide show for Power Point to be shown across multiple screens can be
found on the internet at http//:officerone.tripod.com. When creating new material that crosses multi-screen
boundaries, only the aspect ratio of the final output screen needs to be taken into consideration.
Example: Outputs aspect ratio is 4.25 to 1, DLP projectors with a native resolution of 1280 x 1024 are to be used.
The horizontal screen resolution needs to be 4.25 x the vertical total of 1024 or 4352. Simply use Power Point or
Director to create images that are 4352 x 1024 across the 4 outputs of the graphics card. The images should be left