Before edge blending can occur, the projectors and software application need to be set-up so that an overlapping region between the edges of adjacent projectors is present. In this overlapping area, edge blending is later applied. Three steps are required in order to produce an overlap region:
1) Calculate the overlap region;
2) Align the projectors to the calculated overlap; and
3) Modify the software application to have the same calculated overlap region.
As an example, here we present overlapping regions based upon a three projector setup. Each projector has a resolution of 1280x1024 (SXGA).
Figure 1: Example
overlapping regions of 3 SXGA displays
HELPFUL HINT: It is good to have a complete number of pixels and the same physical screen size when edge blending. However, because of different projector resolutions, it is good to standardize on the same overlapping region. In this example we use a 12.5% region because existing resolutions result in whole pixels:
XGA = 1024 * 0.125 = 128 pixels
SXGA = 1280 * 0.125 = 160 pixels
SXGA+ = 1400 * 0.125 =175 pixels
720p = 1280 * 0.125 = 160 pixels
1080p = 1920 * 0.125 = 240 pixels
In the example described, the total
available resolution of
the three projectors titled horizontally before overlapping is:
3 x 1280 = 3840 x 1024 pixels
Taking our 12.5% overlap region, this
equates to 160 pixels
with our SXGA projectors (1280 x 0.125 = 160 pixels).
As we have two overlapping regions between
our three projectors (as shown in Figure 1), our overall displayed
resolution will
be:
3 x 1280 – 2(160) = 3520 x 1024 pixels.
Once the overlapping regions have been calculated, we can then align the projectors and software.
Figure 2: Projector
layout with overlapping regions
The exact layout of the projectors will change depending upon screen size, screen shape and the optics of specific projectors used. Here for illustrative purposes, we show an example of projector placement on a curved screen with the overlapping regions described above.
Once the projectors are aligned,
overlapped and ready to go,
the software then has to be adjusted to provide the same overlapping
regions.
Below we show an image before and after overlap regions are implemented. Figure 3 shows the original image and Figure 4 shows the overlap regions created to correspond to the same regions as described in Figure 1.
Figure 3: Original
software image
Figure 4: Software
setup to produce overlapped regions
Due to the number of different software applications available, it is beyond the scope of this section to describe how to perform this function for each possible method. However, if you have any further questions, please contact us.
HELPFUL HINT: It is worth noting, that some applications won’t support overlaps as a standard function.
For any further questions on this topic, please contact us.