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I've been really interested in CIH projection for years. Although I don't have a theater room of my own, I'm always dreaming of what I would do given the opportunity to do my own build. One of the concepts I've been interested in is using two identical projectors to produce a 2.35 projected image. You could have a CIH setup without the need for scaling, stretching, squishing ,zooming or cropping. I've searched and searched and never found anyone doing exactly this, so let's think about what it would take.

I propose to use an HTPC as an all in one content source (DVD, BluRay, Netflix, DVR, etc). Most mid to high end video cards have dual DVI output that allow you to connect two displays and treat them as one large combined desktop. If you connect two 4:3 projectors, you would get an effective 2.66:1 aspect ratio projected image. Two 16:9 projectors could also be used, but you'd have a lot of wasted imaged. I realize similar things have been done with blending two CRT based projectors, but I'm talking about using a pair of new digital projectors.

I realize there are difficulties to overcome here. The two big ones that come to mind are aligning the two images on screen and color/image calibration.

I imagine the mounting situation would be greatly simplified by a projector with side to side lens shift. This way, both projectors could be mounted side by side on a single mount in the center of the room and lens shift would be utilized to push each image left and right of center. The mount would likely require some micro adjustment to get the two images aligned perfectly. I realize this could be complicated, but possible.

Second, we have image calibration. While you would have to use two identical projectors, they would probably not have identical calibration. The question, between the calibration in the projector and the large array of adjustment built in to most high end graphics cards, could you get the two images looking identical? Could you keep them looking identical as the bulbs age?

What other road blocks or solutions can you think of? Good, bad or indifferent, I think the concept has merit if it can be properly executed. What do you think?
 

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Its a good thought and Im sure its doable, I do think that getting the image to look identical on both projectors cold be the hardest part. I also think that the joint where the two images meet would be very hard to get exact because of the ever so slight distance variation between each lens.
 

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I got to see Panasonics "blended" CIH system last year at CEDIA 08 (Gold Coast Australia). Impressive stuff, not cost effective though. The images were clean and bright and WIDE. The system did use some overlay and the processing then sorted the pixles out to produce some quite stunning images.

I think in the home, a blended system has too many issues where a single projector and Anamorphic Lens system makes the system more alignment,calibration and end user (WAF) friendly.
 

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I'm not sure it it would be so intensive. The initial setup would be challenging for sure. Once you had it dialed in, then I would think the upkeep would be minimal. I think it would be a pretty "set it and forget it" kind of thing.

Also, you avoid all the issues with having different aspect ratio material, video stretching or compressing, lens sleds or fixed, etc. If I had to teach my wife to figure out what aspect the source is and configure a lens appropriately, it would be no go in my house.

With a system like I'm imagining, the computer handles it all automatically because the native display resolution can handle any image ratio you play in full height.
 

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If you have your projectors ceiling mounted and its below another floor where people walk it will throw them out just enough to have to readjust them constantly. I see your point but logistically its more trouble than its worth in my opinion.
 

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Also as mentioned is the added cost, both hardware (extra projector and dedicated VP) plus your running costs have just doubled.
 

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Having said that, this might provide a good base for 3D :)
 

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Did anybody ever manage to get this to work?

I have been interested in this for a while but I could never find cost effective edge blending software or software that can scale a digital hd image to the sort of resolution you get from two projectors. When I try watching netflix on screen screens through my quadro 6000 using mosaic, I end up with the same size image in the center of the two screens with a huge black border. It works if I don't have it on full screen and just zoom in,but then it doesn't look that good.

If anyone has managed this successfully, I would really preciate a little advice on how and which software was used to scale the image.

I know there is free software (dscaler) for analogue inputs but it doesn't work for blu ray or netflix etc.
 
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