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Thread: Projection Mapping

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    Default Projection Mapping

    What are my best options for a 1366x768 computer resolution? Ive been reading that the computer resolution should match the projector resolution, but a search on google doesnt give me options for this resolution. Do projectors have the built in option to select 4:3 or 16:9?

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    By default, analog scanners are the same deflection angle for X and Y. That means that they scan an area that is square.

    Resolution is measured in pixels or points. Your screen is pixels by pixels. Your scanners are analog and therefore have no particular resolution. Your DAC has a resolution based on the bits per sample. ILDA files store 16 bits per axis. That's 65536 points in X or Y.

    Aspect ratio is width to height.

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    OK, Are you asking if the computer that drives the video projector should match in resolution? Or are you asking about a laser overlay on video?

    If your Asking about a laser overlay to video things are different.

    For laser the Galvo amps and/or the control software can be adjusted to scale as needed. However when you actually get in the field you find the Laser material appears to loose resolution in some cases if you use software scaling. However If you use analog scaling outside the software, life is good as there is almost no loss of apparent resolution until the image gets very small. This is often as simple as adding external scaling and offset pots to the laser projector.

    If this is a laser overlay, is one case where you should actually talk to people who actually do this, like me.

    Steve
    Last edited by mixedgas; 01-23-2015 at 11:20.
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    Thanks for the quick reply. I may have not been clear, but im talking about video mapping with a PJ...not lasers. unless im the one totally missing something here.

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    Generally What you are asking depends on how the scan converter in YOUR particular video projector works. It is far easier to downsample video then it is to line double or upsample video. So your card should be as close as possible or exceed the resolution of the video projector.

    So yeah, you'd like to match with your source if possible. It is also a function of how good your video drivers are.

    I just had some serious fun with a Church installation where the worship laptop video resolution was considerably lower then the projector resolution. End result was installing a tower with a triple output video card, so all streams lined up and the two monitors in the booth matched the projector.

    The low res was not the real issue. The issue was how the hardware added a horizontal offset during scan conversion in the projector. This resulted in one side of the final image consistently clipping. No amount of tweeking the software offsets would help.

    Steve
    Last edited by mixedgas; 01-23-2015 at 11:33.
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    If you plug your video projector into your computer's display adapter you should have a selection of resolutions to choose from.

    For best picture quality, you should choose the native resolution of the projector.

    You might not be able to do this if you copy the screen from say a laptop (same display on both screens).

    If you extend your desktop to use two separate displays, each one can have its own native resolution.

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    ok, i see what you guys are saying. i do not have a projector yet though, so im just trying to find my options.

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    What are you looking for?

    Mitsubishi dropped out of the video projector market because of all of the cheapo off-brands eating up their sales.

    So they told some of their retailers to dump their inventory.

    I got a 3 LCD, 1080p, 5000 lumin commercial projector that had an MSRP of $20,000 when it was introduced in 2008 for $1570, shipped to my house!

    They are even cheaper now!

    I also got a 150 inch pull-down 16:9 screen for our living room (Elite from eBay, about $210).

    My TV is 11 feet wide and over 6 feet high!

    I love it!

    You need some room though. Mine is set up to throw about 22 feet.
    Last edited by james; 01-23-2015 at 11:43.
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  9. #9
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    Getting a quality video card helps. Most laptops flunk here. Guys on VJ forums might have a better answer on what hardware works well.
    Generally I'm reaching for Matrox or high end NVida cards when I work on these things. Which happens once or twice a year in commercial situations.

    I'm particularly weary of the "slide with the mouse" dual Windows video setup. One of Win7s favorite tricks is to wreck havoc if by searching for the first video display device to return an ID stream on the video port and assigning it "Monitor One". This lead to a written procedure requiring the projector to be off prior to boot but on prior to software start, with the booth monitor always on. Getting a better video card allowed MON One to be a fixed ID.

    Annoying stuff like that is why getting reviews of working hardware is important. Better software (the pay to play stuff) usually has tools for dealing with Windows video quirks.

    Steve
    Last edited by mixedgas; 01-23-2015 at 11:52.
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    I use mine every day for TV, PS3 and computer display.

    It has both DVI and analog RGB video inputs.

    I've never had any problem plugging it into any laptop, tablet or even my Android phone.

    You can convert DVI to HDMI with a simple passive adapter plug.

    I makes my tiny Raspberry Pi look freakin' awsome!

    James.
    Last edited by james; 01-23-2015 at 12:02.
    Creator of LaserBoy!
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