Collage Overlapping & Image Size Calculations

tbslytertbslyter Registered User, Hog Beta
edited August 2006 in DL.3/DL.2
Greetings. Just trying to do some image size / throw length calculations for some upcoming projects with DL.2 and I am wondering how much overlap you should allow for when using Collage Generator and figuring total image size?

I.e. We need to fill a 20' x 56' screen with a 2 x 3 array and I would like to keep the zoom as tight as possible for maximum brightness. So.....

1. How far away will we need to be with projectors?
2. What will the total image size be for that array?

What I am really looking for here is a formula or better yet a % of overlap that I can use for figuring Collage screen size in the future. Thanks!

Travis Slyter
Ruehling Associates, Inc.

Comments

  • SBlairSBlair Registered User, HES Alumni
    edited July 2006
    Travis,

    You can find the Throw Distance/Image Size chart here: http://www.highend.com/products/digital_lighting/dl_1-dl_2_projection_chart.asp

    I would plan for about a 20% overlap region for a good blend when using Collage.

    Scott
  • tbslytertbslyter Registered User, Hog Beta
    edited July 2006
    Scott,

    Thanks for your help. I had already located the throw / image size chart hence the question about percentage. I am assuming the 20% is per edge blended, so if you have a center screen in an array with both sides blended it's actually 40% overlap? Thanks again.

    Travis
  • SBlairSBlair Registered User, HES Alumni
    edited July 2006
    I did some real investigation for you. It is ~9% overlap per edge after the image has been keystone corrected. So if you have to do lots of keystone adjustment you'll lose image size due to that and then subtract the 9% per edge at that point.
  • tbslytertbslyter Registered User, Hog Beta
    edited August 2006
    What is the maximum resolution for this configuration as well as the aspect ratio? It is not listed in the array size chart. Thanks.


    Travis Slyter
    Ruehling Associates
  • tbslytertbslyter Registered User, Hog Beta
    edited August 2006
    Also when you say 9% per edge I want to clarify. If you have 2 projectors blending is that 9% for EACH edge from both projectors (18% total) or is it 9 % for the ENTIRE edge with each image only losing 4.5% (9% total)? Thanks.

    Travis Slyter
    Ruehling Associates
  • SBlairSBlair Registered User, HES Alumni
    edited August 2006
    When you overlap two projectors you are overlapping 9% of the edge on one projector to another projector. So for 2 projectors I'd say you are losing 4.5% of the total combined width of those two projectors.
  • tbslytertbslyter Registered User, Hog Beta
    edited August 2006
    Great!

    That helps, so what is the maximum image resultion and aspect ratio of an array 2 high and 3 wide as they are not on the charts? Thanks.

    Travis Slyter
    Ruehling Associates, Inc.
  • SBlairSBlair Registered User, HES Alumni
    edited August 2006
    We don't have a 2x3 as an option as all the blending configuration at the moment. You would need to do two seperate 1x3's if you wanted a 2x3.

    You can see all the options listed here:
    http://www.highend.com/support/digital_lighting/dl2supportguide/Collage-generator/dl2-collage-arrays.asp

    We try to keep the total pixels below 1 million. So you can tweak the resolutions to stay in about that range.
  • tbslytertbslyter Registered User, Hog Beta
    edited August 2006
    Scott,

    Thanks so much for all your help. I went to page that you listed before I posted, hence my question as to why the configuration is not listed. However on the page for console congifuration

    http://www.highend.com/support/digital_lighting/dl2supportguide/Collage-generator/dl2-collage-console-setup.asp

    it listed numerous array configurations that are not listed on the array page, so it's confusing information hence my post. So would I be safe in confirming that not all of the array configurations that are listed in the console configuration instructions are supported yet? Again thanks for all your help.



    Travis Slyter
    Ruehling Associates
  • SBlairSBlair Registered User, HES Alumni
    edited August 2006
    Yep. You are right. I'll see if we can get the other page updated.

    Here's another useful thread on the subject: http://forums.highend.com/showthread.php?t=2387

    In general, you multiply the number of fixtures wide by 640 and the number of fixtures high by 480. Then you scale the resolution down so that when you multiply the resolution widthxheight you are below 1 million pixels. If you do that to all the resolutions we have listed on the Collage content page you will see they will come out at 750k pixels.

    Then read the other thread I posted above and it will go into even more detail about how resolution/compression affect bit rate and performance.
  • tbslytertbslyter Registered User, Hog Beta
    edited August 2006
    Thanks for the info, that helps. So in our application we are simply doing a slide show beteen still photos on a 3 wide x 1 tall array. (We will have to double stack the array for maximum brightness, hence my question about 3 x 2.)

    We will be at the most 2 layers simply to cross fade between photos. According to the chart that maximum image size is for HD movie files which we are not using. So I am assuming that our still files can probably be higher res and closer to the 1 million number (w x h). So the question becomes how close to 1 million can we go will still images and be fine? Thanks again for your patience and all this help.

    Travis Slyter
    Ruehling Associates, Inc.
  • SBlairSBlair Registered User, HES Alumni
    edited August 2006
    Yes, for still files you should be able to go much larger. I don't have any specific numbers as most of our testing tends to concentrate on movie clips which is more challenging.

    I just preload the image a cue before if it is really large if you are seeing any delay in loading due to the size. With the higher resolution movie clips we highly reccommend pre-loading them the cue before in the "Stop and Rewind" mode so the clip is sitting at frame 1 ready to play in all the units when you start it.
  • SBlairSBlair Registered User, HES Alumni
    edited August 2006
    Travis,

    We've updated the content page with recommended sizes for the other Collage configurations.

    http://www.highend.com/support/digital_lighting/dl2supportguide/Collage-generator/dl2-collage-arrays.asp
  • tbslytertbslyter Registered User, Hog Beta
    edited August 2006
    Scott,

    Here is our scenerio. We are doing 3 x 1 array to recreate murals that are usually painted on a cyc. We are doing no moving video just still images with some dissolves in between. We are trying to crop and resize the photos to fit our projection aspect ratio as close as possible so the images will fill the screen. Our ultimate goal for image size is to get as close to pixel per pixel as possible to minimize distortion from stretching and zooming. Normally that would be 1024 x 768 for each projector.

    Your size charts are based on HD video not still photos and of course they are lower res per projector than 1024 x 768, plus I know for total image size you have to subtract 9% per edge. Doing that the total image size would be 2703 x 768. Unfortunately we don't have 3 units to test at the moment.

    My question is can we go the full 2703 x 768 image size so that image is close to pixel by pixel or is that too much data crunching? We can load the next image as early as we need to as we have a lot of time in between images to improve playback performance. If not what is the max resoultion that we can go? If we need to make it smaller, I am assuming the DL-2s will stretch the image to fill the screen so it's important that we keep the aspect ratio the same to minizise distortion. Correct? Thanks.


    Travis Slyter
    Ruehling Associates, Inc.
  • SBlairSBlair Registered User, HES Alumni
    edited August 2006
    Since you are doing still images I think that would work. If you want to get some files made in that resolution I'd be happy to test them for you here in the fixtures.

    The DL.2 is always in a 4:3 aspect ratio since that is a limitation of the projector.
  • tbslytertbslyter Registered User, Hog Beta
    edited August 2006
    Scott I have some images to test, please let me know where to send them. Thanks.

    Travis Slyter
    Ruehling Associates, Inc.
  • SBlairSBlair Registered User, HES Alumni
    edited August 2006
    You can send them to me here:

    http://ftp.highend.com/upload/

    Just select me as the person to mail them to when you upload them.
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