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Thread: Ilda Test Pattern aint doing normal

  1. #11
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    Squares that aren't square are usually software setting or a sign that something isn't square in the projector. Check that the galvo mirrors are straight in the slots and that the mounting block is straight and that the beam enters the block square
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  2. #12
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    Quote Originally Posted by norty303 View Post
    Squares that aren't square are usually software setting or a sign that something isn't square in the projector. Check that the galvo mirrors are straight in the slots and that the mounting block is straight and that the beam enters the block square
    mmmh every software application i tried and every ilda file i loaded has this...

    I can find anything wrong in the projector.
    I have learned some time ago, that if the galvo mirrors are set on home position, do not get signals, and all lasers on, that all beams must touch the galvo mirrors, leave the galvo mirrors straight out of the projector...meaning 90 degrees, and then make white on the wall...
    Maybe the laser beams dont exit the beam aparture window for 90 degrees...but its close to it. is that why the square's are not 100% square?
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  3. #13
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    Quote Originally Posted by borgqueenx View Post
    well the company who sold it to me(phenix) said it was 30kpps at 20 degrees.
    i thought if they were sure of that, and they were.
    Thats their claimed scanner capability.

    I understand that the ILDA file is designed to be scanned at 8 degrees, but I stand to be corrected on that.

  4. #14
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    Quote Originally Posted by borgqueenx View Post
    he company who sold it to me(phenix) said it was 30kpps at 20 degrees. i thought if they were sure of that, and they were.
    Either you misunderstood what they were saying, or they were bullshitting you.

    The standard ILDA test pattern is designed to be scanned at 8 degrees or less. If you have very high performance scanners, you might get a little wider. (Some people have gotten 14 to 15 degrees with the DT-40 Pro scanners, and I've gotten 18.5 degrees out of my ScanPro50 scanners, but only when they've been re-tuned to run at the slower 30K speed.) But it's almost unheard of to get 20 degrees out of the ILDA test pattern when running at 30 K, unless you're running the Cambridge 6215 HP's.

    Note: There is another version of the ILDA test pattern that has a large square outside the main portion of the test pattern. That pattern can be scanned wider than the standard pattern, but it still has it's limits. The picture you posted in your first post in this thread does not show the outer square, so it's unclear which version you were using for that picture.

    However, which pattern you are using is irrelevant at this point. If the center circle starts to distort, you are scanning too wide, no matter which pattern you are displaying. Back off on the scan angle until the circle looks right. Then you can check your tuning...

    The scanners in your projector may be rated for a maximum angle of 20 degrees, but that is under ideal conditions. The ILDA test pattern is an exceptionally demanding image that is anything but ideal. Part of it is actually designed to be impossible to scan perfectly. That center circle you see is actually a 12-sided polygon that is positioned completely outside the center square. Since the scanners are ballistic when they are scanning that portion of the pattern (because the points are so far apart), they round off the corners and you end up with a much smaller circle that is inside the square. If you actually see the points of that 12-sides polygon, you've got something set incorrectly.
    i just tested the 12k scan file...when its made less larger the circle goes into the middle of the retangle.
    That's where it belongs.
    if it scans at a bigger scan angle the circle is way out of line.
    Yep. That's what happens when you over-drive scanners.
    but in both test patterns and sizes, the retangle lines are not 90 90 90 90 degrees.
    Then you may have a problem with the way the scanners are mounted in the scanner block. The beam path through the scanners needs to be at perfect 90 degree angles for each bounce. If it's not, you'll end up with skewing distortion of the pattern. This is a fairly common problem, and can usually be corrected by loosening the mounts for the scanners and rotating them until the angles are correct.

    On the other hand, if you have bowed lines (pincushion distortion) in your image, then you may have a software problem. Many modern laser show software packages include basic geometric correction. Check to be sure that everything is zeroed out in the software. If it isn't, that could be artificially distorting your image. (Also, projecting onto anything other than a vertical wall that is perpendicular to the beam path will cause distortion as well.)

    Adam

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    Quote Originally Posted by buffo View Post
    On the other hand, if you have bowed lines (pincushion distortion) in your image, then you may have a software problem. Many modern laser show software packages include basic geometric correction. Check to be sure that everything is zeroed out in the software. If it isn't, that could be artificially distorting your image. (Also, projecting onto anything other than a vertical wall that is perpendicular to the beam path will cause distortion as well.
    Adam
    the picture i showed you, is that artificially distorting?
    the lines are not in a bow, they are straight, just a ummm...weird shaped retangle.

    il try to move the scanners inside the mount tommorow, see if that fixes anything...
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  6. #16
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    mmmh every software application i tried and every ilda file i loaded has this...

    I can find anything wrong in the projector.
    I have learned some time ago, that if the galvo mirrors are set on home position, do not get signals, and all lasers on, that all beams must touch the galvo mirrors, leave the galvo mirrors straight out of the projector...meaning 90 degrees, and then make white on the wall...
    Maybe the laser beams dont exit the beam aparture window for 90 degrees...but its close to it. is that why the square's are not 100% square?
    I don't think you are quite understanding me.

    IF you look at the mirror in the galvo spindle from the side it should look like this

    =--

    Sometimes, they are glued in and there is a bit of play in the slots so it sets more like this


    =\ (exagerated)

    Although it will look like the beam comes straight out of the projector, any scanned pattern like a square will be a parallelogram instead.
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    You are using Bonetti's defense against me, ah?

    I thought it fitting, considering the rocky terrain.

  7. #17
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    Quote Originally Posted by norty303 View Post
    I don't think you are quite understanding me.

    IF you look at the mirror in the galvo spindle from the side it should look like this

    =--

    Sometimes, they are glued in and there is a bit of play in the slots so it sets more like this


    =\ (exagerated)

    Although it will look like the beam comes straight out of the projector, any scanned pattern like a square will be a parallelogram instead.
    i still dont understand all you said but i guess the white line is not getting out of the projector for a perfect 90 degrees.

    Also, i just played some shows on full 20 degrees at 30k, and there were no weird distortions like on the ilda 30k test frame.
    a graphics show of 7 minutes didnt do anything weird.
    or maybe it was me :P

    Anyways im already pretty wowed today to see the other scanshows then the build in pt-itrust show. a bit flicker to no flickering, and much more awesome stuff.

    I cant wait to make my first show. probaly will be next weekend.

    Tommorow il try tinkering with the galvos in the mount, to move them a bit.

    judging on the image, how much will i need to move the galvo's. like 1mm? :P
    or.... just so i know...
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  8. #18
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    Flickering isn't necessarily the scanners but can also be the play back frame rate so best not to get too side tracked with that.

    If your software supports frame rate reporting then see what frame rates its reporting for the frames you're playing back.

    If they 15fps or less for graphics expect definate flicker. 15-29 may see slight flicker. Above 30 and you should have no problem. With beams, according to what Norty reported to me sometime ago you probably won't have a flicker problem even at quite low frame rates with beams.

    However, this is a side issue. Worry about curing the distortion 1st.

  9. #19
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    Look pretty good if you ask me. You're running them a little too fast or too wide but you can back off the speed or angle and cure that.

  10. #20
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    Also notice the square weirdness...down on the photo the square line goes up from left to right.
    But the at the top of the photo the line goes up from right to left...
    You can see it because my wallpaper behind it.

    EDIT: tried moving the galvo's in their mount today....no effect. the square keeps being a weird square as described above this edit.
    like i said scan angle does not matter, the box/square/retangle keeps doing weird.
    Last edited by borgqueenx; 02-27-2011 at 03:19.
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