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Thread: ILDA Test Pattern

  1. #1
    Join Date
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    Default ILDA Test Pattern

    i tried to do a search for this and about 800 posts came up. what i am looking for is an explanation of how to interpret what i see when scanning the ILDA test pattern. How does it exactly work??
    i am attaching some pics cuz my test pattern scan looks TERRIBLE. BUT- scanning images, text, animations all look great. well, some obviously look better than others, but for the most part, 95% of what i attempt to scan is B+ or better.

    im running CT 6210s with the single axis 678xx amps.

    some pics-
    (Last pic is a pretty detailed logo scan and projection i did. thought it came out pretty good so wanted to post it with these other pics to see if anyone had any explanations!?!?!?!)
    -Marc
    Attached Thumbnails Attached Thumbnails ILDA1.jpg  

    ILDA2.jpg  

    ILDA3.jpg  

    BOYER1.jpg  


  2. #2
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  3. #3
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    Cool

    Hi Marc;

    You scanners need tuning - that much is clear. They're running at different speeds now (one has more gain than the other), which is why the circle looks goofy. Still, you're not far off.

    For info on how to tune, along with a good description of what each part of the pattern is for, have a look at the following links:

    http://www.laserfx.com/Backstage.Las...Scanning1.html
    http://www.laserfx.com/Backstage.Las...Scanning3.html
    http://www.pangolin.com/ILDAtest.html
    http://www.pangolin.com/50K_tests/TestPatternPhotos.htm

    And some more info on tuning tips here:
    http://www.photonlexicon.com/forums/...32&postcount=9
    http://www.photonlexicon.com/forums/...ead.php?t=3402

    I still need to get my scanner tuning tutorial finished. It's on my to-do list...

    Adam

  4. #4
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    Default

    before i tuned



    then i used this guide
    http://www.laser-man.co.uk/2006/inde...d=66&Itemid=76

    and now it looks like this




    Eat Sleep Lase Repeat


    Aluminium Optic Mounts

    http://www.laser-man.co.uk/opticmounts/

  5. #5
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    Cool

    Andy, what galvos are you using? It looks like you've got a lot of noise in the signal. (See the wavy lines on the straight line portions of the test pattern? It shouldn't look like that.)

    For example, this picture shows a set of scanners I worked on that were *really* far out of tune. Yet even so, there isn't any hint of the wavy lines you've got...



    This one shows the scanners after I tweaked them a bit. Note that the bowing in the center is caused by the screen not being flat. (It's a black sheet, and the ceiling fan was moving it around a bit.)



    Pay close attention to the 4 lines at the bottom of the pattern. They should all be parallel and straight. No curving up or down on the right side.

    Adam

  6. #6
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    Default

    ANDY, ADAM-

    Thanks! that tutorial is going to help me immensely. now i just need to figure out what pots correspond to what i need to adjust on my amps. never done scanner tuning before. i am assuming, that this is a VERY sensitive procedure? are the amps and/or scanners forgiving if the adjusting goes above OR beyond some certain *threshold* limit of adjusting? in other words, is there a way that i can actually overdrive the scanner and break it? or is there some sort of inherent safety that wont allow it. i am assuming that the answer is YES, they can be fried QUITE easily! (of course, is ANYTHING with lasers NOT fragile?? lol...)

    i am going to have to try to find a layout or schematic or something of my amp drivers. i remember Cambridge, the few times i spoke with them, being VERY customer friendly. will they supply this info to me you think? (schematic or layout fo rthe proper adjustment pots?)

    and, dumb question, but- "if it aint broke, dont try to fix it..." i understand my ILDA test pattern looks like crap, BUT- if everything else projected looks good, is this neccessary to perform? (the tuning). the ILDA pattern is probably almost like a *stress test* for the scanners correct? in other words, a test to really push them. do they perform like that under normal ooperating circumstances?

    thanks very much!
    -Marc

  7. #7
    Join Date
    Jan 2005
    Location
    Norway
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    Cool

    hmmm..

    I got the DT-40 Pro in both my lasers.
    They both dont give me any good ILDA test pattern !

    The blanking seems like a mess, and the circle is out of place !
    But the graphic on my show is always fine, so I have never bother to do anything about it..

    all I did was to delete the ILD file :P :P

    I dont know how to tune my DT ... :s

  8. #8
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    Default

    yes there was noise but there wont be when i have my new setup.
    Eat Sleep Lase Repeat


    Aluminium Optic Mounts

    http://www.laser-man.co.uk/opticmounts/

  9. #9
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    Rotorua New Zealand
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    Default

    OK .. I'll jump in and get myself even more confused.

    I have DT-40 Pros.. I too see the ILDA pattern not quite as good as it should be.. The circle is somewhat of an ellipse. Test pattern also flickers a lot.

    Would this not be because my DT40's are tuned to around 40K and the ILDA test pattern is 30K ????

    Should I re-tune to 30K ILDA test pattern ??

    I also get quite good graphics results particularly if I run the speed up around 44K PPS (lot less flicker)

    Ray

  10. #10
    Join Date
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    Default

    no scanners play the test pattern without flicker. i have original dt40's

    also you need to make sure you are displaying the test pattern at 30k at 8 degrees.

    any scanners that do not display the test pattern correctly need tuning. if you follow that guide like i did its not hard to do.
    Eat Sleep Lase Repeat


    Aluminium Optic Mounts

    http://www.laser-man.co.uk/opticmounts/

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