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Quadscan Elite/Iscan Pro-What's There Job?

Discussion in 'Projectors, Screens & Video Processors' started by gwbailey, Sep 19, 2001.

  1. gwbailey

    gwbailey
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    I'm new to this PJ game so I'm trying to find out as much info as I can. Now, I keep hearing about the Quadscan and the Iscan, but what do they do?

    What is the differance between the two?

    Do they both line double?

    I think one is a Scaler(Quad), if so what is a Scaler?

    Do I need one? (with a CRT)

    Which is better?

    Feel free to help,

    Please!
     
  2. Rob

    Rob
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    Hi Graham,

    The Iscan is a de interlacer (doubler) whereas the Quad can output higher resolutions. Which one would be better for you (if any) would depend on your projector.What are you planning to use?
     
  3. gwbailey

    gwbailey
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    Rob, or anybody else could you please give me some more details....

    What is a Scaler?

    Thanks for your help so far though!

    As for a PJ, I'm keeping a very open mind for now. So I don't yet know as there is alot to take in for a newby like me. Thats why I'm trying to find out as much as I can! (Quadscan/Iscan/Scalers)

    Although saying that I'm starting to lean towards CRT!(hope that didn't upset anyone)

    Cheers,
     
  4. Rob

    Rob
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    Scalers take an incomming interlaced signal, de interlace and scale to various resolutions (SVGA, XGA etc). The Quadscan also caters for Dila settings as well as double/ triple and quadruple. There arn't that many projectors that can scan this high though. Many are designied for a progressive/line doubled image. If this was the case with the projector of your choice then the Iscan would be the better route. The de interlacing is better on the Iscan and in any case,you wouldn't need a scaler. I'm sure Gordon or Roland could give you more detailed information, but hope this helps.

    Regards Rob.
     
  5. Roland @ B4

    Roland @ B4
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    A scaller<br />Takes the low video resolution (ie DVD,Satalite etc) and atificially increases the information to the ideal resoloution of your display. It increases the number of pixels and thus scales the image up.

    Progressive scan is the same as line doubled

    A single whole video frame is 720 pixels wide by 625 (pal) or 525 (ntsc) high. But the horizontal lines are shown interlaced so infact the actual resoloution is only about 300 -250 lines. compare that to your projector and the image needs scaling up.

    (Were's Richard Ansel when you need him)
     
  6. RichardA

    RichardA
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    Scaler - As previously mentioned it increases the number of scan lines (and pixels) to suit the display. <br />For fixed panel displays (Like LCD, DLP, D-ILA) this means matching to the number of pixels in the panel - this will mean that you do not use the (generally poor) scaler in the projector itself.<br />For CRT it means creating the right number of scan lines, so that they just touch without overlapping. If there are not enough lines you can see the gap, which is distracting. If there are too many, the lines overlap, the phospor in the overlap gets hit with twice as much energy and will tend to flare - which causes the picture to look soft.<br />Different CRT types have different scan line widths (spot size)and so require different numbers of scanlines, consequently a high resolution projector with too few lines can look worse than a lower resolution projector with the right number of lines.

    As a very rough guide;<br />7" basic(e.g. Ellie) line doubled/de-interlaced (480P/576P)

    7" advanced (e.g. Cine 7) 800x600 upto line trippled/720P

    8" (e.g. Cine 8/808) 1024x768

    9" 'older' CRT (e.g. Barco 1209/ Electrohome 9500LC) 1152x864

    9" 'newer' CRT (e.g. Cinemax / Sony G90) 1280x1024 / 1080P

    De-Interlacing and line doubling both come up with the same signal format - but the methods of acheiving it are different!

    A line doubler literally does what it says - it repeats the lines in each field twice - this takes no account of relationships between fields in a frame and does not improve resolution (i.e. each 'frame' of the output signal is made up of the info from one field)

    A de-interlacer puts the respective fields back together to form a complete frame, and then that is repeated twice - for film material his will improve the vertical resolution significantly. A de-interlacer will act just like a doubler for video material however.

    I hope this helps!

    Richard Ansell<br />Snell & Wilcox <br />Freshly back from IBC Amsterdam
     
  7. gwbailey

    gwbailey
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    Thanks guys, Why HCC doesn't get you guys to write the odd few articles in their mag beats hell out of me!

    I'll bet that I'm not the only one who could use some top class help & advice that you guys give!

    So come on HCC sort it out...
     
  8. Nic Rhodes

    Nic Rhodes
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  9. Roland @ B4

    Roland @ B4
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    Rihahard and mine can't spell proper.

    And when excactly are we going to find the time for that then.

    If a line doubler - Doubles<br />and a line tripler - Triples<br />the S&W interpolator - Interpolates

    What does a Faroudger do? - Faroge?
     

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