What is this artifact called ?

561 Views 10 Replies 8 Participants Last post by e vey, May 21, 2002

Gronbek

Discussion Starter · May 3, 2002

Hi,

I cant seem the get my htpc artifact free.

I have one especially annoying artifact.

1. It looks exactly like the windows background screen when you press start and shur down. These vertical shadow lines runnign from top to bottom.

BUT, they are much less visible compared to the shut down screen.

2. Another artifact, when looking at windows grey background at a close distance, 50 cm, i can see the pixels of my ht200DM flashing constantly.

This is not noticable at all on ex. blue, red screens.

What are these artifacts?

I have tried changing VGA cable, changing powerstrip settings but for no good.

Thank you,

Anders

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Phire

· #2 · May 3, 2002

Sounds like a bad scanrate to me.

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Phat Phreddy

· #3 · May 3, 2002

This is not the HTPC this is your projector...

You need to set your pixel clock (usually called Phase and tracking)... If you search for a post by Mark Rejhon titled 'pixel perfect timings with a DILA' or similar you will get a good primer....

A usefull thing to have to set this perfectly is a pattern of black / white squares in various settings (go to my website linked in the sig DL the 3.2 theme and extract the files int there there is one of these I would email it but I am posting from a laptop on holiday in SE Asia so not really near my HTPC)...

Hope this helps

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Phat Phreddy

· #4 · May 3, 2002

I just went to marks website and he has the test pattern for DL there to along with instructions on using it...

Have a look at http://www.marky.com/main/index.html

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Gronbek

Discussion Starter · #5 · May 3, 2002

Shall try the patterns when i get home.

Regarding phase and tracking(frequency), i have tried setting those, but have not succeded to find i a setting that remove the artifacts.

Maybe playing some more with pixel clock in powerstrip will help ?

Thanks,

Anders

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Burned&Warped

· #6 · May 3, 2002

Quote:

Originally posted by Phat Phreddy
....but I am posting from a laptop on holiday in SE Asia so not really near my HTPC)...

Hope this helps

Coincidently where in SE Asia? Singapore?

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Mad Chemist

· #7 · May 3, 2002

Quote:

Originally posted by Gronbek
Shall try the patterns when i get home.

Regarding phase and tracking(frequency), i have tried setting those, but have not succeded to find i a setting that remove the artifacts.

Maybe playing some more with pixel clock in powerstrip will help ?

Thanks,

Anders

I use to have the same problem. I ran my dlp PJ at 72 Hz. I could not get rid of the shimmering with the phase adjustments. I changed to 60 Hz and it all gone.

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Phat Phreddy

· #8 · May 5, 2002

B&W, The land of a thousand smiles... Thailand.

My lady is Thai (I am a Brit) and we met in Vienna... Since then we have been living in Holland and spending increasing amounts of time in Thailand (especially winters !!)... Now found a home here so will be making my base more here than NL...

Posting from a laptop on the balcony with an iced coconut juice via wireless LAN link to satellite ADSL (thank God Shin satellite now has its act together) link... I think this could take a while to get old

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Shaded Dogfood

· #9 · May 5, 2002

spending increasing amounts of time in Thailand

It's a tough job, but I suppose someone has to do it

I remember some of the Thai women who went to business school with me

(keep still, my heart!!)

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Tom Hilton

· #10 · May 21, 2002

Quote:

Originally posted by Phat Phreddy
I just went to marks website and he has the test pattern for DL there to along with instructions on using it...

Have a look at http://www.marky.com/main/index.html

Thanks for the link, Phreddy.

I've recently plunged into the HTPC world, and just visited Mark's website. I must say that achieving "pixel perfection" with a PJ/computer as described by Mark seems an appealing and worthwhile goal to me. However, I don't have a DILA...I have a Dreamvision DL500 Starlight. Has anyone tried Mark's procedures with any other digital projectors, like the DL500 or another of the Davis 450/DLS8 clones?

My new HTPC has already given me what I think is a pretty nice looking picture, so I am a bit cautious right now about the unintentional consequences of tweaking: i.e., inadvertently fouling up the image while trying to "improve" it. As an HTPC neophyte, it would be nice to hear any caveats from more experienced folks before diving straight into the pixel perfecting methodology.

Thanks for any help you can provide.

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e vey

· #11 · May 21, 2002

Quote:

Originally posted by Shaded Dogfood
spending increasing amounts of time in Thailand

It's a tough job, but I suppose someone has to do it

I remember some of the Thai women who went to business school with me (keep still, my heart!!)

Yeah, and they were general's daughters whose marriage had been arranged at age seven to lieutenants who were by then colonels.

Not the kind of guy you would want angry with you . . .

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