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Simulating TV moire pattern

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Fernando MolSimulating TV moire pattern
by on Mar 28, 2012 at 3:56:02 pm

I was wondering if someone knows a cool way to simulate the moire pattern that occurs when you shoot a tv.

I did this once by playing the video in a TV and shooting at it, but I was wondering for a stylistic solution for HD video.

Just for fun

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Dave LaRondeRe: Simulating TV moire pattern
by on Mar 28, 2012 at 4:00:13 pm

What are you talking about: the hum bars that travel up the screen? Snow? Something else? Please specify.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA

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Fernando MolRe: Simulating TV moire pattern
by on Mar 28, 2012 at 7:24:37 pm

Yes, the moving bars.

Got this moire pattern gif example from wikipedia. Not exactly a TV moiré but kind of.

And this is another example of moire patterns of a TV screen (at the beginning of the video, the curved color bars in the sky).

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Kevin CampRe: Simulating TV moire pattern
by on Mar 28, 2012 at 8:04:51 pm

combining cell pattern (setting dispersal to 0 and size to a low value) and turbulent displace will start create a moire pattern.

Kevin Camp
Senior Designer

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Walter SoykaRe: Simulating TV moire pattern
by on Mar 29, 2012 at 5:13:21 am

Moiré patterns are caused by interference between two (or more) sets of lines or shapes. (In acquired footage, you can get Moiré because the lines of an object like a set of electrical wires do not coincide perfectly with the pixel grid of the sensor.)

Adding overlapping and offset or rotated lines, circles, or grids can add Moiré to your image.

If you want a specific Moiré pattern, you can get very fancy and create shape Moiré [link]. This is the same phenomenon that underlies security printing for copy-resistant documents.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events

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Ryan HillRe: Simulating TV moire pattern
by on Mar 30, 2012 at 8:54:45 pm

And the colours in the TV screen moire comes from the RGB on the screen being offset and so you get a slightly different pattern for each colour.

So you can break it down to two simpler problems:
1) Generate greyscale moiresque patterns
2) Use that to create 3 coloured layers of your footage

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