Why do stripy shirts make images, shown on television, go flashy and/or blurry?

Asked by rebbel (35548

) July 13th, 2010

Apparently this only happens when people wear horizontally striped shirts.
And i think also when the shirts are polka dotted.
How is that happening?

A second, related, question if i may:
Why do laptops – and/or computer screens that we see on television (usually in live transmissions, i think) appear to have rolling, horizontal blue beams.
How is that happening?

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6 Answers

Computer screens have a higher resolution than what video cameras can pick up.

As for striped and patterned clothing, there’s something called a moiré pattern where, in the case of TV, a video camera’s pixels create interference with the pattern of the clothing.

aprilsimnel (30749

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That is what i like from Fluther (users)..., they provide good answers.
I am going to read into those phenomenons, @aprilsimnel , thank you!

rebbel (35548

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Actually, regarding the computer question, it’s because the frequency that the computer/TV refreshes at (60Hz, 72Hz) is different than the frequency that the digital video is recorded/transmitted.

andrew (16543

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@andrew – Yes, you explained the screen business better than I did.

aprilsimnel (30749

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You can create your own moire patterns quite easily at home too. Just a wire trashcans or something of that nature and shift them in front of each other and look at different angles You can actually see the moire patterns in the image. The reason this happens is because the eye prefers things of high spacial frequencies over low

El_Cadejo (34610

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