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4hv.org :: Forums :: General Chatting
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What is the formal name for those test targets ?

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Patrick
Wed Jan 28 2015, 02:37AM Print
Patrick Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
What is the name for those circular black and yellow targets? theres also the checkered ones too.
i use them the mythbusters use them, the pentagon and NIHS.

i need a formal name instead of "yellow-black-calibration-thingy."
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Houdini0118
Wed Jan 28 2015, 03:22AM
Houdini0118 Registered Member #8558 Joined: Thu Dec 06 2012, 11:38PM
Location: usa
Posts: 57
Secchi Disk
Link2
looks about right.
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Patrick
Wed Jan 28 2015, 06:17AM
Patrick Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
thanks but, i thonk thats just for turbidity and such, but the ones i need to know of are from frame to frame bash-in and speed analysis.
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Dr. Slack
Wed Jan 28 2015, 07:16AM
Dr. Slack Registered Member #72 Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659
Patrick wrote ...

thanks but, i thonk thats just for turbidity and such, but the ones i need to know of are from frame to frame bash-in and speed analysis.

if you read as far as the third sentence in that link, which starts 'A secondary use ...' then I think you'll have your answer.

I hadn't appreciated why dots or cross hairs are not used. The Secchi pattern is scale invariant as you zoom into it, you can use the same alignment algorithm and metrics regardless of magnification, not true with cross hairs etc.
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