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I need to measure the width of a bar made out of glowing red steel (900-1200 degrees Celsius) using computer vision.

In order to ensure resolution of a 0.5 millimeters/px, the camera is needed to have enough pixels and, considering the field-of-view, to be at a certain distance from the bar.

Can anybody think of a way to use a camera at a distance of 0.5m from the glowing hot bar? Air refrigeration? Refractory enclosure?

Let's talk about it?

Fred
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Marco Souza
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    Are you sure its just not cheaper and more accurate to get a telecentric lens and put it further? Also seems to me that you have made a premature decission for method used – joojaa Jul 05 '18 at 05:33
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    Insulated enclosure with fireproof glass window, air-cooled. Additional bonus: easy to install a dim filter to reduce glare from the glowing steel, which is bound to confuse the camera. – SF. Jul 05 '18 at 08:13
  • Use the glass used in welding goggles - some are available as flat sheets about 2.5" by 4"... – Solar Mike Jul 05 '18 at 08:28
  • thank you all for the replies. @joojaa , the computer vision method was chosen before i had my hands on the project. As an engineer I just gotta make it work. Excelent tip about the telecentric lens, though. I will do some research about the application. Thank you very much for the reply. – Marco Souza Jul 05 '18 at 16:28
  • @SF. we thought about air-cooled enclosures, but had not thought about the fireproof glass. I will do some measuring on the temperatures and design some sketches. Thank you guys. – Marco Souza Jul 05 '18 at 16:28
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    Yeah but why the spcific camera – joojaa Jul 05 '18 at 16:33

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Do you need a single camera, or could you build a precision mount with 2 smaller cameras, each covering one end of the bar? Saves you a ton of pixels. Or, for that matter, a single camera with an external set of path-folding mirrors & prisms so that what the camera "sees" is just the ends of the bars. This is a common approach taken in various laboratory work when only two small non-adjacent regions are of interest.

Carl Witthoft
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