IR Vision Glare

    Hello all,

    Fairly new to FANUC robots and IR Vision as a whole.

    Two of our robots are used to deburr the edges of round steel bars, typically this works fairly well. However, we seem to always have issues with one of them not being able to see the end of the bar because it is too shiny and glares when it tries to look at it. We have tried painting the ends of the bars, we have tried putting polarizing film over the lens. Nothing seems to work out just right, and it's only the one robot. Does anyone have any suggestions on what might be causing this? Maybe its not actually the glare?


    Any tips are greatly appreciated.

  • MOM September 5, 2024 at 3:37 PM

    Approved the thread.

    What kind of camera, lens, and lighting are you using? What's the ambient lighting like? Are your irVision configurations in both robots the same? What version of robot OS and irVision are you using?

    I doubt this is an irVision-specific issue. Rather, it's a standard issue that everyone using Machine Vision struggles with.

    Rule 1 of MV: Lighting is everything
    Rule 2 of MV: Sunlight always beats your lighting. I once had to have a plant skylight painted over b/c a system that worked fine all spring/summer began failing once winter sunlight started coming through at the right angle to hit my work area.

    MV on round objects is always an issue, b/c a direct reflection from any/all light sources is almost guaranteed to hit the camera lens directly. This is typically addressed by using diffuse lighting rather than point sources like ring-lights around the lens. But diffuse lighting rigs tend to be bulky. My favorite solution (when possible) is to use backlighting, so the camera is looking at the silhouette of the object against an evenly-lit background

    Also, most MV lenses have adjustable focus and aperture. Sometimes you need to dial down the aperture to reduce the amount of light hitting the sensor, although that usually drives up exposure time.

    You could have an irVision config issue. irVision has exposure settings and software filters. If both robots have the same camera, lighting (not just hardware but angles), ambient light, etc, I would try comparing the irVision job setups in both robots. Were these units set up by the same person?

    Right now, there is some LED overhead lighting about 50 feet overhead, no skylights. We do use a ring light that shines a red light when it goes to view the bar.

    The settings are the same for both robots, and have been worked on by the same person.

    Im not sure if the aperture has been adjusted or just the focus, I will have to check with the guy that typically adjusts the robots.

    Both robots operate the exact same, angles, approach, light, etc, the only difference is the one we have issues with has a polarizing film on it, which seems to help some, but not completely.

    Which way is the polarizing film rotated? If the polarization is aligned with the long axis of the bar, that might be letting the glare through. Try rotating the film 90deg.

    Try shooting the bar with the ring light off, and with the overhead lighting off, and with both off, and see what happens to the glare. The goal here is to determine what sources are generating the glare. You could have some lighting far away that's bouncing in unexpected directions.

    The film covers the entire camera lens.

    I will try shooting with the ring light off, I can't, unfortunately, turn the overhead lights off, because safety will have a fit.

    I appreciate the ideas.

    I do know part of our issue is the bracket that holds the camera is currently bent and seeing the bars at a slight angle, but we are getting ready to swap that out today actually. Which should help.

    Edited once, last by Chall234 (September 5, 2024 at 4:52 PM).

    Quote from Chall234

    I will try shooting with the ring light off, I can't, unfortunately, turn the overhead lights off, because safety will have a fit.

    Just blocking the overhead light (with an umbrella, say) long enough to take the test shot would serve. The main goal is to get a handle on possible alternate sources of the glare.

    I once had a MV operation fail because of a ceiling lamp over 75m distant -- my camera was looking through a hanging part at a slight upwards angle, and about 1 out of every few hundred parts, the camera's line of sight would line up through a hole in the part with that distant ceiling lamp. That one was easy to determine b/c I could see it in the images, but I couldn't get that light shut off (or shoot it, though I was tempted). Ended up doing a bunch of hacky software changes to try to work around it. Stupid thing never did work 100%....

    Angle will definitely have an effect on glare, so fixing the bracket can't hurt. The key will be the angle of reflection between the light, bar, and lens. If you can duplicate that from the working system, definitely try it.

    Are these cameras fixed or robot-mounted? If the latter, a quick way to play with reflection angles is to just jog the robot a bit in various directions and see if the glare gets better or worse.

    The cameras are mounted on the robots. I will see if adding an offset in certain directions helps with the glare at all.

    We had discussed in the past about building an awning of sorts over the line where the robot sits, I wonder if this might still be a good idea. We have our own weld shop so it may even be pretty cheap to do with just some angle iron and flat stock..

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