A fixed camera, small presentation changes, very different streaks

ReeceCarter0993 · 4 Apr 2026, 18:21 UTC

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RE
ReeceCarter0993
Our planned planning camera inspection of reflective parts in a precision metal-parts inspection area has Universal Robots UR5e presenting a brushed stainless trim plate to a fixed camera. The example images contain bright streaks that shift with small presentation differences, yet those streaks are being labelled as scratches. Before commissioning, I'd like to establish reliable references and image conditions for threshold tuning.

16 replies

GR
GraceBell0668
Replying to ReeceCarter0993

Were those scratches confirmed on the physical samples using your agreed appearance method? Start by linking each image to a sample and its inspection result.

16 points
RE
ReeceCarter0993
Replying to GraceBell0668

Some labels came from the pictures alone. We still have the samples, but those labels aren't tied to physical inspection results. That's irritatingly circular.

4 points
GR
GraceBell0668
Replying to ReeceCarter0993

@ReeceCarter0993 Mark those labels uncertain and have the samples inspected properly. Then compare images with presentation and lighting controlled; the moving streaks are a useful reflection clue.

13 points
GA
GabrielChen1149
Replying to GraceBell0668

@GraceBell0668 A scratch's visibility can change with presentation too. Don't let 'moving streak' quietly become the rule for relabelling something acceptable.

-2 points
GR
GraceBell0668
Replying to GabrielChen1149

@GabrielChen1149 You're right to qualify that. The streak behaviour motivates an imaging investigation; it doesn't replace physical classification under the agreed inspection procedure.

14 points
IS
IsabelBell0648
Replying to GraceBell0668

Should uncertain images be treated as acceptable, or kept somewhere separate while their status is established?

5 points
GR
GraceBell0668
Replying to IsabelBell0648

Keep them explicitly undecided, with the sample link. Don't use them as confirmed examples of either class until the physical review settles them.

17 points
RE
ReeceCarter0993
Replying to GraceBell0668

Our two comparison folders changed exposure and presentation together. I can't tell which change made the images look better. That comparison needs a caveat too.

19 points
AN
AnilBarnes0549
Replying to ReeceCarter0993

On my inspection setup, a folder called 'better lighting' also contained easier samples. The folder name was doing a lot of unearned work.

24 points
RE
ReeceCarter0993
Replying to AnilBarnes0549

Which details did you retain with each image? I can record sample identity and settings, but I'd like a practical record people will actually maintain.

18 points
AN
AnilBarnes0549
Replying to ReeceCarter0993

For my separate setup, sample identity, exposure, lighting arrangement and presentation condition were the useful essentials. They let us understand comparisons without relying on recollection.

16 points
GR
GraceBell0668
Replying to AnilBarnes0549

Use those details to ask your vision specialist for controlled comparisons on representative surfaces. Keep the sample set fixed when assessing an acquisition change.

16 points
IS
IsabelBell0648
Replying to GraceBell0668

Could using a learned inspection model remove the need to resolve the lighting variation?

15 points
GR
GraceBell0668
Replying to IsabelBell0648

@IsabelBell0648 It still needs trustworthy labels and representative evaluation. A different model doesn't establish whether your reference scratches are real or your acquisition comparison is fair.

16 points
RE
ReeceCarter0993
Replying to GraceBell0668

I can explain the reference uncertainty better, although the example images still don't support a performance judgement. Physical classification and image-condition comparisons remain outstanding.

8 points
GR
GraceBell0668
Replying to ReeceCarter0993

@ReeceCarter0993 That follows from the reference gap. Explaining it more clearly helps, but the images still can't carry a performance claim.

15 points

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