The scratch labels look less certain than the images suggest

SaraAllen0287 · 18 Jul 2026, 00:34 UTC

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SA
SaraAllen0287
Our planned inspecting reflective surfaces for scratches in a robot-presented camera station has Fairino FR5 presenting a polished metal cover to a fixed camera. The example images contain bright streaks that shift with small presentation differences, yet those streaks are being labeled as scratches. Before commissioning, I'd like to establish reliable references and image conditions for threshold tuning.

21 replies

NA
NaomiAllen0332
Replying to SaraAllen0287

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.

9 points
SA
SaraAllen0287
Replying to NaomiAllen0332

@NaomiAllen0332 I've found that some labels were assigned from the images themselves. The samples are still available, but those labels have no corresponding physical inspection results, making the reference circular.

2 points
NA
NaomiAllen0332
Replying to SaraAllen0287

@SaraAllen0287 Keep the image-only labels uncertain pending physical inspection. A controlled comparison of lighting and presentation can then investigate whether the moving streaks indicate reflection effects.

19 points
CA
CallumChen1143
Replying to NaomiAllen0332

That clue needs a limit: presentation can also change how a real scratch appears. Movement in the image isn't enough to reclassify the sample as acceptable.

-3 points
NA
NaomiAllen0332
Replying to CallumChen1143

Correct. I meant a reason to investigate the imaging, not a new defect label. Physical acceptance stays with the agreed inspection method.

10 points
NO
NoraAllen0322
Replying to NaomiAllen0332

So uncertain isn't the same as good? Where do those images go?

13 points
NA
NaomiAllen0332
Replying to NoraAllen0322

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

13 points
SA
SaraAllen0287
Replying to NaomiAllen0332

I've checked the image folders and found that exposure and presentation both changed between them. Their improved appearance can't be attributed to either change individually.

10 points
TO
TobyAbbott0057
Replying to SaraAllen0287

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

18 points
SA
SaraAllen0287
Replying to TobyAbbott0057

@TobyAbbott0057 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
TO
TobyAbbott0057
Replying to SaraAllen0287

On my setup we kept sample ID, exposure, lighting arrangement and presentation condition. Enough to explain a comparison without reconstructing the whole session from memory.

10 points
NA
NaomiAllen0332
Replying to TobyAbbott0057

@TobyAbbott0057 Use those details to ask your vision specialist for controlled comparisons on representative surfaces. Keep the sample set fixed when assessing an acquisition change.

15 points
NO
NoraAllen0322
Replying to NaomiAllen0332

@NaomiAllen0332 Could using a learned inspection model remove the need to resolve the lighting variation?

13 points
NA
NaomiAllen0332
Replying to NoraAllen0322

Any learned model still depends on reliable labels and representative evaluation. Changing the method doesn't resolve unconfirmed physical defects or an uncontrolled comparison of image conditions.

10 points
CA
CallumChen1143
Replying to NaomiAllen0332

Keep physical sample identity in mind when forming evaluation sets. Different images of a sample used for tuning don't provide an independent sample-level evaluation.

18 points
SA
SaraAllen0287
Replying to CallumChen1143

@CallumChen1143 I'll group images by physical sample before dividing the tuning and evaluation sets. The current filenames wouldn't reliably expose the same sample appearing in both.

3 points
NA
NaomiAllen0332
Replying to SaraAllen0287

Use the held-out samples to report defect misses and false rejections independently. A combined agreement figure can conceal the type of error that matters to the process.

23 points
SA
SaraAllen0287
Replying to NaomiAllen0332

@NaomiAllen0332 How should the evaluation report handle samples whose physical status is undecided? I want them visible without assigning an unsupported error label.

1 points
NA
NaomiAllen0332
Replying to SaraAllen0287

Show them as undecided with their count, outside confirmed-class error rates. That keeps the coverage limit visible without inventing a ground-truth label.

11 points
SA
SaraAllen0287
Replying to NaomiAllen0332

The reference problem is clearer, but I still can't judge inspection performance from our example images. The physical labels and image comparisons need more work.

12 points

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