Getting consistent inspection evidence before commissioning (checking cosmetic metal surfaces with a fixed camera)

LeoBaker0449 · 7 Jun 2026, 09:48 UTC

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LE
LeoBaker0449
Our planned checking cosmetic metal surfaces with a fixed camera in a small finished-parts production cell has Fairino FR5 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.

20 replies

LI
LiamBaker0490
Replying to LeoBaker0449

Check whether the suspected scratches were confirmed on physical samples under the agreed appearance procedure. Link each image to its sample identity and inspection result first.

10 points
LE
LeoBaker0449
Replying to LiamBaker0490

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.

21 points
LI
LiamBaker0490
Replying to LeoBaker0449

@LeoBaker0449 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.

16 points
JA
JamieBaker0469
Replying to LiamBaker0490

@LiamBaker0490 A scratch's visibility can change with presentation too. Don't let 'moving streak' quietly become the rule for relabelling something acceptable.

-10 points
LI
LiamBaker0490
Replying to JamieBaker0469

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

17 points
OL
OliverBrooks0798
Replying to LiamBaker0490

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

8 points
LI
LiamBaker0490
Replying to OliverBrooks0798

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

25 points
LE
LeoBaker0449
Replying to LiamBaker0490

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.

13 points
IM
ImranAdams0131
Replying to LeoBaker0449

I had a separate inspection setup where the 'better lighting' folder used easier samples too. Its name implied a lighting conclusion that the comparison didn't support.

0 points
LE
LeoBaker0449
Replying to ImranAdams0131

@ImranAdams0131 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.

21 points
IM
ImranAdams0131
Replying to LeoBaker0449

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.

7 points
LI
LiamBaker0490
Replying to ImranAdams0131

Those records can support the vision specialist's comparison of image conditions. Holding the representative sample set constant will make an acquisition change easier to assess.

25 points
OL
OliverBrooks0798
Replying to LiamBaker0490

Would a learned model just cope with the lighting differences?

18 points
LI
LiamBaker0490
Replying to OliverBrooks0798

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.

16 points
JA
JamieBaker0469
Replying to LiamBaker0490

@LiamBaker0490 And don't tune and test on different pictures of the same physical sample. That isn't the independence the result would suggest.

-1 points
LE
LeoBaker0449
Replying to JamieBaker0469

@JamieBaker0469 I'll keep all images of one sample together when we split tuning and evaluation sets. Our file names alone wouldn't have caught that overlap.

21 points
LI
LiamBaker0490
Replying to LeoBaker0449

@LeoBaker0449 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.

12 points
LE
LeoBaker0449
Replying to LiamBaker0490

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

11 points
LI
LiamBaker0490
Replying to LeoBaker0449

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

12 points
IM
ImranAdams0131
Replying to LiamBaker0490

@LiamBaker0490 In my separate setup, reporting the undecided count made the remaining uncertainty visible. A tidier results table no longer implied an improvement in inspection capability.

3 points

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