Sample testing and feasibility laboratory
Good and defective samples sent in by the customer are imaged on the laboratory bench under dome, low-angle bar, back and ring lighting in turn. In every set-up the contrast between the defect and its surroundings is measured; the set-up that separates the defect is selected and feasibility is reported.
The image and contrast value of every set-up go into the feasibility report; the selected set-up enters the proposal design together with camera distance and light angle.
- 01 Sample
- 02 Dome
- 03 Bar
- 04 Backlight
- 05 Ring
The defective sample is placed under the camera; defect and reference regions are defined.
- Contrast
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- Defect width
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Scenes are illustrative simulations; they are not customer references or performance guarantees.
Need
The same defect is visible under one light and vanishes under another: a shallow scratch disappears under a dome, while direct light on a shiny surface blocks the image with glare. Which set-up will work cannot be known without trying.
Solution approach
The sample stays under a fixed camera; the lights are switched on one at a time and images of the same region are taken. In every image the grey-level difference between the defect region and a reference region is computed as contrast. Set-ups above the threshold become candidates; where needed, depth is confirmed with a 3D profile and the result is reported.
Process steps
- 01
Sample
The defective sample is placed under the camera; defect and reference regions are defined.
- 02
Dome
The dome light slides over the sample; an image is taken under diffuse light.
- 03
Bar
The low-angle bar light is switched on; the scratch shines in dark field.
- 04
Backlight
The backlight is switched on; only the silhouette is seen.
- 05
Ring
The ring light is switched on; contrast is measured and the set-up above the threshold is reported.
Let us assess your application together
We test your sample in our laboratory and report on resolution, optics and lighting selection.