Comb teeth in silhouette: inspect repeated narrow gaps
A parallel backlight separates a comb from its background and leaves the spaces between its teeth bright. The real capture shows why the narrowest gaps, rather than the overall part width, should drive the camera trial.
Choose sampling for the smallest gap that must remain open.
Real camera capture
- MethodWhite parallel backlight
- EvidenceReal application-lab capture
- SetupSource light identified; imaging kit proposed
- AcceptanceValidate on your own parts
Lighting application-lab catalog capture
What the camera saw
Cropped from the source test sheet; original test annotations are retained. Captures are not generated or enhanced. Drag a comparison slider, or open any image full size.
The challenge
Fine teeth form a repetitive pattern where one missing or partially filled gap can resemble a normal change in pitch.
The tips, roots and curved outer edge need enough sampling across the entire field.
How it was solved
The catalog identifies the white LS-PHFS180150 parallel backlight. Place the comb in front of the illuminated area and inspect the dark teeth and bright gaps.
The proposed camera and macro lens provide a bench starting point. Confirm the smallest tooth and gap in pixels before setting a rule.
The proposed full-sensor field at 0.03x exceeds the light area. Use a centred 1500 × 1200 px software inspection crop (172.5 × 138 mm) within the illuminated region; the 3D viewing volume shows that inspection region. This does not require a camera hardware-ROI mode.
Why it works
- 1
A transmitted-light arrangement reduces the contribution of surface colour and texture to the tooth outline.
- 2
Parallel illumination is useful to evaluate edge stability; neither it nor a sharp-looking image establishes dimensional accuracy by itself.
Lighting application-lab catalog capture
Evidence you can inspect
The repeated teeth, gaps and curved comb body are visible in silhouette.
The catalog identifies comb inspection and the white LS-PHFS180150; it does not report gap tolerances or defect-detection percentages.
One example of image contrast, without part dimensions, calibrated results or a labelled set of acceptable and defective combs.
From image contrast to a production decision
What to validate on your part
- 01
Challenge the narrow gaps
Include flash, incomplete fill and broken teeth close to your acceptance boundary.
- 02
Check every image position
Confirm focus and gap sampling at the two ends as well as the centre.
- 03
Repeat the loading
Vary placement and tilt within the planned fixture limits and record false calls.
From the demo to your test bench
Parts in this setup
LightTested
LS-PHFS180150
180 x 150 mm Parallel back light source (LS-PHFS180150)
White parallel backlight named in the comb example; 180 × 150 mm luminous area, 215 × 165 × 21.5 mm printed housing.
$169.00
In proposed setup
CameraOur pick
MV-CS050-10GM(NPOE)
Hikrobot MV-CS050-10GM(NPOE) 5 MP GigE area scan camera, IMX264, Gen 2 basic version, Mono, Without PoE
5 MP monochrome global-shutter camera for a bench contrast trial; confirm sampling, sensitivity and exposure on the actual part.
$819.00
In proposed setup
LensOur pick
LS-KF1628M-ML
16mm, F2.8, 1.1", C-mount, Macro lens (52 mm (-0.25X) to 546 mm (-0.03X)) (LS-KF1628M-ML)
Proposed 16 mm C-mount macro lens. The illustration uses its printed 0.03x magnification at 546 mm working distance. The proposed camera sensor gives a derived 281.52 × 235.52 mm field. Confirm field, focus and residual distortion on the actual sample; this is not calibrated measurement accuracy. Inspect only a centred 1500 × 1200 px software crop (172.5 × 138 mm) inside the backlight area; the whole sensor field is not illuminated.
$319.00
In proposed setup
Camera test stationOur pick
LS-BT-XZ-G-8-6045
Camera stand with XZ adjustment and glass tray, height 800 mm (LS-BT-XZ-G-8-6045)
800 mm column, 600 × 450 mm breadboard, XZ adjustment, glass tray and two lighting holders as listed. Proposed bench fixture; confirm loads, travel and camera/lens clamps.
$359.00
In proposed setup
"Tested" identifies the part named in the source. "Our pick" is a proposed alternative or supporting part. Confirm colour, optics, controllers, power supplies, cables and mounting before ordering.
The set-up
| Lighting | White parallel backlight |
|---|---|
| Test light | LS-PHFS180150, white |
| Luminous area (printed) | 180 × 150 mm |
| Camera and lens | Source versions not identified; current proposed parts below |
| 3D spacing | Illustrative, to be confirmed on the sample |
| Derived proposed field | 281.52 × 235.52 mm = sensor dimensions / 0.03x; source field not supplied |
| Illuminated inspection ROI (proposed) | 1500 × 1200 px software crop = 172.5 × 138 mm at 0.03x; full sensor field extends beyond this light, so exclude the unilluminated margins |
| Mounting (proposed) | LS-BT-XZ-G-8-6045; 800 mm column, 600 × 450 mm base, glass tray and two light holders |
Mount the optics with intent
The station is an optical test bench, with its two lighting holders included in the catalog listing. The 3D column and base follow the published height and footprint. Carriages, clamps and part supports are schematic: confirm camera screw pattern, lens support, light fasteners, permissible load and actual travel before ordering.
Complete the electrical system
Select a controller against the exact light voltage, drive mode and power, then confirm camera data/power/I/O cables and a suitable PC. These are not silently added to the proposed optical kit.
Build this system
Start from this setup, adapt it to your part.
The configurator opens with this study's camera, lens, light and station picked. Swap any part, check fit and price, then buy or ask for a quote.
Camera and available lens CAD are published models. Lens and light envelopes use printed dimensions. The linked station uses its published base size and column height; carriage, brackets, fittings, parts and spacing are illustrative. Confirm load, travel, fasteners and clearances before ordering. Light paths explain the arrangement and do not simulate optical performance. Representative part geometry is illustrative, not reconstructed inspection evidence.
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Make the next trial specific.
Tell us the part size, smallest defect or tolerance, available working distance, material and line speed. Include what a good part and a reject look like.
About this case study: the photos and camera images come from the application laboratory of the maker of the lighting and optics we sell, imaged on the parts shown; your results depend on your part, camera and set-up. This is an application-lab study, not a LumaSpec customer deployment. Source figures are reported results; proposed components require a fresh trial. The 3D scene illustrates the arrangement and does not simulate imaging performance.