SWIR Camera Lens for Multilayer Material Inspection: Separating Surface, Coating, Adhesive and Substrate Responses

Multilayer products are among the most difficult materials to inspect with conventional machine vision because the camera does not observe a single optical surface. It may receive information from the outer surface, a transparent or semi-transparent coating, an adhesive or tie layer, and an underlying substrate at the same time. A visible image can therefore look perfectly acceptable even when coating distribution is inconsistent, an internal adhesive layer is missing, a laminate contains local thickness variation, or the substrate beneath a top layer differs from the intended material. SWIR Camera Lens technology for multilayer material inspection becomes valuable when these layers have different wavelength-dependent absorption, reflection or transmission responses within the short-wave infrared region.

The key engineering objective is not merely to “see through” a multilayer product. A useful industrial system must determine which layer is contributing to the recorded SWIR signal and how that contribution changes with wavelength. At one wavelength, the surface coating may dominate the image. At another, the top layer may transmit enough radiation for an adhesive or substrate response to become measurable. A third wavelength may provide a useful reference with limited sensitivity to the defect. Separating these responses is what turns multilayer SWIR imaging from an attractive picture into a repeatable process-control tool.

Research on laminated materials demonstrates the feasibility of this approach. Near-infrared chemical imaging has been used to measure the thickness and spatial homogeneity of adhesive layers located inside multilayer laminates, including hidden adhesive layers that were not directly visible from the surface. Spectral measurements were correlated with coating weight, and imaging was used to identify distribution irregularities across the material. This principle is directly relevant to industrial films, laminated sheets, coated substrates, bonded textiles, polymer structures and other multilayer products where different layers contribute differently to the SWIR signal.

The current Kyptec Automation® SWIR Camera Lens collection contains five focal-length options—8.5 mm, 12.5 mm, 25 mm, 35 mm and 50 mm—giving machine builders flexibility to configure wide-area laminate inspection, intermediate field-of-view systems, localized coating or adhesive analysis and longer-working-distance stations. The live category currently shows exactly five SWIR Camera Lens products across these focal lengths.

Why Multilayer Materials Are Harder to Inspect Than Single-Layer Products

A single opaque surface is comparatively straightforward because most of the light returning to the camera comes from the exposed material. A multilayer system is different. Radiation can be reflected by the top surface, absorbed partly by a coating, transmitted through that coating, scattered inside an adhesive, reflected from the substrate and then attenuated again while travelling back through the upper layers. The resulting pixel value can therefore contain information from several physical layers at once.

This means that an intensity difference cannot automatically be assigned to one cause. A darker region might represent a thicker coating, increased adhesive absorption, a more strongly absorbing substrate, additional moisture, altered surface roughness or simply lower illumination. Successful SWIR multilayer inspection therefore requires a measurement strategy that deliberately separates or suppresses unwanted layer contributions.

Surface Response Should Be Characterized Before Looking Below It

The outer surface is usually the first layer encountered by the illumination and can strongly influence the measurement. Surface gloss, texture, contamination, embossing and coating finish may alter how much SWIR radiation is reflected into the lens. If these effects are not characterized, they can mask weaker signals from underlying layers.

A strong feasibility study begins by imaging the substrate and each layer independently wherever practical. The finished multilayer structure is then compared with these reference samples. This provides a better understanding of which spectral features are introduced by the coating, adhesive or substrate and which are simply caused by surface geometry.

Coatings Can Either Reveal or Hide the Underlying Material

A coating may absorb strongly at one SWIR wavelength while remaining relatively transmissive at another. This wavelength dependence creates one of the most important tools for multilayer inspection. If the coating dominates at wavelength A but becomes less influential at wavelength B, the system can compare the two images to distinguish coating variation from underlying substrate variation.

This is particularly useful for transparent or visually similar coatings where visible inspection provides little contrast. SWIR does not need the coating to have a different colour; it needs the coating's molecular or physical properties to create a measurable infrared response. The practical system should therefore search for wavelengths that maximize the difference between the layer of interest and competing layers.

Adhesive Layers Can Be Measured Even When They Are Hidden

Adhesive inspection is often difficult because the bonding layer sits inside the final laminate. Once the layers are combined, visual access disappears. However, near-infrared chemical imaging research has demonstrated quantitative measurement of hidden adhesive coating weight and spatial distribution inside laminated structures, including detection of lamination defects and non-uniform adhesive application.

For industrial SWIR inspection, this means that a hidden adhesive layer may still be measurable if the surrounding materials transmit sufficient radiation and the adhesive has a distinguishable spectral response. The system must be calibrated for the exact adhesive formulation, application weight, top-layer thickness and substrate because a spectral relationship validated for one laminate should not automatically be transferred to another.

The Substrate Can Contribute Strongly to the Final Pixel Value

Even when the objective is coating or adhesive inspection, the substrate can influence the measured signal. A dark, highly absorbing substrate may reduce the returned signal across many wavelengths, while a reflective substrate may increase it. Two products with identical coatings but different substrate batches could therefore produce different SWIR intensity.

This is why a multilayer inspection system should avoid relying on one absolute grayscale threshold whenever substrate variability is significant. Reference wavelengths, ratios or multivariate classification can help separate layer-specific behaviour from common substrate shifts.

SWIR Layer Separation Is a Spectral-Decoupling Problem

The central idea in multilayer inspection is spectral decoupling. Rather than asking whether the whole product looks different, the engineer identifies wavelengths where the individual layers behave differently enough to separate their contributions. A coating-sensitive wavelength can emphasize the top layer, an adhesive-sensitive wavelength can highlight the bond layer, and a substrate-sensitive or reference wavelength can help normalize the measurement.

This approach is especially valuable when several layers overlap spatially. The camera sees all of them at the same x-y position, so spatial separation alone cannot isolate the defect. Spectral separation provides an additional dimension that can distinguish materials occupying the same image location.

Single-Wavelength Imaging Can Work When One Layer Dominates Strongly

A complex multispectral system is not always necessary. If one adhesive or coating has a strong absorption feature and the surrounding materials remain relatively neutral at that wavelength, a single selected SWIR band may provide sufficient pass/fail contrast.

This can simplify the production system considerably because illumination, exposure and processing remain straightforward. However, single-wavelength inspection becomes less robust when substrate batches, surface finish or layer thickness vary widely. The decision should therefore follow real sample testing rather than an assumption that more wavelengths are always better.

Two-Wavelength Ratios Can Improve Layer Selectivity

A useful multilayer architecture compares a wavelength that is sensitive to the target layer with another wavelength that behaves more like a reference. Dividing or normalizing the two measurements can reduce common changes caused by illumination, distance or broad substrate reflectance.

For example, if both wavelengths respond similarly to the substrate but only one responds strongly to the adhesive, a ratio can increase adhesive-specific contrast. This does not eliminate every confounding variable, but it can make the measurement more stable than a raw intensity threshold.

Multispectral Imaging Is Valuable When Several Layers Must Be Distinguished

When coating, adhesive and substrate responses overlap strongly, multiple spectral bands may be required. Each wavelength adds another measurement of the same physical location, allowing classification models to separate materials based on their combined spectral pattern instead of relying on one intensity value.

The production system should still use only as many bands as necessary. Collecting additional wavelengths increases acquisition and processing complexity. A strong development workflow may start with spectrally rich measurements, identify the most discriminative wavelengths and then reduce the production system to a smaller set of bands.

Top-Layer Thickness Controls How Much Information Reaches the Camera

Even a relatively transmissive outer layer can eventually suppress information from below if it becomes sufficiently thick. Radiation must pass through the upper material before reaching the adhesive or substrate and then, in reflection geometry, pass back through it again.

This means multilayer SWIR feasibility depends not only on material chemistry but also on physical thickness. Samples representing the minimum, nominal and maximum expected top-layer thickness should all be tested. A system that works on a thin laboratory laminate may lose contrast on the thickest production version.

Adhesive Thickness and Adhesive Coverage Should Be Treated Separately

A missing adhesive region and a slightly thin adhesive region are different detection problems. Complete absence may create a large spectral difference, while a small coating-weight deviation may produce only a subtle shift.

Near-infrared imaging research has shown that adhesive coating weight can be correlated quantitatively with spectral response in laminated structures, and spatial imaging can map adhesive homogeneity across the sample. This demonstrates why production specifications should define whether the system needs simple presence/absence inspection or quantitative adhesive-weight monitoring.

Local Voids and Unbonded Regions Can Create Multilayer Response Changes

A void changes more than the presence of adhesive. It can introduce an air gap, alter reflection at the interface and change the effective optical path. This may produce SWIR contrast even when the materials themselves remain unchanged.

However, the contrast mechanism depends heavily on layer composition and geometry. A void that is highly visible in one laminate may be almost invisible in another. Production testing should therefore include deliberately created voids, partial bonds and known good interfaces so the system can establish which defect classes are truly separable.

Surface Contamination Can Mimic an Internal-Layer Defect

Oil, moisture, dust or process residue on the outer surface can absorb or scatter SWIR radiation and produce a signal change that resembles a coating or adhesive variation. Because the system is measuring radiation after it interacts with the complete optical stack, it cannot automatically know whether the difference originated at the surface or deeper inside.

A robust classifier should therefore include likely surface contaminants during validation. If surface residue and internal adhesive loss produce different spectral patterns, several wavelengths can help distinguish them. If they remain too similar, an additional inspection condition or process-control step may be required.

Reflection Geometry Is Often the Most Practical Industrial Arrangement

In reflection-mode SWIR imaging, illumination and camera are positioned on the same side of the material. This is attractive for continuous webs, laminated panels and conveyor-based products because no optical access is required behind the product.

The limitation is that deeper layers must influence the radiation that returns through the upper material. If the surface or top coating absorbs too strongly, internal information may be weak. Reflection geometry should therefore be tested at the exact production wavelength and layer thickness.

Transmission Geometry Can Increase Sensitivity to Internal Layers

When optical access exists on both sides of the product, transmission imaging can provide stronger information about the total multilayer stack because the radiation passes through the material before reaching the camera. Variations in coating, adhesive, film thickness or internal layer composition can change transmitted intensity.

Transmission is particularly useful for thin films and relatively transparent laminates. Thick, opaque or strongly absorbing substrates may prevent enough radiation from reaching the camera, making reflection a more practical choice.

Mixed Pixels Can Hide Narrow Adhesive and Coating Defects

If a narrow missing-adhesive line occupies only part of one camera pixel, that pixel records a mixture of defective and acceptable material. The spectral difference becomes diluted and may fall below the classification threshold.

This is why minimum defect size and field of view are as important as wavelength selection. A chemically strong absorption feature cannot compensate for inadequate spatial sampling. The lens must place enough pixels across the smallest defect that matters commercially.

Wide-Area Multilayer Inspection With Kyptec Automation® KL-1408

The Kyptec Automation® KL-1408 8.5 mm SWIR Camera Lens can be evaluated where a relatively broad laminate, coated sheet or conveyor region must remain inside one image. The live Kyptec Automation® SWIR collection confirms 8.5 mm as one of the five available focal lengths.

This type of geometry can be useful for monitoring broad coating uniformity or identifying large missing-layer areas, provided the smallest defect still occupies sufficient pixels. Wider coverage should never be selected purely to reduce camera count if doing so makes the required defect too small to measure reliably.

Balanced Coverage With Kyptec Automation® KL-1410

The Kyptec Automation® KL-1410 12.5 mm SWIR Camera Lens can be considered where a system needs a balance between physical coverage and local sampling. For multilayer inspection, this type of intermediate field can be useful when both broad coating patterns and localized adhesive irregularities must remain visible.

The correct lens still depends on actual sensor size, working distance and required object-space sampling. Focal length should therefore be selected after the minimum adhesive or coating feature is defined.

Localized Layer Analysis With Kyptec Automation® KL-1412

The Kyptec Automation® KL-1412 25 mm SWIR Camera Lens can be evaluated when the inspection is concentrated on a smaller bond line, coating edge, overlap region or multilayer interface. A tighter field assigns more sensor pixels to the area of interest and can improve measurement of small layer variations.

This does not increase spectral separation by itself. The wavelength still determines whether the adhesive or coating can be distinguished; the lens determines how well that contrast is represented spatially.

Longer Focal Lengths Can Support Remote Multilayer Inspection

Some lamination, coating and converting machines make it difficult to place a camera close to the product because of rollers, heated zones, moving tooling or protective structures. The Kyptec Automation® KL-1414 35 mm SWIR Camera Lens and Kyptec Automation® KL-1416 50 mm SWIR Camera Lens provide narrower focal-length options within the same dedicated SWIR portfolio. The live category confirms both focal lengths among the current five products.

These models can be evaluated when a restricted inspection region must be observed from greater stand-off. Working distance should still be calculated together with illumination intensity and required resolution because longer distance can reduce available signal.

900–1700 nm Coverage Provides Useful Spectral Flexibility

Multilayer materials rarely have one universal inspection wavelength. A polymer coating may provide useful contrast at one spectral region, an adhesive may respond more strongly at another, and the substrate may become more or less visible depending on wavelength.

A SWIR Camera Lens intended for approximately 900–1700 nm imaging therefore provides useful flexibility during wavelength development. Kyptec Automation®'s dedicated SWIR Camera Lens portfolio allows engineers to select the field of view while maintaining access to this broader short-wave infrared region through the appropriate SWIR imaging system.

Aperture Selection Affects Both Signal and Layer Measurement Stability

Layer-sensitive wavelengths can produce weak returned signals, especially when radiation must travel through several materials. A larger aperture increases the amount of light reaching the sensor and can help maintain short exposure times on fast production lines.

However, multilayer products can vary slightly in height or thickness. The aperture setting must therefore maintain enough depth of field to keep the relevant surface and inspection plane adequately focused. The production setting should balance optical signal against focus tolerance rather than treating maximum light collection as the only priority.

Calibration Samples Should Be Designed Layer by Layer

A powerful multilayer calibration set should include more than just “good” and “bad” finished products. It should contain isolated variations such as normal coating with reduced adhesive, normal adhesive with reduced coating, alternative substrate batches, known voids, surface contamination and several layer thicknesses.

This structured approach reveals whether the system is genuinely identifying the target layer or merely responding to another correlated variable. It also produces stronger training data for machine-learning or chemometric classification because each source of variation is represented independently.

Production Drift Should Be Monitored With Stable References

Lamination processes change over time. Adhesive temperature, coating viscosity, web tension, substrate supplier, surface treatment and environmental conditions may all influence the optical response.

A stable reference material or reference region can help determine whether a gradual intensity change originates from the process or from illumination and optical drift. Revalidation should also be performed when any layer chemistry, thickness or supplier changes significantly.

Why Kyptec Automation® Is a Strong Optical Platform for Multilayer Inspection

The current Kyptec Automation® SWIR Camera Lens collection contains five focal lengths—8.5 mm, 12.5 mm, 25 mm, 35 mm and 50 mm—covering the principal geometric choices required for broad laminate inspection, intermediate fields, localized adhesive analysis and greater stand-off. The live collection currently confirms exactly five products across those focal lengths.

This flexibility is especially useful for multilayer systems because spectral and geometric requirements must be solved separately. The useful wavelength is determined by how the coating, adhesive and substrate interact with SWIR radiation, while focal length is determined by field of view, working distance and minimum defect size. Kyptec Automation® therefore provides a focused SWIR Camera Lens platform that allows OEMs and system integrators to build the optics around the actual multilayer inspection problem rather than forcing one lens geometry across every application.

Frequently Asked Questions About SWIR Camera Lenses for Multilayer Material Inspection

1. Can SWIR imaging distinguish a coating from the substrate underneath it?

Yes, when the coating and substrate have sufficiently different wavelength-dependent responses. The strongest approach is to identify wavelengths where the coating absorbs or reflects differently while the substrate remains relatively stable. Comparing those measurements can reduce substrate influence and emphasize coating behaviour. The result depends on coating thickness, substrate chemistry and the amount of SWIR radiation able to pass through the upper layer.

2. Can SWIR inspect adhesive that is hidden inside a laminate?

Yes, in suitable material combinations. Near-infrared chemical imaging has demonstrated measurement of hidden adhesive coating weight and spatial distribution inside laminated structures, including detection of internal non-uniformity. The surrounding layers must transmit enough radiation, and the adhesive must provide measurable spectral contrast for the production system to work reliably.

3. Can SWIR measure adhesive thickness inside multilayer materials?

It can potentially estimate coating weight or thickness when the spectral response changes consistently with adhesive quantity. Published research has correlated NIR reflection spectra with adhesive-layer thickness and used calibration models for quantitative in-line monitoring. A production system requires its own calibration using independently measured adhesive levels for the exact laminate structure.

4. Can SWIR detect missing adhesive without opening the laminate?

Potentially, yes. A missing adhesive region can produce a different spectral response from a correctly bonded region if the adhesive contributes significantly to the measured wavelengths. Detection becomes easier when the defect occupies enough pixels and the top material does not completely suppress the signal. Known missing-adhesive samples should be included during system validation.

5. How can a SWIR system tell whether a defect is in the coating or the adhesive?

One image may not be sufficient because both layers can change intensity. A stronger system uses wavelengths selected so that coating and adhesive responses differ from one another. A coating-sensitive band, adhesive-sensitive band and stable reference band can provide enough information for classification. Calibration samples in which each layer is varied independently are essential for proving that the classifier identifies the correct layer.

6. Can SWIR separate surface contamination from an internal adhesive defect?

Sometimes, but this depends on their spectral differences. Surface oil, moisture or residue may create strong absorption and can mimic deeper-layer changes in a single-band image. Multispectral comparison can help if the contaminant and adhesive have different spectral signatures. If their responses overlap too strongly, another inspection condition may be required to avoid false classification.

7. Is SWIR useful for transparent or translucent coatings?

Yes. A coating does not need to be visibly opaque to be detectable in SWIR. Transparent materials can still contain molecular bonds that absorb selected short-wave infrared wavelengths. This makes SWIR particularly valuable for functional coatings that are difficult to distinguish from the substrate under visible illumination.

8. Can SWIR inspect multilayer polymer films?

It can be highly useful when individual polymer layers have sufficiently different SWIR absorption or transmission. The method is especially promising for multilayer films where one layer is visually transparent but spectrally distinct. Film thickness and layer order must be included during feasibility testing because both influence how much information reaches the camera.

9. Is reflection or transmission better for hidden-layer inspection?

Neither is universally better. Reflection is easier to integrate because the camera and illumination can remain on one side, but information from deeper layers must return through the upper materials. Transmission can provide stronger sensitivity to the total stack when radiation can pass through the product and optical access exists on both sides. The better geometry is the one that gives the strongest repeatable separation for the specific target layer.

10. How does top-layer thickness affect SWIR inspection of an adhesive underneath?

Increasing top-layer thickness can reduce the radiation reaching the adhesive and attenuate the returning signal. A system that clearly detects adhesive beneath a thin film may become less sensitive when the same film becomes thicker. The complete production thickness tolerance should therefore be represented during validation, not just the nominal sample.

11. Can SWIR detect coating non-uniformity across a wide web?

Yes, if the coating has adequate spectral contrast and the lens provides sufficient cross-web spatial sampling. Large-area NIR chemical imaging has been demonstrated for monitoring coating or adhesive distribution across laminated materials. The system must also correct for illumination variation so edge-to-edge brightness changes are not mistaken for coating non-uniformity.

12. Can multilayer SWIR inspection work at production-line speed?

It can, but exposure time, available illumination, wavelength, product speed and required defect resolution must be engineered together. Narrow spectral bands and multiple absorbing layers can reduce signal, while fast motion limits exposure. The production test should therefore be carried out at real line speed because static laboratory images can overestimate achievable image quality.

13. When should Kyptec Automation® KL-1408 be considered for multilayer inspection?

The Kyptec Automation® KL-1408 8.5 mm SWIR Camera Lens can be considered when a relatively broad laminate, coated sheet or conveyor area must fit within one image. Its wider geometry can be useful for large-area coating or layer-uniformity mapping, provided the smallest defect remains sufficiently sampled. It is one of five focal-length options currently listed in the Kyptec Automation® SWIR category.

14. When is Kyptec Automation® KL-1412 useful for adhesive inspection?

The Kyptec Automation® KL-1412 25 mm SWIR Camera Lens can be evaluated when inspection is concentrated on a smaller bond line, overlap or localized adhesive region. The narrower physical field can place more available pixels across a small defect, which is important when adhesive variation is spatially narrow. Wavelength selection must still create the material contrast before the tighter optical field can improve detection.

15. When should a 35 mm or 50 mm SWIR Camera Lens be evaluated?

The Kyptec Automation® KL-1414 35 mm SWIR Camera Lens and Kyptec Automation® KL-1416 50 mm SWIR Camera Lens can be considered when mechanical restrictions require a narrower field or additional stand-off from the laminate or coating process. Both focal lengths are currently part of Kyptec Automation®'s five-product SWIR range. The working distance should be verified together with available SWIR illumination and required feature size.

16. Can the same calibration be used after changing the adhesive supplier?

It should not be assumed. Two adhesives designed for the same mechanical purpose can have different SWIR absorption because their formulations differ. Even a formulation change from the same supplier can alter the spectral response enough to affect a calibrated model. Any significant adhesive, coating or substrate change should therefore trigger verification with known-good and known-defect samples.

17. Can SWIR tell exactly which physical layer a defect is in?

Only when the spectral and calibration strategy has been designed to make that distinction. A raw SWIR image does not automatically contain a layer label. The system must be trained using samples where surface, coating, adhesive and substrate variations are independently controlled. If each defect type produces a sufficiently distinct spectral response, classification can associate the signal with the most likely layer.

18. What information should an OEM prepare before selecting a SWIR Camera Lens for multilayer inspection?

The OEM should define the complete layer stack, material composition, thickness range, target defect, minimum defect size, likely useful wavelengths, required field of view, working distance, line speed and whether reflection or transmission is practical. Once the spectral feasibility is confirmed, the five focal lengths in the Kyptec Automation® SWIR Camera Lens collection can be compared according to geometric requirements. Lens selection should follow the multilayer measurement problem rather than precede it.

19. What is the biggest mistake when designing a multilayer SWIR inspection system?

The most serious mistake is assuming that a dark or bright region belongs automatically to the layer of interest. Every pixel may contain contributions from surface reflection, coating absorption, adhesive, substrate and illumination geometry. The correct system deliberately separates these contributions through wavelength choice, controlled samples and reference measurements. Without that process, apparent coating or adhesive defects can actually be caused by unrelated substrate or surface variation.

20. Why is Kyptec Automation® a strong choice for multilayer SWIR machine vision?

Kyptec Automation® provides a dedicated SWIR Camera Lens collection with 8.5 mm, 12.5 mm, 25 mm, 35 mm and 50 mm focal lengths, giving OEMs flexibility to configure broad laminate inspection, intermediate fields, localized adhesive analysis and longer-working-distance systems. The live category currently confirms exactly these five products. This focused range is valuable because multilayer inspection requires the spectral problem and geometric problem to be solved independently. Once the correct wavelength has separated coating, adhesive or substrate behaviour, Kyptec Automation® gives system designers practical focal-length options for translating that contrast into a production-ready field of view.

Conclusion

SWIR Camera Lens technology provides a particularly strong approach for multilayer material inspection because it allows machine-vision systems to work with wavelength-dependent material behaviour instead of relying only on surface appearance. A multilayer product can contain several optically active regions at the same image position: the exposed surface, a functional coating, a bonding layer and the underlying substrate. The challenge is therefore not simply detecting a difference but establishing which layer created that difference.

SWIR provides a route to that separation when the individual layers absorb, reflect or transmit selected wavelengths differently. A coating-sensitive wavelength can emphasize the outer layer, another wavelength may penetrate farther and reveal adhesive behaviour, while a reference band can help reduce substrate or illumination effects. Research on laminated materials demonstrates that near-infrared chemical imaging can measure the spatial distribution and coating weight of hidden adhesive layers inside multilayer structures and can identify lamination irregularities under suitable conditions. This makes layer-specific SWIR inspection a practical engineering direction rather than merely a theoretical possibility.

The strongest production systems are built from controlled comparisons. Surface-only, coating-only, adhesive-varied and substrate-varied samples should be measured independently wherever possible. Thickness tolerance, contamination, voids and supplier variation should then be added so the classifier learns which spectral changes belong to the intended defect and which represent normal process variation. For quantitative adhesive or coating measurements, the optical response should be correlated with independent ground-truth values rather than interpreted directly as thickness from raw image intensity.

The lens must then translate this spectral distinction into adequate spatial information. Broad multilayer sheets may require wide coverage, while localized glue lines and overlap regions require finer object-space sampling. Restricted machinery may demand additional working distance. The current Kyptec Automation® SWIR Camera Lens collection provides 8.5 mm, 12.5 mm, 25 mm, 35 mm and 50 mm focal lengths, allowing the system geometry to be matched to these different production requirements.

For machine builders and industrial buyers, the most effective design sequence is to identify the layer of interest, prove that its SWIR response can be separated from the other layers, select the smallest useful set of wavelengths, define the required FOV and minimum defect size, and only then choose the appropriate SWIR Camera Lens. When developed in this order, Kyptec Automation® SWIR Camera Lenses provide a strong optical foundation for advanced inspection of coatings, adhesive layers, laminates, bonded structures and other multilayer industrial materials where conventional visible imaging cannot reliably separate the individual material responses.