SWIR Camera Systems for Plastic Sorting
Max Reijngoudt
SWIR cameras offer a significant advantage in PET plastic sorting, surpassing traditional methods in accuracy and efficiency. SWIR technology leverages the near-infrared spectrum to penetrate materials and identify their chemical composition, enabling precise separation of PET plastic from contaminants.
- Disclaimer: This article uses PET plastic case as an example, but the guidelines apply to all SWIR-based plastic identification and sorting systems.
Efficient PET plastic sorting is an essential step in recycling workflows, and traditional approaches, such as manual inspection and near-infrared (NIR) imaging, have well-documented limitations.
Manual sorting is slow and prone to human error, and NIR cameras may struggle to distinguish between plastics with similar optical characteristics. These constraints have encouraged the exploration of alternative technologies that can improve accuracy and consistency in material identification.
- Short-wave infrared (SWIR) cameras offer one such option. SWIR imaging operates at different wavelengths than NIR, allowing it to detect material properties that are not visible in standard inspection systems. In the context of PET sorting, SWIR technology can contribute to:
Enhanced Material Detection
SWIR wavelengths capture chemical and structural information, allowing PET to be distinguished from visually similar plastics.
Consistent Performance
Sorting remains reliable even with variations in color, lighting, or surface contamination, supporting faster processing.
Lower Contamination
Precise identification reduces non-PET impurities, producing cleaner recycled PET.
Versatile Use
SWIR can detect different plastic types, making it suitable for a wider range of recycling applications.
How SWIR Cameras Improve Plastic Sorting
SWIR camera systems have a wide range of applications in PET plastic sorting, including:
By implementing SWIR camera systems, recycling facilities can improve their overall efficiency, reduce costs, and produce higher-quality recycled PET plastic.
Machine Vision Camera for Plastic Sorting
Selecting the right imaging system is essential for effective PET plastic sorting using SWIR technology.
This technology works by analyzing the spectral signatures of different plastics, allowing the system to accurately distinguish between materials that may appear similar to the human eye. It captures precise images of moving plastics, ensuring minimal motion blur and distortion, which is critical for high-speed sorting processes.
Additionally, features such as thermoelectric cooling help reduce noise and maintain consistent image quality, even in challenging environments.
- For this application, we recommend the MARS-138-95GM-P-TN-SWIR camera.
Technical Specifications
| Interface | GigE Vision |
| Resolution | 1280x1024 |
| Shutter type | Global Shutter |
| Color/Monochrome | Mono SWIR |
| Frame rate (fps) | 95 |
| Pixel size (um) | 5.0 |
Industrial Lens for Plastic Sorting
Choosing the right SWIR lens is crucial for enhancing the performance of machine vision systems in plastic sorting.
The lens determines how clearly and accurately materials are captured, influencing the system’s ability to reliably distinguish between different types of plastics. Factors such as optical distortion, focal length, and spectral sensitivity all contribute to consistent and precise identification, even in challenging lighting conditions or when materials have similar appearances.
- For this application, we recommend a SWIR lens, specifically the C-Mount 25mm lens 'VA-LCM-1.3MP-25MM-F1.8-020-SWIR'.
Technical Specifications
| Resolution (megapixel) | 1 |
| Mount | C |
| Image format / circle | 1/2" |
| Minimum object distance (MOD) - Max | 100mm - 5000mm |
| Focal length (mm) | 25 |
| Aperture / iris | Manual iris |
| Aperture (min) | F1.8 |
Industrial Lighting for Plastic Sorting
Proper illumination is critical for SWIR machine vision in industrial plastic sorting. SWIR lighting enhances contrast based on the spectral absorption and reflectance of different polymers, enabling reliable differentiation that visible-light systems cannot achieve.
- For this application, we recommend two options: SWIR Ring Light or SWIR Bar Light.
SWIR ring and bar lights provide different illumination geometries: ring lights offer uniform, lens-centered lighting for small or curved plastics, while bar lights give wide, directional coverage for high-speed conveyors. Each has trade-offs in coverage, intensity, and integration.
Below, you can compare detailed information about the SWIR Ring Light and SWIR Bar Light.
SWIR RING LIGHT APPLICATIONS
SWIR Ring Light Applications:
- Identification of curved plastic objects (bottles, rounded containers).
- Close-range inspection tasks with consistent geometry.
- Material differentiation on small or medium-sized conveyor lanes.
- Systems where lens-centric illumination is preferred for accuracy.
SWIR Bar Light Applications:
- Wide conveyor belts with mixed plastic waste streams.
- High-speed sorting where short exposure times are necessary.
- Detection of different plastic types on flat or semi-flat surfaces.
- Large-scale sorting systems require broad illumination coverage.
Industrial Lighting Guide
SWIR Ring Light
SWIR Bar Light
Image Processing for Plastic Sorting
Image processing is a key component of any SWIR-based plastic sorting system, enabling the extraction of spectral information needed to distinguish different polymers. The software must support SWIR image formats, provide reliable analysis tools, and integrate smoothly with GenICam-compatible cameras.
Common platforms used in SWIR plastic inspection include:
- MVTec Halcon – Advanced machine vision tools for spectral and material analysis.
- Cognex VisionPro – Industrial software for reliable inspection and classification.
- MATLAB / OpenCV – Flexible environments for custom algorithms and research.
- Zebra Aurora Vision – Visual programming tools for inspection and object detection.
An available SDK supports image capture and camera control across PCs and embedded systems such as NVIDIA TX and Raspberry Pi on Windows, Linux, and Android.
Choosing the right image processing environment ensures accurate material identification and optimized performance in SWIR plastic sorting applications.
Support for SWIR Camera Systems
Looking to design a SWIR-based plastic sorting system or another machine vision solution? Our expert engineering team is ready to assist you.
Get in touch using the form below, and do not forget to explore our datasheets for detailed technical information!
These Go Well Together
MARS-138-95GM-P-TN-SWIR, IMX990, 1280x1024, DUAL USE X061 NL0074CDIU0179833, 95fps, 1/2 inch, Global shutter, CMOS, Mono
VA-LCM-1.3MP-25MM-F1.8-020-SWIR, LENS SWIR C-mount 1.3MP 25MM F1.8 1/2 inch VISIBLE SWIR
SWIR Ring light series VA-SWIR-RL, Select your size / wavelength, Industrial illumination
