In the food and pharmaceutical industries, quality control isn’t just about brand reputation—it’s about consumer safety and regulatory compliance. Machine vision systems powered by specialized FA (Factory Automation) lenses have become essential tools for ensuring product integrity, detecting contaminants, and verifying packaging quality at production speeds that would be impossible for human inspectors.
This comprehensive guide examines how FA lenses are applied across food and pharmaceutical manufacturing, the key inspection challenges they address, and how to select the right lenses for specific applications.
What Are the Main Vision Inspection Categories in Food and Pharmaceutical Manufacturing?
The main vision inspection categories in food and pharmaceutical manufacturing are presence/absence inspection, defect detection, dimensional inspection, positioning/alignment verification, code/date verification, and 3D inspection. Each category addresses specific quality control requirements mandated by industry regulations and standards to ensure product safety, consistency, and compliance.
These inspection types form the foundation of modern quality control systems in regulated industries where errors can have serious consequences for consumer safety.
How FA Lenses Support Critical Food Inspection Applications
1.Presence/Absence Inspection
Food manufacturers must verify that all product components are present before shipping. Common applications include:
Presence Inspection for Seasoning Packets
Presence inspection for seasoning packets uses machine vision systems with FA lenses to verify that each package contains the required seasoning packets before sealing. This typically employs contrast-based detection with wide-angle FA lenses (8-16mm focal length) positioned above conveyor lines, ensuring every product meets packaging requirements.
These systems can inspect hundreds of packages per minute, with some high-speed lines exceeding 600 units per hour. The right lens selection is critical—too narrow a field of view would miss packets near package edges, while insufficient resolution would fail to differentiate between packet types.
Juice Box Straw Inspection
Missing straws are among the top consumer complaints for juice boxes. Vision systems using FA lenses verify each package has its straw correctly attached. These systems typically require:
- Short working distance FA lenses (12-25mm)
- High resolution for detecting small objects against similar backgrounds
- Specialized lighting to enhance contrast between straws and packaging
Bottle Count in Cases
Beverage manufacturers must ensure each case contains the correct number of bottles or cans. This application uses:
- Wide-angle FA lenses for complete case visibility
- Lower resolution requirements than other applications
- Structured illumination to enhance container edges
- Software algorithms that count distinct objects
2.Defect Inspection
Appearance Inspection of Plastic Caps
Appearance inspection of plastic caps uses high-resolution FA lenses (typically 16-35mm with low distortion characteristics) to detect defects including cracks, deformations, color variations, and contamination. These systems require precise focus control and often employ telecentric lenses when dimensional accuracy is critical for cap sealing performance.
The ideal lens configuration depends on cap size and defect specifications, with most systems capable of identifying defects as small as 0.1mm. Color sorting applications require additional consideration for chromatic aberration correction in the FA lens selection.
Foreign Particle Detection in Food Products
One of the most critical safety applications is detecting foreign materials in food products:
- Glass fragments in jelly or sauce products
- Metal shards in packaged foods
- Plastic pieces in liquid products
- Organic contamination like insect parts
These applications often require:
- High magnification FA lenses (35-75mm)
- Superior contrast capabilities
- Specialized lighting techniques (backlight, darkfield, polarized)
- Multi-camera setups with different lens configurations
Pasta Contamination and Hole Inspections
Pasta products require inspection for both contamination and structural defects. Vision systems detect:
- Foreign material mixed with pasta
- Missing pieces or broken pasta
- Proper formation of pasta shapes
- Holes in filled pasta products
These applications typically use mid-range FA lenses (16-35mm) combined with structured lighting to enhance textural differences.
3.Dimensional Inspection
Packaging Seal Inspection
Packaging seal inspection uses FA lenses with low distortion characteristics to verify the integrity of seals on flexible packaging, blister packs, and sealed containers. These systems typically employ directional lighting to highlight seal edges and telecentric lenses when precise dimensional measurements are required, detecting gaps as small as 0.05mm that could compromise product sterility or freshness.
FDA and other regulatory requirements make this inspection critical for pharmaceutical products, where package integrity ensures medication safety and efficacy.
Label Alignment Inspection
Proper label positioning is essential for both regulatory compliance and brand presentation. These systems typically use:
- Mid-range FA lenses (16-35mm)
- High resolution for detecting fine text and graphics
- Specialized software algorithms for measuring alignment angles
- Multiple cameras for wrap-around label inspection
4.Positioning/Alignment Applications
Pattern Inspection for Can Orientation
Ensuring cans are oriented correctly for labeling or filling operations requires:
- Wide field of view FA lenses
- Pattern recognition capabilities
- High-speed image processing
- Integration with production line controls
Robot Guidance for Packaging
Robot guidance for packaging uses FA lenses to identify product positions and orientations for automated picking and placing. These systems require FA lenses with minimal distortion (typically under 0.1%) and consistent center-to-edge sharpness to provide accurate spatial coordinates. The focal length selection depends on the working area size, with most applications using 8-25mm lenses mounted on fixed or robot-mounted cameras.
Modern robot guidance systems can direct multiple robots simultaneously, requiring synchronization between multiple cameras with matched FA lenses.
5.Verification Inspection
Print Inspection Applications
Critical text and code verification includes:
- “Best by date” printing inspection
- Lot code verification
- Barcode scanning and grading
- Medical information leaflet verification
These applications require:
- High resolution FA lenses (often 50mm+ focal length)
- Macro focusing capabilities
- Specialized lighting to enhance print contrast
- OCR/OCV software integration
Date, Lot Code, and Barcode Inspections
Date, lot code, and barcode inspections verify that products display the correct tracking information for regulatory compliance and recall management. These systems typically use high-resolution FA lenses (35-75mm) with working distances of 150-300mm, combined with specialized lighting techniques like low-angle illumination to enhance contrast on challenging surfaces such as metal, glass, or plastic packaging.
Pharmaceutical applications must achieve 100% verification rates for these codes, requiring redundant systems and superior optical performance.
6.3D Machine Vision Inspections
Advanced applications leverage 3D vision technology for:
Chocolate Bar Inspections
Chocolate products require both visual inspection and shape verification, using:
- Laser triangulation with specialized FA lenses
- Multiple camera angles
- Height and volume measurements
- Surface texture analysis
Tablet Blister Pack Inspection
Pharmaceutical tablet packaging requires comprehensive inspection:
- Presence of all tablets
- Correct tablet color and shape
- Blister seal integrity
- Proper fill level in each pocket
How to Select the Right FA Lens for Food and Pharmaceutical Applications
Working Distance and Field of View
The working distance and field of view requirements determine the appropriate focal length for an FA lens in food and pharmaceutical inspection. To calculate the required focal length, multiply the sensor size by the working distance and divide by the desired field of view. For example, with a 2/3″ sensor (8.8mm width), 300mm working distance, and 150mm field of view requirement, you would need a lens with approximately 17.6mm focal length.
Most food and pharmaceutical applications require a working distance that provides clearance for products and conveyor systems while maintaining the necessary resolution. Common configurations include:
- Close-range inspection (50-200mm): 8-16mm focal length lenses
- Mid-range inspection (200-500mm): 16-35mm focal length lenses
- Long-range inspection (500mm+): 35-75mm focal length lenses
Resolution Requirements
Resolution needs depend on the smallest features that must be detected:
- Barcode reading: Minimum 10 pixels per narrow bar
- Text verification: 15-20 pixels per character height
- Defect detection: 3-5 pixels across the smallest defect
- Dimensional measurement: 10+ pixels across the measured feature
To calculate the required resolution, divide the field of view by the camera’s pixel count, then ensure this pixel size is adequate for your smallest feature.
Lighting Considerations
The interaction between lighting and FA lenses significantly impacts inspection quality:
- Backlighting works best with standard FA lenses for silhouette inspection
- Directional lighting requires lenses with good flare control
- Diffuse lighting pairs well with most standard FA lenses
- Polarized lighting may require specialized coatings on FA lenses
Environmental Factors
Food and pharmaceutical environments present specific challenges:
- Washdown requirements: Select sealed, IP-rated lens housings
- Temperature fluctuations: Choose lenses with stable focus across operating temperatures
- Vibration: Use lenses with locking mechanisms for focus and aperture
- Limited space: Consider compact lens designs that maintain optical quality
Regulatory Compliance
Certain applications require specific considerations:
- Pharmaceutical validated systems often require documentation of lens specifications
- Food-grade environments may need stainless steel lens housings
- 21 CFR Part 11 compliance may impact the entire vision system, including lens selection
Key FA Lens Specifications for Food and Pharmaceutical Applications
Aperture Requirements
The aperture (F-number) of an FA lens affects several aspects of the inspection system:
- Larger apertures (lower F-numbers like F1.4 or F1.8) gather more light, enabling:
- Shorter exposure times for fast-moving products
- Lower intensity lighting requirements
- Better performance in light-limited environments
- Smaller apertures (higher F-numbers like F8 or F11) provide:
- Extended depth of field for products with height variations
- Reduced optical aberrations
- More consistent edge-to-edge sharpness
Most food and pharmaceutical applications benefit from FA lenses with variable apertures, allowing system optimization during setup.
Distortion Characteristics
Distortion in FA lenses refers to the geometric inaccuracy where straight lines appear curved in the image. For measurement and alignment applications in food and pharmaceutical inspection, distortion should typically be less than 0.5%. Applications involving precise dimensional measurements often require telecentric lenses, which eliminate perspective distortion entirely, allowing accurate measurements regardless of working distance variations.
Standard FA lenses typically specify distortion as a percentage, with premium lenses offering values below 0.1% for critical applications.
Contrast and MTF Performance
Modulation Transfer Function (MTF) measures how well a lens preserves contrast at different spatial frequencies. For food and pharmaceutical applications:
- Higher MTF values ensure better detection of subtle defects
- Edge contrast performance affects measurement accuracy
- Color applications require good MTF across the visible spectrum
Premium FA lenses provide MTF curves as part of their specifications, allowing informed selection for specific applications.
Lens Mount Compatibility
Most machine vision cameras in food and pharmaceutical applications use standardized mounts:
- C-mount: Most common for industrial cameras
- CS-mount: Requires an adapter for C-mount lenses
- F-mount: Used for some higher-resolution applications
- M42: Found in some specialized systems
Ensure your selected FA lens matches your camera’s mount type or use appropriate adapters.
Real-World Case Studies: FA Lenses in Action
Case Study 1: Pharmaceutical Blister Pack Inspection
A pharmaceutical manufacturer needed to verify 100% of blister packs for:
- Tablet presence in each pocket
- Correct tablet color and shape
- Seal integrity
- Foil printing quality
Solution: A multi-camera system using 16mm FA lenses for wide field inspection and 35mm FA lenses for detailed print verification. The system included:
- Diffuse dome lighting to eliminate foil reflections
- F5.6 aperture setting for adequate depth of field
- Custom triggers synchronized with the production line
- Redundant inspection points to ensure 100% verification
Results: Zero defective packages shipped, with false reject rates below 0.02%, and throughput of 1,800 packs per hour.
Case Study 2: Foreign Object Detection in Jarred Food Products
A food manufacturer needed to detect glass fragments, metal pieces, and other contaminants in clear jar products.
Solution: A custom inspection station using:
- 12mm FA lenses for jar presence and cap verification
- 50mm high-resolution FA lenses for product inspection
- Specialized backlight and side-light combinations
- Multiple inspection angles to eliminate blind spots
Results: Detection of contaminants down to 0.3mm in size, with production speeds of 400 jars per minute and integration with automated rejection systems.
Case Study 3: Date Code Verification on Beverage Containers
A beverage company needed to verify date codes on various container types with different surface properties.
Solution: A flexible system using:
- 35mm FA lenses with low distortion characteristics
- Adjustable angle cameras to handle different container shapes
- Polarized lighting to reduce reflections from curved surfaces
- OCR software optimized for dot-matrix and laser-etched codes
Results: 99.8% read rate across all container types, with the ability to verify both printed and etched codes at line speeds of 1,200 containers per minute.
Future Trends in FA Lens Technology for Food and Pharmaceutical Inspection
Higher Resolution Support
As camera sensors advance to 20+ megapixels, FA lenses are evolving to support these higher resolutions with:
- Improved optical designs that maintain contrast at higher spatial frequencies
- Better correction for chromatic aberration
- Enhanced manufacturing precision for more consistent performance
Compact, High-Performance Designs
Newer FA lens designs offer better performance in smaller packages:
- Reduced lens length through advanced optical formulas
- Lighter weight for robot-mounted applications
- Maintained optical quality despite size reduction
Integration with Advanced Imaging Technologies
FA lenses are being adapted for specialized imaging techniques:
- Hyperspectral imaging for enhanced contaminant detection
- UV and IR imaging for specialized inspection tasks
- Polarization imaging for stress analysis in packaging
Conclusion: Selecting the Right FA Lens for Your Application
The right FA lens is a critical component in food and pharmaceutical inspection systems. By carefully considering your specific requirements for working distance, resolution, environmental factors, and lighting conditions, you can select lenses that provide the optical performance needed for your application.
Remember these key points when selecting an FA lens:
- Match the focal length to your working distance and field of view requirements
- Ensure the lens resolution supports your smallest feature detection needs
- Consider environmental factors like washdown requirements and temperature variations
- Choose appropriate aperture capabilities for your depth of field and lighting conditions
- Verify compatibility with your camera mount and sensor size
For the most demanding food and pharmaceutical applications, consider consulting with vision system specialists who can recommend specific lenses based on your exact requirements and help validate system performance against your quality standards.
Looking for high-quality FA lenses for your food or pharmaceutical inspection application? Explore our selection of industrial-grade fixed focal length lenses designed specifically for demanding inspection environments.
