Written by Helen Derbyshire, Product Manager at Knight Optical
The optical components involved in modern food inspection
Written by Helen Derbyshire, Product Manager at Knight Optical
information. Polarising filters can reduce glare from reflective packaging materials such as plastic films and foil seals, while bandpass filters isolate selected wavelengths to improve the visibility of defects, contaminants or product features.
Food manufacturers are increasingly relying on machine vision systems to improve quality control, reduce waste and maintain high production speeds. From inspecting fresh produce and bakery products to verifying labels and packaging, automated inspection systems make thousands of inspection decisions every minute.
While cameras, software and artificial intelligence often receive the most attention, inspection performance ultimately depends on the quality of the optical system collecting the data.
A typical machine vision inspection system follows a straightforward process:
Illumination > optical assembly > image sensor > processing software > action
Light reflected from a product passes through an optical assembly before reaching the camera sensor. This assembly typically includes lenses and optical filters that determine image quality, contrast and the system’ s ability to distinguish acceptable products from defects or contaminants. The captured image is then analysed by software, which may
58 FDPP- www. fdpp. co. uk reject a product, adjust a process parameter or trigger an operator alert.
The quality of the inspection result depends on the quality of the image captured. Information lost through poor image quality, insufficient contrast or optical distortion cannot be fully recovered during processing.
Lens selection plays a significant role. Food production lines often combine high throughput, varying product sizes and challenging operating conditions. The optical system must provide sufficient resolution to identify small defects while maintaining a field of view wide enough to inspect products moving continuously along a conveyor.
Distortion must also be controlled. In applications involving dimensional measurement, package verification or product sizing, image distortion can affect measurement accuracy, particularly towards the edge of the field of view. Low-distortion lenses help maintain measurement consistency across the inspection area.
Optical filters are used to improve image contrast and isolate specific
Many food manufacturers are also adopting near-infrared( NIR), multispectral and hyperspectral imaging technologies. Unlike conventional colour cameras, these systems collect information beyond the visible spectrum. This can reveal bruising in fruit before it becomes visible, distinguish foreign materials from food products, assess moisture content and identify variations in composition.
These techniques are finding increasing use in automated sorting systems, where inspection accuracy directly affects yield, waste reduction and product consistency.
As automation becomes more sophisticated, machine vision systems are expected to deliver faster inspections, greater traceability and more reliable quality control. Behind these advances are the optical components that determine what the system can see.
From precision lenses and optical filters to multispectral imaging optics, they remain a fundamental part of modern food inspection technology.
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