What Is Hyperspectral Technology?

Hyperspectral technology is an advanced sensing and imaging approach that captures information from across the electromagnetic spectrum with unprecedented detail. Unlike conventional imaging systems that record only three color channels (red, green, and blue), this sophisticated approach collects data from hundreds of narrow, contiguous spectral bands for each pixel. The result is a three-dimensional data cube where two dimensions represent spatial information and the third contains detailed spectral information.

The power of this technology lies in its ability to detect and identify materials based on their unique spectral signatures – the specific ways different substances absorb, reflect, and emit electromagnetic radiation across various wavelengths. These spectral signatures function as optical fingerprints, enabling precise identification of materials that may appear identical to conventional cameras.

This approach extends beyond the visible spectrum, spanning ultraviolet, visible, near-infrared, shortwave infrared, and in some cases, mid-wave and longwave infrared regions. This comprehensive coverage allows for detection of phenomena invisible to conventional sensing methods. The evolution of hyperspectral camera technology has dramatically expanded these capabilities over time, as documented in this history of hyperspectral imaging.

How Hyperspectral Imaging Technology Works

Hyperspectral imaging technology operates by capturing the spectral signature of materials – the unique way each substance interacts with light across different wavelengths. This spectral information reveals molecular composition and physical properties that remain hidden to conventional imaging methods.

Data Acquisition Methods

Three primary approaches are used to collect hyperspectral data:

1. Whiskbroom (Point Scanning): Collects the complete spectrum for a single spatial point, then sequentially moves to cover the entire scene point by point. This approach achieves high spectral resolution, making it ideal for laboratory analysis where acquisition speed is less critical.
   
2. Pushbroom (Line Scanning): Captures a complete spectrum for an entire line of pixels simultaneously, then builds the image line by line as the sensor moves. This balances resolution with reasonable speeds, making it suitable for airborne, satellite, and industrial conveyor applications.
   
3. Snapshot: Captures the entire spectral data cube in a single exposure. This method excels at capturing dynamic scenes where movement would cause distortion in scanning approaches, though often with some trade-off in resolution.
   

System Components

A typical imaging system consists of five key elements:

1. Light Source: Either natural or controlled illumination across wavelengths of interest. The quality of illumination significantly impacts measurement accuracy.
   
2. Optics: Specialised lenses that focus light while minimising chromatic aberration across a wide spectral range, requiring advanced materials beyond conventional photography lenses.
   
3. Spectral Separation Element: Divides light into its constituent wavelengths using prisms, diffraction gratings, tunable filters, or interferometers. This component determines resolution capabilities.
   
4. Detector Arrays: Specialised sensors that convert light into electrical signals. Silicon-based detectors cover UV to near-IR, while more exotic materials are needed for longer wavelengths.
   
5. Data Processing System: Computing hardware and software that transform raw measurements into actionable information. Modern systems increasingly leverage the power of IoT integration to enable real-time processing and automated decision-making.
   

Data Processing Workflow

The processing workflow typically involves calibration, atmospheric correction (for remote sensing), dimensionality reduction, and feature extraction/analysis, enabling material analysis with precision that conventional imaging cannot match.

Key Applications of Hyperspectral Technology

Agriculture and Food Safety

• Early detection of plant stress and disease, with Living Optics’ field systems providing real-time monitoring to identify nutrient deficiencies before visual symptoms appear
• Soil composition analysis for precision agriculture
• Non-destructive evaluation of crop ripeness and quality
• Detection of food contaminants, where Living Optics HSI camera can detect issues invisible to conventional imaging
• Assessment of plant water status for irrigation management

Environmental Monitoring

• Mapping of vegetation types and ecosystem health
• Detection of water pollutants and harmful algal blooms
• Monitoring of forest health, with Living Optics’ drone-mounted solution providing assessments to detect plant stress that might hint at an infestation before trees show visible stress
• Identification of mineral deposits
• Tracking environmental changes for climate studies

Medical and Life Sciences

• Real-time visualisation of tissue types, helping surgeons identify tumor margins with greater precision during cancer operations
• Non-invasive detection of tissue abnormalities
• Verification of drug composition in pharmaceutical quality control
• Forensic analysis and material identification
• Advanced imaging for biomedical research

Industrial and Manufacturing

• Detection of defects and contaminants in manufacturing, with hyperspectral camera technology enabling automated quality control at production speeds
• Automated sorting of materials, enabling recycling facilities to differentiate between plastic types that appear identical to the naked eye
• Ore grade estimation in mining operations
• Pipeline monitoring in oil and gas industries
• Non-destructive analysis of art materials for conservation

Defence and Security

• Identification of camouflaged objects, with applications in enhanced object detection that far exceed conventional imaging capabilities
• Recognition of hazardous materials, where Living Optics has developed a portable system that allows first responders to identify dangerous substances from a safe distance
• Enhanced imaging in challenging conditions
• High-confidence target identification, tracking and reacquisition
• Monitoring of areas for security

Hyperspectral vs. Traditional Imaging – What Sets It Apart?

Spectral Resolution

While traditional cameras capture just three broad bands (RGB) and multispectral systems typically collect 4-15 bands, hyperspectral systems acquire hundreds of narrow, contiguous bands. This higher spectral resolution enables detection of subtle features and discrimination between visually similar materials.

Material Identification Capabilities

The comprehensive spectral information allows for precise identification of materials based on their unique signatures, detection of specific chemical compounds, and quantitative measurement of material concentrations.

Beyond Human Vision

This advanced imaging extends beyond human vision capabilities by capturing information from ultraviolet to infrared regions, detecting subtle variations undetectable visually, and providing objective, quantitative measurements.

Data Richness and Analysis Potential

The three-dimensional data cubes provide orders of magnitude more information than conventional images, enabling multiple analyses from a single acquisition.

Limitations and Considerations

Despite its advantages, hyperspectral technology comes with certain challenges including higher equipment costs, larger data volumes requiring substantial processing, and more complex data interpretation.

The unique capabilities of spectral imaging make it an increasingly valuable tool for applications requiring detailed material analysis beyond what conventional imaging can provide.