Terahertz (THz) technology is an active area of research, but only in recent years has the application of THz waves (T waves) in food and agricultural industries been explored. Terahertz Technology: Principles and Applications in the Agri-Food Industry describes the operating principles of THz technology and discusses applications and advantages of the THz regime of the electromagnetic spectrum for use in the agri-food industry. The agri-food industry is focusing on the development of non-destructive quality evaluation techniques that can provide accurate analysis quickly and are environmentally friendly. Among such techniques is THz technology that provides a novel noninvasive approach to quality assessment and safety assurance of agri-food products. The low energy of T waves is best suited for the analysis of sensitive biomaterials and does not cause photoionization. Therefore, THz imaging is complementary to X-ray imaging. Although accessing the THz spectrum is tedious by conventional devices, the combination of optics and electronics principles has opened a dimension of research in this field.
This book provides an overview of THz spectroscopy and imaging, system components, types of THz systems, and applications and advantages of THz for applications in the agri-food industry. It describes the basic working mechanism, operating principle, operation modes, and system components of THz spectroscopy and imaging. Various advancements in THz technology related to agricultural and food applications are discussed that could serve as a guidebook for all those working and interested in non-destructive food assessment techniques.
Key Features:
- Explores broader applications of the THz regime in the agri-food sector
- Describes system components, different forms of THz systems, and the working principle of T waves for spectroscopic and imaging techniques
- Provides insights on future research needs for industrial implementation of THz technology
- Complements the knowledge of other existing non-destructive spectroscopy and imaging techniques for food analysis
Although books on biomedical applications of THz have been published, no book is available that deals with applications in the agri-food industry. Hence, Terahertz Technology is beneficial for undergraduate and graduate students and those food industry professionals involved in research related to non-destructive quality assessment and imaging techniques.
Author(s): T. Anukiruthika, Digvir S. Jayas
Publisher: CRC Press
Year: 2023
Language: English
Pages: 289
City: Boca Raton
Cover
Half Title
Title Page
Copyright Page
Contents
Preface
Acknowledgments
About the Authors
1. THz Technology: A Non-Destructive Approach
1.1. Introduction
1.2. Applicability of Electromagnetic Spectrum
1.3. Emerging Non-Destructive Analytical Methods
1.4. THz Radiation and Material Characterization
1.5. Overview of THz Sources and Detectors
1.5.1. Solid-State Oscillators
1.5.2. Optically Pumped Gas Lasers
1.5.3. THz Semiconductor Lasers
1.5.4. Laser-Driven THz Emitters
1.5.5. Free Electron-Based Sources
1.5.6. Frequency Multipliers
1.6. Instrumentation, Methodology, and Techniques
1.6.1. Progress in THz Sources
1.6.2. Progress in THz Detectors
1.7. Novel Trends and Applications of THz Waves
1.7.1. Non-Food Applications
1.7.2. Food Applications
1.8. Recent Research and Advancements
1.9. Summary
2. Terahertz Spectroscopy
2.1. Introduction
2.2. Physics of THz Waves
2.3. Terahertz Spectroscopy
2.3.1. Instrumentation and Working Principle
2.3.2. Basics of THz Spectroscopy Systems
2.3.3. Classification Based on THz Source Technology
2.3.3.1. Harmonic Generation and Frequency Multiplication
2.3.3.2. Mixing of Optical Sources
2.3.3.3. Electron Beam Sources
2.3.3.4. Tunable Sideband Sources
2.3.3.5. Femtosecond Sources
2.4. Generation and Detection of THz Radiation
2.4.1. Photoconductive THz Generation and Detection
2.4.2. Broadband and Narrow Band THz Generation and Detection
2.4.3. Optical Rectification and Electro-Optical Sampling Methods
2.4.4. Nonlinear Generation and Detection of THz Pulses
2.5. Different Forms of THz Spectroscopy
2.5.1. THz Time-Domain Spectroscopy
2.5.2. Time-Resolved THz Spectroscopy (TRTS)
2.5.3. THz Emission Spectroscopy (TES)
2.5.4. THz Gas Spectroscopy (TGS)
2.5.5. THz Attenuated Total Reflection Spectroscopy (THz-ATRS)
2.5.6. Comparison of Sensitivity in Different Modes of THz Spectroscopy
2.6. Spectral Data Acquisition and Analysis
2.7. Challenges, Limitations, and Current Research Advancements
2.8. Summary
3. THz Imaging
3.1. Introduction
3.2. THz Imaging – System Components and Operating Principle
3.3. THz Imaging Techniques
3.3.1. Pulsed THz Imaging
3.3.1.1. THz Time-Domain Imaging
3.3.1.2. THz Real-Time Imaging
3.3.1.3. THz Far-Field Imaging
3.3.1.4. THz Near-Field Imaging
3.3.2. Continuous Wave THz Imaging
3.3.2.1. Coherent Detection of CW-THz
3.3.2.2. Incoherent Detection of CW-THz
3.3.3. Summary of Imaging Systems
3.4. Tomographic Imaging
3.4.1. THz Diffraction Tomography
3.4.2. THz Tomosynthesis
3.4.3. THz Time of Flight
3.4.4. 3D THz Holography
3.4.5. Fresnel Lenses-Based THz Approach
3.4.6. Synthetic Aperture Processing
3.4.7. Time Reversal THz Imaging
3.4.8. THz Computed Tomography
3.5. Imaging Analysis
3.5.1. Characterization of Pharmaceutical Solids
3.5.1.1. Tablet Microstructure
3.5.1.2. Cracks and Delamination
3.5.1.3. Porosity
3.5.1.4. Disintegration Testing
3.5.2. Polymeric Film Analysis
3.5.2.1. Coating Uniformity
3.5.2.2. Functional Coatings
3.5.2.3. Sensor Calibration
3.5.2.4. In-Line Sensing
3.5.3. Chemical Imaging
3.6. Recent Advancements, Challenges, and Limitations
3.7. Summary
4. Spectral Measurements, Image Acquisition, and Processing
4.1. Introduction
4.2. THz Spectral Data Analysis
4.3. THz Signals in Time and Frequency Domains
4.4. Signal Preprocessing
4.4.1. Apodization Function
4.4.2. Zero-Filling Function
4.5. Data Processing and Reconstruction
4.5.1. Direct Method
4.5.1.1. Measuring Dataset from Physical Phenomenon to Reconstruction
4.5.1.2. Radon Transforms
4.5.1.3. Fourier Slice Theorem
4.5.1.4. Acquisition Properties
4.5.2. Iterative Reconstructions
4.5.2.1. Algebraic Methods
4.5.2.2. Stochastic Methods
4.5.3. Propagation Beam Assessment and Modeling
4.6. Data Transformation
4.7. Chemometrics
4.7.1. Classification Models
4.7.1.1. Principal Component Analysis
4.7.1.2. Support Vector Machine
4.7.1.3. Least-Squares Support Vector Machine
4.7.1.4. Linear Discriminant Analysis
4.7.1.5. Partial Least Squares
4.7.1.6. Principal Component Regression
4.7.1.7. Artificial Neural Network
4.7.1.8. Back Propagation Neural Network
4.7.1.9. Random Forest
4.7.1.10. Discriminant Analysis and Distance Match
4.7.2. Performance Evaluation of Prediction Models
4.7.3. Software Used for Chemometrics
4.8. Data Processing and Feature Extraction
4.8.1. Qualitative Assessment
4.8.2. Quantitative Assessment
4.9. Considerations and Current Perspectives
4.10. Summary
5. Molecular Characterization of Biomaterials
5.1. Introduction
5.2. Diverse Applications of THz Systems
5.2.1. Security Monitoring
5.2.2. Packaging Industry
5.2.3. Pharmaceutical Industry
5.2.4. Archaeological Applications
5.2.5. Food Industry
5.3. Scope of THz Spectroscopy in Material Characterization
5.3.1. Characterization of Crystalline Materials
5.3.1.1. Identification of Polymorphism
5.3.1.2. Crystalline Phase Transitions
5.3.1.3. Determination of Glass Transition Point
5.3.2. Characterization of Amorphous Materials
5.3.2.1. Onset of Crystallization
5.4. Qualitative and Quantitative Measurements in the Agri-Food Sector
5.4.1. Carbohydrates and Sugars
5.4.2. Proteins and Amino Acids
5.4.3. Lipids and Fatty Acids
5.4.4. Micronutrients
5.4.5. Moisture Content
5.5. Technological Advancements and Futuristic Applications
5.6. Summary
6. THz Technology: An Inspection and Identification Tool
6.1. Introduction
6.2. THz System for Safety and Quality Monitoring
6.2.1. Detection of Antibiotics
6.2.2. Detection of Foreign Bodies
6.2.3. Detection of Toxic Compounds
6.2.4. Detection of Adulterants
6.3. Industries in the Development of THz Systems
6.4. Summary
7. THz Technology – Agricultural Applications
7.1. Introduction
7.2. Scope of THz in the Agricultural Sector
7.3. THz Applications in the Agricultural Sector
7.3.1. Nature and Composition of Materials
7.3.2. Seed Quality Evaluation
7.3.3. Discrimination of Transgenic Crops and Seeds
7.3.4. Seed Inspection and Identification
7.3.5. Detection of Pesticide Residues
7.3.6. Detection of Heavy Metals
7.3.7. Plant Physiology and Growth
7.3.8. Detection of Crop Diseases
7.3.9. Hydrology and Drought Stress Monitoring
7.4. Spectral Assessment in Crop Science
7.4.1. Spatial Distribution of Plant Leaf Constituents
7.4.2. Monitoring of Stress Levels in Plants
7.4.3. Spatiotemporal Variability of Water
7.5. Summary
8. THz Technology for Quality Monitoring and Control
8.1. Introduction
8.2. THz Technology for Food Safety
8.3. THz Applications in Food Processing Control and Quality Monitoring
8.3.1. Microbial Characterization
8.3.2. Biochemical Sensing
8.3.3. Food Microbial Analysis
8.3.4. Operation and Process Control
8.3.5. Food Packaging
8.4. Perspectives and Limitations
8.5. Summary
9. Future Prospects, Opportunities, and Challenges
9.1. Background
9.2. Viewpoints on THz Waves
9.3. Prospects of THz Spectral Imaging
9.4. Constraints and Barriers
9.5. Recent Trends in THz System Components
9.6. Summary
References
Index
