Sensors for Industrial Inspection

Inductive Proximity Switches.- Inductive Sensing.- Skin Effect.- Magnetic Inductive Proximity Sensors.- Mounting Considerations.- Hysteresis.- Target Approach.- Body Styles and Sizes.- Welding Proof.- Applications.- 4.3 Capacitive Proximity Sensors.- Capacitive Sensing.- Target Materials.- 4.4 Photoelectric Proximity Switches.- Photoelectric Sensing.- Sensor Configurations.- 4.5 Interfacing Proximity Sensors.- 5. Tactile Sensors.- 5.1 Introduction.- 5.2 Resistive techniques.- Conductive rubber.- Conductive Plastics.- Carbon Fibre.- Tactile Arrays.- 5.3 Piezoelectric Effect.- Piezoelectric Film.- 5.4 Magnetic effects.- Magnetoresistance.- Magnetoelastic & Magnetostrictive Materials.- 5.5 Optical Techniques.- Touch Vision.- Touch Finger.- 5.6 3-D Tactile Sensors.- 6. Surface Finish.- 6.1 Introduction.- 6.2 Stylus Instruments.- Stylus Protection.- Stylus Selection.- Mounting Arrangements.- Laser Stylus.- 6.3 Profile Analysis.- Sample and Assessment Lengths.- 6.4 Surface Reflection.- Roughness and Waviness from Surface Scattering.- 6.5 Laser Scanning.- Polarised Laser Scanning.- 6.6 Visual Analysis of Texture.- Statistical Classification.- Structural Approaches.- Spectral Approaches (Fourier Analysis).- 6.7 Optical Sectioning (Structured Light).- 6.8 Roughness Gauging.- 6.9 Crack Detection.- 7. Structural Analysis.- 7.1 Introduction.- 7.2 Photoelastic Stress Analysis.- Stress Direction.- Stress Magnitude.- Stress Polarity.- 3-D Model Analysis.- Stress Freezing.- 7.3 Thermoelastic Stress Analysis.- 7.4 Transient Thermography.- 7.5 Acoustic Emission - Stress Wave Sensing.- IndividualTransients.- Multiple Transients.- Continuous Emission.- Applications.- Locating the Source.- Sensor Design.- 7.6 X-ray Inspection.- 7.7 Gamma-Radiation.- 7.8 Beta-Particles.- 7.9 Viscosity.- 7.10 Eddy current sensing.- 7.11 Ultrasonic Inspection.- Compression and Shear Waves.- Velocity.- Wavelength.- Probe Design.- Data Acquisition and Display.- 7.12 Acoustic Flaw Detection.- 7.13 Hardness Testing.- 8. Temperature Sensing.- 8.1 Introduction.- Units of Temperature.- 8.2 Metallic Resistance Thermometers.- Platinum Resistance Thermometers.- Linearity.- Installation.- Low Temperature Resistance Sensors.- 8.3 Thermistors.- Thermal Characteristics.- Current Limiting Applications.- Positive Temperature Coefficient Thermistors (PTC).- Installation Considerations.- 8.4 Thermocouples.- Seebeck Effect.- Thermocouple Types.- Thermocouple Materials.- Thermocouple Construction.- Law of Intermediate Metals.- Cold junction compensation.- Connecting Cables.- Temperature Transmitters.- 8.5 Semiconductor Temperature Measurement.- Silicon Junction Diode.- Semiconductor Temperature Sensors.- Temperature Sensing Integrated Circuits.- 8.6 Optical Pyrometers.- Infrared theory.- Planck's Law.- Black bodies.- Radiation Detectors.- Application Considerations.- 8.7 Thermal Imaging.- 8.8 Disappearing Filament.- 8.9 Thermographic Materials.- Temperature sensitive pigments.- Liquid crystals.- 8.10 Thermographic Phosphors.- 8.11 Distributed Fibre Optic Temperature Sensors.- Raman Scattering.- Applications.- 8.12 Thermostats.- Bimetallic Elements.- 8.13 Ceramic Temperature Sensors.- Cooling System Control Application.- 9. Pressure Sensing.- 9.1 Introduction.- 9.2 Capacitance Manometers.- 9.3 Quartz Pressure Sensors.- Electrostatic Pressure Sensors.- Quartz Resonant Pressure Sensors.- 9.4Piezoresistive Pressure Sensors.- 9.5 Strain Gauge Pressure Sensors.- 9.6 LVDT Pressure Transducer.- 9.7 Silicon Pressure Sensors.- 9.8 Vacuum Gauges.- Thermal Conductivity Gauges.- Thermocouple Gauge.- Pirani Gauge.- Thermistor Gauge.- Ionisation Gauges.- 10. Weight.- 10.1 Introduction.- 10.2 Check Weighers.- 10.3 Dynamic Weighing Systems.- 10.4 Hydraulic and Pneumatic Weighing Systems.- 11. Moisture/Humidity.- 11.1 Introduction.- 11.2 Dew Point Instruments.- 11.3 Vapour Pressure Methods / Relative Humidity.- Absolute Humidity of a Gas Mixture.- Relative Humidity of a Gas Mixture.- Equilibrium Relative Humidity.- 11.4 Infrared Moisture Measurement.- Infrared Moisture Sensor.- Infrared Absorption.- 11.5 Microwave Techniques.- 11.6 Quartz Crystal Oscillator.- 11.7 Conductivity.- 11.8 Capacitance Sensors.- 11.9 Diffusion Cell Electrolyte.- 11.10 Calibration.- 12. Gas Detection.- 12.1 Introduction.- Combustible Gas Detectors.- Toxic Gas Detectors.- Sensor Location.- 12.2 Electrochemical Sensors.- 12.3 Semiconductor Detectors.- 12.4 Catalytic Detector (pellistor).- 12.5 Conducting Polymer Gas Detectors.- 12.6 Infrared Spectroscopy.- Molecular Vibrations.- Absorption of Infrared Light.- Photoacoustic Spectroscopy.- 12.7 Thermal Conductivity Detector (TCD).- Katharometer.- 12.8 Photo-Ionisation detector (PID).- 12.9 Ultrasonic Detectors.- 12.10 Paramagnetic Oxygen Analysers.- Magnetic Wind Instruments.- 12.11 Flame Ionisation Detectors (FID).- 12.12 Units of Gas Concentration.- 13. Light and Colour Measurement.- 13.1 Introduction.- 13.2 Units of Light Measurement.- Luminous Flux.- Luminous Intensity.- Illuminance.- 13.3 The Nature of Colour.- Hue.- Saturation.- Intensity.- 13.4 Human Perception of Colour.- Colour Discrimination.- 13.5 CIE Standards.- The Standard Observer.-Colour Sensitivity of the Human Eye.- CIE Chromaticity Diagram.- XYZ System.- Yxy Colour System.- The Lab system.- 13.6 Munsell Colour Wheel.- 13.7 RGB Systems.- RGB Colour Space.- Colour Triangle.- 13.8 Colour Mixing.- Additive and Subtractive Colour Mixing.- Complimentary Colours.- 13.9 Illumination.- Colour Temperature.- Light Sources.- Man Made Light Sources.- Natural Light Sources.- Filters.- Atmospheric Absorbtion.- 13.10 Colour Pigments.- 13.11 Colour Matching.- Metamerism.- 13.12 Colour Measuring Equipment.- Colour Sensing.- Densitometers.- Effects of Polarisation.- Chromameters.- Illuminance Meters.- Luminance Meters.- Spectrophotometers.- Spectral Filter Arrays.- 14. Optics.- 14.1 Introduction.- 14.2 Light - Fundamentals.- 14.3 Laws of optics.- Reflection.- Absorption and Transmission.- Refraction.- Diffraction.- 14.4 Lenses.- Real and Imaginary Images.- Bi-convex Lenses.- Bi-concave Lenses.- Ray Diagrams.- Prisms.- Fresnel Lenses.- Depth of Field - Depth of Focus.- Aperture.- Measuring the Focal Length of an Unknown Lens.- 14.5 Mirrors.- Prism Reflectors.- 14.6 Lens Systems.- Magnifying glass.- Photocopier.- Projector.- 14.7 Lens Defects.- Spherical Abberation.- Chromatic Aberration.- 14.8 Polarised Light.- Polarisation by Reflection.- Double Refraction.- Optical Rotation.- 14.9 Interference Filters.- Band Pass Filters.- Filter Factors.- Correction Filters.- Contrast Filters.- Dichroic Filters.- 14.10 Holography.- 15. Lighting.- 15.1 Introduction.- 15.2 Methods of Illumination.- Front lighting.- Specular Illumination (dark field).- Specular Illumination (light field).- Beam Splitter.- Split Mirror.- Shadow Illumination.- Backlit Illumination.- Retroreflector.- Back Illumination (condenser).- Rear Illumination (collimator).- Rear Offset Illumination.-Structured Light.- Ring Lights.- Diffuse Scattering.- Fibre Optic Light Sources.- Surface Characteristics.- Distribution and Spread of Illumination.- 15.3 Colour.- Spectral Characteristics.- Daylight.- 15.4 Lighting Power Supplies.- Frequency - Ripple and Drift.- Colour Temperature.- Run Up.- High Frequency Operation.- 15.5 Handling Heat Dissipation.- Dichroic Reflectors.- 15.6 Protection Against Lamp Shattering.- 15.7 Lamp Life.- Pre-Ageing of Lamps.- Efficiency.- 15.8 Incandescent lamps.- 15.9 Tungsten Halogen Lamps.- Installation Considerations.- 15.10 Fluorescent Lamps.- Luminescence.- Fluorescent Lamp Output.- High Frequency Fluorescents.- 15.11 Sodium Vapour Discharge Lamps.- 15.12 Neon Lamps.- 15.13 Electronic Flash Tubes.- Xenon Flash Lamps.- 15.14 UV Illumination (black light lamps).- 15.15 Light Emitting Diodes (LED's).- 15.16 Electroluminescence.- Electroluminescent Panels.- 15.17 Lasers.- Gas lasers.- Semiconductor Lasers.- Laser Safety.- 16. Cameras.- 16.1 Introduction.- Solid State Camera Arrays.- Advantage of Solid State Devices.- 16.2 Vidicon Cameras.- Exposure and Scanning.- Dark Current.- Colour Vidicons.- Choice of Target for Vidicons.- 16.3 Photodiode Arrays.- 16.4 Charge Coupled Devices (CCD'S).- Transfer of Charge.- Infrared Sensitivity.- Photosite Shapes.- Area Arrays.- Colour CCD Arrays.- 2 D Images on Linear Arrays.- Very High Resolution 2 D Cameras.- Hexagonal Arrays.- Circular Arrays.- 16.5 Charge Injection Devices (CID's).- 16.6 Ram Cameras.- 16.7 Camera Specification & Performance.- Resolution.- Sensitivity.- Crosstalk.- Linearity and Gamma.- Geometrical Faults.- Blooming.- Lag.- Noise.- Dark Signal.- 16.8 Image Intensifies.- Channel Plate Intensifier.- 16.9 Scanning Rates.- Short Exposures.- Video Images.- 16.10 Flying Spot LaserScanners.- Direction of Reflection.- Dimension Measurement.- 17. Image Processing.- 17.1 Introduction.- Nomenclature and Standards.- 17.2 Thresholding.- Fixed Level Thresholding.- Dynamic Thresholding.- Adaptive Thresholding.- Multi-Level Thresholding.- Spatially Varying Thresholds.- Colour Thresholding.- Threshold Implementation.- 17.3 Grey Scale Transformations.- Histogram Equalisation.- Contrast Expansion.- Square intensity.- 17.4 Multiple Image Averaging.- 17.5 Filtering / Convolutions.- Mean (Average).- Median Filter.- High Pass.- Low Pass.- Lightest.- Darkest.- Intermediate Results.- 17.6 Edge Detection.- Horizontal gradient.- Vertical Gradient.- Sobel.- Dispersion.- Goodman-Smyth.- Roberts.- Laplace.- Complex Edge Detectors.- 17.7 Image Transformation.- Spatial Transformations.- 18. Application of Machine Vision.- 18.1 Introduction.- 18.2 A Low Cost Commercial Vision System.- System Specification.- Inspection Procedure.- Simple Thresholds.- XY Float.- Window Measurements.- Line Gauge Measurements.- 18.3 Area Array Camera Applications.- Inspection of a Plastic Moulded Plug Top.- Clothes Peg.- Edge Enhancements.- 18.4 Line Scan Camera Applications.- Line Scan Cameras for 2-D Image Capture.- Line Scan Camera Measurement Systems.- Lighting Considerations.- Alignment and Focusing.- 'Ruler' Applications.- Biscuit Width & Colour Measurement.- 18.5 Colour Inspection.- Benefits of using Colour.- Colour System Selection.- Chocolate Biscuit Inspection.- Colour Sorting.- Orange Picking.- Commercial Organisations.- References.