Optical Techniques for Industrial Inspection

Transcription

1 Optical Techniques for Industrial Inspection P. Cielo National Research Council of Canada Industrial Materials Research Institute Boucherville, Quebec, Canada ACADEMIC PRESS, INC. Harcourt Brace Jovanovich, Publishers Boston San Diego New York Berkeley London Sydney Tokyo Toronto

2 Contents Preface Chapter 1. Need and Functions of Industrial Inspection Definition and scope of inspection activities in industry Human versus automated inspection Economic factors Quality and income Quality and costs Statistical techniques The control chart Statistical analysis Sampling Inspection requirements in the materials processing and manufacturing industries Metallurgical industry Metal fabricating and automotive industry Pulp and paper Chemical process industries Plastics forming Electronic components 20 xi v

3 vi CONTENTS Chapter 2. Overview of Nonoptical Inspection Techniques Mechanical techniques Mechanical gaging Tactile sensors Ultrasonic inspection Active air propagation techniques Passive airborne techniques Active solid propagation techniques Passive structure borne techniques Radiographic inspection Radiographic imaging Thickness gaging Electromagnetic techniques Direct current methods Eddy current inspection Magnetic particle inspection Microwave inspection Sensors for industrial process control Pressure sensors Fluid sensors Temperature sensors In-process analyzers 72 Chapter 3. Fundamentals of Optical Technology Light sources Incoherent sources Coherent sources Lasers and safety Optical detectors Thermal detectors Photoemissive detectors Photoconductive and photovoltaic devices Image sensing devices Discrete detector arrays Television tubes Detection and noise Environmental noise Light-source noise Electronic noise Noise reduction techniques Environmental noise reduction Light source noise compensation Reduction of electronic noise 128

4 CONTENTS vii 3.7 Optical elements Imaging Systems Optical materials Holographie optical elements Scanning techniques Fiber optics Speckle under coherent illumination 175 Chapter 4. Surface Inspection Random surface profilometry Surface roughness statistics Tactile profilometry Interferometric optical profilometry Geometrical optics based profilometry Surface monitoring by light-scattering techniques Angular spectrum of the scattered light Polarization and coherence properties of the scattered light On-line surface inspection Roughness analysis in rolled produets On-line surface-defect detection Techniques for automatic focusing Angular sensing methods Sonar based approach Image sharpness monitoring 251 Chapter 5. Optical Gaging and Profiling On-line optical metrology Part sizing Alignment techniques Thickness measurement Two-dimensional imaging Principles of image-processing techniques Industrial applications Three-dimensional imaging by incoherent techniques Flying spot scanning methods Pattern projeetion techniques Passive techniques Time-of-flight ranging 307 Chapter 6. Optical Techniques for Nondestructive Testing Holographie nondestructive testing Optical holography 313

5 viii CONTENTS Strain analysis by holographic interferometry Part loading methods and NDT applications Heterodyne holographic interferometry Speckle metrology Speckle photography Speckle interferometry Focused beam testing Vibration sensing by interferometric devices Thermoelastic testing Laser generation and detection of ultrasound Thermal inspection Single spot techniques Thermal imaging techniques A comparative assessment 397 Chapter 7. Optical Sensing for Process Control Fundamentals of process control Elements of automatic control Stability of control loops On-line optical sensing of temperature Infrared thermal sensing On-line industrial applications Optical sensing of flow and speed Doppler velocimetry sensors Other optical techniques for fluid and motion sensing Fiber optic sensors Phase sensors Amplitude sensors An example of an optically controlled process: robotic welding Fundamentals of robotic arc welding Active optical sensors for robotic welding monitoring Passive optical inspection 455 Chapter 8. Optical Techniques for Material Analysis Spectroscopic techniques Overview of the most common optical spectroscopy methods Transmission and reflection spectroscopy Raman and luminescence spectroscopy Spectroscopy of industrial materials Analysis of surface layers 478

6 CONTENTS IX Quality control of epoxy-based products Laser-induced breakdown spectroscopy Nondispersive process analyzers Basic principles In-process material analysis Combustion monitoring Light scattering methods Light scattering by an aggregate of particles Industrial inspection of quasi spherical particles Fiber monitoring in the pulp and paper industry Conclusion 530 References 533 Index 585