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16.7 Resolution number of bits 163
Bit depth
Lateral resolution
16.8 Comparison of film, CR- and DR methods 164
16.9 Impact and status of CR- and DR standards 165
Development of standards
Status of CR standards
Status of DR standards
Impact of standards
Standards for weld inspection
Data exchange and tamper proof standard
16.10 Selection of CR- and DR methods 167
16.11 Applications for CR- and DR methods 168
Corrosion detection
Weld inspection
Dose reduction and controlled area
Automated/mechanised inspection
Girth weld inspection
Useful life of plate and panel
16.12 Work station 171
Hardware and software
Versatility of the software
Archiving and reliability of images
Exchange of data
17. Special radiographic techniques 177
17.1 Image magnification techniques 177
17.1.1 Common image magnification technique 177
17.1.2 High resolution X-ray microscopy 178
Magnification factors
Microfocus and nanofocus X-ray tubes
Tube heads
System set-up
Effect of focal dimensions
Imaging systems for high resolution radiography
17.2 Fluoroscopy, real-time image intensifiers 182
Stationary real-time installations
Portable real-time equipment
17.3 Computer Tomography (CT) 185
Unique features
Computing capacity and scanning time
Reverse engineering
CT metrology
High resolution and defect sizing
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15. Film interpretation and reference radiographs 123
15.1 Film interpretation 123
15.2 The film-interpreter 124
15.3 Reference radiographs 124
Weld inspection
Casting radiography
Examination of assembled objects
16. Digital Radiography (DR) 145
16.1 Introduction to DR 145
16.2 Digital image formation 146
16.3 Digitisation of traditional radiographs 146
16.4 Computed Radiography (CR) 148
Two-step digital radiography
The CR imaging plate
Image development
Scanners-Readers
CR cassettes
Dynamic range-Exposure latitude
Exposure time and noise
Fading
Optimisation
Improvements
16.5 Genuine Digital Radiography (DR) 153
One-step digital radiography
16.5.1 Detector types 153
Direct versus indirect detection
Linear detectors
2D detectors
16.5.2 Fill Factor 155
16.5.3 Flat panel and flat bed detector systems 156
Amorphous silicon flat panels
CMOS detectors and flat bed scanners
Limitations
16.6 Image quality and exposure energy 158
16.6.1 Exposure energy 158
16.6.2 Determination of image quality 159
16.6.3 Indicators of image quality- MTF and DQE 160
Factors influencing image quality
Image quality definitions
Exposure parameters
MTF (Modulation Transfer Function)
DQE (Defective Quantum Efficiency)
Noise, image averaging and DQE