Imaging Sensor Technologies and Applications
Imaging sensors are crucial for electronic imaging systems, including digital cameras, camera modules, medical imaging equipment, night vision equipment, radar and sonar, drones, and many others. This contributed book covers a wide range of frequency, sensing modalities and applications, including x-ray beam imaging sensors, optical scattering sensors, smart visual sensors in robotic systems, tuneable diode Laser absorption spectroscopy (TDLAS) sensors, light detection and ranging (LiDAR) sensors, microwave imaging sensors, electro-magnetic imaging with ultra-wideband (UWB) sensors, synthetic aperture radar (SAR), electrical resistance tomography (ERT) sensors, electrical tomography for medical applications, electro-magnetic tomography (EMT) sensors, micro sensors for cell and blood imaging, and ultrasound imaging sensors. Bringing together information on state of the art research in the field, this book is a valuable resource for engineers, researchers, designers and developers, and advanced students and lecturers working on sensing, imaging, optics, photonics, medical imaging, instrumentation, measurement and electronics.
Inspec keywords: optical sensors; optical radar; synthetic aperture radar; ultrasonic transducers; ultrasonic imaging; biomedical imaging; microwave detectors; microsensors; image sensors; X-ray detection
Other keywords: imaging sensors; tunable diode laser absorption spectroscopy sensors; TDLAS sensors; ERT sensors; optical scattering sensors; X-ray beam imaging sensors; electrical resistance tomography sensors; electromagnetic tomography sensors; CCD sensors; light detection and ranging sensors; robotic systems; microwave imaging sensors; microsensors; cell imaging; ultra-wideband sensors; SAR sensors; medical applications; UWB sensors; blood imaging; ultrasonic imaging sensors; MWI sensors; EMT sensors; smart visual sensors; flame measurement; synthetic aperture radar; LiDAR sensors; CMOS sensors
Subjects: Patient diagnostic methods and instrumentation; Optical radar; Measurement by acoustic techniques; Radar equipment, systems and applications; X-ray and gamma-ray equipment; Microwave circuits and devices; Optical instruments and techniques; Image detectors, convertors, and intensifiers; General electrical engineering topics; Image sensors; Textbooks; Sonic and ultrasonic transducers and sensors; Microsensors and nanosensors; Sensing and detecting devices; Microwave measurement techniques; Biomedical measurement and imaging; X-ray, gamma-ray instruments and techniques
- Book DOI: 10.1049/PBCE116E
- Chapter DOI: 10.1049/PBCE116E
- ISBN: 9781785614972
- e-ISBN: 9781785614989
- Page count: 534
- Format: PDF
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Front Matter
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1 X-ray beam imaging sensors
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A non-destructive method of continuously recording the position and intensity distribution of high -intensity synchrotron radiation X-ray beams is described in detail. The method is based on collecting diffusely scattered radiation from a thin membrane using a pinhole camera consisting of state-of-the-art hybrid pixel X-ray detector. The use of specially coded apertures provides, through iterative deconvolution procedures, very detailed images of the X-ray beam. A theoretical model of the imaging and beam position localisation is presented that provides a way to calculate the device performance based on simple geometric parameters of the system and the available photon flux. The model predictions were verified by experiments. The architecture of the embedded processing platform based on heterogeneous computation that is optimised for real time, high frame rate image processing tasks is outlined. Besides sensor control, image processing and network communication tasks the system also provides four independent feedback control signals that can be used to stabilise beam position and intensity. Some key results obtained at two synchrotrons are presented which show that the proposed instrument is capable of achieving a sub-micrometre precision although sensor pixel size is significantly larger. The system is in operation at several synchrotrons around the world.
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2 Optical scattering sensors
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This chapter will cover four of the commonly used methodologies for particle measurement, that is static light scattering, dynamic light scattering, RGB multi-wavelength light extinction and ultrasonic scattering. For each of these methodologies, the measurement principle, data processing or inversion algorithm, experimental system and some measurement results are included.
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3 Smart visual sensors in robotic systems
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This chapter presents smart visual sensing in robotic system. Smart robotic systems are based on visual feedback and have many applications in real-time, such as in warehouse, search and rescue operations and health care. The objective of visual sensing is to control a robotic system while an error corrector loop is established in desired visual features. This is called visual servoing or hand -eye coordination
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4 CCD and CMOS sensors and their applications in flame measurement
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This chapter introduced the detailed architectures, characteristics, as well as advantages and disadvantages of two imaging sensors, that is CCD and CMOS sensors, and CCD/CMOS-based cameras. It also covers visualisation techniques for advanced flame measurement and characterisation. These techniques can be categorised according to the principle employed. The 2D measurement of flame geometry and luminosity can be achieved using relatively simple imaging techniques. Two-colour pyrometry incorporating with digital imaging and image processing has been an effective approach for 2D measurement of flame temperature. A variety of laser-based imaging techniques have been developed and widely used for the 2D and 3D measurement of laboratory -scale fl ames, particularly the microstructures and the particle velocity profile of the flame.
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5 Tunable diode Laser absorption spectroscopy (TDLAS) sensors
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In the experiments, Lasers scanning across the central wavelength of 7,185 cm-1 are used to reconstruct the absorbance distributions in the test regions. The TDLAS sensor is first installed on steel framework standing on the ground. All the Lasers are checked before the wind tunnel starts to blow and ignite. After the ignition, no visible flame can be seen at the testing section, but the TDLAS sensor enables the flame visible in terms of the spectral absorbance. In the range from 600 K to 1,300 K, the absorbance of water over the spectral centring at 7,185 cm -1 rises along with an increasing temperature. The distributions of water absorbance at different stages of the wind tunnel operations are reconstructed. The distributions show that the absorbance in the centre is significantly larger than that in the other parts, and six typical stages for the temperature rising are listed.
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6 Light detection and ranging (LiDAR) sensors
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In this chapter, a TLS is introduced as a typical TOF LiDAR sensor, including sections on TLS systems, error analysis and applications.
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7 Microwave imaging sensors
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Microwave imaging (MWI) systems are nowadays acquiring an ever-growing importance in numerous application fields, such as non-destructive testing (NDT) in civil and industrial applications, subsurface sensing and ground penetrating radar (GPR) prospection, through-wall imaging (TWI) for security and biomedical imaging. MWI systems use an electromagnetic (EM) radiation to illuminate the structure under test (SUT) and exploit the interaction with it to extract information about its physical and geometrical parameters. MWI sensors are constituted by antennas, which are used to generate the incident radiation and collect the field resulting from the EM interaction with the SUT. This chapter, after a brief introduction to the MWI problem and the configuration of the measurement systems, discusses several typologies of MWI antennas and their applications.
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8 Electro-magnetic imaging with ultra-wideband (UWB) sensors
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Both the multi-step and singe -step solutions to UWB inverse scattering problem are first discussed in this chapter. In the former, the CDF-Broyden update using the refined Polak-Rebiere's non -quadratic approximation will be focused. Meanwhile, the enhanced delay and sum (EDAS) algorithm, which uses the coherence factor and multiply in pair will be the principal topic of the later technique. In both cases the dispersive properties of the media are modelled using Debye first-order system, while the conformal mapping is deployed to accurately map curved geometries. The second part of the chapter focuses on an UWB radar data acquisition system, which is specifically developed to assess the performance of these algorithms experimentally. The hardware consists of custom-designed wideband antennas mounted on arrays and connected to a vector network analyser (VNA) via a 16-channel multiplexer switch unit. This set-up allows measurements be performed in the time domain automatically. Both limited-view and full-view geometries are used for measurements.
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9 Synthetic aperture radar (SAR)
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This chapter introduced the basic concepts of SAR and the principle of 2D target resolution. Obtaining high range resolution with wideband signal and high azimuth resolution with long synthetic array is the basis of the 2D high-resolution imaging. RDA is widely used in SAR imaging processing. Azimuth-translation invariance is the key of RDA. This chapter described the major processing step of RDA, including range compression, range migration correction and azimuth compression, and derives the signal expression of the key step. With the development of SAR imaging requirements, SAR has developed a variety of working modes. This chapter also introduced the working geometry of Stripmap mode, Spotlight mode, Sliding Spotlight mode, TOPS mode and Scan mode, established the unified signal model for multi-modes and analysed the signal property. In imaging processing for multi modes, a unified focusing algorithm based on FrFT is shown, which can simultaneously process Stripmap, Spotlight, Sliding Spotlight and TOPS SAR mode data. The focusing algorithm is parameterised into a rotation angle or a rotation factor, which is determined by the rotation centre distance. Real data of different modes can be well focused by using different and appropriate rotation angles.
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10 Electrical resistance tomography (ERT) sensors and applications
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This chapter is about ERT sensors and systems as well as their applications, including optimal design of electrode arrays and sensor architecture based on an objective function and data acquisition system. DAS includes sinewave generators, signal conditioning circuits, VCCS, signal conditioning circuits and digital demodulation. Some typical applications are introduced, including mixers, pipes, reactors on process vessels and fluidised beds, with various aqueous conductive media, such as water, saline, pseudo plastic fl uids and dairy products. Because ERT has low spatial resolution and high temporal resolution, ERT sensors should be optimised according to the characteristics of the measured object, and SNR and resolution of data acquisition system should be improved. To improve image reconstruction, prior information should be used, for example combining the characteristics of the tested object.
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11 Electrical tomography for medical applications
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Electrical impedance tomography (EIT) has good capability of obtaining images with advantages of non-intrusive, fast response and low cost. It is expected to be an ideal imaging technique for medical applications, particularly for long-time healthcare monitoring. However, as a new imaging technique, it encounters a number of challenges when EIT is applied for clinical applications. Current medical EIT systems show common problems of low spatial resolution, insufficient sensitivity and inaccurate localisation, which may be partially improved by using novel image reconstruction algorithms and mathematical forward models from high resolution image, such as MRI and CT. Developing multi-frequency systems is a trend for further research into medical EIT as they can provide time-difference and frequency-difference information. Operating at multi-frequencies can find optimal operation frequency that produces high image contrast to distinguish lesion and normal tissue. More importantly, by using multi-frequency the problem can be solved when an object is imaged without prior knowledge or when it is impossible to obtain baseline dataset in most clinical cases. Further investigation on multi-frequency EIT is needed to improve hardware design and frequency selection. Most medical EIT systems rely on current-driven for safety reason. However, a voltage-driven EIT system may be more desirable as it is technically easier to implement with high precision and a broader frequency range.
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12 Electro-magnetic tomography (EMT) sensors
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EMT has found increasing applications in industrial processes and biomedical applications, such as imaging molten steel fl ow and detecting brain oedema. Further developments of the technique would benefit from advances in fast forward and inverse solvers, low cost yet high performance systems and new emerging application areas such as in landmine detection, food inspection and security applications.
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13 Micro-sensors for cell and blood imaging
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Cell and blood imaging is a key process for developing biomedical measurement devices. Visualisation for measuring cell concentration distribution can potentially improve the control of cells in micro-fluidic flow, and also it is useful for validating computational models of cells distribution in micro-fluidics. Electrical impedance tomography (EIT) is one of the visualisation technique to measure the electrical conductivity or permittivity distribution within a medium using electrical measurements from a series of electrodes on the surface of the object. EIT uses low frequency (0-10 MHz), low voltage (0-5 V) and low current (0-4 mA). It has advantages, such as no radioactive source, non-invasive, fast and low cost. EIT has been widely used for biological applications.
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14 Ultrasound imaging sensors
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This chapter describes theories and technologies about ultrasound imaging. As a mechanical wave, ultrasound propagates in the imaging zone, and the echoes deliver information about the position and properties of non -uniformities inside the specimen. The most commonly used device for ultrasound transmission and reception is piezoelectric ultrasound transducers and their arrays. Vibration modes and design principles were discussed in detail. Other ultrasound transmission and/ or reception technology include CMUT and optical -based acoustic sensing. Multiple imaging modes are available in ultrasound imaging. Finally, typical ultrasound imaging modes are described, including A -mode, B -mode, M -mode, IUVS, Doppler imaging and harmonic imaging modes.
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Back Matter
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