Neil Salmon

The generalized three-dimensional (3-D) van Cittert– Zernike (VCZ) theorem highlights the opportunity for short-range passive 3-D imaging as a means of screening the entire human body surface of a walking subject for law enforcement applications. Building on passive millimeter-wave (PMMW) aperture synthesis instrumentation development at Beihang Un...

This paper proposes a three-layer electromagnetics model for investigating the interaction of millimetre wave radiation with human skin and clothing as a means to improve security screening technology. Progress in this spectral band is only possible with a deep understanding of the interaction of this radiation with the human body, the clothing and...

Improving the security screening requires good knowledge and understanding of human skin signatures. Our previous publications indicate that the signature of the human skin varies from person to person under a dry and wet state. Human skin is a very sensitive organ and not all material can be applied or attached directly to the skin. Therefore, it...

The physical security of government buildings, banks, schools, higher education institutions, train stations, airports and lastly but not least the people within them has been the key for the sustainability of our society. Day after day, technologies have been invented to improve the physical security of buildings. In this paper a Thru-Vision passi...

Surrogate explosives and shrapnel weapons at a range of 2 metres have been measured using a full polarimetric radar operating over the band 18-26 GHz. Measurements of these items were made as they were standing by themselves and as they were placed on the body, under light clothing. These measurements were compared with measurements made of the div...

Despite the rising interest in the human skin signature over the millimetre wave band there is relatively little information about the human skin reflectance and the dielectric properties of the human skin, and how these varying with locations and between gender, and hydration level of the skin. This paper has investigated the reflectance of the hu...

The paper discusses the scene simulation of radiometric imagers and its use to illustrate the phenomenology of full-body screening of people for weapons and threats concealed under clothing. The aperture synthesis technique is introduced as this offers benefits of wide field-of-views and large depths-of-fields in a system that is potentially confor...

A combined ferrite parametric amplifier and millimeter-wave homodyne interferometer are proposed as an ambient temperature Bell Test. It is shown that the non-linear magnetic susceptibility of the yttrium iron garnet (YIG) ferrite, on account of its narrow line-width Larmor precessional resonance, make it an ideal material for the creation of entan...

The millimeter-wave band is an ideal part of the electromagnetic radiation to diagnose human skin conditions because this radiation interacts only with tissue down to a depth of a millimetre or less over the band range from 30 GHz to 300 GHz. In this paper, radiometry is used as a non-contact sensor for measuring the human skin reflectance under no...

A combined ferrite parametric amplifier and millimeter-wave homodyne interferometer are proposed as an ambient temperature Bell Test. It is shown that the non-linear magnetic susceptibility of the yttrium iron garnet (YIG) ferrite, on account of its narrow line-width Larmor precessional resonance, make it an ideal material for the creation of entan...

The uploaded data file provides details measurements of the dressing materials over the Millimetre-Wave band from 15 GHz to 40 GHz using Vector Network Analyser.

Our recent studies in the human skin signatures indicate a strong correlation between the human skin emissivity and factors such as the body mass index, the gender, the age, and the ethnicities of the participants. The key innovation in this is in recognising that signatures from the human body enable regions of the body to be identified as skin. T...

This paper describes the experimental setup and measurements of the emissivity of porcine skin samples over the band of 80–100 GHz. Measurements were conducted on samples with and without dressing materials and before and after the application of localized heat treatments. Experimental measurements indicate that the differences in the mean emissivi...

This poster presents the concept of a quantum mechanical Bell Test for entangled photons in the millimetre wave band. An entangler and analyser circuit are presented, exploiting coherent integration using radio receiver technology to overcome levels of thermal noise being higher than the flux of entangled photons. Schemes exploiting non-linear elem...

This paper investigates the feasibility of operating a Bell Test for millimetre wave entangled photons using ambient temperature instrumentation, raising the question as to whether this can be done in a regime where the photon energy (hf/e ~ 60 micro-eV at 10 GHz) is far smaller than the thermal energy (kT/e ~ 25 milli-eV at 290 K). It also raises...

Aperture synthesis for passive millimetre wave imaging provides a means to screen people for concealed threats in the extreme near-field configuration of a walk-through portal; a regime where the imager to subject distance is of the order of both the required depth-of-field and the field-of-view. As shown here, the field-of-view in these scenarios...

The Huynen polarisation fork as a representation of the full polarimetric radar signature represents a unique and natural description of a target. This paper investigates the use of full polarimetric radar operating over the band 18-26 GHz to measure the Huynen target parameters of size, orientation, helicity, skip angle and fork angle from a range...

Due to changes in global security requirements attention is turning to new means by which anomalies on the human body might be identified. For security screening systems operating in the millimeter wave band anomalies can be identified by measuring the emissivities of subjects. As the interaction of millimeter waves with the human body is only a fr...

A model for scene simulation is presented which describes quantitatively the recognized phenomenology of passive millimeter wave imaging in land, sea and air scenarios. The model describes objects in a scene as facets giving them electromagnetic properties from their electrical permittivities. This enables polarimetric effects in scenes to be repro...

A radar system is used to obtain information about the structure of dressing materials and hand support cast. The system is used also to assess the feasibility of using active radiation to penetrate dressing materials at different state (dry, wet and with cream) and provide information about the metal plate under the dressing. A comparison is made...

A technique to measure the human skin emissivity in vivo is described for the frequency band 80–100 GHz. Emissivity measurements were performed on 60 participants, 35 males and 25 females, with ages ranging from 20 to 60 years. Results show that the emissivity of males is higher than that of females. The study suggests a trend in the emissivities w...

A half-space electromagnetic model of human skin over the band 30–300GHz was constructed and used to model radiometric emissivity. The model showed that the radiometric emissivity rose from 0.4 to 0.8 over this band, with emission being localized to a layer approximately one millimeter deep in the skin. Simulations of skin with differing water cont...

Over the past few decades technology in the millimetre wave band has shown a steady and consistent development and increased usage, with a wide variety of devices and system architectures (imaging, non-imaging, radiometers and radars) sensors becoming available. As an imaging sensor, these systems can deliver spatial resolutions of less than the wa...

Aperture synthesis for passive millimetre wave imaging provides a means to screen people for concealed threats in the extreme near-field configuration of a portal, a regime where the imager to subject distance is of the order of both the required depth-of-field and the field-of-view. Due to optical aberrations, focal plane array imagers cannot deli...

With the performance of millimeter wave security screening imagers improving (reduced speckle, greater sensitivity, and better spatial resolution) attention is turning to identification of anomalies which appear on the human body. Key to this identification is the understanding of how the emissive and reflective properties vary over the human body...

The development and measurements are described of a frequency modulated continuous wave (FMCW) mono-static millimetre wave full polarimetric radar, operating at k-band (18 to 26 GHz). The system has been designed to explore the feasibility of using full polarimetry for the detection of concealed weapons, and person borne improvised explosive device...

In England and Wales, around 3750 people are admitted to hospital annually with burn and scald injuries1. Current assessment and monitoring of wound healing is through visual inspection, necessitating the removal of dressing materials. The removal of dressing layers can cause medical problems, be uncomfortable or painful to the patient. Currently,...

In England and Wales, around 3750 people are admitted to hospital annually with burn and scald injuries [1]. Current assessment and monitoring of wound healing is through visual inspection, necessitating the removal of dressing materials. The removal of dressing layers can cause medical problems, be uncomfortable or painful to the patient. Currentl...

Visual inspection is the current protocol for monitoring the wound healing progress. This protocol gives an excellence indicator about the state of the wound and the healing progress, and more importantly, it can detect signs of infections such as exudates, redness, swelling, heat, functionality of the infected part and pus draining (Cunha, 2016)....

This paper presents the theory and algorithm of how a three-dimensional (3D) image can be generated using cross-correlations of radiometric emission from a source measured using antennas in the near field. An example of how the algorithm is used to create 3D images of emission measured from a noise source is presented, indicating the presence of Fr...

This paper investigates by simulation the use of the three-dimensional aperture synthesis imaging technique to image three-dimensional extended sources. Software was written to access the three-dimensional information from computer graphics models in the formats of *.dxf and *.3ds and use these to generate synthetic cross-correlations, as if they w...

This paper presents part of a feasibility study into the use of the aperture synthesis passive imaging technique to screen vehicles for persons. The aperture synthesis technique is introduced and shown how in the near-field regime of a vehicle screening scenario that a three-dimensional imaging capability is possible. A suggested antenna receiver a...

The aperture synthesis technique, historically used for imaging in radio astronomy, is generalized to three dimensions as a means to generating 3-D images in the near-field. The technique uses a multi-channel electronic cross-correlator and an array of radio receivers to generate a 3-D visibility function. This is transformed by a 3-D inverse Fouri...

This report summarizes recent work on passive and active millimeter-wave imaging technology, with a major focus on passive imaging, recognizing that sparse arrays will be used more and more in the future. The use of MMW imaging has been shown to be a robust and versatile imaging modality that serves to complement visible and infrared imaging system...

The three dimensional (3D) aperture synthesis imaging technique investigated here is a generalisation of the classic two-dimensional radio astronomy technique with refinements for the near-field so it can be applied a personnel security screening portal. This technique can be viewed as a novel form of diffraction emission tomography and extends pre...

An extension of the radio astronomy technique of aperture synthesis imaging into novel near-field three-dimensional microscopy is discussed. The basics of near-field aperture synthesis imaging are overviewed and results of demonstrators and simulations are presented. Spatial variations in the phase of near-field aperture synthesis signals are exami...

Image processing techniques can be used to improve the cost-effectiveness of future interferometric Passive MilliMetre Wave (PMMW) imagers. The implementation of such techniques will allow for a reduction in the number of collecting elements whilst ensuring adequate image fidelity is maintained. Various techniques have been developed by the radio a...

The unique selling proposition of millimetre wave technology for security screening is that it provides a stand-off or portal scenario sensing capability for non-metallic threats. The capabilities to detect some non-metallic threats are investigated in this paper, whilst recommissioning the AVSEC portal screening system at the Manchester Metropolit...

This paper investigates by simulation some of the capabilities of near-field and three-dimensional imaging which are made possible by accessing phase and amplitude of electric fields from radiometric emission using aperture synthesis systems. The aperture synthesis technique is the main stay of high resolution radio astronomy and is investigated he...

The feasibility of screening hand luggage for concealed threat items such as Person-Borne Improvised Explosive Devices (PBIED's) both metallic and non-metallic, together with handguns and at millimetre wavelengths is investigated. Previous studies by the authors and others indicate that hand baggage material and fabric is much more transmissive and...

The feasibility of screening hand luggage for concealed threat items such as Person-Borne Improvised Explosive Devices (PBIED's) both metallic and non-metallic, together with handguns and at millimetre wavelengths is investigated. Previous studies by the authors and others indicate that hand baggage material and fabric is much more transmissive and...

Recent military conflicts have shown the importance and necessity of proper surveillance and reconnaissance in order to plan and carry out well-directed military strikes against hostile forces and infrastructures. In mountainous regions or in highly urbanized areas imaging orientation for data acquisition would be desirable to avoid information gap...

A large 1.6 m aperture mechanically scanning quasi-optical millimetre wave imaging system designed for active use [1] has been investigated for its passive millimetre wave (PMMW) imaging capabilities. This raises new challenges for this imager, as the person / background contrast in indoor security scenarios at these frequencies is in the region of...

Satellite Low Noise Block-down convertors (LNBs) have been evaluated for use in amplitude and intensity interferometry. LNBs have been found to have a high performance to cost ratio which is beneficial for any sensor system. They are investigated here for a diversity of applications from the derisking of subsystems for next generation aperture synt...

The relatively short wavelength of mm-wave and THz radiation coupled with good transmission through many dielectric materials allows images to be formed of concealed objects. This chapter gives an overview of the detectors, their associated circuitry, and system developments over the past 10 years, focussing on personnel security screening. We will...

This PDF file contains the front matter associated with SPIE Proceedings Volume 8544, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

This paper discusses the phase effects in the near-field associated with aperture synthesis imaging. The results explain why in some regions of the near-field it is possible to use Fourier transform techniques on a visibility function to create images. However, to generate images deep inside the near-field alternative processing techniques such as...

This PhD programme is contributing to the development of Passive Millimetre-Wave Imagers (PMMWI) using the principles of interferometric aperture synthesis and digital signal processing. The principal applications are security screening, all-weather flight aids and earth observation. To enhance the cost-effectiveness of PMMWI systems the number of...

A passive detection device is disclosed comprising a plurality of antennas, receivers, and a digital beamformer, wherein the antennas and receivers are adapted to receive radiation of millimetre wavelengths from a near field region, to process and digitise it. The beamformer is adapted to process the received information and to generate static imag...

This contains the front matter associated with SPIE Proceedings Volume 8188, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

This paper examines the sourcing of low cost components for next generation passive millimetre wave (PMMW) aperture synthesis imagers. Splitting the elements of the imager into antennas/receivers, analogue to digital converters (ADCs), digital signal processors (DSP) and a host computer, technologies are identified that can minimise the cost of the...

The first video rate imagery from a proof-of-concept 32-channel 22 GHz aperture synthesis imager is reported. This imager has been brought into operation over the first half of year 2011. Receiver noise temperatures have been measured to be ~453 K, close to original specifications, and the measured radiometric sensitivity agrees with the theoretica...

A millimeter wave imaging apparatus and method capable of identifying the presence of relatively thin dielectric materials is disclosed. The method involves taking a plurality of millimeter wave images of a scene at different frequencies and analyzing the images at different frequencies to look for frequency dependent effects in the scene. Relative...

The first passive millimetre wave (PMMW) imagery is presented from two proof-of-concept aperture synthesis demonstrators, developed to investigate the use of aperture synthesis for personnel security screening and all weather flying at 94 GHz, and satellite based earth observation at 183 GHz [1]. Emission from point noise sources and discharge tube...

This paper discusses a practical and affordable approach to the accurate calibration of electronic beam-forming passive millimetre-wave imagers. With the aim of calibrating imagers with radiometric sensitivities DeltaT < 1 K, we have constructed a thermal radiation source at ambient temperature that fills the imager field-of-view at close range and...

An improved millimeter wave illumination system includes at least one primary source of millimeter wave radiation, a reflecting surface and a baffle comprising a plurality of exit apertures arranged such that at least some of the radiation from the source is reflected from the reflective surface before proceeding to the baffle, characterized in tha...

This Applied Optics feature issue spotlights developments in the emerging areas of millimeter, sub millimeter, and terahertz imaging.

Millimetre and terahertz radiation penetration into materials enables non-destructive testing capabilities for the aerospace industry, either remotely using imaging technology or locally using microscope type diagnostics. This paper presents measurements made on Norcoat and Prosial, used in the aerospace industry for thermal insulation and on carbo...

A security portal comprises an array of antenna elements and associated receivers sensitive in a frequency band chosen from within the centimetric to sub-millimetre wavelengths, the antenna array being located on a moveable panel. Radiation with the frequency band from a target person or object is measured at a first and second time within the near...

The papers included in this volume were part of the technical conference cited on the cover and title page. Papers were selected and subject to review by the editors and conference program committee. Some conference presentations may not be available for publication. The papers published in these proceedings reflect the work and thoughts of the aut...

A radical new approach to Passive Millimetre Wave Imaging has been proposed in which all of the discrete receiver modules that are used in current systems are replaced with a single integrated staring focal plane array. In addition, the frequency of operation, at 220GHz, will offer superior spatial resolution within an acceptable array size, compar...

Radiometers detect radio wavelength electromagnetic radiation and typically have an antenna (16), an amplifier (18) and a detector (20). All three of these components have response characteristics that may be dependent on temperature, and in the case of systems using radiometer arrays dependent upon temperatures throughout the system. Different tem...

This paper overviews the development of digital beam-forming passive millimetre wave (PMMW) imagers at the frequencies of 22.51 GHz, 91.65 GHz, and 183.31 GHz. These systems are demonstrators for imager architectures that can evolve into security screening products, all weather flying aids, satellite based imagers for planetary observation and test...

QinetiQ has used a suite of modelling tools to predict the millimetric plume signatures from a range of ballistic missile types, based on the accepted theory that Bremsstrahlung emission, generated by the collision of free electrons with neutral species in a rocket motor plume, is the dominant signature mechanism. Plume signatures in terms of radia...

Passive millimeter wave (PMMW) imaging technology offers great potential for modern sensing, scanning, and security needs. In security screening equipment, PMMW can see through a variety of clothing and baggage materials and is effective in detecting both metallic and non-metallic threats, such as plastic and ceramic weapons. PMMW can also provide...

An illumination source of predominantly non-directional and incoherent millimeter-wave radiation for illuminating an area for passive millimeter-wave imaging comprises a container with at least a partly reflective internal surface and a plurality of exit apertures and a primary source of millimeter-wave radiation for emitting millimeter-wave rad...

This paper reviews digital beam-forming as an alternative technology for the development of passive millimetre wave (PMMW) imagers. Considering recent technology developments and end-user requirements, digital beam-forming is an attractive prospect for a new architecture of PMMW security imager. The radiometric sensitivity in PMMW electronic beam-f...

This paper reviews the use of digital beam-forming technology for the passive millimetre wave (PMMW) imagers. Considering the mathematics of beam-forming, the developments in technology and the end user requirement, this new architecture of PMMW imager might offer an attractive prospect for security scanning technology. The radiometric sensitivity...

This paper reviews digital beam-forming as an alternative technology for the development of passive millimetre wave (PMMW) imagers. Considering recent technology developments and end-user requirements, digital beam-forming is an attractive prospect for a new architecture of PMMW security imager. The radiometric sensitivity in PMMW electronic beam-f...

This paper describes the further development of a scene simulation model to include the phenomenology of scattering. Scattering gives rise to increased absorption within media and forward and backscatter leads to a modification of the subject illumination. The amount of scattering from objects is linked to the relation between the radiation wavelen...

This paper describes the further development of a scene simulation model by the introduction of multiple reflections and subjects with backgrounds. Inclusion of these features enables more realistic imagery to be created, reproducing known phenomenology in passive millimetre wave imagery, such as specular reflections of objects in concrete or tarma...

Radiometers detect radio wavelength electromagnetic radiation and typically have an antenna (16), an amplifier (18) and a detector (20). All three of these components have response characteristics that may be dependent on temperature, and in the case of systems using radiometer arrays dependent upon temperatures throughout the system. Different...

The need to develop passive millimetre wave imaging systems which have better spatial resolution and sensitivity, to offer powerful discrimination capabilities, is great. On the other hand, many deployment scenarios dictate the system footprint to be smaller than that of existing imagers. This dilemma may be resolved by replacing the bulky quasi-op...

The need to develop passive millimetre wave imaging systems which have better spatial resolution and sensitivity, to offer powerful discrimination capabilities, is great. On the other hand, many deployment scenarios dictate the system footprint to be smaller than that of existing imagers. This dilemma may be resolved by replacing the bulky quasi-op...

The benefits of moving up in frequency from the millimetre wave region towards a frequency of 1 THz are those of smaller systems and better diffraction limited image resolutions. Limitations will be examined, considering effects such as the absorption in the atmosphere, various materials, the human body and fundamental radiometric noise limitations...

This paper describes the general requirements and an approach to scene simulation in millimetre wave radiometric imaging that is based on multi faceted semitransparent layered media in the earth"s three-dimensional geometry. The driving attributes in this field are essentially the transparency of clothing for security scanning and the transparency...

A millimetre wave imaging apparatus comprises a scanning mechanism, a reflector lens and a receiver array. The scanning mechanism comprises two wedge prisms which scan radiation incident upon them across the receiver array in an elliptical pattern. This optical configuration is such that the pupil plane, defined by the scanning mechanism, is loc...

This paper reviews the feasibility and requirements of scanning passive millimetre wave imaging systems based on the latest electronic technologies. The sensitivities, bandwidths and field-of-views of imaging radiometers are examined on the basis of large numbers (several hundreds) of distributed antennas and receivers. Transfer functions and point...

It is well known that millimetre wave systems can penetrate poor weather and battlefield obscurants far better than infrared or visible systems. Thermal imaging in this band offers the opportunity for passive surveillance and navigation, allowing military operations in poor weather. We have previously reported a novel real time mechanically scanned...

An object detection apparatus which includes a radiation source in the form of an amplifier and a detection arrangement. The apparatus has a tuner which determines a coherence length. The apparatus detects an object which is buried/concealed at a depth, d, is beneath a surface provided that the depth, d is less than the coherence length. To be a...

This paper reviews incoherent detection polarimetry as used in passive millimetre wave imaging. The Stokes' parameters are discussed together with the information content contained in polarimetric passive millimetre wave images. Experimental polarimetric data is presented and used to generate images of the Stokes' parameters. The degree of polarisa...

This paper describes scene simulation in passive millimetre wave imaging. The appearance of metal and plastic objects are modelled lying flat on earth, as viewed at grazing incidence (from a ground platform) and perpendicularly (from an air platform), using a passive millimetre wave imager. The assumptions and essential physics behind the simulatio...

This paper describes scene simulation in passive millimetre wave imaging. The appearance of flat metal and plastic objects is simulated, as viewed from a grazing incidence angle, using a passive millimetre wave imager. The assumptions and essential physics behind the simulation are reviewed. The simulations are made in the atmospheric window at 90...

This paper reviews incoherent detection polarimetry as use din passive millimeter wave imaging. The Stokes' parameters are discussed together with the information content contained in polarimetric passive millimeter wave images. Experimental polarimeter data is presented and used to generate images of the Stokes' parameters. The degree of polarizat...

The movements of clouds and moist air are responsible for temporal changes in sky radiation temperatures. Detailed here are measurements of the sky radiation temperatures made during periods of cloud movement and light rain. The measurements were made over the frequency bands 26 to 40 GHz (in the ka-band) and 90 to 98 GHz (in the w-band) using a di...

The movements of clouds and moist air are responsible for temporal changes in sky radiation temperatures. Detailed are measurements of the sky radiation temperatures made during periods of cloud movement and light rain. The measurements were made over the frequency bands 26 to 40 GHz (in the ka-band) and 90 to 98 GHz (in the w-band) using a direct...

This paper investigates the use of the rotational molecular resonance lines of carbon monoxide for the detection of this gas. Active and passive techniques are investigated, concluding that a passive technique is feasible but that an active technique is not. The passive technique would use a three channel spectral radiometer tuned on and around the...

Passive millimetre wave imaging systems have been developed and their applications investigated at DERA Malvern for several years. In this paper the applications of passive millimetre wave imaging for the detection of exhaust gases is investigated. In principle, this is feasible over the whole of the millimetre wave band. DERA has developed the wor...

Coherent effects in passive centimeter and millimeter wave emission used to detect landmines is investigated. The work concentrates on the modeling of the radiation temperatures of buried metal and plastic plates. A two interface model, which uses the dielectric constants of the media, is used to predict the radiation temperatures. Conclusions are...

This paper describes a novel real time mechanically scanned passive millimeter wave imager. This imager produces a field of view of 40 degree(s) X 20 degree(s) with diffraction limited performance and a 25 Hz frame update rate. It is relatively inexpensive because the scene is imaged using 32 direct detection receivers with a frequency of operation...

A w-band passive millimeter imager is proposed for use on a helicopter platform. The atmospheric transmission through fog and rain is much higher in the millimeter wave band than it is in the visible or infrared regions of the spectrum. This property enables passive millimeter wave imaging systems to offer recognizable imagery in adverse weather co...