Design and development of a high-performance passive millimeter-wave imager for aeronautical applications

Lettington, Alan H.; Dunn, Dennis; Alexander, Naomi E.; Wabby, Anas; Lyons, B. N.; Doyle, Rory; Walshe, John; Attia, Magdy F.; Blankson, Isaiah M.

doi:10.1117/12.546518

Cited by 11 publications

(7 citation statements)

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“…Both approaches which were discussed in the preceding paragraphs can be realized with mirrors. A Risley type beam steering device for mm-waves based on rotating mirrors is discussed in reference [8].…”

Section: Beam Steering With Macro-optical Mirrorsmentioning

confidence: 99%

Novel laser beam steering techniques

Tholl

2006

SPIE Proceedings

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The paper summarizes laser beam steering techniques for power beaming, sensing, and communication applications. Principles and characteristics of novel mechanical, micro-mechanical and non-mechanical techniques are compiled. Micro-lens based coarse beam steering in combination with liquid crystal or electro-optical phase control for fine steering is presented in more detail. This review addresses beam steering devices which modulate the phase distribution across a laser beam and excludes intra-cavity beam steering, beam steering based on combining tuneable lasers with dispersive optical elements, active optical phased arrays, and optical waveguides.

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Section: Beam Steering With Macro-optical Mirrorsmentioning

confidence: 99%

Novel laser beam steering techniques

Tholl

2006

SPIE Proceedings

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“…The imager design is based on a patented scanning system [1]. Figure 1(a) shows the basic components of the scanning system that consist of rotating and folding mirror optics.…”

Section: Imager Design and Developmentmentioning

confidence: 99%

Illumination strategies to achieve effective indoor millimeter wave imaging for personnel screening applications

et al. 2005

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The ability of millimetre-waves (mm-wave) to penetrate obscurants -be they clothing, fog etc. -enables unique imaging applications in areas such as security screening of personnel and landing aids for aircraft. When used in an outdoor application, the natural thermal contrast provided by cold sky reflections off of objects allow for direct imaging of a scene. Imaging at mm-wave frequencies in an indoor situation requires that a thermal contrast be generated in order to illuminate and detect objects of interest. In the case of a portal screening application the illumination needs to be provided over the imaged area in a uniform, omni-directional manner and at a sufficient level of contrast to achieve the desired signal to noise ratio at the sensor. The primary options are to generate this contrast by using active noise sources or to develop a passive thermally induced source of mm-wave energy. This paper describes the approaches taken to developing and implementing an indoor imaging configuration for a mmwave camera that is to be used in people screening applications. The camera uses a patented mechanical scanning method to directly generate a raster frame image of portal dimensions. Imaging has been conducted at a range of frequencies with the main focus being on 94GHz operation. Experiences with both active and passive illumination schemes are described with conclusions on the merits or otherwise of each. The results of imaging trials demonstrate the potential for using mm-wave imaging in an indoor situation and example images illustrate the capability of the camera and the illumination methods when used for personnel screening.

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“…When compared with active detection systems, PMMW imaging systems don't emit electromagnetic waves and there is no speckle and glint effect, in addition the passive operation mode can benefit the advantages of concealment and interference immunity [3]. Moreover, the ability of millimeter-wave (MMW) to penetrate through smoke, fog, clouds and clothing of certain thickness makes PMMW imaging an attractive approach in a wide range of military and civil practical applications [4], [5], [6], which include remote sensing, blind landing, precision guidance, concealed contraband detection and etc.…”

Section: Introductionmentioning

confidence: 98%

Radiometer uncertainty equation research of 2D planar scanning PMMW imaging system

Zhang

2009

SPIE Proceedings

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With advances in millimeter-wave technology, passive millimeter-wave (PMMW) imaging technology has received considerable concerns, and it has established itself in a wide range of military and civil practical applications, such as in the areas of remote sensing, blind landing, precision guidance and security inspection. Both the high transparency of clothing at millimeter wavelengths and the spatial resolution required to generate adequate images combine to make imaging at millimeter wavelengths a natural approach of screening people for concealed contraband detection. And at the same time, the passive operation mode does not present a safety hazard to the person who is under inspection. Based on the description to the design and engineering implementation of a W-band two-dimensional (2D) planar scanning imaging system, a series of scanning methods utilized in PMMW imaging are generally compared and analyzed, followed by a discussion on the operational principle of the mode of 2D planar scanning particularly. Furthermore, it is found that the traditional radiometer uncertainty equation, which is derived from a moving platform, does not hold under this 2D planar scanning mode due to the fact that there is no absolute connection between the scanning rates in horizontal direction and vertical direction. Consequently, an improved radiometer uncertainty equation is carried out in this paper, by means of taking the total time spent on scanning and imaging into consideration, with the purpose of solving the problem mentioned above. In addition, the related factors which affect the quality of radiometric images are further investigated under the improved radiometer uncertainty equation, and ultimately some original results are presented and analyzed to demonstrate the significance and validity of this new methodology.

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Design and development of a high-performance passive millimeter-wave imager for aeronautical applications

Cited by 11 publications

References 0 publications

Novel laser beam steering techniques

Novel laser beam steering techniques

Illumination strategies to achieve effective indoor millimeter wave imaging for personnel screening applications

Radiometer uncertainty equation research of 2D planar scanning PMMW imaging system

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