&lt;title&gt;Passive millimeter-wave camera flight tests&lt;/title&gt;

Moffa, P.J.; Yujiri, L.; Jordan, Karen; Chu, R.; Agravante, Hiroshi H.; Fornaca, S.

doi:10.1117/12.391830

Cited by 15 publications

(7 citation statements)

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“…In the first, a large array of millimeter-wave receivers is placed in the focal plane of a lens. 5,6 This allows high frame rates to be achieved because the entire image is acquired at once. The second approach is to build up an image over a 2-D plane by mechanically scanning an antenna with a Paper 08050R received Apr.…”

Section: Introductionmentioning

confidence: 99%

“…The last ten years have seen increasing interest in millimeterwave imaging systems, [1][2][3][4][5][6][7][8][9] generally operating around 94 GHz. These imaging systems have less spatial resolution than optical or infrared systems, as a consequence of the much longer wavelength; however, they have an advantage over optical and infrared sensors in their ability to see through clouds, fog, smoke, and clothing materials.…”

Section: Introductionmentioning

confidence: 99%

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Design and testing of an active 190-GHz millimeter-wave imager

Timms

2010

J. Electron. Imaging

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The design and testing of an active 190-GHz imaging system is presented. The system features two beam-scanning antennas, one of which transmits a vertical fan beam, and the other which receives a horizontal fan beam. By correlating the transmitted and received signals, an output is obtained that is proportional to the millimeter-wave reflectivity at the intersection of the two fan beams. Beam scanning is obtained by rotating a small subreflector within each antenna, allowing rapid scanning. The system has an angular resolution of 0.3 deg, a field of view of 14 × 14 deg, and operates at a standoff distance of 5 m.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Design and testing of an active 190-GHz millimeter-wave imager

Timms

2010

J. Electron. Imaging

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“…The last ten years have seen increasing interest in millimeter-wave imaging systems [1][2][3][4][5][6][7] , generally operating around 35 or 94GHz. These imaging systems have less spatial resolution than optical or infrared systems as a consequence of the much longer wavelength, however they have an advantage over optical and infrared sensors in their ability to see through clouds, fog, smoke and clothing materials.…”

Section: Introductionmentioning

confidence: 99%

“…The first is to place an array of millimeter-wave receivers in the focal plane of a lens 5,6 . This allows high frame rates to be achieved because the entire image is acquired at once.…”

Section: Introductionmentioning

confidence: 99%

A 190GHz active millimeter-wave imager

et al. 2007

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The design and testing of a 190 GHz imaging system is presented. The system features two beam-scanning antennas; the first transmits a horizontal fan beam and the second receives a vertical fan beam. By correlating the signals from the antennas, an estimate of the millimeter-wave reflectivity at the intersection of the fan beams is obtained. Each fan beam is scanned by rotating a small subreflector within the antenna; this simple rotation motion allows rapid scanning. The system is portable, currently approximately 0.6m × 0.6m × 2m high; the key size constraint is imposed by the 450 mm aperture length of the antennas. The imager has an angular resolution of 0.25° and a field of view of 14° × 14°, resulting in a raw image of approximately 50 × 50 pixels. The raw image is processed using super-resolution techniques. Images will be presented which show the capability of the system to image metallic and ceramic objects beneath clothing. These images were obtained by illuminating the scene with signals from a frequency-doubled Gunn oscillator. While this paper focuses on active imaging, the system can also operate in passive mode with reduced sensitivity.

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“…In the last ten years many passive millimeter-wave imaging systems [1][2][3][4][5][6][7] have been proposed. Even though they have less spatial resolution than optical or infrared systems as a consequence of their longer wavelength, they have an advantage over optical and infrared sensors in their ability to see through clouds, fog, smoke and clothing.…”

Section: Introductionmentioning

confidence: 99%

Passive mm-wave imaging using two scanning fan-beam antennas

Timms

Archer

et al. 2007

SPIE Proceedings

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A prototype cross-correlating 190 GHz passive mm-wave imaging system has been developed. This system is based on the Mills Cross system used for radio astronomical imaging. It uses two pillbox antennas arranged in a T configuration. Each antenna generates a fan beam and the two fan beams are orthogonal to each other. By cross-correlating signals received from the two antennas, an output is obtained which is proportional to the millimeter-wave intensity radiated from the target at the intersection of the two fan beams. Beam scanning is generated by rotating a small sub-reflector inside each antenna. As a result, these relatively heavy antennas are stable during scanning and a high frame rate can be achieved. Another advantage of this approach is that only two receivers are required. The baseline (the displacement between phase centers of the two antennas) of this system is not zero, because the phase centers of the two antennas are not located at the same position. The baseline generates a fringe in the imaging system and its influence on the performance of the system is analyzed in this paper. The scanning speed of this system is also much faster than that of the Mills Cross imaging system and its influence on the resolution is also analyzed. It is found that the effect of the scanning speed is minimized when the beam scans along the equal-phase line of the fringe. This system can also be used as an active imaging system and this is discussed in another paper.

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<title>Passive millimeter-wave camera flight tests</title>

Cited by 15 publications

References 0 publications

Design and testing of an active 190-GHz millimeter-wave imager

Design and testing of an active 190-GHz millimeter-wave imager

A 190GHz active millimeter-wave imager

Passive mm-wave imaging using two scanning fan-beam antennas

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