Radio-wave tomography of hidden objects for safety systems

Abstract

Nowadays the problem of remote sensing of various objects and people to prevent transportation and storage of weapons, explosives, and other forbidden objects becomes urgent in connection with strengthening security measures on counteraction to terrorism all over the world. Methods based on x-ray, magnetic induction, and radar sensing are developed intensively. Methods of x-ray sensing, as a rule, are applied to lifeless objects; in some countries, irradiation of people even by low-power x-rays is forbidden. Methods based on application of magnetic fields are suitable for detecting metal objects; however, they are inapplicable for detecting dielectric targets such as explosives or ceramic knifes. Radio-wave methods are relatively safe for people and allow any objects, including dielectric ones, to be detected. For this reason, methods of micro-wave radar sensing are developed intensively all over the world

Ultrabroad-band tomography of remote objects

“…It can be seen that pulses are distorted upon their reflection from the curved surface of the reflector; thus, their summation with consideration for delays is difficult. In this connection, in order to solve the inverse problem using a scattered field it is necessary to use the method of instrument functions [1]. At a sufficient volume of recorded data and short sounding pulses, the response to a point heteroge neity approaches the "smeared" δ function, thus allowing us to identify the results of focusing with the distribution of dielectric permittivity Δε.…”

Microwave tomography of radiopaque objects

“…It is sufficient only to perform temporal focusing along the depth. The duration of a pulse deter mines the depth resolution of the irregularity [1].…”

“…The problems of the detec tion and identification of prohibited articles in baggage or luggage are also in this group. Although these problems are not simple, a large variety of efficient solutions based on the use of the radiation focusing phenomenon has been developed for them [1].…”

Results of Radio Images Focusing of Three-Dimensional Objects by using Multi-Frequency Multistatical Radiohologram and the Method of Rear Projections

“…К настоящему времени выполнено и опубликовано значительное число работ, посвященных общим принципам функционирования и теории по-строения радиоголографических изображений объектов на основе метода муль-тистатических радиоголограмм (МРГ) [1][2][3][4][5][6][7][8]. Метод существенно отличается от известного ранее метода классических радиоголограмм (КРГ) [9][10][11]. Каче-ственно отличия методов КРГ и МРГ сводятся к следующим положениям.…”