Abstract: A system for characterizing a dielectric object situated adjacent to an electrically conductive surface comprises a radiation source configured to radiate electromagnetic energy toward the dielectric object, and a receiver configured to receive scattered electromagnetic energy scattered by the dielectric object and the electrically conductive surface. The system may further comprise a control subsystem, coupled to the radiation source and the receiver, that determines an apparent focal point within the object, determines a phase shift associated with the scattered electromagnetic energy with respect to the electromagnetic energy radiated by the radiation source, and determine a thickness and an index of refraction of the object based, on the apparent focal point and the phase shift. The system may determine the apparent focal point by scanning a calculated focus point of the radiated energy through different depths of the object, and searching for a peak in an amplitude of the scattered energy.

Abstract: In some aspects, the disclosure is directed methods and systems for screening an unconstrained subject. A plurality of transmitters may be spatially distributed on two sides along a path of movement of a subject. Each of the transmitters may transmit, in sequence, radiation to be scattered from the subject. A plurality of sensors may be spatially distributed on the two sides and coherently configured with respect to the plurality of transmitters. The plurality of sensors may collect measurements of scattered radiation corresponding to the radiation transmitted by each of the plurality of transmitters. An imaging module may generate, based on the collected measurements, a two-dimensional or three-dimensional reconstruction estimate of body surface of the subject with one or more attached foreign objects.

Abstract: A system for characterizing a dielectric object situated adjacent to an electrically conductive surface comprises a radiation source configured to radiate electromagnetic energy toward the dielectric object, and a receiver configured to receive scattered electromagnetic energy scattered by the dielectric object and the electrically conductive surface. The system may further comprise a control subsystem, coupled to the radiation source and the receiver, that determines an apparent focal point within the object, determines a phase shift associated with the scattered electromagnetic energy with respect to the electromagnetic energy radiated by the radiation source, and determine a thickness and an index of refraction of the object based, on the apparent focal point and the phase shift. The system may determine the apparent focal point by scanning a calculated focus point of the radiated energy through different depths of the object, and searching for a peak in an amplitude of the scattered energy.

Abstract: In some aspects, the disclosure is directed to signal processing methods and systems for identifying a material on a body of a person using electromagnetic radiation. A radar system may measure a first reflection of radiation incident on a body of a person. The first reflection may be from a surface of the body. The radar system may measure a second reflection of the radiation. The second reflection may be from a first material residing on or proximate to the surface of the body. An analyzer may determine, relative to the first reflection, a delay in the second reflection due to propagation of a portion of the radiation through the first material. The analyzer may determine, based on the delay, at least one of: the first material and a dielectric constant of the first material.

Abstract: In some aspects, the disclosure is directed methods and systems for screening an unconstrained subject. A plurality of transmitters may be spatially distributed on two sides along a path of movement of a subject Each of the transmitters may transmit, in sequence, radiation to be scattered from the subject. A plurality of sensors may be spatially distributed on the two sides and coherently configured with respect to the plurality of transmitters. The plurality of sensors may collect measurements of scattered radiation corresponding to the radiation transmitted by each of the plurality of transmitters.

Abstract: In some aspects, the disclosure is directed methods and systems for establishing a wideband radar system for imaging. A receiver of a radar imaging system may receive a set of phase measurements for each of a plurality of frequency bands, each of the plurality of frequency bands established by up-converting or down-converting a base frequency band. A phase adjuster of the radar imaging system may identify, from each region of overlap between consecutive frequency bands of the plurality of frequency bands, a phase difference between corresponding sets of the phase measurements. The phase adjuster may adjust one or more sets of the phase measurements based on the identified phase differences to generate an image across the plurality of frequency bands.

Abstract: In some aspects, the disclosure is directed methods and systems for granular imaging of a distribution of tissues. A tomographic device may acquire a first image of a distribution of tissues, the first image including a plurality of pixels. A tomographic image processor may translate at least some of the plurality of pixels of the first image into a plurality of values representative of a distribution of dielectric constants corresponding to the distribution of tissues. A nearfield radar imaging (NRI) system may generate a second image of the distribution of tissues based on the plurality of values.

Abstract: A system and method for determining a volume of a body, body part, object, or stimulated or emitted field and identifying surface anomalies of the object of interest. A first set of image data is acquired corresponding to the object of interest from an imaging device. Depth data and a second set of image data is acquired from a structured light emitter including at least one sensor. A processor receives the first and second set of image data and based thereon, generates a resultant image including the depth data. A display is configured to display the resultant image to identify surface anomalies. A geometric model is applied to the resultant image to calculate a volume of the object of interest.

Abstract: In some aspects, the disclosure is directed to signal processing methods and systems for identifying a material on a body of a person using electromagnetic radiation. A radar system may measure a first reflection of radiation incident on a body of a person. The first reflection may be from a surface of the body. The radar system may measure a second reflection of the radiation. The second reflection may be from a first material residing on or proximate to the surface of the body. An analyzer may determine, relative to the first reflection, a delay in the second reflection due to propagation of a portion of the radiation through the first material. The analyzer may determine, based on the delay, at least one of: the first material and a dielectric constant of the first material.

Abstract: In some aspects, the disclosure is directed methods and systems for focusing millimeter-wave radiation to a line for scanning a target object. A source may provide millimeter-wave radiation, and may include a substantially point source. A reflector may include a surface with an elliptical cross-section within a first plane and a curved cross-section within a second plane perpendicular to the first plane. The curved cross-section may be shaped differently from the elliptical cross-section within their respective planes. The surface may focus the millimeter-wave radiation from the source at a line on a third plane parallel to or coinciding with the second plane. The line may be located at an approximate location where a target object is expected to be positioned. At least one sensor may measure the millimeter-wave radiation from the reflector scattered off the target object.