A hidden chamber detector includes a linear frequency modulated continuous wave (LFMCW) radar, a synthetic aperture radar (SAR) imaging processor, and a time division multiple access (TDMA) multiple input multiple output (MIMO) antenna array, including a plurality of transmitting and receiving (Tx-Rx) antenna pairs. A Tx-Rx antenna pair is selected, in a time division manner, as a Tx antenna and an Rx antenna for the LFMCW radar. The LFMCW radar is configured to transmit an illumination signal, receive an echo signal, convert the echo signal to a baseband signal, collect baseband samples, and send the collected samples to the SAR imaging processor. The SAR imaging processor is configured to receive the collected samples, collect structure/configuration of the antenna array and scanning information, and form an SAR image based on the collected samples, the structure/configuration of the antenna array, and the scanning information.

An imaging system to reconstruct a reflectivity image of a scene including an object moving with the scene. A tracking system to track a deforming object to estimate an object deformation for each time step. Sensors acquire snapshots of the scene, each acquired snapshot of the object includes measurements in the object deformation for that time step, to produce a set of object measurements with deformed shapes over the time steps. Compute a correction to estimates of object deformation for each time step, with matching measurements of the corrected object deformation for each time step to measurements in the acquired snapshot of object for that time step. Select a corrected deformation over other corrected deformations for each time step, according to a distance between the corrected deformation and the estimate of the deformation, to obtain a final estimate of the deformation of the deformable object moving in the scene.

A radio frequency (RF) imaging device comprises an optical position sensor, an RF sensor assembly, a processor, and a memory. The optical position sensor captures an optical image of a field of view and outputs data representing the optical image. The RF sensor assembly is disposed at a first position and receives an RF signal for capturing an RF image of a portion of a space disposed behind a surface at the first position and outputs data representing the RF signal. The processor receives the data representing the optical image and the RF signal, and determines that an optical signature of a reference marker is present in the optical image. If the optical signature is present in the optical image, the processor defines the first position of the RF assembly as a reference position. The memory stores the data representing the RF signal in association with the reference position.

A radio frequency (RF) imaging device comprises a position sensor, an RF sensor assembly, an optical sensor, a processor, and a memory. The position sensor determines a position of the RF imaging device relative to a surface. The RF sensor assembly captures RF image data representing an RF image of a portion of a space behind the surface at the determined position. The optical sensor captures optical image data representing an optical image of the surface at the determined position. The processor produces a composite image in which at least one or more portions of the RF image and one or more portions of the optical image that correspond to the same position relative to the surface are simultaneously viewable. The RF image data and the optical image data are stored in the memory in association with position data derived from the determined position of the RF imaging device.

A radio frequency (RF) imaging device comprises an RF sensor assembly, a position sensor, a processor, and a memory. The RF sensor assembly receives an RF signal for capturing an RF image of a portion of a space behind a surface. The position sensor receives a plurality of signals respectively emitted by a plurality of position markers at known positions relative to the surface. The processor determines a plurality of angles at which the plurality of signals respectively arrive at the position sensor and determines, based on the plurality of angles and the known positions of the plurality of position markers, a position of the RF imaging device relative to the surface. The memory stores the RF image in association with the determined position of the RF imaging device. A time-of-flight or triangulation of signal data may be used for position determination.

A radio frequency (RF) imaging device comprising a display receives a three-dimensional (3D) image that is a superposition of two or more images having different image types including at least a 3D RF image of a space disposed behind a surface. A plurality of input control devices receive a user input for manipulating the display of the 3D image. Alternatively or additionally, the radio frequency (RF) imaging device may receive a three-dimensional (3D) image that is a weighted combination of a plurality of images including a 3D RF image of a space disposed behind a surface, an infrared (IR) image of the surface, and a visible light image of the surface. A user input may specify changes to the weighted combination. In another embodiment, the RF imaging device may include an output device that produces a physical output indicating a detected type of material of an object in the space.

A radio frequency (RF) imaging device comprises a position sensor, an optical sensor, a processor, and an output. The position sensor determines a position of the RF imaging device relative to a surface. The optical sensor captures optical image data representing an optical image of an area of the surface. The optical image data is associated with position data representing a position relative to the surface derived from the determined position of the RF imaging device. The derived position data corresponds to the area of the surface imaged by the optical sensor. The processor produces a composite image in which one or more portions of the optical image data are simultaneously viewable with RF image data representing an RF image of a space behind the surface at the same position as the optical image data. The output displays the composite image. The output may be a projector.

A frame body may be parallel to and proximate with a surface of a structure and extend substantially horizontally from a first side to a second side. A connecting portion may be provided to be attached to a cable to provide for vertical movement of the frame body. A robotic arm may be affixed proximate to a bottom of the frame body and be able to move horizontally during penetrative imaging of the surface. Moreover, the robotic arm may extend to an end proximate with the surface, and a penetrative imaging portion may be attached to the robotic arm near the end proximate with the surface. The robotic arm may rotate, vertically moving the penetrative imaging portion during penetrative imaging of the surface. In addition, the penetrative imaging portion may be separately rotated about three orthogonal axes of rotation (yaw, pitch, roll) to achieve various angles of approach and orientation to the surface.

Data is received characterizing a plurality of measurements for a scene received by a plurality of sensor elements forming a sensor array. A plurality of scene sub-domains is mapped to the plurality of sensor elements. A plurality of voxels associated with one of the plurality of scene sub-domains is mapped to a plurality of measurement sub-domains. One or more scattering coefficients of the scene is determined by applying the mapping to the received data. Related apparatus, systems, techniques, and articles are also described.

An apparatus for detecting objects includes a transceiver configured to generate a radar signal, a radar having a transmit antenna configured to transmit the radar signal, and a receive antenna configured to sense a return signal in response to a transmission of the radar signal. The apparatus also includes a processor configured to detect an object based on the return signal. One or more of the transmit antenna or the receive antenna include offset spiral feed antennas.