Abstract: An encoder of a terahertz (THz)-based absolute positioning system used for decoding patterns from THz-band measurements. The encoder includes a scale with a multi-layer reflective/transmissive structure having a matrix with rows. Each row of the matrix corresponds to a plurality of patterns, such that each pattern is used to form a measurement. An emitter emits a THz waveform to the scale. A receiver is used to measure amplitudes of the THz waveform reflected from the scale. A memory stores data including predetermined positions of the emitter based on the patterns of the layers from the scale. Wherein one or more processors can determine a position of the emitter from the measurements of the amplitudes received by the receiver, based on the stored data. An output interface can be used to render the position of the emitter.

Abstract: An encoder of a terahertz (THz)-based absolute positioning system used for decoding patterns from THz-band measurements. The encoder includes a scale with a multi-layer reflective/transmissive structure having a matrix with rows. Each row of the matrix corresponds to a plurality of patterns, such that each pattern is used to form a measurement. An emitter emits a THz waveform to the scale. A receiver is used to measure amplitudes of the THz waveform reflected from the scale. A memory stores data including predetermined positions of the emitter based on the patterns of the layers from the scale. Wherein one or more processors can determine a position of the emitter from the measurements of the amplitudes received by the receiver, based on the stored data. An output interface can be used to render the position of the emitter.

Abstract: A scanner includes an emitter configured to emit a wave in a direction of propagation to penetrate layers of a structure of a target object and a receiver configured to measure intensities of the wave reflected by the layers of the target object. The scanner also includes a hardware processor configured to partition the intensities of the reflected wave into a set of segments, such that each segment is the reflection from a corresponding layer of the target object, defining a multi-layered structure of the target object; and reconstruct images of the layers of the target object from corresponding segments using a joint-layer hierarchical image recovery that prevents an increase in sparsity of the layers of the target object in the direction of propagation of the wave. An output interface is configured to render the reconstructed images of layers of the target object.