US 12,260,518 B2
Single-pixel imaging through dynamic scattering media
Mark Bashkansky, Alexandria, VA (US); Samuel Park, McLean, VA (US); and John F. Reintjes, Alexandria, VA (US)
Assigned to The Government of the United States of America, as represented by the Secretary of the Navy, Arlington, VA (US)
Filed by The Government of the United States of America, as represented by the Secretary of the Navy, Arlington, VA (US)
Filed on Mar. 10, 2022, as Appl. No. 17/691,172.
Claims priority of provisional application 63/185,509, filed on May 7, 2021.
Prior Publication US 2022/0375034 A1, Nov. 24, 2022
Int. Cl. G06T 5/00 (2024.01); G06T 5/10 (2006.01)
CPC G06T 5/00 (2013.01) [G06T 5/10 (2013.01)] 9 Claims
OG exemplary drawing
 
1. An apparatus for single-pixel imaging of a target to be imaged through a scattering medium, comprising:
an illuminator comprising a pulsed laser source, a spatial light modulator (SLM), a beam splitter, and a reference detector;
a receiver comprising collecting optics, a single-pixel bucket detector, and a fast storage scope; and
a data processor/controller comprising a computer programmed with appropriate software including a reconstruction algorithm and having sufficient bandwidth and memory to control the apparatus and to process and analyze digital signals and reconstruct an image of the target;
wherein the pulsed laser source emits a series of fast-pulse illumination beams directed through a scattering medium at the target;
wherein the SLM imposes a pseudo-random pattern on each of the illumination beams, the illumination beam with imposed pattern forming a corresponding target pattern on the target when the illumination beam travels through the scattering medium and strikes the target, the imposed pattern and the corresponding target pattern being updated by the SLM at a rapid rate;
wherein the illumination beam and corresponding target pattern reflect off the target and travel back through the scattering medium and are received by the collecting optics, the collecting optics directing the reflected beam with its corresponding target pattern into the bucket detector, the bucket detector converting the reflected beam and corresponding target pattern into an electrical signal that is directed into the fast storage scope;
wherein the data processor/controller receives a digital signal from a reference detector that serves as a time reference for gating the signal from the target and provides a measure of the transmitted laser intensity that is used to normalize the signals reflected from the target;
wherein the data processor/controller receives digital signals corresponding to the patterns initially applied by the SLM to the illumination beams and digital signals corresponding to the patterns in the illumination beams at the target;
wherein the fast storage scope further receives and stores a digital signal of the time trace for each target pattern, the stored time traces being digitally gated to record a single value for each trace corresponding to a distance of the target from the storage scope and to discard signals corresponding to the scattering medium the fast storage scope storing the undiscarded signals as a time sequence of illumination beams and corresponding target patterns;
wherein the data processor/controller normalizes the digital signal according to the transmitted laser energy for each target pattern, and applies a digital high-pass filter to remove the slower signal variations produced by dynamic changes in fog density over time; and
wherein, using the filtered signal variations and the target patterns and using the programmed reconstruction algorithm, the data processor/controller generates an image of the target.