Polarisation-modulated photon-counting 3D imaging based on a negative parabolic pulse model.

Area of Science:

• Optics and Photonics
• 3D Imaging Technologies
• Photon Counting Techniques

Background:

• Indirect time-of-flight (ToF) methods offer high spatial resolution in 3D imaging.
• Existing indirect ToF methods fail with weak echo signals (e.g., <1 photon).
• Weak signal detection is crucial for advanced 3D imaging applications.

Purpose of the Study:

• To develop a novel 3D imaging method capable of detecting and ranging extremely weak echo signals.
• To overcome the limitations of current indirect ToF methods in low-light conditions.
• To enhance the accuracy and performance of 3D imaging for challenging environments.

Main Methods:

• A novel polarization-modulated photon-counting 3D imaging method was proposed.
• A negative parabolic pulse model (NPPM) was utilized for signal analysis.
• A computational method based on Poisson negative log-likelihood was developed to calculate distance from photon counts and polarization states.
• An experimental system integrating dual-axis galvo scanning was constructed.

Main Results:

• The proposed method successfully measures weak signals by counting photons from repetitive laser emissions.
• Millimeter-level ranging accuracy was achieved.
• Superior 3D imaging performance was demonstrated even with average received echo signals below 0.05 photons per emission.
• The NPPM effectively reduced ranging error by estimating time-varying echo signal distributions.

Conclusions:

• The novel polarization-modulated photon-counting method effectively addresses the challenge of imaging with ultra-weak echo signals.
• The technique offers a significant advancement for high-resolution 3D imaging in low-light or sparse signal conditions.
• This method expands the applicability of time-of-flight 3D imaging to scenarios previously considered unfeasible.