High-resolution and high-speed 3D tracking of microrobots using a fluorescent light field microscope

Area of Science:

• Micro-robotics
• Optical Imaging
• Biomedical Engineering

Background:

• Accurate imaging and tracking are essential for microrobots navigating complex 3D environments.
• Conventional microscopy, while sensitive, has limited depth of field and lacks 3D imaging capabilities, hindering microrobot studies.
• Fluorescent imaging (FI) is a high-resolution technique but is constrained by these limitations.

Purpose of the Study:

• To develop a high-resolution, high-speed 3D tracking method for microrobots.
• To overcome the limitations of conventional microscopy for microrobot imaging.
• To enable precise tracking of microrobots in three dimensions.

Main Methods:

• Proposed a fluorescent light field microscope (FLFM) system designed for microrobot tracking.
• Developed a 3D tracking algorithm utilizing digital refocusing for microrobot localization.
• Designed the FLFM system considering the dimensions of a representative helical microrobot (150 μm body length, 50 μm screw diameter).

Main Results:

• Achieved a 30 frames per second (fps) data acquisition rate.
• Obtained a lateral resolution of 10 μm and an axial resolution of approximately 40 μm.
• Demonstrated tracking accuracy of about 9 μm over a 1,200×1,200×326 μm³ volume.
• Validated the method through simulations and experimental tracking of microrobots.

Conclusions:

• The FLFM-based method provides enhanced depth of field and 3D imaging capability from a single shot, surpassing conventional FI.
• The developed tracking method successfully provides microrobot trajectories with good lateral resolution.
• This advancement is crucial for detailed analysis and control of microrobots in complex environments.