Traditional solutions for long term imaging of living small biological specimens and microorganisms lack efficiency
due to computationally expensive algorithms, and field of view limitations in optical microscopes. This paper
describes a new algorithm that allows for real time tracking of multiple 1mm nematodes called Caenorhabditis
elegans with a novel optical microscope design called the Adaptive Scanning Optical Microscope (ASOM), developed
at the Center for Automation Technologies and Systems (CATS). Based on the real time experimentation,
an improved algorithm to track multiple worms in the presence of entanglements is generated. The stages of
this development start with an enhanced digital motion controller for the ASOM high speed scanning mirror
to suppress undesired vibrations that limit the system capacity to track multiple organisms. The second phase
is the integration of the ASOM apparatus, the high speed motion control, and a base tracking algorithm, all
which allows for rapid image acquisition to track multiple C. elegans in real time. The base algorithm was
developed at CATS and has been proven to track a single C. elegans in real time. Results demonstrating the
efficacy of the complete system are presented. Lastly, an enhanced tracking algorithm is described that shows
improved accuracy and robustness in tracking worms even when they become entangled. Taking into account
the unique ASOM design, individual segments of the worm are tracked throughout an image sequence, and a
mosaic pattern covering the entire worm is subsequently created. The algorithm takes advantage of geometric
and dynamic knowledge of the C. elegans such as size, and movement patterns. The enhanced algorithm is tested
on previously recorded footage. Simulated tracking experiments also illustrate the effectiveness of the enhanced
algorithm and are presented.
For a wide range of applications in biology, medicine, and manufacturing, the small field of view associated with
high resolution microscope systems poses a significant challenge in practice. This paper describes an optical
microscope design, called the Adaptive Scanning Optical Microscope (ASOM), which uses a MEMS deformable
mirror working with a specially designed scanning lens to achieve a greatly expanded field of view. Most adaptive
optics systems (e.g. telescopes and ophthalmology instruments) are designed to achieve near ideal performance
under nominal operating conditions and primarily use the adaptive optics element to compensate for a time
varying disturbance to the wavefront that is external to the optical system. In contrast to this approach,
the deformable mirror in the ASOM is an integral component of the optical system and the static (glass)
optical elements have been specifically designed to match the shape correcting capabilities of the deformable
mirror. Using a high speed steering mirror coordinated with the deformable mirror actuation voltages, the
ASOM operates by scanning over the workspace and should achieve diffraction limited imaging over a region
approximately two orders of magnitude larger in area than a traditional microscope design. With the rapid
scanning capabilities allowed by the high speed steering mirror and by acquiring a complete image during each
exposure, the ASOM offers advantages in dynamically reconfigurable and adaptable imaging with no agitation
to the workspace. After describing the design and operating principle of the ASOM, we present results from a
low cost ASOM prototype.
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