When vision is provided through thermal-imaging systems field-of-view is reduced, effectively the soldier must operate with severe tunnel vision and so there is a requirement for a system which provides automated warning and immersive imaging. We present a computational multi-aperture thermal infrared (MA-TIR) imaging system with single-photon range imaging to provide enhanced video-rate detection of obscured biological signatures in clutter. Our multi-camera computational imaging system creates a 360° panoramic image, and we employ synthetic baseline integral imaging (SBII) for the construction of three-dimensional thermal scenes, including detection of occluded objects. We further fuse thermal imaging with covert time-correlated single-photon counting (TCSPC) LIDAR to provide the complementary capability of video-rate ranging with the ability to detect and classify targets through clutter, particularly based on movement signatures. Finally, we demonstrate the ability to discriminate between biological scene components and static clutter based on temporal modulations of picosecond resolution TCSPC returns.
Phase space provides the natural formalism with which to formulate optical imaging problems as a system with constraints. We consider the general formulation of optical imaging problems and look at two examples. The first example is a completely asymmetric freeform prism that has titled surfaces. The second example is a gradient index medium that is exactly solvable. This gives an alternative formalism to standard Seidel aberrations and nodal aberration theory, which can be used in the design process.
Phase space provides the natural formalism with which to formulate optical imaging problems as a system with constraints. We consider the general formulation of optical imaging problems and look at two examples. The first example is a completely asymmetric freeform prism that has titled surfaces. The second example is a GRIN media that is exactly solvable. This gives an alternative formalism to standard Seidel aberrations and nodal aberration theory that can be used in the design process.
We describe how the use of multiple-camera imaging systems provides an interesting alternative imaging modality to conventional single-aperture imaging, but with a different challenge: to computationally integrate diverse images while demonstrating an overall system benefit. We report the use of super-resolution with arrays of nominally identical longwave infrared cameras to yield high-resolution imaging with reduced track length, while various architectures enable foveal imaging, 4π and 3D imaging through the exploitation of integral imaging techniques. Strikingly, multi-camera spectral imaging using a camera array can uniquely demonstrate video-rate imaging, high performance and low cost.
We consider using phase space techniques and methods in analysing optical ray propagation in head mounted display systems. Two examples are considered that illustrate the concepts and methods. Firstly, a shark tooth freeform geometry, and secondly, a waveguide geometry that replicates a pupil in one dimension. Classical optics and imaging in particular provide a natural stage to employ phase space techniques, albeit as a constrained system. We consider how phase space provides a global picture of the physical ray trace data. As such, this gives a complete optical world history of all of the rays propagating through the system. Using this data one can look at, for example, how aberrations arise on a surface by surface basis. These can be extracted numerically from phase space diagrams in the example of a freeform imaging prism. For the waveguide geometry, phase space diagrams provide a way of illustrating how replicated pupils behave and what these imply for design considerations such as tolerances.
We consider using the Alvarez lens concept to perform focal length change in conventional optical systems. The Alvarez pair are a good example of freeform surfaces that are used to imprint a deformation into the propagating wavefront. In addition, we try to better understand the paraxial theory of each freeform component in building up to a composite lens system. An example dual field of view system in the medium wave infrared is presented. An inherent feature of the Alvarez pair is the axial symmetry breaking due to both the finite air gap between the cubic surfaces and the transverse movement of the pair. This has implications for the wavefront at the image plane. Having developed the first order theory one can better understand misalignment tolerances and how these produce certain wavefront aberrations. Most notably, misalignments lead to simple expressions in terms of the Zernike polynomials.