Chromotomography is a form of hyperspectral imaging that uses a prism to simultaneously record spectral and spatial information, like a slitless spectrometer. The prism is rotated to provide multiple projections of the 3D data cube on the 2D detector array. Tomographic reconstruction methods are then used to estimate the hyperspectral data cube from the projections. This type of system can collect hyperspectral imagery from fast transient events, but suffers from reconstruction artifacts due to the limited-angle problem. Several algorithms have been proposed in the literature to improve reconstruction, including filtered backprojection, projection onto convex sets, subspace constraint, and split- Bregman iteration. Here we present the first direct comparison of multiple methods against a variety of simulatedtargets. Results are compared based on both image quality and spectral accuracy of the reconstruction, where previous literature has emphasized imaging only. In addition, new algorithms and HSI quality metrics are proposed. We find the quality of the results depend strongly on the spatial and spectral content of the scene, and no single algorithm is consistently superior over a broad range of scenes.
Noncontact measurements of flexible and moving structures have the challenge of obtaining high speed, accurate
and registered data over a long range. Many noncontact measurement methods are based on the object staying
aligned with the sensor. Yet sometimes the desired loading is a result of the motion interacting with structural
dynamics as is the case with aeroelasticity. Triangulation of video data can capture large scale motion, but
limits the speed and accuracy of the measurement. Laser vibrometry can capture minute, structural vibrations
but must be aligned to the point of interest. This paper presents a method of registering a laser vibrometer
steering system to a motion capture system. The basis of calibration lies on determining the location of the laser
steering system through the videogrammetry capture volume for dynamic in-flight tracking and measurement.
A method for using video capture of the laser is presented to determine registered lines through the capture
volume. Results of the calibration are sufficient to have the laser track within half a degree for distances over
4m. The laser is then able to be open-loop steered with static and dynamic accuracies presented. This system
can provide real-time structural awareness enabling active control.