Scholarship & Research
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Item Combining spectral and polarimetric methods to classify cloud thermodynamic phase(Montana State University - Bozeman, College of Engineering, 2019) Tauc, Martin Jan; Chairperson, Graduate Committee: Joseph A. Shaw; David W. Riesland, Laura M. Eshelman, Wataru Nakagawa and Joseph A. Shaw were co-authors of the article, 'Radiance ratios for CTP discrimination' submitted to the journal 'Journal of applied remote sensing' which is contained within this thesis.; Wataru Nakagawa and Joseph A. Shaw were co-authors of the article, 'The SWIR three-channel polarimeter for cloud thermodynamic phase detection' in the journal 'Optical engineering' which is contained within this thesis.Cloud thermodynamic phase--whether a cloud is composed of spherical water droplets or polyhedral ice crystals--is an important parameter for optical communication with space-based instruments, remote sensing of the atmosphere, and, perhaps most importantly, understanding weather and climate. Although some methods exist to detect the phase of clouds, there is still a need for passive remote sensing of cloud thermodynamic phase due to its low-cost, scalability, and ease of use. Two methods for cloud thermodynamic phase classification employ spectral radiance ratios in the short-wave infrared, and the S 1 Stokes parameter, a polarimetric quantity. In this dissertation, the combination of the two methods is realized in an instrument called the short-wave infrared three-channel polarimeter. The coalescence of radiance ratios in the short-wave infrared and polarization channels oriented parallel and perpendicular to the scattering plane provides better classification of cloud phase than either method independently. Despite the improvement, the low-cost system suffered from hardware and software limitations, which caused an increase in noise and polarimetric artifacts. These errors are analyzed and a subset of low-noise data shows even better classification ability. All together, the results attained from the deployment of the polarimeter in early 2019 showed promise that the combination of the two methods is an improvement over past techniques.Item Development of a smart camera system on an FPGA(Montana State University - Bozeman, College of Engineering, 2016) Whitaker, Monica Jane; Chairperson, Graduate Committee: Ross K. SniderIn recent years, hyperspectral cameras have been appearing in many applications that need more information than what conventional color cameras can provide. A hyperspectral camera is able to capture data ranging in wavelengths from the visible spectrum all the way into the infrared. In this way, it is able to 'see' hundreds of colors, much more than the human eye or any standard camera that typically uses only 3 spectral values (corresponding to the standard red, green, and blue colors). Due to the large amount of data that these cameras can generate at increasingly faster frame rates, conventional computers are not able to perform all the necessary processing in real-time. Because of this limitation, a new system is needed to perform the image processing. This master's thesis is meant to contribute to the development of a smart camera targeted for hyperspectral image processing using a Field Programmable Gate Array (FPGA) and object sorting with a prototype waterfall system. Through the use of a Hardware Description Language (HDL), a currently used image processing algorithm has been implemented to classify pixels. Additionally, design and test of an architecture for full object classification has been developed for the FPGA. High-speed transceivers are used to move data between multiple FPGA development boards. When paired with a hyperspectral camera and a monochrome line scan camera, this prototype system is capable of scanning objects in freefall and deciding within milliseconds whether or not to keep the object. This decision will dictate the action of air jets to displace unwanted objects. This full system is potentially of interest to small businesses or farms as it will enable farmers to perform their own premium bulk sorting in a cost effective manner.Item Enhanced step mode FTIR position control(Montana State University - Bozeman, College of Engineering, 2005) Inberg, R. Brandon; Chairperson, Graduate Committee: Steven R. ShawThis thesis presents a modification to a typical Fourier transform infrared (FTIR) spectrometer to achieve finer spatial sampling and increased frequency range for step-scan experiments with little modification to the existing hardware. Commercially available step-scan FTIR spectrometers currently have the ability to measure spectra up to 15798 cm_1, which is limited by a HeNe reference laser used for controlling the mirror's position. The proposed technique involves using a digital signal processor (DSP) to measure the HeNe reference signal and estimate the mirror position. The DSP then outputs a new synthetic signal that is used by the spectrometer to control the mirror to finer steps, allowing it to measure spectrums up to 47394 cm_1. Enhanced closed-loop mirror position data is presented to show the quality of the DSP estimate along with spectrograms taken of an erbium crystal to show the overall spectral improvements. To validate the erbium crystal enhanced step-scan spectrogram, a continuous scan experiment is given for comparison. The results demonstrate previously unattainable step-scan performance.Item Computer based characterization of a spatial-spectral (s2) material signal processor(Montana State University - Bozeman, College of Engineering, 2006) Khallaayoun, Ahmed; Chairperson, Graduate Committee: Richard WolffThe Spectrum Lab has developed a computer based model for a new generation processor where one of its applications promises improvement in current and future generation Radars. This processor is named the S2CHIP (Spatial Spectral Coherent Holographic Integrating Processor). The purpose of this work is to characterize the S2CHIP under different conditions in terms of signal strength, noise level and dynamic range. The characterization has been done using a new simulator developed at the Spectrum Lab based on the Maxwell-Bloch equations. This tool enabled us to simulate various effects based not only on the material properties but also effects based on the laser source and other components that make up the overall system. Laser beam geometry, material thickness, integration processing, and material and laser coherence time are addressed in this thesis. These simulations give a good measure on the performance of the S2CHIP.