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Massively-parallel Fourier-transform spectral imaging and hyperspectral image processing
Optics & Laser Technology Density sensing by a photothermal vibration Seiki Inaba *, Kazuhiro Hane ** *Gifu N a t i o n a l College of Technology, **Nagoya University 9th Meeting on Lightwave Sensing Technology, Japanese Society o f Lightwave Sensing Technology, J a p a n Society of Applied Physics An optical sensing system for the densities of liquid and gas is described which uses the resonance frequency shift of a membrane vibrated by a photothermal effect. The resonance frequency is decreased by the reaction force from the gas or liquid. In gas, it decreases monotonically with increasing pressure from 10 to 100 kPa. The resonance frequency for a very small cantilever made by a micromachining technique was also evaluated. In water, the resonance was observed first with a small resonance Q-value compared with that in air. With increasing liquid density, the resonance frequency for the membrane decreased. The liquid density can be determined optically with an accuracy of _+7.5 mg cm
3.
Massively-parallel Fourier-transform spectral imaging and hyperspectral image processing K. ltoh D e p a r t m e n t of Applied Physics, Osaka University 9th Meeting on Lightwave Sensing Technology, Japanese Society of Lightwave Sensing Technology, J a p a n Society of Applied Physics Conventional spectral imaging techniques are briefly reviewed and two kinds of massively-parallel techniques for spectral imaging, based on Fourier transform spectroscopy, are demonstrated. One makes use of a Michelson interferometer and the other a liquid-crystal polarization interferometer. A proposal for widening the field of view of the liquidcrystal interferometer is presented. Methods for compression and segmentation of hyperspectral images are demonstrated. Compression is based on DCT (Discrete Cosine Transform) and a fast method for segmentation of the coded images is suggested. An approach for segmentation that makes use of neural-network computation is also presented.
Vector quantization for hyperspectral images using neural network
Abstracts Optical information processing by synthesis of coherence function Kazuo Hotate, Toru Okugawa Research Center for A d v a n c e d Science a n d (RCAST), The University of T o k y o
Technology
9th Meeting o n Lightwave Sensing Technology, Japanese Society of Lightwave Sensing Technology, J a p a n Society of Applied Physics We propose an optical parallel information processing technique adopting the synthesis of an optical coherence function by using direct frequency-modulation of a laser diode. An optical coherence function having a delta-function-like shape can be synthesized by modulating the laser frequency with an appropriate waveform. We recently proposed and discussed two ways to synthesize the optical coherence function having the delta-function-like shape. In this optical parallel information processing system, selectively extracting two-dimensional information from a three-dimensional semitransparent object, as well as other operations between two-dimensional information, can be carried out. Selective extraction of two-dimensional information from an object was successfully performed in a basic experiment.
Lightwave-controllable interconnects with liquid-crystal TV spatial light modulators Takeshi Takahashi*, Yukihiro Ishiit *Chinon Industries Inc, t U n i v e r s i t y of Industrial Technology 9th Meeting on Lightwave Sensing Technology, Japanese Society of Lightwave Sensing Technology, J a p a n Society o f Applied Physics A new design technique is presented for multilevel phase gratings for the iterative generation of spot arrays by using liquid-crystal TV spatial light modulators (LCSLMs). The LCTV acts as a lightwavecontrollable modulator. When the phases are displayed on LCSLMs, the phase response as a function of voltages is deteriorated owing to limited phase performance. The implementation of iterative feedback processes directly on an LCSLM-optic system is useful for making the correction of the deterioration of the displayed phases. The experimental results with a 15 × 15 array of spots are shown by using two mutually orthgonally aligned LCSLMs. The technique can be applicable to arbitrary point-to-array connections with odd symmetric multilevel phase gratings.
Multiplication of dynamic speckle correlation using liquid crystal TV
T. Inoue, K. Yamatani, K. ltoh, Y. Ichioka
Q. C. Zhang, S. Toyooka, H. Kadono
D e p a r t m e n t o f Applied Physics, Osaka University
Saitama University
9th Meeting on Lightwave Sensing Technology, Japanese Society o f Lightwave Sensing Technology, J a p a n Society of Applied Physics
9th Meeting on Lightwave Sensing Technology, Japanese Society of Lightwave Sensing Technology, J a p a n Society o f Applied Physics
We propose a self-organizating neural network in order to design a codebook for vector quantization of hyperspectral images. The structure of this network is a ring of units. The self-organizing algorithm of the network uses the quantization errors at every unit, and changes the weight vectors of the units gradually to equalize these errors. In simulations, the network is compared with two well-known techniques, LBG algorithm and Kohonen self-organizing maps. Results show that the distortions of the network are lower than those of the conventional techniques. Vector quantization of real hyperspectral-image data using the proposed network is presented. The compression rate reached is about 0.08 with an acceptable distortion.
The addition of several speckle patterns arising from different illuminated points is taken and displayed on a liquid crystal television (LCTV) panel which is used as a shadow filter. The light passing through the LCTV panel is converged to corresponding image points. The light intensity at any image point varies with the change of the cross-correlation between the video speckle pattern on the panel and the live speckle pattern from the corresponding illuminated point. Correlation characteristics of multiple speckle patterns are investigated. Two channel vibration experiments were done to demonstrate this method, and the experimental results agree well with the theoretical ones.
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Optics & Laser Technology Vol 25 No 3 1993
3.
Massively-parallel Fourier-transform spectral imaging and hyperspectral image processing K. ltoh D e p a r t m e n t of Applied Physics, Osaka University 9th Meeting on Lightwave Sensing Technology, Japanese Society of Lightwave Sensing Technology, J a p a n Society of Applied Physics Conventional spectral imaging techniques are briefly reviewed and two kinds of massively-parallel techniques for spectral imaging, based on Fourier transform spectroscopy, are demonstrated. One makes use of a Michelson interferometer and the other a liquid-crystal polarization interferometer. A proposal for widening the field of view of the liquidcrystal interferometer is presented. Methods for compression and segmentation of hyperspectral images are demonstrated. Compression is based on DCT (Discrete Cosine Transform) and a fast method for segmentation of the coded images is suggested. An approach for segmentation that makes use of neural-network computation is also presented.
Vector quantization for hyperspectral images using neural network
Abstracts Optical information processing by synthesis of coherence function Kazuo Hotate, Toru Okugawa Research Center for A d v a n c e d Science a n d (RCAST), The University of T o k y o
Technology
9th Meeting o n Lightwave Sensing Technology, Japanese Society of Lightwave Sensing Technology, J a p a n Society of Applied Physics We propose an optical parallel information processing technique adopting the synthesis of an optical coherence function by using direct frequency-modulation of a laser diode. An optical coherence function having a delta-function-like shape can be synthesized by modulating the laser frequency with an appropriate waveform. We recently proposed and discussed two ways to synthesize the optical coherence function having the delta-function-like shape. In this optical parallel information processing system, selectively extracting two-dimensional information from a three-dimensional semitransparent object, as well as other operations between two-dimensional information, can be carried out. Selective extraction of two-dimensional information from an object was successfully performed in a basic experiment.
Lightwave-controllable interconnects with liquid-crystal TV spatial light modulators Takeshi Takahashi*, Yukihiro Ishiit *Chinon Industries Inc, t U n i v e r s i t y of Industrial Technology 9th Meeting on Lightwave Sensing Technology, Japanese Society of Lightwave Sensing Technology, J a p a n Society o f Applied Physics A new design technique is presented for multilevel phase gratings for the iterative generation of spot arrays by using liquid-crystal TV spatial light modulators (LCSLMs). The LCTV acts as a lightwavecontrollable modulator. When the phases are displayed on LCSLMs, the phase response as a function of voltages is deteriorated owing to limited phase performance. The implementation of iterative feedback processes directly on an LCSLM-optic system is useful for making the correction of the deterioration of the displayed phases. The experimental results with a 15 × 15 array of spots are shown by using two mutually orthgonally aligned LCSLMs. The technique can be applicable to arbitrary point-to-array connections with odd symmetric multilevel phase gratings.
Multiplication of dynamic speckle correlation using liquid crystal TV
T. Inoue, K. Yamatani, K. ltoh, Y. Ichioka
Q. C. Zhang, S. Toyooka, H. Kadono
D e p a r t m e n t o f Applied Physics, Osaka University
Saitama University
9th Meeting on Lightwave Sensing Technology, Japanese Society o f Lightwave Sensing Technology, J a p a n Society of Applied Physics
9th Meeting on Lightwave Sensing Technology, Japanese Society of Lightwave Sensing Technology, J a p a n Society o f Applied Physics
We propose a self-organizating neural network in order to design a codebook for vector quantization of hyperspectral images. The structure of this network is a ring of units. The self-organizing algorithm of the network uses the quantization errors at every unit, and changes the weight vectors of the units gradually to equalize these errors. In simulations, the network is compared with two well-known techniques, LBG algorithm and Kohonen self-organizing maps. Results show that the distortions of the network are lower than those of the conventional techniques. Vector quantization of real hyperspectral-image data using the proposed network is presented. The compression rate reached is about 0.08 with an acceptable distortion.
The addition of several speckle patterns arising from different illuminated points is taken and displayed on a liquid crystal television (LCTV) panel which is used as a shadow filter. The light passing through the LCTV panel is converged to corresponding image points. The light intensity at any image point varies with the change of the cross-correlation between the video speckle pattern on the panel and the live speckle pattern from the corresponding illuminated point. Correlation characteristics of multiple speckle patterns are investigated. Two channel vibration experiments were done to demonstrate this method, and the experimental results agree well with the theoretical ones.
202
Optics & Laser Technology Vol 25 No 3 1993