Journal ArticleDOI
Implementation problems in Hadamard transform spectrometry
TLDR
In this paper, a block diagram description of HTS and the spectrum-recovery process is presented and a computer simulation of this model has been developed and can be used to examine the effects of certain nonidealities that may typically be encountered.Abstract:
The multiplex advantage offered by Hadamard transform spectrometry (HTS) can improve the signal-to-noise ratio (SNR) at the output of a spectrometer. However, additional processing of the spectrometer output is required to recover the individual spectral components. A block diagram description of HTS and the spectrum-recovery process is presented. A computer simulation of this model has been developed and can be used to examine the effects of certain nonidealities that may typically be encountered. Traditionally, the inverse Hadamard transform (IHT) has been used as the spectrum-recovery method, but the IHT does not take into account the nonidealities associated with the multiplexing process. Two spectrum-recovery methods that address the problems of nonidealities are presented. The relative performance of all three methods is compared with regard to mean square error (MSE) and the computational efficiency of the algorithms necessary to implement the schemes. An example application is described, and the performance of the three spectrum-recovery schemes is discussed. >read more
Citations
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Journal ArticleDOI
Chemical Mapping in the Mid- and Near-IR Spectral Regions by Hadamard Transform/FT-IR Spectrometry
TL;DR: In this paper, a movable 2D Hadamard encoding mask is obtained and combined with conventional FT-IR spectrometers for use in both the mid and near-infrared spectral regions.
Journal ArticleDOI
Dual-Beam Near-Infrared Hadamard Spectrophotometer:
TL;DR: In this article, a dual-beam Hadamard multiplexed spectrophotometer is described, which is intended to work in the near-infrared region of the electromagnetic spectrum (900-1800 nm).
Journal ArticleDOI
Highly Multiplexed Optically Sectioned Spectroscopic Imaging in a Programmable Array Microscope
TL;DR: In this paper, a second-order Hadamard transform system is described in which a single one-dimensional mask serves for both illumination and detection, and the system verifies earlier predictions that the optical spreading function along the transform axis can be inferred from the echoes arising in secondorder systems using sequence lengths of 2n-1.
Journal ArticleDOI
A model for incorporating the effects of nonzero switching-time constants in electrooptic masks used in Hadamard-transform spectrometry
Jize Xiong,R.A. Dyer,S.A. Dyer +2 more
TL;DR: Two complete system models that incorporate the effects of both static and dynamic nonidealities inHadamard-transform spectrometers are developed and recovery schemes applicable for each system model are devised.
Journal ArticleDOI
Development and implementation of a general-purpose Hadamard-Transform spectrometer simulation program
TL;DR: Important features of the Hadamard-transform spectrometer simulation program are presented and an example source file is presented, which specifies the blocks to be included, the input and output variables of each block, the mask size, and the values of various other constants used by the program.
References
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Journal ArticleDOI
A Visible Near-Infrared Hadamard Transform Spectrometer Based on a Liquid Crystal Spatial Light Modulator Array: A New Approach in Spectrometry
TL;DR: In this paper, a stationary Hadamard encodement mask was designed from a liquid crystal display, which can be installed and positioned in a dispersive instrument, allowing the selected Hadamards encoded spectral elements to be focused on a single detector.
Journal ArticleDOI
A Fast Spectrum-Recovery Method for Hadamard Transform Spectrometers Having Nonideal Masks
TL;DR: In this article, a computationally inexpensive method for the recovery of spectra from measurements obtained with Hadamard transform spectrometers having nonideal masks is presented, requiring only O(N[log 2N + 2] arithmetic operations.
Journal ArticleDOI
An Efficient Method for Recovering the Optimal Unbiased Linear Spectrum-Estimate from Hadamard Transform Spectrometers Having Nonideal Masks
TL;DR: A spectrum-recovery method is presented which efficiently computes an optimal unbiased linear spectrum-estimate for measurements obtained with Hadamard transform (HT) spectrometers having nonideal masks.
Proceedings ArticleDOI
An introduction to Hadamard spectrometry and the multiplex advantage
TL;DR: In this article, the authors consider a special class of problems in which the dominant noise source in the spectrum measurements is the noise generated in the detector itself and they show that the signal-to-noise ratio of the spectrum estimates can be improved by a multiplexing technique known as Hadamard spectrometry.
Journal ArticleDOI
On the Mean-Square Error of Various Spectrum-Recovery Techniques in Hadamard Transform Spectrometry
TL;DR: In this article, three spectrum-recovery techniques for an HT spectrometer having a nonideal electro-optic mask are considered in terms of the mean-square error (MSE) associated with a given estimate.