Hadamard transform spectrometry

Dyer, Stephen A.

doi:10.1016/0169-7439(91)80119-b

Cited by 18 publications

(3 citation statements)

References 11 publications

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“…The Hadamard scan creates a set with several wavelengths multiplexed at a time and then decodes the individual wavelengths. The Hadamard scan collects much lighter and offers a higher SNR than a column scan [ 28 ]. However, this is very dependent on the spectrum being measured and the system used to measure it.…”

Section: Instrumentationmentioning

confidence: 99%

An Affordable NIR Spectroscopic System for Fraud Detection in Olive Oil

Melendreras

Soldado

Costa‐Fernández

et al. 2023

Sensors

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Adulterations of olive oil are performed by adding seed oils to this high-quality product, which are cheaper than olive oils. Food safety controls have been established by the European Union to avoid these episodes. Most of these methodologies require expensive equipment, time-consuming procedures, and expert personnel to execute. Near-infrared spectroscopy (NIRS) technology has many applications in the food processing industry. It analyzes food safety and quality parameters along the food chain. Using principal component analysis (PCA), the differences and similarities between olive oil and seed oils (sesame, sunflower, and flax oil) have been evaluated. To quantify the percentage of adulterated seed oil in olive oils, partial least squares (PLS) have been employed. A total of 96 samples of olive oil adulterated with seed oils were prepared. These samples were used to build a spectra library covering various mixtures containing seed oils and olive oil contents. Eighteen chemometric models were developed by combining the first and second derivatives with Standard Normal Variable (SNV) for scatter correction to classify and quantify seed oil adulteration and percentage. The results obtained for all seed oils show excellent coefficients of determination for calibration higher than 0.80. Because the instrumental aspects are not generally sufficiently addressed in the articles, we include a specific section on some key aspects of developing a high-performance and cost-effective NIR spectroscopy solution for fraud detection in olive oil. First, spectroscopy architectures are introduced, especially the Texas Instruments Digital Light Processing (DLP) technology for spectroscopy that has been used in this work. These results demonstrate that the portable prototype can be used as an effective tool to detect food fraud in liquid samples.

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Section: Instrumentationmentioning

confidence: 99%

An Affordable NIR Spectroscopic System for Fraud Detection in Olive Oil

Melendreras

Soldado

Costa‐Fernández

et al. 2023

Sensors

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“…Using this method, it is possible to create linearly independent geometric basis vectors. One such linearly independent basis is the Hadamard matrix, which has been used in the design of stationary encoding masks in the fields of spectrometry and imaging [12][13][14]. What began as a one dimensional approach was extended to multi-dimensional problems [15][16][17], resulting in methods applicable to the RSM design optimization.…”

Section: Decoupling Andmentioning

confidence: 99%

Rotating scatter mask optimization for gamma source direction identification

Holland

Bevins

Burggraf

et al. 2018

Nuclear Instruments and Methods in Physics Research Section A:

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Rotating scattering masks have shown promise as an inexpensive, lightweight method with a large field-of-view for identifying the direction of a gamma emitting source or sources. However, further examination of the current rotating scattering mask design shows that changing the geometry may improve the identification by reducing or eliminating degenerate solutions and lower required count times. These changes should produce more linearly independent characteristics for the mask, resulting in a decrease in the mis-identification probability. Three approaches are introduced to generate alternative mask geometries. The eigenvector method uses a spring-mass system to create a geometry basis. The binary approach uses ones and zeros to represent the geometry with many possible combinations allowing for additional design flexibility. Finally, a Hadamard matrix is modified to examine a decoupled geometric solution. Four criteria are proposed for evaluating these methodologies. An analysis of the resulting detector response matrices demonstrates that these methodologies produced masks with superior identification characteristics than the original design. The eigenvector approach produces the least linearly dependent results, but exhibits a decrease in average efficiency. The binary results are more linearly dependent than the eigenvector approach, but this design achieves a higher average efficiency than original. The Hadamard-based method produced a lower maximum, but a higher average linear dependence than the original design. Further possible design enhancements are discussed.

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“…6,7 With increased signal, a system can transition from being dark-noise-limited to shot-noise-limited. Furthermore, by using only a single detector, these systems can avoid fixed-pattern noise caused by various pixel non-uniformities.…”

Section: Signal-to-noise Ratiomentioning

confidence: 99%

Latest developments in Texas Instruments DLP near-infrared spectrometers enable the next generation of embedded compact, portable systems

Pruett

2015

Next-Generation Spectroscopic Technologies VIII

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Designing the next generation of embedded compact, portable near-infrared (NIR) spectrometers while meeting aggressive cost and form factor targets requires novel technologies and creative system designs. New miniature spectrometer architectures are enabled by Texas Instruments DLP R ⃝ technology. The ability to provide programmable spectral filters using high speed, accurate light modulation with a micro-electro mechanical systems (MEMS) based architecture enables systems with features and sampling techniques that were previously not possible. System design considerations and the latest developments in DLP spectrometer architectures will be presented.

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Hadamard transform spectrometry

Cited by 18 publications

References 11 publications

An Affordable NIR Spectroscopic System for Fraud Detection in Olive Oil

An Affordable NIR Spectroscopic System for Fraud Detection in Olive Oil

Rotating scatter mask optimization for gamma source direction identification

Latest developments in Texas Instruments DLP near-infrared spectrometers enable the next generation of embedded compact, portable systems

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