Modified linear model correction: A calibration transfer method without standard samples

NIR news ◽  
2018 ◽  
Vol 29 (8) ◽  
pp. 24-27 ◽  
Author(s):  
Jin Zhang ◽  
Xiaoyu Cui ◽  
Wensheng Cai ◽  
Xueguang Shao
Keyword(s):  
Linear Model ◽  
Near Infrared ◽  
High Efficiency ◽  
Correction Method ◽  
Standard Samples ◽  
Calibration Transfer ◽  
Practical Applications ◽  
Model Correction ◽  
Transfer Method ◽  
Model Similarity

Calibration transfer without standard samples is essential for practical applications of near infrared spectroscopy because, sometimes, it is difficult or even impossible to obtain the standard samples for measuring their spectra on the secondary instrument. In this work, a modified linear model correction method is proposed for improving the transfer accuracy and computational efficiency. The constraint of linear model correction was replaced by a robust convex equation to restrict the model similarity in the optimization. The near infrared dataset of pharmaceutical tablet measured with different instruments are used to test the performance of the method. The result shows that a modified linear model correction achieves a high efficiency of the transfer while the computational complexity can be considerably reduced. The method may provide a robust way in practical application.

scholarly journals Calibration Transfer Based on Affine Invariance for NIR without Transfer Standards

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1802 ◽  
Author(s):  
Yuhui Zhao ◽  
Ziheng Zhao ◽  
Peng Shan ◽  
Silong Peng ◽  
Jinlong Yu ◽  
...  
Keyword(s):  
Affine Transformation ◽  
Near Infrared ◽  
Nir Spectroscopy ◽  
Regression Coefficients ◽  
Rank Test ◽  
Affine Invariance ◽  
Standard Samples ◽  
Calibration Transfer ◽  
Practical Applications ◽  
Predicted Values

Calibration transfer is an important field for near-infrared (NIR) spectroscopy in practical applications. However, most transfer methods are constructed with standard samples, which are expensive and difficult to obtain. Taking this problem into account, this paper proposes a calibration transfer method based on affine invariance without transfer standards (CTAI). Our method can be utilized to adjust the difference between two instruments by affine transformation. CTAI firstly establishes a partial least squares (PLS) model of the master instrument to obtain score matrices and predicted values of the two instruments, and then the regression coefficients between each of the score vectors and predicted values are computed for the master instrument and the slave instrument, respectively. Next, angles and biases are calculated between the regression coefficients of the master instrument and the corresponding regression coefficients of the slave instrument, respectively. Finally, by introducing affine transformation, new samples are predicted based on the obtained angles and biases. A comparative study between CTAI and the other five methods was conducted, and the performances of these algorithms were tested with two NIR spectral datasets. The obtained experimental results show clearly that, in general CTAI is more robust and can also achieve the best Root Mean Square Error of test sets (RMSEPs). In addition, the results of statistical difference with the Wilcoxon signed rank test show that CTAI is generally better than the others, and at least statistically the same.

scholarly journals High-efficiency broadband achromatic metalens for near-IR biological imaging window

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yujie Wang ◽  
Qinmiao Chen ◽  
Wenhong Yang ◽  
Ziheng Ji ◽  
Limin Jin ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Large Scale ◽  
Near Infrared ◽  
High Efficiency ◽  
Numerical Aperture ◽  
Biological Imaging ◽  
Material Loss ◽  
Practical Applications ◽  
Aspect Ratios ◽  
Polarization Insensitive

AbstractOver the past years, broadband achromatic metalenses have been intensively studied due to their great potential for applications in consumer and industry products. Even though significant progress has been made, the efficiency of technologically relevant silicon metalenses is limited by the intrinsic material loss above the bandgap. In turn, the recently proposed achromatic metalens utilizing transparent, high-index materials such as titanium dioxide has been restricted by the small thickness and showed relatively low focusing efficiency at longer wavelengths. Consequently, metalens-based optical imaging in the biological transparency window has so far been severely limited. Herein, we experimentally demonstrate a polarization-insensitive, broadband titanium dioxide achromatic metalens for applications in the near-infrared biological imaging. A large-scale fabrication technology has been developed to produce titanium dioxide nanopillars with record-high aspect ratios featuring pillar heights of 1.5 µm and ~90° vertical sidewalls. The demonstrated metalens exhibits dramatically increased group delay range, and the spectral range of achromatism is substantially extended to the wavelength range of 650–1000 nm with an average efficiency of 77.1%–88.5% and a numerical aperture of 0.24–0.1. This research paves a solid step towards practical applications of flat photonics.

Scalable calibration transfer without standards via dynamic time warping for near-infrared spectroscopy

2019 ◽  
Vol 11 (35) ◽  
pp. 4481-4493 ◽  
Author(s):  
Congming Zou ◽  
Huimin Zhu ◽  
Junru Shen ◽  
Yue He ◽  
Jiaen Su ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Dynamic Time Warping ◽  
Near Infrared ◽  
Nir Spectroscopy ◽  
Time Warping ◽  
Calibration Transfer ◽  
Transfer Method ◽  
Dynamic Time

A standard-free calibration transfer method has been developed for NIR spectroscopy based on variable penalty dynamic time warping.

scholarly journals PLS Subspace-Based Calibration Transfer for Near-Infrared Spectroscopy Quantitative Analysis

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1289 ◽  
Author(s):  
Yuhui Zhao ◽  
Jinlong Yu ◽  
Peng Shan ◽  
Ziheng Zhao ◽  
Xueying Jiang ◽  
...  
Keyword(s):  
Least Squares ◽  
Near Infrared ◽  
Least Squares Method ◽  
Ordinary Least Squares ◽  
Rank Test ◽  
Transfer Model ◽  
Calibration Model ◽  
Least Squares Regression ◽  
Standard Samples ◽  
Calibration Transfer

In order to enable the calibration model to be effectively transferred among multiple instruments and correct the differences between the spectra measured by different instruments, a new feature transfer model based on partial least squares regression (PLS) subspace (PLSCT) is proposed in this paper. Firstly, the PLS model of the master instrument is built, meanwhile a PLS subspace is constructed by the feature vectors. Then the master spectra and the slave spectra are projected into the PLS subspace, and the features of the spectra are also extracted at the same time. In the subspace, the pseudo predicted feature of the slave spectra is transferred by the ordinary least squares method so that it matches the predicted feature of the master spectra. Finally, a feature transfer relationship model is constructed through the feature transfer of the PLS subspace. This PLS-based subspace transfer provides an efficient method for performing calibration transfer with only a small number of standard samples. The performance of the PLSCT was compared and assessed with slope and bias correction (SBC), piecewise direct standardization (PDS), calibration transfer method based on canonical correlation analysis (CCACT), generalized least squares (GLSW), multiplicative signal correction (MSC) methods in three real datasets, statistically tested by the Wilcoxon signed rank test. The obtained experimental results indicate that PLSCT method based on the PLS subspace is more stable and can acquire more accurate prediction results.

Improvement of a Standard-Free Method for Near-Infrared Calibration Transfer

2002 ◽  
Vol 56 (8) ◽  
pp. 1098-1106 ◽  
Author(s):  
Huwei Tan ◽  
Stephen T. Sum ◽  
Steven D. Brown
Keyword(s):  
Diffuse Reflectance ◽  
Near Infrared ◽  
Finite Impulse Response ◽  
Current Signal ◽  
Improved Method ◽  
Calibration Transfer ◽  
Additional Advantage ◽  
Signal Correction ◽  
One Step ◽  
Transfer Method

Previously, a standard-free method using the finite impulse response (FIR) filter was successfully employed to transfer the NIR spectra of caustic brines, analgesics, and terpolymer resins. This paper carries the FIR transfer method one step further, leading to an improved algorithm that makes the transfer more robust and general by avoiding transfer artifacts in the filtered spectra. Investigations of the theoretical aspects and application examples of diffuse reflectance NIR datasets show that in comparison with our previous version the improved method is much easier to use and gives artifact-free transferred spectra. The improved method also compares favorably with other current signal correction methods for calibration transfer. With the additional advantage of not requiring a subset of standards to be measured on main and remote instruments, the proposed method is a very useful alternative for calibration transfer.

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