Moving-window bis-correlation coefficients method for visible and near-infrared spectral discriminant analysis with applications

Abstract

The moving-window bis-correlation coefficients (MW-BiCC) was proposed and employed for the discriminant analysis of transgenic sugarcane leaves and β-Thalassemia with visible and near-infrared (Vis-NIR) spectroscopy. The well-performed moving-window principal component analysis linear discriminant analysis (MW-PCA-LDA) was also conducted for comparison. A total of 306 transgenic (positive) and 150 nontransgenic (negative) leave samples of sugarcane were collected and divided to calibration, prediction, and validation. The diffuse reflection spectra were corrected using Savitzky-Golay (SG) smoothing with first-order derivative (d=1), third-degree polynomial (p=3) and 25 smoothing points (m=25). The selected waveband was 736-1054nm with MW-BiCC, and the positive and negative validation recognition rates (VREC+, VREC-) were 100%, 98.0%, which achieved the same effect as MW-PCA-LDA. Another example, the 93 β-Thalassemia (positive) and 148 nonthalassemia (negative) of human hemolytic samples were collected. The transmission spectra were corrected using SG smoothing with d=1, p=3 and m=53. Using MW-BiCC, many best wavebands were selected (e.g., 1116-1146, 1794-1848 and 2284-2342nm). The VREC+ and VREC-were both 100%, which achieved the same effect as MW-PCA-LDA. Importantly, the BiCC only required calculating correlation coefficients between the spectrum of prediction sample and the average spectra of two types of calibration samples. Thus, BiCC was very simple in algorithm, and expected to obtain more applications. The results first confirmed the feasibility of distinguishing β-Thalassemia and normal control samples by NIR spectroscopy, and provided a promising simple tool for large population thalassemia screening.