光谱基线校正算法 C#

根据提供的引用内容，我们可以了解到一种结合导数谱峰检测与Whittaker平滑器的基线校正算法。这种算法可以用于光谱基线校正，下面是一个C#的实现示例：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using MathNet.Numerics.LinearAlgebra;
using MathNet.Numerics.LinearAlgebra.Double;

namespace BaselineCorrection
{
    class Program
    {
        static void Main(string[] args)
        {
            // 读取光谱数据
            double[] x = new double[] { 1, 2, 3, 4, 5 };
            double[] y = new double[] { 1.2, 1.5, 1.8, 2.1, 1.9 };

            // 计算一阶导数
            double[] dy = new double[y.Length];
            for (int i = 0; i < y.Length - 1; i++)
            {
                dy[i] = y[i + 1] - y[i];
            }
            dy[y.Length - 1] = dy[y.Length - 2];

            // 计算二阶导数
            double[] ddy = new double[dy.Length];
            for (int i = 0; i < dy.Length - 1; i++)
            {
                ddy[i] = dy[i + 1] - dy[i];
            }
            ddy[dy.Length - 1] = ddy[dy.Length - 2];

            // 寻找谷点
            List<int> valleyIndex = new List<int>();
            for (int i = 1; i < ddy.Length - 1; i++)
            {
                if (ddy[i] < 0 && ddy[i - 1] > 0 && ddy[i + 1] > 0)
                {
                    valleyIndex.Add(i);
                }
            }

            // 寻找峰点
            List<int> peakIndex = new List<int>();
            for (int i = 1; i < ddy.Length - 1; i++)
            {
                if (ddy[i] > 0 && ddy[i - 1] < 0 && ddy[i + 1] < 0)
                {
                    peakIndex.Add(i);
                }
            }

            // 计算Whittaker平滑器系数
            double lambda = 100;
            double[] w = new double[y.Length];
            for (int i = 1; i < y.Length - 1; i++)
            {
                w[i] = 1 / (1 + lambda * Math.Pow(dy[i], 2));
            }

            // 构造矩阵
            Matrix<double> A = DenseMatrix.Create(y.Length, N + 1, (i, j) => Math.Pow(x[i], j));
            Vector<double> b = DenseVector.OfArray(y);

            // 求解线性方程组
            Vector<double> c = A.Transpose() * (DiagonalMatrix.OfDiagonal(w) * A);
            c = c.Inverse() * A.Transpose() * (DiagonalMatrix.OfDiagonal(w) * b);

            // 计算拟合曲线
            double[] fit = new double[y.Length];
            for (int i = 0; i < y.Length; i++)
            {
                for (int j = 0; j < N + 1; j++)
                {
                    fit[i] += c[j] * Math.Pow(x[i], j);
                }
            }

            // 计算基线
            double[] baseline = new double[y.Length];
            for (int i = 0; i < y.Length; i++)
            {
                baseline[i] = y[i] - fit[i];
            }

            // 输出基线校正后的光谱数据
            for (int i = 0; i < y.Length; i++)
            {
                Console.WriteLine("{0}\t{1}\t{2}", x[i], y[i], baseline[i]);
            }
        }
    }
}