傅里叶变换和傅立叶描述符在Java上提取形状特征

// 导入相关库
import java.util.Arrays;
import java.util.List;
import org.apache.commons.math3.complex.Complex;
import org.apache.commons.math3.transform.DftNormalization;
import org.apache.commons.math3.transform.TransformType;
import org.apache.commons.math3.util.Pair;

// 定义一个函数，用于提取形状特征
public Pair<Double, Double> extractShapeFeatures(String shape) {
    // 将输入字符串转换为字符数组
    char[] shapeArray = shape.toCharArray();
    
    // 计算形状数组的傅里叶描述符
    int n = shapeArray.length;
    Complex[] fftArray = new Complex[n];
    for (int i = 0; i < n; i++) {
        fftArray[i] = new Complex(shapeArray[i], 0);
    }
    Complex[] fftShape = DftNormalization.scale(fftArray);
    
    // 计算形状数组的傅里叶变换
    DftNormalization.transform(fftShape, DftNormalization.STANDARD);
    
    // 计算形状数组的形状特征
    int m = shapeArray.length;
    double peak = 0, valley = 0, overall = 0, asymmetry = 0, fractal = 0, lacunarity = 0, energy = 0;
    for (int i = 0; i < m; i++) {
        if (shapeArray[i] == '1') {
            peak++;
        } else if (shapeArray[i] == '2') {
            valley++;
        }
    }
    overall = (double) peak / (double) m;
    for (int i = 0; i < m; i++) {
        if (shapeArray[i] == '1') {
            asymmetry += (double) Math.abs(fftShape[i].getReal() - overall);
        }
    }
    energy = DftNormalization.calculateEnergy(fftShape);
    
    // 返回形状特征
    return new Pair<>(overall, asymmetry / (double) peak);
}

String shape = "12345";
Pair<Double, Double> features = extractShapeFeatures(shape);
System.out.println("Overall shape features: " + features.getKey());
System.out.println("Asymmetry: " + features.getValue());