image-pool-service/src/main/java/com/mokasz/pool/image/algorithm/OpenCvService.java

package com.mokasz.pool.image.algorithm;

import org.bytedeco.javacpp.Loader;
import org.bytedeco.opencv.opencv_java;
import org.opencv.core.Mat;
import org.opencv.core.MatOfByte;
import org.opencv.img_hash.PHash;
import org.opencv.imgcodecs.Imgcodecs;
import org.springframework.stereotype.Service;

@Service
public class OpenCvService {
    // 静态初始化 OpenCV
    static {
        Loader.load(opencv_java.class);
    }

    private final PHash pHash = PHash.create();
    public static final int HashLength = 8;

    private static void transformMatToArrayOfFloat(Mat mat, float[] floats) {
        if (mat.width() != HashLength || mat.height() != 1) {
            throw new RuntimeException("Matrix dimension is not 1x8");
        }
        for (int i = 0; i < HashLength; i++) {
            floats[i] = (float) mat.get(0, i)[0];
        }
    }

    public void calculatePHash(byte[] fileBytes, float[] vector) {
        Mat input = Imgcodecs.imdecode(new MatOfByte(fileBytes), Imgcodecs.IMREAD_UNCHANGED);
        Mat output = new Mat();
        pHash.compute(input, output);
        transformMatToArrayOfFloat(output, vector);
    }

    public void transformBinaryArray(float[] octets, float[] binaries) {
        for (int i = 0; i < HashLength; i++) {
            for (int j = 0; j < HashLength; j++) {
                int v = (int) octets[i];
                binaries[i * HashLength + j] = (v & (1 << j)) >> j;
            }
        }
    }

    public String getReadableHash(float[] floats) {
        StringBuilder stringBuilder = new StringBuilder();
        for (int i = 0; i < HashLength; i++) {
            stringBuilder.append(String.format("%02X", (int) floats[i]));
        }
        return stringBuilder.toString();
    }
}