前言
最近公司孵化一個項(xiàng)目趾盐，里面涉及到大量的原創(chuàng)照片及圖片搬泥，目前我們使用的明文水印，不但對用戶體驗(yàn)有一定影響唯沮，并且這種水印也極其容易被破壞脖旱，之前了解到一種基于傅里葉變換實(shí)現(xiàn)的盲水印堪遂，這種盲水印技術(shù)相比普通水印，不僅具有更好的用戶視覺體驗(yàn)萌庆，安全性亦是拉了普通水印幾條街
早在16年溶褪，阿里的內(nèi)部泄密事件發(fā)生后，一位知乎大神在知乎上對這種技術(shù)已經(jīng)給出了很詳細(xì)的解釋践险，帖子中也給出了相關(guān)理論和matlab代碼及對其水印的安全測評 ：阿里巴巴公司根據(jù)截圖查到泄露信息的具體員工的技術(shù)是什么猿妈？ - 知乎
整個過程大概如下
- 打水印
先將原圖片進(jìn)行 離散傅里葉變換 到頻域，加上水印后再通過離散傅里葉逆變換到空間域恢復(fù)圖片 - 解水印
將打有水印的圖片通過傅里葉變換到頻域巍虫，提取出水印
本篇文章主要介紹 JAVA 結(jié)合OpenCV實(shí)現(xiàn)盲水印服務(wù)彭则，并對其進(jìn)行封裝，供整個系統(tǒng)各個服務(wù)進(jìn)行調(diào)用
搭建OpenCV開發(fā)環(huán)境占遥，加載OpenCV動態(tài)庫
環(huán)境：JDK1.8 + Maven3.x + IntelliJ IDEA 2018.2.5 + OpenCV2.4.13 + Windows
- OpenCV2.4.13 下載地址
安裝OpenCV
其實(shí)安裝程序做的也就是把Opencv內(nèi)容解壓到你所選擇的目錄下面而已
新建一個Maven項(xiàng)目 File --> Project Strcture --> Project Settings --> Libraries 點(diǎn)擊+號 把opencv-2413.jar引入
1540465259781.png
添加 OpenCV動態(tài)庫
1540465439928.png
1540465479941.png
點(diǎn)擊 Apply
1540465519128.png
創(chuàng)建工具類 ImgWatermarkUtil.java
import org.opencv.core.*;
import org.opencv.imgproc.Imgproc;
import java.util.ArrayList;
import java.util.List;
/**
* @author yangxiaohui
* @Date: Create by 2018-10-25 19:14
* @Description: 添加圖片盲水印工具類
*/
public class ImgWatermarkUtil {
private static List<Mat> planes = new ArrayList<Mat>();
private static List<Mat> allPlanes = new ArrayList<Mat>();
/**
* <pre>
* 添加圖片文字水印
* <pre>
* @author Yangxiaohui
* @date 2018-10-25 19:16
* @param image 圖片對象
* @param watermarkText 水印文字
*/
public static Mat addImageWatermarkWithText(Mat image, String watermarkText){
Mat complexImage = new Mat();
//優(yōu)化圖像的尺寸
//Mat padded = optimizeImageDim(image);
Mat padded = splitSrc(image);
padded.convertTo(padded, CvType.CV_32F);
planes.add(padded);
planes.add(Mat.zeros(padded.size(), CvType.CV_32F));
Core.merge(planes, complexImage);
// dft
Core.dft(complexImage, complexImage);
// 添加文本水印
Scalar scalar = new Scalar(0, 0, 0);
Point point = new Point(40, 40);
Core.putText(complexImage, watermarkText, point, Core.FONT_HERSHEY_DUPLEX, 1D, scalar);
Core.flip(complexImage, complexImage, -1);
Core.putText(complexImage, watermarkText, point, Core.FONT_HERSHEY_DUPLEX, 1D, scalar);
Core.flip(complexImage, complexImage, -1);
return antitransformImage(complexImage, allPlanes);
}
/**
* <pre>
* 獲取圖片水印
* <pre>
* @author Yangxiaohui
* @date 2018-10-25 19:58
* @param image
*/
public static Mat getImageWatermarkWithText(Mat image){
List<Mat> planes = new ArrayList<Mat>();
Mat complexImage = new Mat();
Mat padded = splitSrc(image);
padded.convertTo(padded, CvType.CV_32F);
planes.add(padded);
planes.add(Mat.zeros(padded.size(), CvType.CV_32F));
Core.merge(planes, complexImage);
// dft
Core.dft(complexImage, complexImage);
Mat magnitude = createOptimizedMagnitude(complexImage);
planes.clear();
return magnitude;
}
private static Mat splitSrc(Mat mat) {
mat = optimizeImageDim(mat);
Core.split(mat, allPlanes);
Mat padded = new Mat();
if (allPlanes.size() > 1) {
for (int i = 0; i < allPlanes.size(); i++) {
if (i == 0) {
padded = allPlanes.get(i);
break;
}
}
} else {
padded = mat;
}
return padded;
}
private static Mat antitransformImage(Mat complexImage, List<Mat> allPlanes) {
Mat invDFT = new Mat();
Core.idft(complexImage, invDFT, Core.DFT_SCALE | Core.DFT_REAL_OUTPUT, 0);
Mat restoredImage = new Mat();
invDFT.convertTo(restoredImage, CvType.CV_8U);
if (allPlanes.size() == 0) {
allPlanes.add(restoredImage);
} else {
allPlanes.set(0, restoredImage);
}
Mat lastImage = new Mat();
Core.merge(allPlanes, lastImage);
return lastImage;
}
/**
* <pre>
* 為加快傅里葉變換的速度俯抖，對要處理的圖片尺寸進(jìn)行優(yōu)化
* <pre>
* @author Yangxiaohui
* @date 2018-10-25 19:33
* @param image
* @return
*/
private static Mat optimizeImageDim(Mat image) {
Mat padded = new Mat();
int addPixelRows = Core.getOptimalDFTSize(image.rows());
int addPixelCols = Core.getOptimalDFTSize(image.cols());
Imgproc.copyMakeBorder(image, padded, 0, addPixelRows - image.rows(), 0, addPixelCols - image.cols(),
Imgproc.BORDER_CONSTANT, Scalar.all(0));
return padded;
}
private static Mat createOptimizedMagnitude(Mat complexImage) {
List<Mat> newPlanes = new ArrayList<Mat>();
Mat mag = new Mat();
Core.split(complexImage, newPlanes);
Core.magnitude(newPlanes.get(0), newPlanes.get(1), mag);
Core.add(Mat.ones(mag.size(), CvType.CV_32F), mag, mag);
Core.log(mag, mag);
shiftDFT(mag);
mag.convertTo(mag, CvType.CV_8UC1);
Core.normalize(mag, mag, 0, 255, Core.NORM_MINMAX, CvType.CV_8UC1);
return mag;
}
private static void shiftDFT(Mat image) {
image = image.submat(new Rect(0, 0, image.cols() & -2, image.rows() & -2));
int cx = image.cols() / 2;
int cy = image.rows() / 2;
Mat q0 = new Mat(image, new Rect(0, 0, cx, cy));
Mat q1 = new Mat(image, new Rect(cx, 0, cx, cy));
Mat q2 = new Mat(image, new Rect(0, cy, cx, cy));
Mat q3 = new Mat(image, new Rect(cx, cy, cx, cy));
Mat tmp = new Mat();
q0.copyTo(tmp);
q3.copyTo(q0);
tmp.copyTo(q3);
q1.copyTo(tmp);
q2.copyTo(q1);
tmp.copyTo(q2);
}
}
測試：
import org.opencv.core.Core;
import org.opencv.core.Mat;
import static org.opencv.highgui.Highgui.imread;
import static org.opencv.highgui.Highgui.imwrite;
/**
* @author yangxiaohui
* @Date: Create by 2018-10-25 19:42
* @Description:
*/
public class Main {
static{
//加載opencv動態(tài)庫
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
}
public static void main(String[] args){
Mat img = imread("stzz.jpg");//加載圖片
Mat outImg = ImgWatermarkUtil.addImageWatermarkWithText(img,"testwatermark");
imwrite("stzz-out.jpg",outImg);//保存加過水印的圖片
//讀取圖片水印
Mat watermarkImg = ImgWatermarkUtil.getImageWatermarkWithText(outImg);
imwrite("stzz-watermark.jpg",watermarkImg);//保存獲取到的水印
}
}
加水印前：
image.png
加水印后：
image.png
讀取的水印：
image.png
