代码实现思路:
1.将二维图像数据线性化
2.使用K-means聚类;分离出背景色
3.背景与人物像素二值化
4.腐蚀 + 高斯模糊:图像与背景交汇处高斯模糊化
5.更换背景色以及交汇处融合处理
代码:
- #include <opencv2/opencv.hpp>
- #include <iostream>
- using namespace std;
- using namespace cv;
- int main(int argc, char** argv) {
- Mat src = imread("../img/toux.jpg");
- if (src.empty()) {
- printf("could not load image...\n");
- return -1;
- }
- imshow("原图", src);
- // 1.将二维图像数据线性化
- Mat data;
- for (int i = 0; i < src.rows; i++) //像素点线性排列
- for (int j = 0; j < src.cols; j++)
- {
- Vec3b point = src.at<Vec3b>(i, j);
- Mat tmp = (Mat_<float>(1, 3) << point[0], point[1], point[2]);
- data.push_back(tmp);
- }
- // 2.使用K-means聚类;分离出背景色
- int numCluster = 4;
- Mat labels;
- TermCriteria criteria = TermCriteria(TermCriteria::EPS + TermCriteria::COUNT, 10, 0.1);
- kmeans(data, numCluster, labels, criteria, 3, KMEANS_PP_CENTERS);
- // 3.背景与人物二值化
- Mat mask = Mat::zeros(src.size(), CV_8UC1);
- int index = src.rows * 2 + 2; //获取点(2,2)作为背景色
- int cindex = labels.at<int>(index);
- /* 提取背景特征 */
- for (int row = 0; row < src.rows; row++) {
- for (int col = 0; col < src.cols; col++) {
- index = row * src.cols + col;
- int label = labels.at<int>(index);
- if (label == cindex) { // 背景
- mask.at<uchar>(row, col) = 0;
- }
- else {
- mask.at<uchar>(row, col) = 255;
- }
- }
- }
- //imshow("mask", mask);
- // 4.腐蚀 + 高斯模糊:图像与背景交汇处高斯模糊化
- Mat k = getStructuringElement(MORPH_RECT, Size(3, 3), Point(-1, -1));
- erode(mask, mask, k);
- //imshow("erode-mask", mask);
- GaussianBlur(mask, mask, Size(3, 3), 0, 0);
- //imshow("Blur Mask", mask);
- // 5.更换背景色以及交汇处融合处理
- RNG rng(12345);
- Vec3b color; //设置的背景色
- color[0] = 217;//rng.uniform(0, 255);
- color[1] = 60;// rng.uniform(0, 255);
- color[2] = 160;// rng.uniform(0, 255);
- Mat result(src.size(), src.type());
- double w = 0.0; //融合权重
- int b = 0, g = 0, r = 0;
- int b1 = 0, g1 = 0, r1 = 0;
- int b2 = 0, g2 = 0, r2 = 0;
- for (int row = 0; row < src.rows; row++) {
- for (int col = 0; col < src.cols; col++) {
- int m = mask.at<uchar>(row, col);
- if (m == 255) {
- result.at<Vec3b>(row, col) = src.at<Vec3b>(row, col); // 前景
- }
- else if (m == 0) {
- result.at<Vec3b>(row, col) = color; // 背景
- }
- else {/* 融合处理部分 */
- w = m / 255.0;
- b1 = src.at<Vec3b>(row, col)[0];
- g1 = src.at<Vec3b>(row, col)[1];
- r1 = src.at<Vec3b>(row, col)[2];
- b2 = color[0];
- g2 = color[1];
- r2 = color[2];
- b = b1 * w + b2 * (1.0 - w);
- g = g1 * w + g2 * (1.0 - w);
- r = r1 * w + r2 * (1.0 - w);
- result.at<Vec3b>(row, col)[0] = b;
- result.at<Vec3b>(row, col)[1] = g;
- result.at<Vec3b>(row, col)[2] = r;
- }
- }
- }
- imshow("背景替换", result);
- waitKey(0);
- return 0;
- }
结果:
视频背景替换思路:
视频帧背景替换关键API:
1、 cvtColor(frame, hsv, COLOR_BGR2HSV); //转换颜色域
2、 inRange(hsv, Scalar(35, 43, 46), Scalar(155, 255, 255), OutImg); //提取背景
代码:
- #include <opencv2/opencv.hpp>
- #include <iostream>
- using namespace cv;
- using namespace std;
- Mat replace_and_blend(Mat &frame, Mat &mask);
- Mat background_01;
- Mat background_02;
- int main(int argc, char** argv) {
- // start here...
- background_01 = imread("D:/vcprojects/images/bg_01.jpg");
- background_02 = imread("D:/vcprojects/images/bg_02.jpg");
- VideoCapture capture;
- capture.open("D:/vcprojects/images/01.mp4");
- if (!capture.isOpened()) {
- printf("could not find the video file...\n");
- return -1;
- }
- char* title = "input video";
- char* resultWin = "result video";
- namedWindow(title, CV_WINDOW_AUTOSIZE);
- namedWindow(resultWin, CV_WINDOW_AUTOSIZE);
- Mat frame, hsv, mask;
- int count = 0;
- while (capture.read(frame)) {
- cvtColor(frame, hsv, COLOR_BGR2HSV);
- inRange(hsv, Scalar(35, 43, 46), Scalar(155, 255, 255), mask);
- // 形态学操作
- Mat k = getStructuringElement(MORPH_RECT, Size(3, 3), Point(-1, -1));
- morphologyEx(mask, mask, MORPH_CLOSE, k);
- erode(mask, mask, k);
- GaussianBlur(mask, mask, Size(3, 3), 0, 0);
- Mat result = replace_and_blend(frame, mask);
- char c = waitKey(1);
- if (c == 27) {
- break;
- }
- imshow(resultWin, result);
- imshow(title, frame);
- }
- waitKey(0);
- return 0;
- }
- Mat replace_and_blend(Mat &frame, Mat &mask) {
- Mat result = Mat::zeros(frame.size(), frame.type());
- int h = frame.rows;
- int w = frame.cols;
- int dims = frame.channels();
- // replace and blend
- int m = 0;
- double wt = 0;
- int r = 0, g = 0, b = 0;
- int r1 = 0, g1 = 0, b1 = 0;
- int r2 = 0, g2 = 0, b2 = 0;
- for (int row = 0; row < h; row++) {
- uchar* current = frame.ptr<uchar>(row);
- uchar* bgrow = background_02.ptr<uchar>(row);
- uchar* maskrow = mask.ptr<uchar>(row);
- uchar* targetrow = result.ptr<uchar>(row);
- for (int col = 0; col < w; col++) {
- m = *maskrow++;
- if (m == 255) { // 背景
- *targetrow++ = *bgrow++;
- *targetrow++ = *bgrow++;
- *targetrow++ = *bgrow++;
- current += 3;
- } else if(m==0) {// 前景
- *targetrow++ = *current++;
- *targetrow++ = *current++;
- *targetrow++ = *current++;
- bgrow += 3;
- } else {
- b1 = *bgrow++;
- g1 = *bgrow++;
- r1 = *bgrow++;
- b2 = *current++;
- g2 = *current++;
- r2 = *current++;
- // 权重
- wt = m / 255.0;
- // 混合
- b = b1*wt + b2*(1.0 - wt);
- g = g1*wt + g2*(1.0 - wt);
- r = r1*wt + r2*(1.0 - wt);
- *targetrow++ = b;
- *targetrow++ = g;
- *targetrow++ = r;
- }
- }
- }
- return result;
- }
视频中绿布替换成风景背景:
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