opencv-2、小案例集合

一、綠布摳圖-背景圖替換

主要是基于影像色彩空間，轉換為HSV色彩空間實作mask層提取、然后通過一些簡單的影像處理比如形態學開閉操作、高斯模糊等到完整的mask區域，運用mask區域生成權重系數，對綠幕影像與背景影像重新融合生成一個新輸出影像，完成摳圖，

自己代碼實作

代碼實踐

//視頻綠布切割背景替換
void QuickDemo::beijing_tihuan_demo()
{
	VideoCapture captureCamear("D:/01.mp4");
	//get視頻屬性 注意也是可以set設定的 但是注意如果是攝像頭的話他硬體是否支持set的引數
	int frame_width = captureCamear.get(CAP_PROP_FRAME_WIDTH);
	int frame_height = captureCamear.get(CAP_PROP_FRAME_HEIGHT);
	int frame_counts = captureCamear.get(CAP_PROP_FRAME_COUNT);
	int fps = captureCamear.get(CAP_PROP_FPS);
	std::cout << "frame_width = " << frame_width << std::endl;
	std::cout << "frame_height = " << frame_height << std::endl;
	std::cout << "frame_counts = " << frame_counts << std::endl;
	std::cout << "fps = " << fps << std::endl;

	//CAP_PROP_FOURCC  獲取原來的編碼型別   注意size的大小不能變
	VideoWriter writer("D:/test.mp4", captureCamear.get(CAP_PROP_FOURCC), fps, Size(frame_width, frame_height), true);
	VideoCapture Camerwriter("D:/lane.avi");
	Mat frameCamear;
	Mat frameVedio;
	while (true)
	{
		captureCamear.read(frameCamear);//讀取視頻 每一幀 從而操作視頻就是操作影像了
		Camerwriter.read(frameVedio);
		Mat hsv;
		cvtColor(frameCamear, hsv, COLOR_BGR2HSV);
		Mat mask;
		inRange(hsv, Scalar(35, 43, 46), Scalar(77, 255, 255), mask);//輸入hsv影像、 根據綠色作為分界則傳入hsv綠色的hsv最大最下值
		//imshow("inRange mask", mask);//只有黑白  把綠色都變成1白色 其他變成0黑色
		resize(frameVedio, frameVedio, Size(frame_width, frame_height), 0, 0, INTER_LINEAR);
		bitwise_not(mask, mask);//取反 黑變白 白變黑   就是相當于把綠色部分變成0黑色、人部分變成1白色
		frameCamear.copyTo(frameVedio, mask);
		writer.write(frameVedio);//寫入檔案
		if (frameVedio.empty())
		{
			break;
		}
		imshow("frame", frameVedio);
		int c = waitKey(10);
		if (c == 27)
			break;
	}
	//captureVedio.release();
	captureCamear.release();//攝像頭資源需要釋放
	writer.release();//視頻寫入變數也需要釋放資源
}

參考賈志剛老師的代碼實踐

代碼實踐

//加入高斯模糊的綠布摳圖替換
Mat background_01;
Mat background_02;
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 = 0.0;
	int r = 0, g = 0, b = 0;

	int b1 = 0, g1 = 0, r1 = 0;
	int b2 = 0, g2 = 0, r2 = 0;

	for (int row = 0; row < h; row++) {
		uchar* current = frame.ptr<uchar>(row);
		uchar* bgrow = background_01.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) {
				*targetrow++ = *current++;
				*targetrow++ = *current++;
				*targetrow++ = *current++;
				bgrow += 3;
			}
			else {
				// 背景像素
				b1 = *bgrow++;
				g1 = *bgrow++;
				r1 = *bgrow++;

				// 目標前景像素
				b2 = *current++;
				g2 = *current++;
				r2 = *current++;

				// 混合權重
				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;
}
void QuickDemo::beijing_tihuan_demo1()
{
	background_01 = imread("D:/8519639.jpg");
	background_02 = imread("D:/2.png");
	resize(background_02, background_02, Size(background_01.cols, background_01.rows));
	VideoCapture capture;
	capture.open("D:/01.mp4");
	if (!capture.isOpened()) {
		printf("could not load video file...\n");
		return ;
	}
	VideoCapture captureTwo;
	captureTwo.open("D:/dushuhu.mp4");


	char* title = "input video";
	char* matting_title = "video matting result";
	namedWindow(title, WINDOW_AUTOSIZE);
	namedWindow(matting_title, WINDOW_AUTOSIZE);
	Mat frame, hsv, mask;
	Mat frame2;
	int count = 0;
	Size S = Size((int)capture.get(CAP_PROP_FRAME_WIDTH),
		(int)capture.get(CAP_PROP_FRAME_HEIGHT));
	while (capture.read(frame)) {
		if (captureTwo.read(frame2)) {
			resize(frame2, background_01, frame.size());
		}
		else {
			background_02.copyTo(background_01);//如果背景視頻播放完畢就是要背景 圖片替代
		}
		cvtColor(frame, hsv, COLOR_BGR2HSV);
		inRange(hsv, Scalar(35, 43, 46), Scalar(155, 255, 255), mask);

		// 形態學腐蝕操作
		//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(title, frame);
		imshow(matting_title, result);
	}

	waitKey(0);
	return ;

}