使用OpenCV在网络摄像头上绘制 [英] Draw on webcam using OpenCV

问题描述

我想使用OpenCV在网络摄像头屏幕上绘制/绘画。因为我从一个凸轮读取，帧是不断变化，所以我试图找出一种方法来保存或保存在当前帧的绘图，并将其用于下一帧。下面的代码允许你在屏幕上绘制，但当它得到下一帧，绘图已经走了，它开始。

I want to draw/paint on a webcam screen using OpenCV. Since I'm reading from a cam, the frames are constantly changing, so I'm trying to figure out a way to keep or save the drawing on the current frame and use it for the next frame. The code below allows you to draw on the screen but when it gets the next frame, the drawing is gone and it starts over.

有人可以帮助我...感谢。

Could someone please help me ... Thanks.

          CvCapture *input;
          input = cvCaptureFromCAM( 0 );

          cvSetMouseCallback("Demo",&on_mouse, 0);

                 for(;;)
                    {
                        frame = cvQueryFrame(input);

                        if(!image)
                        {
                            image = cvCreateImage( cvSize(frame->width, frame->height), IPL_DEPTH_8U, 3);
                            screenBuffer = cvCreateImage( cvSize(frame->width, frame->height), IPL_DEPTH_8U, 3);
                        }

                        cvCopy(frame, image, 0);

                        if(drawing) //drawing is a global variable
                        { 
                           cvCircle(image, cvPoint(last_x,last_y), 10,CV_RGB(red,green,blue), -1, CV_AA, 0);
                           cvCopy(image, screenBuffer, 0);
                        }

                        cvShowImage( "Demo", screenBuffer );
                }


        void on_mouse( int event, int x, int y, int flags, void* param )
        {
            last_x = x;
            last_y = y;

            if(event==CV_EVENT_LBUTTONDOWN)
                {
                    drawing = 1;
                }
        }

推荐答案

变成单独的图像，然后是cvAdd（），即在视频图像显示之前。

Draw into a separate image and then cvAdd() that to the video image immediately before dispalying it

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