我有以下代码执行背景减法，然后使用 findContours 在前景对象周围绘制边界。
// frame - Input frame from a camera.
// output - Output frame to be displayed.
void process(cv:: Mat &frame, cv:: Mat &output) {
cv::cvtColor(frame, gray, CV_BGR2GRAY);
// initialize background to 1st frame
if (background.empty())
gray.convertTo(background, CV_32F);
// convert background to 8U
background.convertTo(backImage,CV_8U);
// compute difference between current image and background
cv::absdiff(backImage,gray,foreground);
// apply threshold to foreground image
cv::threshold(foreground,output,threshold,255,cv::THRESH_BINARY_INV);
// accumulate background
cv::accumulateWeighted(gray, background, learningRate, output);
// Find regions of interest
std::vector<std::vector<cv::Point> > v; // Detected foreground points
cv::findContours(output,v,CV_RETR_LIST,CV_CHAIN_APPROX_NONE);
// Sort to find the entry with the most points at the beginning.
// This is done to overcome noisy input.
std::sort(v.begin(), v.end(), DescendingCompare);
cv::Mat drawing = frame;
std::vector<std::vector<cv::Point>> contours_poly(1);
// Determine an approximate polygon for v[0] which is the largest contour
cv::approxPolyDP( cv::Mat(v[0]), contours_poly[0], 3, false );
// Draw polygonal contour
cv::Scalar color = cv::Scalar( 0,0,255 );
cv::drawContours( drawing, contours_poly, 0, color, 2, 8, std::vector<cv::Vec4i>(), 0, cv::Point() );
// Show in a window
output = drawing;
v.clear();
}
该图像只是一个空白的白色背景，但 findContours() 正在返回具有图像 4 个边缘的轮廓。这最终成为找到的最大轮廓，否定了我在代码中的逻辑。有没有办法解决这个问题？我希望它在屏幕为空白时返回一个空向量。
另外，无论如何可以改进此代码以提高效率吗？