Background Matting

C++: Background Matting

Background matting use only one segmentation model to generate a human body mask. This mask can figure out which pixels belong to humans and which belong to the background. This output can be used for background replacement (like in the Google Meet app). The segmentation model was taken from this implementation (opens in a new tab) by nihui (opens in a new tab), the author of the NCNN framework. The author also has a webpage for a live demo on web browsers. (opens in a new tab).

Source code: src/examples/demo_background_matting.cpp.

#include "daisykit/flows/background_matting_flow.h"
#include "third_party/json.hpp"
#include <stdio.h>
#include <fstream>
#include <iostream>
#include <opencv2/opencv.hpp>
#include <streambuf>
#include <string>
using namespace cv;
using namespace std;
using json = nlohmann::json;
using namespace daisykit::types;
using namespace daisykit::flows;
int main(int, char**) {
  std::ifstream t("configs/background_matting_config.json");
  std::string config_str((std::istreambuf_iterator<char>(t)),
  cv::Mat background = cv::imread("images/background.jpg");
  cv::cvtColor(background, background, cv::COLOR_BGR2RGB);
  BackgroundMattingFlow flow(config_str, background);
  Mat frame;
  VideoCapture cap(0);
  while (1) {
    cap >> frame;
    cv::Mat rgb;
    cv::cvtColor(frame, rgb, cv::COLOR_BGR2RGB);
    cv::Mat draw = rgb.clone();
    cv::Mat mask = flow.Process(rgb);
    flow.DrawResult(draw, mask);
    cv::cvtColor(draw, draw, cv::COLOR_RGB2BGR);
    imshow("Image", draw);
  return 0;

Update the configurations by modifying config files in assets/configs.