OpenCVで加工した画像をwebsocketでクライアントに送るためのソースです。

opencv_websocket.rb

require 'opencv'
require 'em-websocket'
require 'base64'

EM::run do
  cap = OpenCV::CvCapture.open
  det_file = "/usr/local/share/OpenCV/haarcascades/haarcascade_frontalface_default.xml"
  det = OpenCV::CvHaarClassifierCascade::load det_file
  connections = Array.new

  EM::WebSocket.start(:host => '0.0.0.0', :port => 51234) do |ws|
    ws.onopen do |handshake|
      puts 'connected'
      connections.push(ws)
    end

    ws.onclose do |handshake|
      puts 'closed'
      connections.delete(ws)
    end
  end

  EM::defer do
    loop do
      sleep 0.1
      next if connections.size == 0

      img = cap.query
      img = img.resize OpenCV::CvSize.new 640, 360
      det.detect_objects(img).each do |rect|
        puts "detect!! : #{rect.top_left}, #{rect.top_right}, #{rect.bottom_left}, #{rect.bottom_right}"
        img.rectangle! rect.top_left, rect.bottom_right, :color => OpenCV::CvColor::Red
      end
      mat = img.to_CvMat
      data = Base64.encode64(mat.encode('.jpg').pack('C*'))

      connections.each do |con|
        con.send(data);
      end
    end
  end
end