Page 35 - Read Online
P. 35

Page 133                         Tang et al. Intell Robot 2022;2(2):130­44  I http://dx.doi.org/10.20517/ir.2022.07

                                                 Two consecutive
                                                    frames   Count the number of
                                                               changing pixels



                                                   The previous                      Background updating
                                     Input video    few frames  Establish the initial
                                      sequence                background model






                                                   Edge         Foreground     Shadow
                                                  detection      detection     removal
                                                  based on       based on      based on
                                                   Canny          ViBE        HSV color
                                                  method         method        space






                                                                Output the
                                                               detection results

                               Figure 1. Flow diagram of the improved ViBe-based approach for moving object detection.


               tation threshold, which can also obtain a better performance in complex dynamic backgrounds but cannot
               effectively remove shadows.



               3. METHODS
               In this paper, the problem of moving object detection based on ViBe method is studied. The basic idea of the
               ViBe method uses neighboring pixels to establish the background model and then compares the background
               model with the current pixel value to detect the foreground. There are three main steps in the ViBe method,
               namely the background initialization, the foreground object detection, and the background model updating.
               Aiming at the problems in the three main steps, some improvements are proposed in this study. The flow chart
               of the proposed approach is shown in Figure 1 and the main steps of the proposed approach are introduced in
               detail as follows.


               3.1. Mode method based background modeling
               The initial background selection is the first step in the ViBe-based method, which will directly influence the
               detection results. If it can be extracted correctly, the accuracy of the object detection will increase. In general,
               the ViBe method uses the first frame as the initial background [41] , namely



                                                       (  ,   ) =       (  ,   )                       (1)

               where   (  ,   ) is the pixel value of the background and       (  ,   ) is the pixel value of the first frame in the video.
               Although the method using the first frame is simple and efficient, it will fail when there is a moving object
               in the first frame. To deal with this problem, some improvements are proposed, such as the mean method,
               which needs to store more video frames and has the problem of shadows [42] . In this paper, the mode method
               is introduced to extract the initial background frame [43] . The basic idea of the mode method for background
               modeling is that few previous frames are used to obtain an optimized background model. The pixel value of
   30   31   32   33   34   35   36   37   38   39   40