利用光流跟踪汽车。为什么矢量绘制得不正确

Question

我是新的光流和计算机视觉在一般情况下，我开始工作与一个简单的演示例子从Matlab。

它的目的是使用视频并将运动矢量绘制到屏幕上。我使用以下代码：

%% initialization
close all
clear all

% Create reader

reader = vision.VideoFileReader;
reader.Filename = 'viptraffic.avi';

   % Create viewer
   viewer = vision.DeployableVideoPlayer;
   %%viewer.FrameRate = 10;

%Create Optical Flow
optical = vision.OpticalFlow; %how pixels are moving from one frame to the next
optical.OutputValue = 'Horizontal and vertical components in complex form'; %will allow         us to draw a vector
%%%on the vision so that we see how the pixels are moving from one frame to the next

%%We pass the horizontal and vertical components to the shape inserter
%%below

% Display vector fields
shapes = vision.ShapeInserter;
shapes.Shape = 'Lines';
shapes.BorderColor = 'white';

R = 1:4:120;%%downsample the optical flow field
C = 1:4:160;%%downsample the optical flow field

[Cv, Rv] = meshgrid (C, R); %%% display a grid on the image and take every fourth value


Rv = Rv(:)';
Cv = Cv(:)';

 %% Execution
 reset(reader)

 %Set up for stream
 while ~isDone(reader)

 I = step(reader);
 of = step(optical,rgb2gray(I));
 size(of)

 ofd = of(R,C);
 size(ofd)


 H = imag(ofd)*20;
 V = real(ofd)*20;


 %Draw lines on top of image
 lines = [Rv;Cv; Rv+H(:)'; Cv+V(:)']; %%start and a finish , start+movement,   end+movement
 % lines = [Cv;Rv;Cv;Rv];
 Ishp = step(shapes,I,lines);

 step(viewer,Ishp);

 end
 release(viewer);

我不知道为什么向量线绘制得不正确。

有谁可以帮我？

谢谢

PS:结果如下：

​

Answer 1

试着使用

lines = [Rv(:); Cv(:); Rv(:)+H(:); Cv(:)+V(:)];

而不是

lines = [Rv;Cv; Rv+H(:)'; Cv+V(:)'];

更好的是，如果您有一个最新版本的Matlab，尝试使用insertShape函数而不是vision.ShapeInserter。

编辑：如果您有计算机视觉系统工具箱的最新版本，请尝试新的光流函数：opticalFlowHS、opticalFlowLK、opticalFlowLKDoG和opticalFlowFarneback。