Detect Cars in Video using regionprops

Question

Nguyen Nguyen 2023-2-1

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1904310-detect-cars-in-video-using-regionprops

评论： Nguyen Nguyen 2023-2-1

Hi all,

I'm trying to write a code that detect cars from a video. Right now I'm trying to get the regionprops to work, it doesn't look like it's working at all since it's just giving random boxes and not connecting to the resulted video. Any help is greatly appreciated! Thank you.

clear all
close all
clc
%% Access Video
trafficVid= VideoReader('traffic.mj2');
gs = read(trafficVid,71);
implay('traffic.mj2'); %Explore video
%% Develop Algorithm
darkCarValue = 50;
darkCar = rgb2gray(gs);
noDarkCar = imextendedmax(darkCar, darkCarValue);
sedisk = strel('disk',2);
noiseFreeObject = imopen(noDarkCar, sedisk);
imshow(noiseFreeObject);
title('Object After Removing Noise');
%% Apply Algorithm
nframes = trafficVid.NumberOfFrames;
I = read(trafficVid, 1);
taggedCars = zeros([size(I,1) size(I,2) 3 nframes], class(I));
for k = 1 : nframes
    singleFrame = read(trafficVid, k);
    % Convert to grayscale to do morphological processing.
    I = rgb2gray(singleFrame);
    noDarkCars = imextendedmax(I, darkCarValue);
    % Remove lane markings and other non-disk shaped structures.
    noiseFreeObject = imopen(noDarkCars, sedisk);
    % Remove small structures.
    noiseFreeObject = bwareaopen(noiseFreeObject, 150);
    taggedCars(:,:,:,k) = singleFrame;
    stats = regionprops(noiseFreeObject, 'BoundingBox','Centroid');
   for object = 1:length(stats)
       bb = stats(object).BoundingBox;
       bc = stats(object).Centroid;
       rectangle('Position',bb,'EdgeColor','g','LineWidth',2);
   end
end
%% Results
frameRate = trafficVid.FrameRate;
implay(taggedCars,frameRate);

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Nguyen Nguyen 2023-2-1

在 MATLAB Online 中打开

@prasanth s this works!

I have an extra question if you have time. I want the code to detect all cars, not just black cars. But when I took out the lines that I think are used to exclude the black cars it doesn't work anymore. Do you know why?

clear all
close all
clc
%% Access Video
trafficVid= VideoReader('traffic.mj2');
gs = read(trafficVid,71);
implay('traffic.mj2'); %Explore video
%% Develop Algorithm
%darkCarValue = 50;
darkCar = rgb2gray(gs);
%noDarkCar = imextendedmax(darkCar, darkCarValue);
sedisk = strel('disk',2);
noiseFreeObject = imopen(darkCar, sedisk);
imshow(noiseFreeObject);
title('Object After Removing Noise');
%% Apply Algorithm
nframes = trafficVid.NumberOfFrames;
I = read(trafficVid, 1);
taggedCars = zeros([size(I,1) size(I,2) 3 nframes], class(I));
for k = 1 : nframes
    singleFrame = read(trafficVid, k);
    % Convert to grayscale to do morphological processing.
    I = rgb2gray(singleFrame);
    % noDarkCars = imextendedmax(I, darkCarValue);
    % Remove lane markings and other non-disk shaped structures.
    noiseFreeObject = imopen(I, sedisk);
    % Remove small structures by removing all pixels less than 150 px.
    noiseFreeObject = bwareaopen(noiseFreeObject, 150);
    bw = bwlabel(noiseFreeObject);
    stats = regionprops(noiseFreeObject, 'BoundingBox','Centroid');
   for object = 1:length(stats)
       bb = stats(object).BoundingBox;
       bc = stats(object).Centroid;
       rectangle('Position',bb,'EdgeColor','g','LineWidth',2);
   end
   figure(1),imshow(noiseFreeObject,[])
end

prasanth s 2023-2-1

在 MATLAB Online 中打开

following code includes black car detection using a theshold value 200

clear all
close all
clc
%% Access Video
trafficVid= VideoReader('traffic.mj2');
gs = read(trafficVid,71);
%% Develop Algorithm
darkCarValue = 50;
darkCar = rgb2gray(gs);
noDarkCar = imextendedmax(darkCar, darkCarValue);
sedisk = strel('disk',2);
noiseFreeObject = imopen(noDarkCar, sedisk);
imshow(noiseFreeObject);
title('Object After Removing Noise');
%% Apply Algorithm
nframes = trafficVid.NumberOfFrames;
I = read(trafficVid, 1);
taggedCars = zeros([size(I,1) size(I,2) 3 nframes], class(I));
figure;
for k = 1 : nframes
    singleFrame = read(trafficVid, k);
    % Convert to grayscale to do morphological processing.
    I = rgb2gray(singleFrame);
    noDarkCars = imextendedmax(I, darkCarValue);
    % Remove lane markings and other non-disk shaped structures.
    noiseFreeObject = imopen(noDarkCars, sedisk);
    % Remove small structures.
    noiseFreeObject = bwareaopen(noiseFreeObject, 150);
    
    DarkCars = ~imextendedmax(I, 200);
    DarkCars = imopen(DarkCars, sedisk);
    DarkCars = imdilate(DarkCars, strel('disk',2));
    DarkCars = bwareaopen(DarkCars, 150);
    
    noiseFreeObject=noiseFreeObject|DarkCars;
    taggedCars(:,:,:,k) = singleFrame;
    stats = regionprops(noiseFreeObject, 'BoundingBox','Centroid');
   for object = 1:length(stats)
       bb = stats(object).BoundingBox;
       bc = stats(object).Centroid;
       rectangle('Position',bb,'EdgeColor','g','LineWidth',2);
   end
   
        figure(1),imshow(noiseFreeObject,[])
end
%% Results
% frameRate = trafficVid.FrameRate;
% implay(taggedCars,frameRate);