在matlab中從視頻中減去背景圖像

Question

我想從視頻中讀取前20幀，將這些圖像保存在一個文件夾以及通過取這20個圖像的中間值獲得的背景圖像中。然後，我試圖從視頻中的每幀中減去此背景圖像，並將輸出寫入新視頻。但最終，我只是在新視頻中獲得黑色輸出，並收到以下警告： 警告：沒有視頻幀寫入此文件。該文件可能無效。

在VideoWriter.VideoWriter> VideoWriter.close在307 在VideoWriter.VideoWriter> VideoWriter.delete在256 在Framextraction在43

我該怎麼辦？

clear all; 
clc; 
thresh=100; 
workingDir = 'D:/DDP/proj3'; 
mkdir(workingDir) 
mkdir(workingDir,'images') 
vid= VideoReader('D:/DDP/sample1.3gp'); 

for k=1:20 
img = readFrame(vid); 
filename = [sprintf('%01d',k-1) '.jpg']; 
imwrite(img,fullfile(workingDir,'images',filename))  
end 
folder = 'D:\DDP\proj3\images\'; 
filelist = dir(fullfile(folder,'*.jpg')); 
filelist = strcat(folder, filesep, {filelist.name}); 

images = zeros(720,1280,3, numel(filelist), 'double'); 
for i=1:numel(filelist) 
images(:,:,:,i) = double(imread(filelist{i})); 
end 
background = uint8(median(images, 4)); 
imwrite(background,'D:\DDP\proj3\images\background.jpg','jpg') 

fr_size = size(BW1); 
width = fr_size(2); 
height = fr_size(1); 
fg = zeros(height, width); 
vid.CurrentTime = 0; % Rewind video reader 
VW = VideoWriter('D:/DDP/proj3/new'); 
open(VW); 
while hasFrame(vid) 
fr = readFrame(vid); 
fr_diff = abs(double(fr) - double(background)); 
for j=1:width 
for k=1:height 
if ((fr_diff(k,j) > thresh)) 
fg(k,j) = 255; 
else 
fg(k,j) = 0; 
end 
end 
end 
writeVideo(VW,double(fg)/255); 

end 
close(VW) 
cc= VideoReader('D:/DDP/proj3/new.avi'); 
cd= VideoWriter('D:/DDP/proj3/new1'); 
open(cd); 
while hasFrame(cc); 
    s=readFrame(cc); 
    J = imnoise(s,'salt & pepper',0.02); 
    img_filtered = J; 
    for c = 1 : 3 
    img_filtered(:, :, c) = medfilt2(J(:, :, c), [3, 3]); 
    end 
writeVideo(cd, double(img_filtered)/255); 
end 
close(cd); 

Answer 1

在您的代碼中，錯誤來自您沒有將視頻閱讀器倒帶到第一幀的事實。您發佈的代碼似乎與您對背景圖片數據類型爲double類型的評論不一致。如果你使用imread來讀取背景圖像，它應該是uint8類型。這是我的建議：

workingDir = 'D:/DDP'; 
mkdir(workingDir) 
mkdir(workingDir,'images') 
vid= VideoReader('D:/DDP/samplee.3gp'); 

for k=1:20 
    img = readFrame(vid); 
    filename = [sprintf('%01d',kk-1) '.jpg']; 
    imwrite(img,fullfile(workingDir,'images',filename))  
end 
folder = 'D:\DDP\images\'; 
filelist = dir(fullfile(folder,'*.jpg')); 
filelist = strcat(folder, filesep, {filelist.name}); 

images = zeros(720,1280,3, numel(filelist), 'double'); 
for i=1:numel(filelist) 
    images(:,:,:,i) = double(imread(filelist{i})); 
end 
background = uint8(median(images, 4)); % Convert background image to uint8 type 
imwrite(background,'D:\DDP\images\background.jpg','jpg') 

vid.CurrentTime = 0; % Rewind video reader 
VW = VideoWriter('D:/DDP/new'); 
open(VW); 
while hasFrame(vid) 
    CDatas(:,:,:) = readFrame(vid) - background;  
    writeVideo(VW,CDatas); 
end 
close(VW)