我希望删除视频中的移动阴影。我遵循this article中提到的步骤，但在swt输出上应用阈值操作之前和之后得到相同的结果。没有得到预期的输出......谁能告诉我我做错了什么？ 删除阴影的步骤：
（i）阅读视频。
（ii）颜色转换后分割h s v成分
（iii）对帧的s和v分量应用平稳小波变换
（iv）计算s和v分量的各个swt输出的偏斜值
（v）将值1和0分配给＆＃39; s和v＆＃39;如果v的swt大于v的偏度值，则同样对于s也是如此。 （vi）对s和v进行反向扫描 （vii）结合h s和v
clc; % Clear the command window.
close all; % Close all figures (except those of imtool.)
imtool close all; % Close all imtool figures.
clear; % Erase all existing variables.
workspace; % Make sure the workspace panel is showing.
fontSize = 22;
movieFullFileName = fullfile('cam4v.mp4');
% Check to see that it exists.
if ~exist(movieFullFileName, 'file')
strErrorMessage = sprintf('File not found:\n%s\nYou can choose a new one,
or cancel', movieFullFileName);
response = questdlg(strErrorMessage, 'File not found', 'OK - choose a new
movie.', 'Cancel', 'OK - choose a new movie.');
if strcmpi(response, 'OK - choose a new movie.')
[baseFileName, folderName, FilterIndex] = uigetfile('*.avi');
if ~isequal(baseFileName, 0)
movieFullFileName = fullfile(folderName, baseFileName);
else
return;
end
else
return;
end
end
try
videoObject = VideoReader(movieFullFileName);
% Determine how many frames there are.
numberOfFrames = videoObject.NumberOfFrames;
vidHeight = videoObject.Height;
vidWidth = videoObject.Width;
numberOfFramesWritten = 0;
% Prepare a figure to show the images in the upper half of the screen.
figure;
% screenSize = get(0, 'ScreenSize');
% Enlarge figure to full screen.
set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
% Ask user if they want to write the individual frames out to disk.
promptMessage = sprintf('Do you want to save the individual frames out to
individual disk files?');
button = questdlg(promptMessage, 'Save individual frames?', 'Yes', 'No',
'Yes');
if strcmp(button, 'Yes')
writeToDisk = true;
% Extract out the various parts of the filename.
[folder, baseFileName, extentions] = fileparts(movieFullFileName);
% Make up a special new output subfolder for all the separate
% movie frames that we're going to extract and save to disk.
% (Don't worry - windows can handle forward slashes in the folder
name.)
folder = pwd; % Make it a subfolder of the folder where this m-file
lives.
outputFolder = sprintf('%s/Movie Frames from %s', folder,
baseFileName);
% Create the folder if it doesn't exist already.
if ~exist(outputFolder, 'dir')
mkdir(outputFolder);
end
else
writeToDisk = false;
end
% Loop through the movie, writing all frames out.
% Each frame will be in a separate file with unique name.
for frame = 1 : numberOfFrames
% Extract the frame from the movie structure.
thisFrame = read(videoObject, frame);
% Display it
hImage = subplot(2, 2, 1);
image(thisFrame);
caption = sprintf('Frame %4d of %d.', frame, numberOfFrames);
title(caption, 'FontSize', fontSize);
drawnow; % Force it to refresh the window.
% Write the image array to the output file, if requested.
if writeToDisk
% Construct an output image file name.
outputBaseFileName = sprintf('Frame %4.4d.png', frame);
outputFullFileName = fullfile(outputFolder, outputBaseFileName);
% Stamp the name and frame number onto the image.
% At this point it's just going into the overlay,not actually
getting written into the pixel values.
text(5, 15, outputBaseFileName, 'FontSize', 20);
% Extract the image with the text "burned into" it.
frameWithText = getframe(gca);
% frameWithText.cdata is the image with the text
% actually written into the pixel values.
% Write it out to disk.
imwrite(frameWithText.cdata, outputFullFileName, 'png');
end
if frame == 1
xlabel('Frame Number');
ylabel('Gray Level');
% Get size data later for preallocation if we read
% the movie back in from disk.
[rows, columns, numberOfColorChannels] = size(thisFrame);
end
% Update user with the progress. Display in the command window.
if writeToDisk
progressIndication = sprintf('Wrote frame %4d of %d.', frame,
numberOfFrames);
else
progressIndication = sprintf('Processed frame %4d of %d.', frame,
numberOfFrames);
end
disp(progressIndication);
% Increment frame count (should eventually = numberOfFrames
% unless an error happens).
numberOfFramesWritten = numberOfFramesWritten + 1;
% Now let's do the differencing
alpha = 0.5;
if frame == 1
Background = thisFrame;
else
% Change background slightly at each frame
% Background(t+1)=(1-alpha)*I+alpha*Background
Background = (1-alpha)* thisFrame + alpha * Background;
end
% Display the changing/adapting background.
subplot(2, 2, 3);
imshow(Background);
title('Adaptive Background', 'FontSize', fontSize);
% Do color conversion from rgb to hsv
x=rgb2hsv(thisFrame);
y=rgb2hsv(Background);
% Split the hsv component to h,s,v value
Hx = x(:,:,1); Hy = y(:,:,1);
Sx = x(:,:,2); Sy = y(:,:,2);
Vx = x(:,:,3); Vy = y(:,:,3);
%Find the absolute diffrence between h s v value of current and
previous frame
dh=(abs(double(Hx) - double(Hy)));
ds1=(abs(double(Sx) - double(Sy)));
dv1=(abs(double(Vx) - double(Vy)));
%Perform the swt2 transformation on difference of s and v value
[as,hs,vs,ds] = swt2(ds1,1,'haar');
[av,hv,vv,dv] = swt2(dv1,1,'haar');
%Compute the skewness value of 'swt of v'
sav=skewness(av(:));
shv=skewness(hv(:));
svv=skewness(vv(:));
sdv=skewness(dv(:));
%Compute the skewness value of 'swt of s'
sas=skewness(as(:));
shs=skewness(hs(:));
svs=skewness(vs(:));
sds=skewness(ds(:));
% Do the shadow detection based on the output of swt and skew of 'v'
value
% Compare swt v output with its skew value if the av >=sav then av is
assigned to one else it becomes zero.This operation continues till variable i
b=(av>=sav); f= (as>=sas);
c=(hv>=shv); g=(hs>=shs);
d=(vv>=svv); h=(vs>=svs);
e=(dv>=sdv); i=(ds>=sds);
% Remove the shadows based on 'and operation
j=(b&f); l=(d&h);
k=(c&g); m=(e&i);
% Do inverse swt operation
recv = iswt2(b,c,d,e,'haar');
recs= iswt2(j,k,l,m,'haar');
%Combine the value of h,s and v
de_shadow=cat(3,dh,recs,recv);
rgb=hsv2rgb(de_shadow);
% Plot the image.
subplot(2, 2, 4);
imshow(rgb);
title('output Image', 'FontSize', fontSize);
end
% Alert user that we're done.
if writeToDisk
finishedMessage = sprintf('Done! It wrote %d frames to
folder\n"%s"', numberOfFramesWritten, outputFolder);
else
finishedMessage = sprintf('Done! It processed %d frames of\n"%s"',
numberOfFramesWritten, movieFullFileName);
end
disp(finishedMessage); % Write to command window.
uiwait(msgbox(finishedMessage)); % Also pop up a message box.
% Exit if they didn't write any individual frames out to disk.
if ~writeToDisk
return;
end
% Ask user if they want to read the individual frames from the disk,
% that they just wrote out, back into a movie and display it.
promptMessage = sprintf('Do you want to recall the individualframes\nback
from disk into a movie?\n(This will take several seconds.)');
button = questdlg(promptMessage, 'Recall Movie?', 'Yes', 'No', 'Yes');
if strcmp(button, 'No')
return;
end
% Create a VideoWriter object to write the video out to a new, different
file.
writerObj = VideoWriter('Newcam4v.mp4');
open(writerObj);
% Read the frames back in from disk, and convert them to a movie.
% Preallocate recalledMovie, which will be an array of structures.
% First get a cell array with all the frames.
allTheFrames = cell(numberOfFrames,1);
allTheFrames(:) = {zeros(vidHeight, vidWidth, 3, 'uint8')};
% Next get a cell array with all the colormaps.
allTheColorMaps = cell(numberOfFrames,1);
allTheColorMaps(:) = {zeros(256, 3)};
% Now combine these to make the array of structures.
recalledMovie = struct('cdata', allTheFrames, 'colormap',allTheColorMaps)
for frame = 1 : numberOfFrames
% Construct an output image file name.
outputBaseFileName = sprintf('Frame %4.4d.png', frame);
outputFullFileName = fullfile(outputFolder, outputBaseFileName);
% Read the image in from disk.
thisFrame = imread(outputFullFileName);
% Convert the image into a "movie frame" structure.
thisFrame=imresize(thisFrame,[452, 231]);
recalledMovie(frame) = im2frame(thisFrame);
% Write this frame out to a new video file.
writeVideo(writerObj, thisFrame);
end
close(writerObj);
% Get rid of old image and plot.
delete(hImage);
% Create new axes for our movie.
subplot(1, 3, 2);
axis off; % Turn off axes numbers.
title('Movie recalled from disk', 'FontSize', fontSize);
% Play the movie in the axes.
movie(recalledMovie);
% Note: if you want to display graphics or text in the overlay
% as the movie plays back then you need to do it like I did at first
% (at the top of this file where you extract and imshow a frame at a
time.)
msgbox('Done this experiment!');
catch ME
% Some error happened if you get here.
strErrorMessage = sprintf('Error extracting movie frames
from:\n\n%s\n\nError: %s\n\n)', movieFullFileName, ME.message);
uiwait(msgbox(strErrorMessage));
end