Key Frames Extraction in a Video

Hello Everyone

I am working on a assignment "key frames extraction in a video sequence" Method that i am using as follows

   ->extracts frames one by one
   ->histogram difference between two consecutive frames using imhist() and 
     imabsdiff()
   ->calculate mean and standard deviation of difference and threshold
   ->continue till end of video
   ->again extracts frames one by one
   ->histogram difference between two consecutive frames using imhist() and 
     imabsdiff()
   ->compare this difference with threshold and if it is greater than threshold     
      select it as a key frame
   ->continue till end of video

is this method correct??

if anyone have good solution plz help me with the code

thanks in advance

my simple code

   vid = 'Wildlife 00_00_20-00_00_30.avi';
   readerobj = mmreader(vid);

   for k=1:  readerobj.NumberOfFrames

           I=read(readerobj,k);
           if(k~= readerobj.NumberOfFrames)
                 J=read(readerobj,k+1);
                 sss=absdif(I,J);
                 X(k)=sss;
           end

   end

   mean=mean2(X)
   std=std2(X)
   threshold=std+mean*4

   for k=1: readerobj.NumberOfFrames

       I =  read(readerobj,k);

       if(k~=readerobj.NumberOfFrames)

        J=   read(readerobj,k+1);

        sss=absdif(I,J);

        if(sss>mean)

            imwrite(J,strcat('D:\',Names{k+1}));

       end

   end

% absdif function

   function [ res ] = absdif( I,J )

       k=rgb2gray(I);
       l=rgb2gray(J);
       m=imhist(k);
       n=imhist(l);
       dif=imabsdiff(m,n);
       res=sum(dif);

   end

[msp]

i m getting error in following line imwrite(J,strcat('D:\',Names{k+1})); unable to write Please see whats the error.

[Walter Roberson]

Do you have write access to the D:\ directory?

[Walter Roberson]

Construct the name in one line and then use it in the next. That way you will be able to check the validity of the name construction. Also consider using fullfile() instead of strcat()

[Walter Roberson]

filename = fullfile('D:\', sprintf('frame_%05d.tiff', k) );
imwrite(J, filename);

[msp]

above code is extracting Key frame even though some duplicate or redundant frame are coming what change should make in the code.

[msp]

any replies

[Walter Roberson]

Perhaps you need to im2double() the frames.

[msp]

can u help me out where i should make the changes in the above code so that key frames will extracted correctly please.

[msp]

please any replies

[msp]

no reply ?

[Walter Roberson]

Nope.

[msp]

hello sir when i save frames of video they are not saved continuously they save in random order of index say example

frame_0015, frame_00124 so on... i want to save them continuously like index from 1 to n from frame_001,frame_002.... so on.

filename = fullfile('D:\', sprintf('frame_%05d.JPG', k) ); imwrite(J, filename);

help me please

[Walter Roberson]

Before the for loop,

frc = 0;

Then change the filename assignment to

frc = frc + 1;
filename = fullfile('D:\', sprintf('frame_%05d.JPG', frc));

[msp]

thank you sir.

[rujul mankad]

"threshold=std+mean*4 " for this how can we identify that it should be 4..and can we give global threshold?

[abhishek patel]

i m geting error in following line X(k)=sss.... Subscripted assignment dimension mismatch.

[Ashvini babaleshwar]

m getting error at last function part, can u please help me.

[Walter Roberson]

Please post the entire error message, everything in red. Also since there were several revisions suggested to the posted code, please post your code so we know what we are dealing with.

[k swati subudhi]

i am getting an error like this :Undefined function 'absdif' for input arguments of type 'uint8'. what should i do ??

[Walter Roberson]

Use imabsdiff instead of absdif

[Shivam Thakur]

Sir I work in one video project.When I try this code I get the error is " subscripted Assignment Dimension mismatch"....in line X(k)=sss.please solve the error sir.

Answer 1

[Rajendra Oli]

Is cnn algorithm used in this code?

[Walter Roberson]

No, cnn is not used in the above code.

It might be possible to develop a key frame extraction algorithm that uses Convolutional Neural Networks as part of the algorithm, but this is not such an algorithm.

http://ieeexplore.ieee.org/document/8311477/ CNN based key frame extraction for face in video recognition

https://www.slideshare.net/SuhasPillai1/key-frame-extraction-for-salient-activity-recognition Key Frame Extraction for Salient Activity Recognition

https://link.springer.com/chapter/10.1007%2F978-981-10-7305-2_51 Deep Key Frame Extraction for Sport Training