# IMAGE PROCESSING

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" Two roads diverged in a wood, and I,
I took the one less traveled by,
And that has made all the difference "-Robert Frost

### How to get frames from a video

MATLAB CODE to get images from video:
To extract frames from a video.
Frames can be obtained from a video and converted into images. To convert a video frame into an image, the MATLAB function ‘frame2im’ is used.
To read a video in avi format, the function ‘aviread’ is used.  The original format of the video that I am using as an example is .gif file format. I converted the .gif file format image into an avi format video. Learn how to convert a gif image into a video...
For instance, in the ‘fun.avi’ video I am interested in the frame number 58. So I am converting the 58th frame into an image.
MATLAB CODE:
%How to get frames from a video

mov=aviread('fun.avi');

Im=frame2im(mov(1,58));
figure,imshow(Im);

 Frame 58
The above process can be done using 'mmreader' function also.

MATLAB CODE:

Vobj=mmreader('fun.avi');

Im=read(Vobj,58);
imshow(Im);

After playing the video, I thought of modifying some frames. So I converted the frames from 58 to 64 into images and added a smiley to the images by performing image arithmetic operations.

Then I converted those images into frames and saved as a video file in ‘smiley.avi’.

Lmov=aviread('smiley.avi');

MIm=frame2im(Lmov(1,1));
figure,imshow(MIm);

 Modified Frame 58

%Preallocating the structure array
frame=struct('cdata',1,'colormap',cell([1 91]));

I added the modified frames to the original video.

%Modify the video in the middle
frame(1,1:57)=mov(1,1:57);
frame(1,58:87)=Lmov(1,1:30);
frame(1,88:91)=mov(1,64:67);
implay(frame,5);

If we are interested in playing only some of the frames in the original video then, we can view those frames alone. Here I am interested in viewing the frames from 27 to 33.

%Part of the video
scz=figure;
set(scz, 'position', [300 100  size(Im,1)+130 size(Im,2)-100]);
FRange=[1 27:33];
%Here 1 is for the number of times the video has to be repeated
%27:33 indicates the frames from 27 to 33.
movie(scz,mov,FRange,5);

We can also save the desired frames into a file. An avifile object is created with the file name ‘VidPart.avi’. Then the desired frames from 27 to 33 are added by using the syntax ‘addframe’.

%To save the desired part alone

obj=avifile('VidPart.avi','FPS',5);
obj=addframe(obj,mov(27:33));
obj=close(obj);
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#### 15 comments:

dwiheriyanto said...

Nice article. Thanks for your tips, I really appreciate it.

akuinginlulus said...

Hi,
Thanks for your tips, I really appreciate it.
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RG Masand said...

ok thanks....this article was very useful
but i hav one doubt....
what if i want to extract the images and save in a seprate folder on the hard disk ??

Aaron Angel said...

@RG Masand

Use 'imwrite' function to store the images separately in a folder.

navya said...

Hi there, awesome site. I thought the topics you posted on were very interesting.
Image Processing India

Suhan Das said...

Index exceeds matrix dimensions.
im gettin this error wht t do?

Suhan Das said...

Index exceeds matrix dimensions.
im grttin this error while running frame2im wht t do?

Aaron Angel said...

@Suhan Das
kindly check whether you are using 'frame2im' for one frame only or if you are using looping concept then check for the index range. If you are still getting the error, mail me with details.

Happy Reading!

Mathan Kumar said...

what if i want to extract the images and save in a seprate folder on the hard disk ??

Mathan Kumar said...

what if i want to extract the images and save in a separate folder on the hard disk ??
plz give an example of 'imwrite' function.. thankyou

hasdi suhastra said...

Nice.. thanks

Ngô Quốc Trường said...

nice thanks

Srinath Srinivasan said...

`How to display all frames simultaneously ????

Srinath Srinivasan said...

how to display all frames simultaneously...???

siva said...

i need code for Unusual Event Detection in Low Resolution
Video for enhancing....

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