Convert live colour video into gray scale video?

7 views (last 30 days)
Hi,
I am using MATLAB for image processing.I need to have a gray scale video saved in disk. Please can you help me to manipulate the following script in order to give a gray scale video.I changed the set(vid, 'ReturnedColorspace', 'rgb') to set(vid, 'ReturnedColorspace', 'grayscale'), but it shows error (Error using im2frame
Indexed movie frame must have a non-empty colormap).
imaqreset;
%warning('off','all'); %.... diable warining msg ...;
vid = videoinput('winvideo',1, 'YUY2_640x480');
set(vid, 'FramesPerTrigger', Inf);
set(vid, 'ReturnedColorspace', 'rgb');
% vid.FrameRate =30;
vid.FrameGrabInterval = 1; % distance between captured frames
start(vid)
aviObject = VideoWriter('myVideo.avi'); % Create a new AVI file
open(aviObject);
for iFrame = 1:50 % Capture 100 frames
% ...
% You would capture a single image I from your webcam here
% ...
I=getsnapshot(vid);
%imshow(I);
F = im2frame(I); % Convert I to a movie frame
writeVideo(aviObject,F); % Add the frame to the AVI file
end
close(aviObject); % Close the AVI file
stop(vid);
thanks
  2 Comments
Koohyar
Koohyar on 6 Sep 2020
Many thanks for your comments, please can you show me where should I call rgb2gray()? it goes to each frame? gray = rgb2gray(vid)?

Sign in to comment.

Accepted Answer

Amrtanshu Raj
Amrtanshu Raj on 9 Sep 2020
Hi,
You can modify your code like this to get the desired results.
CODE :
imaqreset;
%warning('off','all'); %.... diable warining msg ...;
vid = videoinput('winvideo',1, 'YUY2_640x480');
set(vid, 'FramesPerTrigger', Inf);
set(vid, 'ReturnedColorspace', 'rgb');
% vid.FrameRate =30;
vid.FrameGrabInterval = 1; % distance between captured frames
start(vid)
aviObject = VideoWriter('myVideo.avi'); % Create a new AVI file
open(aviObject);
for iFrame = 1:50 % Capture 100 frames
% ...
% You would capture a single image I from your webcam here
% ...
I=getsnapshot(vid);
%changes made here
grayimg = rgb2gray(I); % Convert rgb image to grayscale img
%imshow(I);
F = im2frame(grayimg); % Convert grayimg to a movie frame
writeVideo(aviObject,F); % Add the frame to the AVI file
end
close(aviObject); % Close the AVI file
stop(vid);
  6 Comments
Image Analyst
Image Analyst on 29 May 2022
@almog haviv There are numerous comments all over. What lines are you confused about?

Sign in to comment.

More Answers (0)

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!