snapshot problem in video processing

i have a problem with snapshot in my codes.i can;t take a frame for remove noise.the program have error

Undefined function 'snapshot' for input arguments of type 'matlab.graphics.primitive.Image'.

Error in Untitled4 (line 10)

img= snapshot(c);

clear
clc 
vid= VideoReader('viptraffic.avi'); %reading video file by VideoReader function


for i=1:vid.NumberofFrames %its a loop for noise removing and showing video online
    
    img=read(vid,i); %reading video frame
    c=imshow(img)
    img= snapshot(c);
end

[Turlough Hughes]

Inputs for snapshot are can be either (i) a cameraboard object, or (ii) a webcam object, wherehas you are inputting an Image object. See this part of the documentation. Aside from that your frame, for a given iteration of the loop, will be stored in img.

[Turlough Hughes]

Why are you using the snapshot function in the first place, are you trying to read data from a camera connected to your computer, or is the goal here to simply modify footage from viptraffic.avi?

[mehrdad jafari]

tnx for your reply,

i want to take a image,when video is playing and then work on noise and show it again.

[Walter Roberson]

What is it you want to take an image of? A camera connected to the computer? Or a frame from the video that is playing?

[mehrdad jafari]

video playing

Answer 1

[Turlough Hughes]

snapshot() is intended for use with a cameraboard object or webcam object and you are attempting you input an image object.

You want to take a image,when video is playing and then work on noise and show it again

To modify the frames and then view the results/create a new video of the modified frames you can do so as follows:

clear
clc 
vid= VideoReader('viptraffic.avi'); %reading video file by VideoReader function
player = vision.VideoPlayer; % launch videoplayer
v = VideoWriter('newfile.avi'); % make object for saving modified video
open(v)
for i=1:vid.NumFrames
    frame=read(vid,i); % get video frame
    modifiedframe = frame; % make a copy
    
    % Perform steps to modify each frame here:
    modifiedframe(:,:,[2 3]) = 0; % for example show red stream only
    
    % show results in video player
    step(player,[frame modifiedframe]) % alternatively: step(player,modifiedframe)
    writeVideo(v,modifiedframe); % write modified frame to your new video file.
    pause(0.05)
end
close(v) 

I opted to show before and after side by side in the videoplayer.

As for noise removal, there a numerous ways to do so.

some considerations:

https://uk.mathworks.com/help/images/noise-removal.html

https://www.researchgate.net/post/Is_this_code_for_Gaussian_filter_to_remove_a_noise_from_an_image_correct

[mehrdad jafari]

i used noise removal by above code, but i want to take a image when video is playing and then do noise removal with bellow or your code.

K = wiener2(J,[5 5]);

[mehrdad jafari]

all the code i saw, didn't give me any clicking on video for choose a frame

[Walter Roberson]

I recommend starting with the File Exchange contribution videofig https://www.mathworks.com/matlabcentral/fileexchange/29544-figure-to-play-and-analyze-videos-with-custom-plots-on-top which already has callbacks programmed in to it, making it easier to adapt for your purposes.