Adding Gausian Noise to Video

Hello! i am using a Video Compression Code made by "naveen V"

below is the code they used for the video compression

ImFolder=uigetdir;
pngFile = dir(strcat(ImFolder,'\*.png'));
S = [pngFile(:).datenum];
[~,S] = sort(S);
pngFiles = pngFile(S);
VideoFile=strcat(ImFolder,'\Video');
writeObj = VideoWriter(VideoFile);
fps= 15;
writeObj.FrameRate = fps;
open(writeObj);
for t= 1:length(pngFiles)
Frame=imread(strcat(ImFolder,'\',pngFiles(t).name));
writeVideo(writeObj,im2frame(Frame));
end
close(writerObj);

I would like to ask how to apply gaussian noise and reed solomon FEC into the code for the purpose of measuing BER of the system.

[Jonas]

you can add gaussian noise to the image by using Frame=Frame+round(factor*randn(size(Frame))). You can increase the effect of noise with the factor variable (you have to set it yourself). If 1, most values are approx in the range +-4

[Matt Alvarez]

i apologize for my lack of understanding but i would like to ask how to implement that here. This was the code that was used to turn the video into multiple frames as i understodd from you comment that i should add gaussian noise per image.

when i tried changing it from "Frame" to "frames" it gave me an error shown below

Error using +

Integers can only be combined with

integers of the same class, or scalar

doubles.

vid=VideoReader('videopart.mp4');

no=vid.NumberOfFrames;

for i=1:1:no

frames=read(vid,i);

base=sprintf('Image%d.png',i);

ful=fullfile(pwd,base);

frames=frames+round(4*randn(size(frames)))

imwrite(frames,ful);

im(i)=image(frames);

end

[Jonas]

interesting, i don't have problems doing this this (2022a). What is the class of frames? if it is e.g. uint16 you can also use

Frame=Frame+uint16(factor*randn(size(Frame)))

if it is uint8

Frame=Frame+uint8(factor*randn(size(Frame)))

Answer 1

[Siraj]

Hi!

I understand that you're trying to make a video from PNG files, add Gaussian noise to the frames, and analyze the Bit Error Rate (BER). However, you're running into an error that says, "Error using +: Integers can only be combined with integers of the same class, or scalar doubles." This error hints at a data type mismatch between your image data and the noise you're adding. To resolve this, ensure that the data types match when you're adding the noise to the frames.

To overcome this issue, you can utilize the "imnoise" function, which allows you to introduce noise to an image. This function offers control over the type of noise you want to apply and lets you adjust the noise's intensity. For more detailed information about the "imnoise" function, you can refer to the following link.

https://www.mathworks.com/help/images/ref/imnoise.html

I've included the code below for improved clarity.

% Prompt the user to select a folder containing PNG files 
ImFolder = uigetdir; 

% List all PNG files in the selected directory 
pngFile = dir(fullfile(ImFolder, '*.png')); 

% Sort the PNG files by modification date 
S = [pngFile(:).datenum]; 
[~, S] = sort(S); 
pngFiles = pngFile(S); 

% Define the path for the output video 
VideoFile = fullfile(ImFolder, "Video"); 

% Create a VideoWriter object for video creation 
writeObj = VideoWriter(VideoFile); 

% Set the frames per second (fps) for the video 
fps = 15; 
writeObj.FrameRate = fps; 

% Open the VideoWriter object to start writing the video 
open(writeObj); 

% Loop through each PNG file in the sorted list 
for t = 1:length(pngFiles) 
    % Read the PNG file 
    Frame = imread(fullfile(ImFolder, pngFiles(t).name)); 
    
    % Add Gaussian noise to the frame 
    NoisyFrame = imnoise(Frame, "gaussian"); 
    
    % Convert the noisy frame and write it to the video 
    writeVideo(writeObj, im2frame(NoisyFrame)); 
end 

% Close the VideoWriter object to save the video 
close(writeObj); 

Hope this helps.