How can I work out signal to noise ratio of doppler waveform images? Any possible way?

Answer 1

[Nithin]

Hi Samay,

I understand that you want to find the SNR (Signal to Noise Ratio) of the given doppler waveform image.

To implement this, kindly refer to the following code snippet:

image = imread('q1.png'); % Reading the provided image
 
if size(image, 3) == 3 % converting the image into grayscale
    grayImage = rgb2gray(image);
else
    grayImage = image;
end
 
image_size = size(grayImage);
disp(['Image dimensions: ', num2str(image_size)]);
 
signal_region = grayImage(50:150, 100:500); % using the grayscale image for region extraction
noise_region = grayImage(291:391, 100:500); % Adjusting the noise region indices to be within the bounds of the image
 
% Computation of mean and standard deviation:
signal_mean = mean(double(signal_region(:)));
noise_std = std(double(noise_region(:)));
 
if noise_std ~= 0 
    snr_dB = 20 * log10(signal_mean / noise_std); % calculation of SNR in dB
    disp(['SNR of Doppler waveform image: ', num2str(snr_dB), ' dB']);
else
    disp('Noise standard deviation is zero, SNR cannot be calculated.');
end

For more information regarding “imread”, “rgb2gray”, “size” and “std”, kindly refer to the following documentation:

https://www.mathworks.com/help/matlab/ref/imread.html

https://www.mathworks.com/help/matlab/ref/rgb2gray.html

https://www.mathworks.com/help/matlab/ref/size.html

https://www.mathworks.com/help/matlab/ref/std.html

I hope this answer helps you.

Regards,

Nithin Kumar.