How MATLAB waveforms are denoised

Summary. Hello, glad your question, not necessarily, depends on the type and intensity of the noise. The purpose of denoising in the value filtering method is to replace the noise in the image with the average value of the adjacent pixels in order to reduce the noise in the image and thus improve the image quality.

However, if the noise is too strong, then the denoised image may be blurry than the image before the denoise.

Hello, glad your question, not necessarily, depends on the type and intensity of the noise. The purpose of denoising in the value filter method is to replace the noise in the image with the average value of the adjacent pixels, masking the leakage to reduce the noise in the image, thereby improving the image quality. However, if the noise is too strong and the macro segment is bad, the denoised image may be blurry than the image before the denoise.

Fellow, I really didn't understand, I can be more specific.

Hello, to put it simply, the MATLAB median filter method is lower after denoising than before denoising, which means that the noise is suppressed, but at the same time, useful information is suppressed, making the overall signal weaker. This is because the value filter works: it changes the value of each pixel to the median of the pixels around it, which means that the noise is suppressed, but the useful information is also suppressed, because their pixel value may be changed.

(1)j = imnoise(i,type);

2)j = imnoise(i,type,parameters);

where i is the gray matrix of the original image, and j is the gray matrix of the image after adding noise.

In general, it is sufficient to use (1) to indicate that the parameters are allowed to be modified, and (1) to use the default parameters;

As for type, there can be five types, namely:'gaussian'(Gaussian white noise),'localvar'(zero-mean Gaussian white noise in relation to the grayscale value of the image),'poisson'(Poisson noise),'salt & pepper'(salt and pepper noise) and'speckle'(speckle noise); The setting of the parameter value in specific (2) can be based on personal needs; For the rest of the situation and if you still don't understand, please refer to the MATLAB help file.

Use here'salt & pepper'(Salt and Pepper Noise) and set its parameter to. Examples of this are as follows:

l = imread(‘image_;

j = imnoise(l, ‘salt & pepper’,

imshow(j);An immediate pop-up window shows the added noise.

Stored at 100% quality with added noise, the default value of quality is 75

The above program means adding salt and pepper noise to the original image, but be careful to put the image in the same subdirectory as the m file of the above program.

You can add a low-pass filter, or you can try median filtering and smoothing techniques.