Four or two-D discrete wavelet transformStatement: This article is my understanding of the wavelet, not guarantee correctness and rigor.Reference: "Digital Image processing" Gonzalez P3171. OverviewA two-dimensional scale function and three two-dimensional wavelet functions can be combined with a given scale function and a wa
I wanted to teach myself about 2 years ago. Wavelet analysis, also read a few of the wavelet analysis of the book. But it is not understood that you see a chapter. No way, who let me level too low. Simply recalled, I have read at least a few books on wavelet analysis:Tri Jintai "Introduction to
1.MATLAB program Writing Step 1, the wavelet W (t) and the original function f (t) are compared to the beginning of the calculation coefficient c. The coefficient c indicates the similarity between the partial function and the wavelet.
2. Move the wavelet to the right K unit, get the wavelet w (t-k), repeat 1. Repeat t
personally suggest usingWdencmpThe reason is that it is simple and reliable, and can generate demonstration files and PNG files that require wavelet compression and reconstruction. In the final part, I will focus on explaining and discussing the problem that the PNG file of the reconstructed image will become larger after the use of wavelet compression. I hope that you will be able to study it in depth.
Special Note: This series of articles has been combined with the mathematical principles of image Processing series of articles, now the Fourier transform part of the basic introduction is complete. You can refer to the mathematical principles in the image processing of the total catalogue (http://blog.csdn.net/baimafujinji/article/details/48467225)
Whether it is learning signal processing, or doing image, audio and video processing research, you can never avoid a content, is the Fourier transf
, the actual work is not good. , and is accompanied by spectral subtraction with music noise. At the same time, the above methods in speech enhancement, need to know some characteristics or statistical characteristics of noise, and in the absence of prior knowledge of noise, it is difficult to extract speech signals from noisy speech signals.
The wavelet transform is a time-frequency local analysis method which has been developed rapidly in recent 10
/***********************Wavelet transform appeared background ***********************/In order to ensure the quality of certain reconstruction, image coding can represent images by removing various redundancy in the image and minimizing the number of bits.Long-term image coding mainly uses discrete cosine transform (DCT) as the main technology of transformation coding, however, there are some problems: (1) There are obvious block effects using DCT tra
P.s. () thanks to the netizen 'Li Ming yangyan ', he pointed out a major bug in mydwt and myidwt, see the one-dimensional signal wavelet decomposition and reconstruction program published today. P.s.: (last November) a series of articles on Wavelet Transform and image processing were published in, sharing their experiences and programming in the process of learning wave
[DWT Note] Fourier transformation and Wavelet Transformation
I. Preface
The signals we often encounter, such as sine, cosine, and even complex ECG, EEG, and seismic waves, are all signals in the time domain. We also become the original signal, but normally, the information we obtain in the original signal is limited. Therefore, in order to obtain more information, we need to perform mathematical transformation on the original signal to obtain the sign
Thank you so much:http://blog.sina.com.cn/u/1861445474Http://blog.chinaaet.com/detail/3083.html
The threshold denoising of signal is realized in MATLAB, which mainly includes two aspects: threshold denoising and threshold acquisition .
1. Threshold Acquisition
The functions implemented in MATLAB are ddencmp, Thselect, Wbmpen, and WWDCBM, and their usage is briefly explained below.
The DDENCMP format has the following three types of calls:(1) [THR,SORH,KEEPAPP,CRIT]=DDENCMP (In1,in2,x)(2) [thr,so
Https://zhuanlan.zhihu.com/p/22450818?refer=dong5The first answer: Can you explain the relationship between Fourier analysis and wavelet analysis in a popular mode? -Dong-dong knows the answer to the thump.Current income column.From the Fourier transform to the wavelet transform, is not a completely abstract thing, can speak very image. The wavelet transform has
Original Address:How to change the decomposition coefficients and reconstruct the image after wavelet packet decomposition.
Author:Yang Storm
At present, the introduction of the Image wavelet packet transformation matlab Programming of the book is not many, but there are several, but they are a lot of MATLAB in the relevant functions of the help to re-describe it
From the Fourier transform to the wavelet transform, is not a completely abstract thing, can speak very image. The wavelet transform has definite physical meaning, if we look at the problems that we face when we put forward it, we can sort out a very clear idea.I'll follow the sequence of the Fourier –> short-time Fourier transform –> wavelet transform, tell me w
Both Fourier transform and wavelet transform are essentially the same. They convert signals between time and frequency domains and find some intuitive information from seemingly complex data, then analyze it. Because the signal is more simple and intuitive in the frequency domain than in the time domain,Most of the signal analysis work is carried out in the frequency domain.. Music is an excellent example of time/frequency analysis. Music score is the
Both Fourier transform and wavelet transform are essentially the same. They convert signals between time and frequency domains and find some intuitive information from seemingly complex data, then analyze it. Because the signal is often simpler and more intuitive in the frequency domain than in the time domain, most of the signal analysis work is carried out in the frequency domain. Music is an excellent example of time/frequency analysis. Music score
Both Fourier transform and wavelet transform are essentially the same. They convert signals between time and frequency domains and find some intuitive information from seemingly complex data, then analyze it. Because the signal is often simpler and more intuitive in the frequency domain than in the time domain, most of the signal analysis work is carried out in the frequency domain. Music is an excellent example of time/frequency analysis. Music score
wavelet threshold denoising based on Matlab
Thank you so much:http://blog.sina.com.cn/u/1861445474Http://blog.chinaaet.com/detail/3083.html
The threshold denoising of signal is realized in MATLAB, which mainly includes two aspects: threshold denoising and threshold acquisition.
1. Threshold acquisition
The functions implemented in MATLAB are ddencmp, Thselect, Wbmpen, and WWDCBM, and their usage is briefly explained below.
The DDENCMP format has the
Links: http://www.zhihu.com/question/22864189/answer/40772083
Article recommended by: Yang Xiaodong
From the Fourier transform to the wavelet transform, is not a completely abstract thing, can speak very image. The wavelet transform has definite physical meaning, if we look at the problems that we face when we put forward it, we can sort out a very clear idea.The following is the sequence of the Fourier-to
When the call to the Wavefast function found that MATLAB does not have this function, by looking up the wavelet transformation of the M file, saved into a function file can be directly invoked.
Matlab Source code:(1) wave2gray.m
function w = Wave2gray (c, S, scale, border)%wave2gray Display wavelet decomposition.
% W = Wave2gray (C, S, SCALE, BORDER) displays and returns a%
Last November, a series of articles on wavelet transform and image processing were published, and the experiences and programs in the process of learning wavelet were put on the internet and shared with everyone. Six months, thank you for your attention and help, in the mutual discussion and exchange, I constantly from the questions raised by everyone to expand their knowledge, the theory of
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