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Description: 于傅里叶变换的图像加密技术研究
具体是将一幅图像用 fft 变换到频域
在频域中进行加密 我考虑的是通过随机相位来加密的方法，请问用matlab怎样实现
加密后在通过 ifft 得到加密后的图象
-Fourier transform in the image encryption technology to study the details of an image is to use fft transformed to the frequency domain in the frequency domain I consider encryption is through random-phase approach to encryption, Will the use of Matlab how to achieve the adoption of encryption ifft be encrypted images
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Size: 1024 |
Author: 李建成 |
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Description: matlab下对图像进行fft变换，平滑，锐化，中心化傅立叶正变换得到大正方形，小正方形，斜正方形。对其频谱进行中心化处理。图像的平滑和锐化，利用拉普拉斯算子。-Matlab right image fft transform, smoothing, sharpening, is the center of the Fourier transform large square, small square, ramp square. Its spectrum treatment center. Image sharpening and smoothing, using Laplace operator.
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Size: 1032192 |
Author: zidan |
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Description: OFDM仿真
参数：
％ 子载波数 128
％ 位数/ 符号 2
％ 符号数/ 载波 1000
％ 训练符号数 0
％ 循环前缀长度 8 (1/16)*T
％ 调制方式 4-QAM
％ 多径信道数 3
％ IFFT Size 128
％ 信道最大时延 2
-OFDM simulation parameters : % subcarriers median number of 128%/2% Symbol Symbol/Carrier Training 1000% 0% Symbol few cyclic prefix length 8 (1/16)* T% modulation 4-QAM% multi-path channel number 3% 128% Size IFFT letter Maximum delay 2
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Size: 19456 |
Author: 高源 |
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Description: ＯＦＤＭ程序 波形如下
子载波数 128
％ 位数/ 符号 2
％ 符号数/ 载波 100
％ 训练符号数 0
％ 循环前缀长度 8 (1/16)*T
％ 调制方式 4-QAM
％ 多径信道数 3
％IFFT Size 128
％ 信道最大时延 2-OFDM waveform procedures following subcarriers median number of 128%/2% Symbol Symbol/Carrier 100% Training a few symbols 0% cyclic prefix length 8 (1/16)* T% modulation 4-QAM% multi-path channel number 3% IFFT Size 128% maximum delay Channel 2
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Size: 4096 |
Author: 唐成玉 |
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Description: Matlab实现快速傅立叶变换、FFT和IFFT计算线性卷积、IIR数字滤波器、FIR数字滤波器实验的相关资料，有源代码和仿真图-Realize Matlab Fast Fourier Transform, FFT and IFFT computing linear convolution, IIR digital filters, FIR digital filter of the relevant experimental data, source code and simulation of Figure
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Size: 57344 |
Author: 王旭 |
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Description: 用Matlab以及c语言求语音序列的倒谱
这某段语音信号求FFT、取模、取log、IFFT得到倒谱，并画图。选取一段进行分析，分别对浊音和清音各自求倒谱。-Using Matlab, as well as for c language serial Cepstral voice that voice signal for a certain period of FFT, check mode, check log, IFFT been cepstrum, and drawing. Select a section of the analysis, respectively, and the voiceless to voiced their demand cepstrum.
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Size: 4096 |
Author: 海德 |
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Description: some kinds of frequency interpolations.which are used to processing frequency and IFFT to image spce to new image
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Size: 1024 |
Author: xiaozhi |
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Description: 加深对图像变换的理解。计算图像的傅立叶变换J，进行频谱搬移并显示；计算J的逆变换IFFT，并显示。-Deepen the understanding of the image transform. Fourier transform calculation of image J, the spectrum to move and display calculated J inverse transform IFFT, and displayed.
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Size: 28672 |
Author: Ashtray |
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Description: DAB发送端仿真，包括编码，删余，QPSK映射，频率交织，差分调制，循环嵌缀，加NULL、PRS,IFFT，信道-DAB sending end simulation, including coding, cut more than, QPSK mapping, interwoven frequency, differential modulation, the cycle is made up of inlay, plus NULL, PRS, IFFT, channel
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Size: 5120 |
Author: Aries |
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Description: ofdm 仿真的程序，包括参数定义，fft，ifft，调制解调等源码，很好用啊！-OFDM simulation procedures, including the definition of parameters, fft, ifft, modulation and demodulation, such as source code, with very good ah!
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Size: 4096 |
Author: zhangweijin |
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Description: 摘要:为了提高图像复原算法的性能 ,提出了一种改进的奇异值分解法估计图像的点扩散函数。从图像的退化离散模型
出发 ,对图像进行逐层分块奇异值分解 ,并自动选取奇异值重组阶数以减少噪声对估计的影响。利用理想图像奇异值向
量平均能谱指数模型 ,估计点扩散函数奇异值向量的频谱 ,再反傅里叶变换得到其时域结果。实验结果表明 ,该方法能
在不同信噪比情况下估计成像系统的点扩散函数 ,估计结果比原有估计方法有所提高 ,有望为图像复原算法的预处理提
供一种有效的手段。-Abstract : To improve the performance of image restoration algorithms , a modified Singular Value De2
[ ] [ ]
composition SVD method was proposed to estimate the Point Spread Function PSF of an imaging
system. Using the discrete image degradation model , a block2based SVD filter scheme was applied for
the image denoising with an automatically determined singular value rank. After the spectra of PSF
singular vectors were estimated under an exponential model for the averaged spectra of un2degraded
image singular vectors , the IFFT was used to get the time2domain estimation of the PSF. The experi2
mental results show that this proposed method can be applied to estimate the PSF of the imaging sys2
tem under a wide SNR range and its performance is better than the original method. It may be used as
an effective method for the image preprocessing in image restoration problems.
[ ]
Key words: image restoration Point Spread Function PSF block2based Singular Value Decomposi2
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Author: zy |
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Description: 还在为“基于MATLAB的OFDM系统仿真”的朋友，可以看看我总结的资料！
该代码通过综合了本站中的两个源代码，在MATLAB 7.0下完成OFDM系统的完美仿真：音频数据采集->S/P转换->16QAM映射->IFFT处理->添加CP->P/S->理想/多径信道传送->……（FFT等）->传输结果比较（前后频谱图、可以直接通过听前后的音频文件来辨别系统的好坏-理想信道时音质前后相同）。在此还要感谢那两位站员提供相关的代码，也希望能对其他人有帮助。更希望本站能吸引更多的编程爱好者再创佳绩。-KEYWORD:OFDM MATLAB 7.0 CP IFFT FFT P/S S/P
Also for the " Based on MATLAB simulation of the OFDM system," a friend, you can see my summary of the information! The code through a combination of the two site source code, MATLAB 7.0 at complete perfection OFDM system simulation: Audio Data Acquisition-> S/P conversion-> 16QAM mapping-> IFFT processing-> Add CP-> P/S-> ideal/multi-path channel transmission-> ... ... (FFT, etc.)-> transmission results (before and after the frequency spectrum can be directly before and after listening to audio files to identify the system good or bad- when the ideal channel before and after the same sound quality). This would also like to thank at the two stations to provide the relevant code, also hope to have helped others. I also hope to attract more site programming enthusiasts new heights.
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Size: 8192 |
Author: sunshinepwf |
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Description: MATLAB实现的无源RC、LC滤波器设计系统。可设计LP、HP、BP、BS四种滤波器，附带设计结果-MATLAB realization of passive RC, LC filter design system. Can be designed LP, HP, BP, BS in four filters, with the design results
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Size: 45056 |
Author: wangzhen |
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Description: 一个相对完整的OFDM通信系统的仿真设计，包括编码，调制，IFFT，上下变频，高斯信道建模，FFT，PAPR抑制，各种同步，解调和解码等模
块，并统括系统性能的仿真验证了系统设计的可靠性。
-A relatively complete simulation of the OFDM communication system design, including coding, modulation, IFFT, frequency up and down, Gaussian channel model, FFT, PAPR suppression, a variety of synchronization, demodulation and decoding block mode , and system performance omnibus simulation to verify the reliability of system design.
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Size: 37888 |
Author: LX |
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Description: 这是一个基于空时分组编码的MIMO_OFDM通信系统的仿真设计。此系统包括QPSK调制解调，IFFT调制，空时编解码，基于训练符号的信道估计等通信模块。
-This is a space-time block coding based on MIMO_OFDM Communication System Simulation and Design. The system consists of QPSK modulation and demodulation, IFFT modulation, space-time coding and decoding, symbol-based channel estimation training, such as communication module.
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Size: 12288 |
Author: william |
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Description: IT gives the IFFT of the given signal
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Size: 1024 |
Author: deva |
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Description: IFFT的MATLAB实现，很具参考价值-IFFT of the MATLAB implementation, it is a reference value
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Size: 5120 |
Author: 张朝文 |
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Description: OFDM下行的仿真1、产生要传输随机数；
2、进行调制；
3、串并转换；
4、进行IFFT操作（代码中有用到共轭对称向量的IFFT为实数进行简化计算）；
5、增加循环前缀；
6、并串转换；
7、输出前滤波；
8、增加信道噪声（加性高斯白噪声）；
9、接收端串并转换；
10、去除循环前缀；
11、进行FFT变换；
12、信号解调；
13、误比特率计算；
-OFDM downlink simulation 1, have to be transmitted random number 2, the modulation 3 series and transforms 4, the IFFT operation (code useful to conjugate symmetric vector of the IFFT of real numbers to simplify calculations) 5, the increase in circulating prefix 6, and string conversion 7, the output before the filter 8, increased channel noise (additive white Gaussian noise) 9, the receiver string and conversion 10, removal of cyclic prefix 11, the FFT transform 12 , the signal demodulation 13, bit error rate
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Size: 112640 |
Author: 刘洋 |
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Description: 这是一个通信系统的仿真，是用SIMULINK的S-FUNCTION方式编写的，共有20个M文件，1个DOC文件，本系统的仿真设计到编码、调制、IFFT、上下变频、高斯信道建模、FFT、PAPR抑制、各种同步、解调和解码等模块，每个模块都用详细的代码和注释，并通过了系统性能的仿真验证了系统设计的可靠性，可以直接拿来仿真整个系统，也可来学习各个部分的设计。-This is a communication system simulation, is the S-FUNCTION SIMULINK approach to the preparation, a total of 20 M file, a DOC file, the system simulation design to coding, modulation, IFFT, and down conversion, Gaussian channel model , FFT, PAPR suppression, various synchronization, demodulation and decoding modules, each module with a detailed code and comments, and system performance through simulation and verification of the reliability of system design, simulation of the entire system can be directly used, also to learn the various parts of the design.
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Size: 38912 |
Author: masong |
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Description: 快速傅里叶和逆快速傅里叶的马特拉博代码，还是挺简单的代码，但是挺好用的-matlab code of fft and ifft
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Size: 1024 |
Author: wxj |
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