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用VB写的画出波纹的程序(Written by VB painted corrugated procedures)

本人图像处理的期末课程作业，使用模式识别自动识别验证码。老师都给好评哦(I end image processing course work, the use of pattern recognition automatic identification code)

通过对图像进行逆透视变化，得到图像的俯视图，即鸟瞰图(Through the inverse perspective change of the image, we can get the top view of the image, that is aerial view.)

说明：  能够检测图片的特征点，利用DOG算子，实际测试方便，算法清晰，有相关参考文章链接(Be able to detect image feature points)

说明：  1. 掌握利用脉冲响应不变法设计IIR数字滤波器的原理和具体方法。 2. 加深理解数字滤波器与连续时间滤波器之间的技术指标转化。 3. 掌握脉冲响应不变法设计IIR数字滤波器的优缺点及使用范围(1. Master the principle and specific method of designing IIR digital filter with impulse response invariant method. 2. Deepen the understanding of the technical index transformation between digital filter and continuous time filter. 3. Master the advantages, disadvantages and application scope of the design of IIR digital filter by the pulse response invariant method)

说明：  编程实现灰度图像的频域滤波算法。使用Matlab实现不延拓和延拓两个版本。对于延拓和不延拓版本，在理想低通滤波器、巴特沃斯低通滤波器和高斯低通滤波器上比较两者的区别；对于延拓版本，比较不同参数设置对上述三种滤波器滤波结果的影响。(Program to realize the filtering algorithm of gray image in frequency domain. Matlab is used to realize two versions of no extension and extension. For the extension version and the non extension version, the differences between the ideal low-pass filter, Butterworth low-pass filter and Gauss low-pass filter are compared; for the extension version, the effects of different parameter settings on the above three filter results are compared.)

能量检测法是一种比较简单的信号检测方法[1]， 属于信号的非相干的检测， 直接对时域信号采样值求模，然后平方即可得到；或利用FFT转换到频域，然后对频域信号求模平方也可得到。它无需知道检测信号的任何先验知识，对信号类型也不作限制。 实际上，能量检测是在一定频带范围内作能量积累，如果积累的能量高于一 定的门限，则说明信号的存在；如果低于一定的门限，则说明仅有噪声。能量检 测的出发点是信号加噪声的能量大于噪声的能量。能量检测方法对信号没有作任何假设，是一种盲检算法。 此代码“利用FFT转换到频域，然后对频域信号求模平方”方法来实现对用户的检测。(In fact, energy detection is used for energy accumulation in a certain frequency range. If the accumulated energy is higher than a certain threshold, the existence of the signal is indicated. If the threshold is lower than the threshold, then only noise is indicated. The starting point of energy detection is that the energy of signal plus noise is greater than that of noise. The energy detection method does not make any assumptions about the signal, and it is a blind detection algorithm. This code "converts the frequency domain into the frequency domain by FFT, then calculates the square of the square of the frequency domain signal" to realize the detection of the user.)

说明：  图像匹配相关文献7篇，主要有小波变换用于理论研究及匹配的算法实现。对于刚进行图像匹配研究的人员很有帮助(Matching literature 7, mainly used for theoretical research on wavelet transform and matching algorithm. Matching of the images for just the staff very helpful)

Canny算子的分步骤实现，基于C语言，一共6部分，学习图像处理参考(Canny operator steps to achieve, based on the C language, a total of 6 parts, the study of image processing reference)

说明：  实现脉搏波信号心率变异性分析,时域分析，频域分析和非线性分析(HRV analysis of the PPG signals)