chap4

说明：  分析了如何利用小波变换技术对图像进行信息融合使读者从整体上对医学图像融合技术有一个比较清楚直观的理解 (Analysis of how to use wavelet transform to the image information fusion, so that readers from the whole of the medical image fusion technology has a relatively clear and intuitive understanding.)

通过阈值去噪，最关键的就是要确定最佳阈值T 的大小.如果阈值太小，可以保留更多的小波系数，但同时噪声也被保留；相反，阈值太大，可以消除更多的噪声，但重要图像特征又将被滤掉，引起偏差.目前使用的阈值分为全局阈值和局部阈值.全局阈值对各层所有的小波系数或同一层内的小波系数都是统一的；局部阈值则是根据当前系数周围的局部情况来确定合适的阈值，具有灵活性.(Threshold denoising, the most critical is to determine the optimal threshold T s size. If the threshold is too small, you can retain more of the wavelet coefficients, but the noise was retained the contrary, the threshold is too large, can be eliminatedmore noise, but the important image features in turn be filtered out, causing bias current threshold is divided into a global threshold and local threshold. global Threshold the wavelet coefficients of all the wavelet coefficients of the layers or on the same floorare unity local threshold is based on the local situation of the current coefficient around to determine the appropriate threshold, with flexibility.)

demo中基本上整理了目前常用的所有边缘检测算子，并添加了自定义的frei-chen、kirsch、direcedge、PrewittCompass、RobinsonCompass边缘检测算子function函数。此外，还有Ruzon罗盘算子的matlab实现程序，能对灰度图像的边缘加以检测。(demo, basically compiled all the commonly used edge detection operator, and add a custom frei-chen, kirsch, direcedge, PrewittCompass, RobinsonCompass edge detection operator function function. In addition, there Ruzon compass operator procedures matlab realize, can be gray-scale image edge detection.)

这是冈萨雷斯版数字图像处理中的几个函数的实现，包括gmean,以及书中的例题5.7和5.10。(This is the realization Gonzalez version Several digital image processing functions, including gmean, and examples in the book of 5.7 and 5.10.)

对l1最小化的处理，其中包括全面的l1范数的解得算法，运用tv全变分最小的解决方法，适合于单像素以及图像处理的研究者参考。(L1 minimization, including the full L1 norm solution algorithm, the use of TV total variation, the smallest solution, suitable for single pixel and image processing researchers reference.)

区域生长算法，通过设置种子点来实现,代码注释完整(region grow algorithm with matlab)

说明：  通过生成秘钥得到一串具有一定长度的扩频码，将原始消息序列以扩频码的长度过采样产生过采样消息序列，并将扩频码以原始消息序列的长度多次重复成伪随机序列，再令过采样消息序列与伪随机序列异或就可以生成扩频消息序列。在频率域下，将扩频消息序列以一定的嵌入强度自适应地嵌入原始图像，得到的图像具有较强的鲁棒性，比起直接嵌入，扩频水印在受到攻击后恢复出的水印信息误码率要低得多。并且扩频码长度越长，容错率就越高，鲁棒性就越好。(A sequence of spread spectrum codes with a certain length is obtained by generating a secret key. The oversampling message sequence is generated by oversampling the original message sequence with the length of the spread spectrum code, and the spread spectrum code is repeated into a pseudo-random sequence with the length of the original message sequence for many times, and then the spread spectrum message sequence can be generated by making the difference between the oversampling message sequence and the pseudo-random sequence. In the frequency domain, the spread spectrum message sequence is adaptively embedded into the original image with a certain embedding strength, and the resulting image has strong robustness. Compared with direct embedding, the error rate of the watermark information recovered from the attack of spread spectrum watermark is much lower. And the longer the spreading code length, the higher the fault tolerance rate and the better the robustness.)

利用 svt算法解决 Rpca算法的放缩问题，牛刀小试，大家见谅！(Solves the Robust PCA relaxation)

说明：  图像特征提取的四种算法，花了很大的力气才弄来的！和大家分享！(Four types of image feature extraction algorithm, to spend a great deal of effort to get the! To share with you all!)

说明：  高斯尺度差角点检测算法 将轮廓曲线在不同尺度下的演化差异的变化量作为角点响应函数并提出相应的 DoG 检测算子(Gauss scale difference corner detection algorithm)