image-information-hiding

多尺度加权的rentinex算法实现图像增强，里面用到了高斯滤波对图像进行滤波，可以去除大部分的噪声，平滑图像效果较突出，3个高斯尺度对图像做滤波后加权在一起得到多尺度信息的图像。(Multiscale weighted rentinex algorithm is used to enhance the image. Gauss filter is used to filter the image, which can remove most of the noise. The smoothing effect of the image is prominent. Three Gaussian scales are filtered and weighted together to get the multi-scale information of the image.)

实现对鱼眼图像的校正 我自己执行过 可以使用(it can realise the rectification of the fish eye image )

具体实现思路：以4位数字的验证码为例 1、人工将验证码的4位数字每位对应的代码存入数据库中，每位存入0-9对应的代码，每个数可以多存这样可以提高识别率; 2、获取验证码以后，对其进行去背景、灰度处理、去噪点处理、分片处理以后生成每位数字对应的代码; 3、去背景色，这一步的目的是把验证码和背景颜色区别开来。4、去噪声：这一步要取出图像上的孤立点。这些孤立点被认为是噪声。  孤立点的定义：某个点，周围没有与该点等值的点。  或者某个连接块，该连接块的元素的个数小于某个给定值K， 把元素个数很小的连接块也定义为孤立点，有助于去处噪声。  去噪声算法：参照去背景算法。 5、图像锐化：图像锐化的目的是增强边界。这一步是可选的。看验证码的情况，这一步可以跳过。 6、图片有效区域截取：这个操作是将图片除验证码字符以外的边框去掉，只留下验证码字符图片，这样保证分片的准确性。 7、图片分片处理，这个处理是将整个图片分割成单个字符图片。8、拿分片图像生成的代码(eg:000111110011…..)与DB中已有代码相比较，取得相似度最高的即要验证码的字符;   注：如果DB的样本越多，识别的准确率也越高，但是速度会相应变慢

DCT域图像水印算法，并根据携密载体提取秘密信息(DCT domain image watermarking algorithm, and extract secret information according to the carrier.)

用c语言实现一些简单的图像处理功能，如灰度化、旋转、拷贝等(Some simple image processing functions, such as gray scale, rotation, copy, etc., are implemented in C language.)

作为信息隐藏的重要分支，数字水印是一种有效的数字产品版权保护和数据安全维护技术。近年来数字水印技术成为了信息安全领域的研究热点，也得到了较大的发展。基于变换域的水印技术是目前研究的热点和重点。本文系统介绍了数字水印的原理和应用方法，概要介绍了数字水印的几种主流算法，并重点研究了一种基于离散余弦变换(DCT)数字图像水印算法，并借助 MATLAB编程工具，实现数字水印的嵌入和提取仿真，以及为测试鲁棒性而对水印图像进行攻击实验。(As an important branch of information hiding, digital watermarking is an effective copyright protection of digital products and data security maintenance technology. In recent years, digital watermarking has become a hot research field of information security, has also been considerable development. Transform domain watermarking technique based on the current research focus and focus. This system describes the principles and applications of digital watermarking methods, an overview of several mainstream digital watermarking algorithms, and focus on a discrete cosine transform (DCT) digital image watermarking, and with the MATLAB programming tools, digital watermark embedding and extraction simulation, as well as test the robustness of the watermark image on the attack experiments.)

批量读取tiff影像并计算月份NDVI最大值(use matlab to read tiff and calculate NDVI)

图像的傅里叶变换。在代码中实现了将两幅图像的幅度谱和相位谱进行交换，进而理解两者在图像显示中的作用(Fourier transform of the image. Implemented in the code will be two images amplitude spectrum and phase spectrum of exchange, and thus to understand both the role of the image display)

meanshift算法，及其在图像处理方面的应用(meanshift algorithm)

说明：  python实现的运用brief算法提取特征点的图像拼接(The implementation of Python using brief algorithm to extract feature points of image mosaic)