中文说明：应用背景有 ；数字图像处理的拉斐尔C.冈萨雷斯书4例实施（第四章）。在这里你可以找到：1 - 2 - a_sample_dft ； ；高通滤波器3-letter_recognition ；4-lowpass滤波器关键技术此代码是适合那些想要开始图像处理可以帮助他们看到在这个例子的结果；数字图像处理由拉斐尔C.冈萨雷斯书（4章）。
English Description：
Application backgroundThere is implementation of 4 examples of Digital Image Processing book by Rafael C. Gonzalez (Chapter4). here you can find :1- a_sample_dft 2- highpass filter 3-letter_recognition 4-lowpass filterKey Technologythis code is appropriate for who wants to start image processing and it can help them to see the result of the examples in Digital Image Processing book by Rafael C. Gonzalez (Chapter 4).