https://www.jianshu.com/p/b923cd47ac4a

http://fourier.eng.hmc.edu/e161/lectures/dct/dct.html

http://fourier.eng.hmc.edu/e161/lectures/dct/node1.html

http://fourier.eng.hmc.edu/e161/lectures/dct/node2.html

中文翻译过来的：http://blog.sina.com.cn/s/blog_626631420100xvxd.html

GitHub:

https://github.com/latex2html/latex2html/

维基百科：https://en.wikipedia.org/wiki/Discrete_cosine_transform

有图：https://www.cnblogs.com/byeyear/p/4513255.html

信号大全：https://www.cnblogs.com/byeyear/category/537879.html