Introduction to Image and Video Processing
1. Analog v.s. Digital Signals
1.1 Signals
A function containing information about the behavior or nature of some phenomenon of interest.
1.2 Analog to Digital Signals
Sound : acoustic signal( x(t) ) -> electrical signal ->discrete-time signals--quantization--> discrete amplitude (the two above is called digital signals) ->electrical signal ->acoustic signal
image:
1.3 Sampling
Consider a digital image (256*256),which mean it has 256 rows and 256 columns, and it's an eight bit image which means each element of picture which is called pixel has 256 values.
如果我们down-sampling 图片，我们就把在水平面上的value和竖直面上的value留下一个来
zero-order hold就是用一个pixel中一个的小格的数值用于其他63个小格，就会得到右一的马赛克的图片。
一般来说，采样间隔越大，所得图像像素数越少，空间分辨率低，质量差，严重时出现马赛克效应；采样间隔越小，所得图像像素数越多，空间分辨率高，图像质量好，但数据量大。
1.4 Quantization
8 bit的图片相当于有256个不同灰度的values；
量化等级越多，所得图像层次越丰富，灰度分辨率高，图像质量好，但数据量大；量化等级越少，图像层次欠丰富，灰度分辨率低，会出现假轮廓现象，图像质量变差，但数据量小.
Quantization is a reversible process in the sense that you can recover the original image after it undergoes quantization.
选择：False 量化是不可逆的
2. Image and Video Signals
没啥好记的,都是介绍性的内容
3. Electromagnetic Spectrum
以介绍图片为主就不多记了