DIP_review_2_1(1)
DIP_review_2_1 - Frequency Domain Filtering(1)
1.Fourier Transform formula
Four types of Fourier Transform
时域非周期
时域周期
频域非周期
CTFT(时间频域均连续)
FS(CT,频域离散,时域连续)
频域周期
DTFT(时间离散,频域连续)
DFT(DT,时间频域均离散)
FS(CT) => x(t)=∑k=−∞∞akejkw0tx(t) = \sum_{k=-\infty}^{\infty}a_ke^{jkw_0t}x(t)=∑k=−∞∞akejkw0t 频率离散且无周期
ak=1T∫Tx(t)e−jkw0ta_k = \frac{1}{T}\int_T x(t)e^{-jkw_0t}ak=T1∫Tx(t)e−jkw0t 时间连续且周期
CTFT => X(jw)=∫−∞∞x(t)e−jwtdtX(jw) = \int_{-\infty}^{\infty}x(t)e^{-jwt}dtX(jw)=∫−∞ ...
DIP_quiz_1
DIP_quiz_1 - Digital image fundamentals
Q1
Definition of path in the pixel part
Calculation of three different types of distances in the pixel part
What you should mainly focus on is the definition of V. In our ppt, example of binary value image is V=1V = {1}V=1, and example of Gray-scale image is V=[Lmin,Lmax]V = [Lmin, Lmax]V=[Lmin,Lmax]. Therefore when you are finding a path, you need only to pay attention to the value in V and this is enough.
Q2
Property of convolution
Calculation of corr ...
DIP_review_1
DIP_review_1 - Digital image fundamentals
1.Introduction
信号的分类
Analog signal 模拟信号
连续时间信号,且具有连续值的波峰
许多自然界的信号是模拟的
Quantized boxcar signal
连续时间信号,但离散值波峰
存在于数字电路
sampled-data signal 采样信号 -> 将坐标轴数字化,即离散时间
离散时间,但连续值波峰
可视为对模拟信号用周期性脉冲采样
Digital signal 数字信号 ->将峰值数字化,即离散波峰
离散时间,且离散值波峰
是采样信号量化后的结果
Pixel/Voxel
数字图像由有限个数量的Pixel组成,Pixel中包含着位置和Intensity value的信息,主要用来表示图像的的灰度值,颜色,高度和不透明度等重要信息
用(x,y)作为Pixel在图像中的坐标,f(x,y)作为其对应的幅值即Intensity or brightness(color)
2.Human visual system, perc ...