Scipy简介

Scipy简介

• Scipy依赖于Numpy
• Scipy包含的功能：最优化、线性代数、积分、插值、拟合、特殊函数、快速傅里叶变换、信号处理、图像处理、常微分方程求解器等
• 应用场景:Scipy是高端科学计算工具包，用于数学、科学、工程学等领域
• Scipy由一些特定功能的子模块组成:
  

图片消噪处理

• scipy.fftpack模块用来计算快速傅里叶变换
  速度比传统傅里叶变换更快，是对之前算法的改进
  图片是二维数据，注意使用fftpack的二维转变方法

from scipy.fftpack import fft2, ifft2
import matplotlib.pyplot as plt
%matplotlib inline
import numpy as np
#读取照片数据
moon = plt.imread('moonlanding.png')	==>
array([[ 0.04705882,  0.        ,  0.23921569, ...,  0.        ,
         0.00392157,  0.53333336],
       [ 0.        ,  0.        ,  0.67843139, ...,  0.10196079,
         0.29019609,  0.        ],
       [ 0.72156864,  0.10980392,  0.60392159, ...,  0.        ,
         0.21568628,  1.        ],
       ..., 
       [ 0.00392157,  0.        ,  1.        , ...,  1.        ,
         1.        ,  0.95686275],
       [ 0.        ,  0.        ,  0.15686275, ...,  0.        ,
         0.        ,  0.35294119],
       [ 1.        ,  0.52156866,  0.04705882, ...,  0.        ,
         0.        ,  1.        ]], dtype=float32
#数据形式 
moon.shape		==> (474, 630)
#展示图片
plt.imshow(moon, cmap='gray')
#cmap 指定RGB的Z值，如果是三维数组则忽略cmap值
# 可选择的颜色映射参数为：Accent, Accent_r, Blues, Blues_r, BrBG, BrBG_r, BuGn, BuGn_r, BuPu, BuPu_r, CMRmap, CMRmap_r, Dark2, Dark2_r, GnBu, GnBu_r, Greens, Greens_r, Greys, Greys_r, OrRd, OrRd_r, Oranges, Oranges_r, PRGn, PRGn_r, Paired, Paired_r, Pastel1, Pastel1_r, Pastel2, Pastel2_r, PiYG, PiYG_r, PuBu, PuBuGn, PuBuGn_r, PuBu_r, PuOr, PuOr_r, PuRd, PuRd_r, Purples, Purples_r, RdBu, RdBu_r, RdGy, RdGy_r, RdPu, RdPu_r, RdYlBu, RdYlBu_r, RdYlGn, RdYlGn_r, Reds, Reds_r, Set1, Set1_r, Set2, Set2_r, Set3, Set3_r, Spectral, Spectral_r, Vega10, Vega10_r, Vega20, Vega20_r, Vega20b, Vega20b_r, Vega20c, Vega20c_r, Wistia, Wistia_r, YlGn, YlGnBu, YlGnBu_r, YlGn_r, YlOrBr, YlOrBr_r, YlOrRd, YlOrRd_r, afmhot, afmhot_r, autumn, autumn_r, binary, binary_r, bone, bone_r, brg, brg_r, bwr, bwr_r, cool, cool_r, coolwarm, coolwarm_r, copper, copper_r, cubehelix, cubehelix_r, flag, flag_r, gist_earth, gist_earth_r, gist_gray, gist_gray_r, gist_heat, gist_heat_r, gist_ncar, gist_ncar_r, gist_rainbow, gist_rainbow_r, gist_stern, gist_stern_r, gist_yarg, gist_yarg_r, gnuplot, gnuplot2, gnuplot2_r, gnuplot_r, gray, gray_r, hot, hot_r, hsv, hsv_r, inferno, inferno_r, jet, jet_r, magma, magma_r, nipy_spectral, nipy_spectral_r, ocean, ocean_r, pink, pink_r, plasma, plasma_r, prism, prism_r, rainbow, rainbow_r, seismic, seismic_r, spectral, spectral_r, spring, spring_r, summer, summer_r, tab10, tab10_r, tab20, tab20_r, tab20b, tab20b_r, tab20c, tab20c_r, terrain, terrain_r, viridis, viridis_r, winter, winter_r


# 傅里叶变换消噪

# 把时域空间转换到频域空间
f_moon = fft2(moon)