小波变换matlab总结 目录
一、预置工具 ........................................................................................................................... 4
1.预置信号 ...................................................................................................................... 4 2.预置小波 ...................................................................................................................... 4 3.滤波器函数 .................................................................................................................. 6
wfilters函数....................................................................................................... 6 4.量化编码 ...................................................................................................................... 6
wcodemat函数....................................................................................................... 6 5.阈值获取 ...................................................................................................................... 6
ddencmp函数 ......................................................................................................... 6 thselect函数....................................................................................................... 7 wbmpen函数 ........................................................................................................... 7 wdcbm函数 .............................................................................................................. 7 6.阈值去噪 ...................................................................................................................... 8
wden函数 ................................................................................................................ 8 wdencmp函数 ......................................................................................................... 8 wthresh函数 ......................................................................................................... 9 wthcoef函数 ......................................................................................................... 9 wpdencmp函数....................................................................................................... 9
二、小波变换函数 ................................................................................................................. 12
单尺度一维小波变换 ..................................................................................................... 12
cwt一维连续小波变换 ......................................................................................... 12 dwt一维离散小波变换 ......................................................................................... 12 idwt一维离散小波逆变换 .................................................................................. 13 upcoef 一维小波系数重构 ................................................................................ 13 多尺度一维小波变换 ..................................................................................................... 14
wavedec多尺度一维分解 ................................................................................... 14 waverec多尺度一维重构 ................................................................................... 15 appcoef低频系数提取 ....................................................................................... 16 detcoef高频系数提取 ....................................................................................... 16 wrcoef多尺度小波系数重构 ............................................................................. 17 一维静态（平稳）小波变换 ......................................................................................... 18
swt一维平稳小波变换 ......................................................................................... 18 iswt一维平稳小波逆变换 .................................................................................. 18 实例 ......................................................................................................................... 19 单尺度二维小波变换 ..................................................................................................... 19
dwt2二维离散小波变换 ...................................................................................... 19 idwt2二维离散小波逆变换 ................................................................................ 20 upcoef2二维系数重构 ....................................................................................... 20 多尺度二维小波变换 ..................................................................................................... 21
wavedec2多尺度二维分解 ................................................................................. 21 waverec2多尺度二维重构 ................................................................................. 22 appcoef2低频系数提取 ..................................................................................... 23 detcoef2高频系数提取 ..................................................................................... 23
wrcoef2多尺度小波系数重构 ........................................................................... 24 二维静态（平稳）小波变换 ......................................................................................... 26
swt2二维静态小波变换 ...................................................................................... 26 iswt2二维静态小波逆变换 ................................................................................ 26 实例 ......................................................................................................................... 26 直接调用的小波函数 ..................................................................................................... 28
meyer函数 ............................................................................................................ 28 cgauwavf函数..................................................................................................... 28 mexihat函数 ....................................................................................................... 28 morlet函数 ......................................................................................................... 29 symwavf函数 ....................................................................................................... 29
三、图像接口调用 ................................................................................................................. 30
使用图形接口做一维连续小波分析 ..................................................................... 30 使用图形接口做一维离散小波分析 ..................................................................... 33 使用图形接口分析复信号 ..................................................................................... 36 使用图形接口做一维除噪分析 ............................................................................. 36
四、小波变换在图像处理中的应用 ..................................................................................... 40
4.1 小波分析用于图像压缩 ........................................................................................ 40
4.1.1 基于小波变换的图像局部压缩 ............................................................... 40 4.1.2 小波变换用于图像压缩的一般方法 ....................................................... 41 4.1.3 基于小波包变换的图像压缩 ................................................................... 45 4.2 小波分析用于图像去噪 ........................................................................................ 47
小噪声阈值去噪 ..................................................................................................... 48 大噪声滤波去噪 ..................................................................................................... 49 少量噪声的小波分解系数阈值量化去噪 ............................................................. 50 4.3 小波分析用于图像增强 ........................................................................................ 52
4.3.1 图像增强问题描述 ................................................................................... 52 4.3.2 图像钝化 ................................................................................................... 53 4.3.3 图像锐化 ................................................................................................... 54 4.4 小波分析用于图像融合 ........................................................................................ 56 4.5 小波分析用于图像分解 ........................................................................................ 57