Mat BoostButterworthFilter( const int &row, const int &col, const float &cutoff, const int &n, const float &boost )const
{
assert( row>1 && col>1 )
assert( cutoff>0 && cutoff<0.5 )
assert( n>=1 )
if ( boost>=1 )
{
return (1-1/boost)*( BHPF( row, col, cutoff, n ) ) + 1/boost
}
else
{
return (1-boost)*BLPF( row, col, cutoff, n) + boost
}
}
/// 巴特沃斯高通滤波器
Mat CIllumNorm::BHPF( const int &row, const int &col, const float &cutoff, const int &n )
{
return 1-BLPF( row, col, cutoff, n )
}
/// 巴特沃斯低通滤波器
/*
cutoff is the cutoff frequency of the filter 0 - 0.5
n is the order of the filter, the higher n is the sharper
1
f = --------------------
2n
1.0 + (w/cutoff)
*/
Mat BLPF( const int &row, const int &col, const float &cutoff, const int &n )
{
assert( row>1 && col>1 )
assert( cutoff>0 && cutoff<0.5 )
assert( n>=1 )
Mat X = Mat::zeros( row, col, CV_32F )
Mat Y = Mat::zeros( row, col, CV_32F )
if ( col%2 )
{
int t = -(col-1)/2
for ( int j=0 j<col j++ )
{
for ( int i=0 i<row i++ )
{
X.at<float>( i, j ) = ((float)t)/(col-1)
}
t++
}
}
else
{
int t = -col/2
for ( int j=0 j<col j++ )
{
for ( int i=0 i<row i++ )
{
X.at<float>( i, j ) = ((float)t)/col
}
t++
}
}
if ( row%2 )
{
int t = -(row-1)/2
for ( int i=0 i<row i++ )
{
for ( int j=0 j<col j++ )
{
Y.at<float>( i, j ) = ((float)t)/(row-1)
}
t++
}
}
else
{
int t = -row/2
for ( int i=0 i<row i++ )
{
for ( int j=0 j<col j++ )
{
Y.at<float>( i, j ) = ((float)t)/row
}
t++
}
}
Mat H = Mat::zeros( row, col, CV_32F )
/// 计算频域的巴特沃斯分类器
for ( int i=0 i<row i++ )
{
for ( int j=0 j<col j++ )
{
float x = X.at<float>( i, j )
float y = Y.at<float>( i, j )
float radius = sqrtf( x*x + y*y )
/// 1.0 ./ (1.0 + (radius ./ cutoff).^(2*n))
H.at<float>( i, j ) = 1.0 / ( 1.0+std::pow( radius/cutoff, 2*n ) )
}
}
/// shift 将中心点移到左上角
H = CenterShift(H)
return H
}
Mat CenterShift( const Mat &_src )
{
Mat src = Mat_<float>(_src)
Mat dst = Mat::zeros( src.rows, src.cols, src.type() )
int N = src.rows
int D = src.cols
int *rowIndex = new int[N]
int *colIndex =new int[D]
memset( rowIndex, 0, sizeof(rowIndex[0])*N )
memset( colIndex, 0, sizeof(colIndex[0])*D )
/// 行 顺序
int begin = N/2
for ( int i=0 i<N i++ )
{
rowIndex[i] = begin
begin++
if ( begin>=N )
{
begin = 0
}
}
/// 列 顺序
begin = D/2
for ( int i=0 i<D i++ )
{
colIndex[i] = begin
begin++
if ( begin>=D )
{
begin = 0
}
}
/// 重新排序
for ( int i=0 i<N i++ )
{
for ( int j=0 j<D j++ )
{
dst.at<float>( i, j ) = src.at<float>( rowIndex[i], colIndex[j] )
}
}
/// 释放
delete []rowIndex
delete []colIndex
rowIndex = NULL
colIndex = NULL
return dst
}
#define pi 3.14159265358979384626double h(double n)
{
double x
x=1.0/(pi*(n-64))
x*=sin(pi*(n-64))-sin(3*pi/4*(n-64))
x*=0.54-0.46*cos(2*pi*n/128)
x*=r128(n)
return x
}
double r128(double n)
{
double x
/*函数R128的公式你没给出，你自己完成吧*/
return x
}
