Java用傅立叶转化FFT方法对图像处理 数组越界问题

Question

图像处理java傅立叶转换

Answer 1

这是Complex.javapackage src;
//Complex.java//复数的定义
class Complex {

public double re;
public double im;

Complex(){
this.re=0;
this.im=0;
}
Complex(double re){
this.re=re;
this.im=re;
}
Complex(double re,double im){
this.re=re;
this.im=im;
}

public void setRE(double re){
this.re=re;
}
public void setIM(double im){
this.im=im;
}
public double getRE(){
return this.re;
}
public double getIM(){
return this.im;
}

//复数加法
Complex Add(Complex c1,Complex c2){
Complex c=new Complex(0,0);
c.re=c1.re+c2.re;
c.im=c1.im+c2.im;
return c;
}
//复数减法
Complex Sub(Complex c1,Complex c2){
Complex c=new Complex(0,0);
c.re=c1.re-c2.re;
c.im=c1.im-c2.im;
return c;
}
//复数乘法
Complex Mul(Complex c1,Complex c2){
Complex c=new Complex(0,0);
c.re=c1.re*c2.re-c1.im*c2.im;
c.im=c1.re*c2.im+c2.re*c1.im;
//c=Sub(c1,c2);
return c;
}
}

Answer 2

这是Onefftpackage src;
//OneFft.javaimport java.awt.*;public class Onefft {
  
   // 付立叶变换点数
int count;

   //循环变量
   int  i,j,k;
  
   //中间变量
   int bfsize,p;
  
   int power;
  
   Complex[] w,x1,x2,x;
  
   Complex[] fd;
  
  
   public void setData(Complex [] data,int power){
  
     this.power=power;
    
     //角度
   double angle;
    
   //计算傅立叶变换的点数
   count=1<<power;
  
   //分配空间
   w=new Complex[count/2];
   x=new Complex[count];
       x1=new Complex[count];
       x2=new Complex[count];
       fd=new Complex[count];
      
       //初始化
       for(i=0;i<count/2;i++)
       {
       w[i]=new Complex();
       }
       for(i=0;i<count;i++)
       {
       x[i]=new Complex();
       x1[i]=new Complex();
       x2[i]=new Complex();
       fd[i]=new Complex();
       }
      
       //计算加权系数
       for(i=0;i<count/2;i++)
       {
        angle=-i*Math.PI*2/count;
        w[i].re=Math.cos(angle);
         w[i].im=Math.sin(angle);
       }
      
       //将实域点写入x1
       for(i=0;i<count;i++)
       {
       x1[i]=data[i];
      
       }
   }
  
  public Complex [] getData(){
  
       //蝶形运算
       for(k=0;k<power;k++)
       {
        for(j=0;j<1<<k;j++)
        {
           bfsize=1<<(power-k);
           for(i=0;i<bfsize/2;i++)
           {
           Complex temp1=new Complex(0,0);
           Complex temp2=new Complex(0,0);
          
             p=j*bfsize;
             x2[i+p]=temp1.Add(x1[i+p],x1[i+p+bfsize/2]);
            
             temp2=temp1.Sub(x1[i+p],x1[i+p+bfsize/2]);
            
             x2[i+p+bfsize/2]=temp1.Mul(temp2,w[i*(1<<k)]);
           }
         }
         x=x1;
         x1=x2;
         x2=x;
       }
      
      
       //重新排序
       for(j=0;j<count;j++)
       {
        p=0;
        for(i=0;i<power;i++)
        {
             if((j&(1<<i))!=0)
             p+=1<<(power-i-1);
         }
         fd[j]=x1[p];
       }
       return fd;
 }
 

}