我正在为 .net Windows 窗体项目寻找数字低通滤波器代码/库/类,最好用 c、c++ 或 c# 编写。我可能需要设置极数、系数、开窗之类的东西。我不能使用任何可用的 gpl 代码,也不知道那里还有什么。任何建议表示赞赏。
最佳答案
这是我为最近的项目编写的 Butterworth 低通滤波器。
它有一些神奇的数字作为给我的常量。如果您能弄清楚如何使用您的极点、系数等创建魔数(Magic Number),那么这可能会有所帮助。
using System;
using System.Collections.Generic;
using System.Text;
namespace Filter
{
public class ButterworthLowPassFilter
{
//filter fc = 2hz, fs = 10hz
private const int LowPassOrder = 4;
private double[] inputValueModifier;
private double[] outputValueModifier;
private double[] inputValue;
private double[] outputValue;
private int valuePosition;
public ButterworthLowPassFilter()
{
inputValueModifier = new double[LowPassOrder];
inputValueModifier[0] = 0.098531160923927;
inputValueModifier[1] = 0.295593482771781;
inputValueModifier[2] = 0.295593482771781;
inputValueModifier[3] = 0.098531160923927;
outputValueModifier = new double[LowPassOrder];
outputValueModifier[0] = 1.0;
outputValueModifier[1] = -0.577240524806303;
outputValueModifier[2] = 0.421787048689562;
outputValueModifier[3] = -0.0562972364918427;
}
public double Filter(double inputValue)
{
if (this.inputValue == null && this.outputValue == null)
{
this.inputValue = new double[LowPassOrder];
this.outputValue = new double[LowPassOrder];
valuePosition = -1;
for (int i=0; i < LowPassOrder; i++)
{
this.inputValue[i] = inputValue;
this.outputValue[i] = inputValue;
}
return inputValue;
}
else if (this.inputValue != null && this.outputValue != null)
{
valuePosition = IncrementLowOrderPosition(valuePosition);
this.inputValue[valuePosition] = inputValue;
this.outputValue[valuePosition] = 0;
int j = valuePosition;
for (int i = 0; i < LowPassOrder; i++)
{
this.outputValue[valuePosition] += inputValueModifier[i] * this.inputValue[j] -
outputValueModifier[i] * this.outputValue[j];
j = DecrementLowOrderPosition(j);
}
return this.outputValue[valuePosition];
}
else
{
throw new Exception("Both inputValue and outputValue should either be null or not null. This should never be thrown.");
}
}
private int DecrementLowOrderPosition(int j)
{
if (--j < 0)
{
j += LowPassOrder;
}
return j;
}
private int IncrementLowOrderPosition(int position)
{
return ((position + 1) % LowPassOrder);
}
}
}
基思
关于signal-processing - 低通滤波软件?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/344343/