yaneng 2020-01-11
在单片机开发中,经常需要对输入的数据进行过滤处理,如传感器数据输出,AD采样等,合适的滤波处理能达到更好效果。下面分享几种较简单而常用的滤波算法:
A、方法:
B、优点:
C、缺点:
int Filter_Value; int Value; void setup() { Serial.begin(9600); // 初始化串口通信 randomSeed(analogRead(0)); // 产生随机种子 Value = 300; } void loop() { Filter_Value = Filter(); // 获得滤波器输出值 Value = Filter_Value; // 最近一次有效采样的值,该变量为全局变量 Serial.println(Filter_Value); // 串口输出 delay(50); } // 用于随机产生一个300左右的当前值 int Get_AD() { return random(295, 305); } // 限幅滤波法(又称程序判断滤波法) #define FILTER_A 1 int Filter() { int NewValue; NewValue = Get_AD(); if(((NewValue - Value) > FILTER_A) || ((Value - NewValue) > FILTER_A)) return Value; else return NewValue; }
A、方法:
B、优点:
C、缺点:
/* N值可根据实际情况调整排序采用冒泡法*/ #define N 11 char filter() { char value_buf[N]; char count,i,j,temp; for ( count=0;count<N;count++) { value_buf[count] =get_ad(); delay(); } for (j=0;j<N-1;j++) { for (i=0;i<N-j;i++) { if (value_buf>value_buf[i+1] ) { temp = value_buf; value_buf = value_buf[i+1]; value_buf[i+1] = temp; } } } return value_buf[(N-1)/2]; }
A、方法:
N值的选取:一般流量,N=12;压力:N=4
B、优点:
C、缺点:
#define N 12 char filter() { int sum = 0; for (count=0;count<N;count++) { sum + = get_ad(); delay(); } return (char)(sum/N); }
A、方法:
B、优点:
C、缺点:
// 递推平均滤波法(又称滑动平均滤波法) #define FILTER_N 12 int filter_buf[FILTER_N + 1]; int Filter() { int i; int filter_sum = 0; filter_buf[FILTER_N] = Get_AD(); for(i = 0; i < FILTER_N; i++) { filter_buf[i] = filter_buf[i + 1]; // 所有数据左移,低位仍掉 filter_sum += filter_buf[i]; } return (int)(filter_sum / FILTER_N); }
A、方法:
B、优点:
C、缺点:
// 中位值平均滤波法(又称防脉冲干扰平均滤波法)(算法1) #define FILTER_N 100 int Filter() { int i, j; int filter_temp, filter_sum = 0; int filter_buf[FILTER_N]; for(i = 0; i < FILTER_N; i++) { filter_buf[i] = Get_AD(); delay(1); } // 采样值从小到大排列(冒泡法) for(j = 0; j < FILTER_N - 1; j++) { for(i = 0; i < FILTER_N - 1 - j; i++) { if(filter_buf[i] > filter_buf[i + 1]) { filter_temp = filter_buf[i]; filter_buf[i] = filter_buf[i + 1]; filter_buf[i + 1] = filter_temp; } } } // 去除最大最小极值后求平均 for(i = 1; i < FILTER_N - 1; i++) filter_sum += filter_buf[i]; return filter_sum / (FILTER_N - 2); } // 中位值平均滤波法(又称防脉冲干扰平均滤波法)(算法2) #define FILTER_N 100 int Filter() { int i; int filter_sum = 0; int filter_max, filter_min; int filter_buf[FILTER_N]; for(i = 0; i < FILTER_N; i++) { filter_buf[i] = Get_AD(); delay(1); } filter_max = filter_buf[0]; filter_min = filter_buf[0]; filter_sum = filter_buf[0]; for(i = FILTER_N - 1; i > 0; i--) { if(filter_buf[i] > filter_max) filter_max=filter_buf[i]; else if(filter_buf[i] < filter_min) filter_min=filter_buf[i]; filter_sum = filter_sum + filter_buf[i]; filter_buf[i] = filter_buf[i - 1]; } i = FILTER_N - 2; filter_sum = filter_sum - filter_max - filter_min + i / 2; // +i/2 的目的是为了四舍五入 filter_sum = filter_sum / i; return filter_sum; }
A、方法:
B、优点:
C、缺点:
// 限幅平均滤波法 #define FILTER_A 1 int Filter() { int i; int filter_sum = 0; filter_buf[FILTER_N - 1] = Get_AD(); if(((filter_buf[FILTER_N - 1] - filter_buf[FILTER_N - 2]) > FILTER_A) || ((filter_buf[FILTER_N - 2] - filter_buf[FILTER_N - 1]) > FILTER_A)) filter_buf[FILTER_N - 1] = filter_buf[FILTER_N - 2]; for(i = 0; i < FILTER_N - 1; i++) { filter_buf[i] = filter_buf[i + 1]; filter_sum += filter_buf[i]; } return (int)filter_sum / (FILTER_N - 1); }
A、方法:
B、优点:
C、缺点:
// 一阶滞后滤波法 #define FILTER_A 0.01 int Filter() { int NewValue; NewValue = Get_AD(); Value = (int)((float)NewValue * FILTER_A + (1.0 - FILTER_A) * (float)Value); return Value; }
A、方法:
B、优点:
C、缺点:
// 加权递推平均滤波法 #define FILTER_N 12 int coe[FILTER_N] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}; // 加权系数表 int sum_coe = 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12; // 加权系数和 int filter_buf[FILTER_N + 1]; int Filter() { int i; int filter_sum = 0; filter_buf[FILTER_N] = Get_AD(); for(i = 0; i < FILTER_N; i++) { filter_buf[i] = filter_buf[i + 1]; // 所有数据左移,低位仍掉 filter_sum += filter_buf[i] * coe[i]; } filter_sum /= sum_coe; return filter_sum; }
A、方法:
B、优点:
C、缺点:
// 消抖滤波法 #define FILTER_N 12 int i = 0; int Filter() { int new_value; new_value = Get_AD(); if(Value != new_value) { i++; if(i > FILTER_N) { i = 0; Value = new_value; } } else i = 0; return Value; }
A、方法:
B、优点:
C、缺点:
// 限幅消抖滤波法 #define FILTER_A 1 #define FILTER_N 5 int i = 0; int Filter() { int NewValue; int new_value; NewValue = Get_AD(); if(((NewValue - Value) > FILTER_A) || ((Value - NewValue) > FILTER_A)) new_value = Value; else new_value = NewValue; if(Value != new_value) { i++; if(i > FILTER_N) { i = 0; Value = new_value; } } else i = 0; return Value; }