DSP软件开发中常用的8种软件滤波方法示例程序分享
假定从8位AD中读取数据(如果是更高位的AD可定义数据类型为int),子程序为get_ad();
1、限副滤波
/* A值可根据实际情况调整
value为有效值,new_value为当前采样值
滤波程序返回有效的实际值 */
- #define A 10
- char value;
- char filter()
- {
- char new_value;
- new_value = get_ad();
- if ( ( new_value - value > A ) || ( value - new_value > A )
- return value;
- return new_value;
- }
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2、中位值滤波法
/* 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];
- }
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3、算术平均滤波法
- #define N 12
- char filter()
- {
- int sum = 0;
- for ( count="0";count<N;count++)
- {
- sum + = get_ad();
- delay();
- }
- return (char)(sum/N);
- }
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4、递推平均滤波法(又称滑动平均滤波法)- #define N 12
- char value_buf[N];
- char i="0";
- char filter()
- {
- char count;
- int sum=0;
- value_buf[i++] = get_ad();
- if ( i == N ) i = 0;
- for ( count="0";count<N,count++)
- sum = value_buf[count];
- return (char)(sum/N);
- }
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- #define N 12
- char filter()
- {
- char count,i,j;
- char value_buf[N];
- int sum=0;
- 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;
- }
- }
- }
- for(count=1;count<N-1;count++)
- sum += value[count];
- return (char)(sum/(N-2));
- }
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6、一阶滞后滤波法
/* 为加快程序处理速度假定基数为100,a=0~100 */
- #define a 50
- char value;
- char filter()
- {
- char new_value;
- new_value = get_ad();
- return (100-a)*value + a*new_value;
- }
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7、加权递推平均滤波法
/* coe数组为加权系数表,存在程序存储区。*/
- #define N 12
- char code coe[N] = {1,2,3,4,5,6,7,8,9,10,11,12};
- char code sum_coe = 1+2+3+4+5+6+7+8+9+10+11+12;
- char filter()
- {
- char count;
- char value_buf[N];
- int sum=0;
- for (count=0,count<N;count++)
- {
- value_buf[count] = get_ad();
- delay();
- }
- for (count=0,count<N;count++)
- sum += value_buf[count]*coe[count];
- return (char)(sum/sum_coe);
- }
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8、消抖滤波法
- #define N 12
- char filter()
- {
- char count="0";
- char new_value;
- new_value = get_ad();
- while (value !=new_value);
- {
- count++;
- if (count>=N) return new_value;
- delay();
- new_value = get_ad();
- }
- return value;
- }
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