简单的滑动平均滤波器

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楼主 | 2022-11-23 21:53 | 只看该作者回帖奖励

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滤波, 滤波器

滑动平均滤波器在工程中十分常见，这里用C语言设计一个灵活的滑动滤波器库函数，十分简单易用，并且滤波器不使用for循环，大大减少了代码运行时间。

并且滤波器可以使用malloc自动申请内存，也可以不使用malloc函数，然后自己添加数据cache.

滤波效果验证

在长度为10000的幅值为1的正弦波上叠加幅值为1均值为0的噪声，滑动窗口为100，效果如下：

代码如下：

h文件:

复制

#ifndef _SLIDING_AVERAGE_FILTER_H

#define _SLIDING_AVERAGE_FILTER_H



#define SLIDING_AVERAGE_FILTER_USEING_STDLIB  1



typedef struct _sliding_average_filter

{

    int w_size;

    int head;

    float sum;

    float *cache;

} SlidAveFilterObj;



void sliding_average_filter_init(SlidAveFilterObj *filter, int w_size);



float sliding_average_filter(SlidAveFilterObj *filter, float k);



int sliding_average_filter_cache_add(SlidAveFilterObj *filter, float *cache, int w_size);



#endif

复制

#include "sliding_average_filter.h"



#ifdef SLIDING_AVERAGE_FILTER_USEING_STDLIB

 #include <stdlib.h>

 #include <string.h>

#endif





void sliding_average_filter_init(SlidAveFilterObj *filter, int w_size)

{

    #ifdef SLIDING_AVERAGE_FILTER_USEING_STDLIB

     filter->cache = (float*)malloc(sizeof(float) * w_size);

     memset(filter->cache, 0, sizeof(float) * w_size);

    #endif

    

    filter->w_size = w_size;

    filter->sum = 0;

    filter->head = 0;

}



float sliding_average_filter(SlidAveFilterObj *filter, float k)

{

    filter->cache[filter->head] = k;

    filter->head = (filter->head + 1) % filter->w_size;

    filter->sum = filter->sum + k - filter->cache[filter->head];



    return (filter->sum / (float)filter->w_size);

}



int sliding_average_filter_cache_add(SlidAveFilterObj *filter, float *cache, int w_size)

{

    filter->cache = cache;

    filter->w_size = w_size;

    return 0;

}