说明¶

说明

相关性是信号处理中的一个重要概念，通常用于分析信号之间的相似性或依赖性。它在许多应用中都很有用，例如模式识别、时间序列分析和信号检测。

滑动相关¶

数学原理¶

tiny_corr_f32¶

/**
 * @name: tiny_corr_f32
 * @brief Correlation function
 *
 * @param Signal: input signal array
 * @param siglen: length of the signal array
 * @param Pattern: input pattern array
 * @param patlen: length of the pattern array
 * @param dest: output array for the correlation result
 *
 * @return tiny_error_t
 */
tiny_error_t tiny_corr_f32(const float *Signal, const int siglen, const float *Pattern, const int patlen, float *dest)
{
    if (NULL == Signal || NULL == Pattern || NULL == dest)
    {
        return TINY_ERR_DSP_NULL_POINTER;
    }

    if (siglen < patlen) // signal length shoudl be greater than pattern length
    {
        return TINY_ERR_DSP_MISMATCH;
    }

#if MCU_PLATFORM_SELECTED == MCU_PLATFORM_ESP32
    dsps_corr_f32(Signal, siglen, Pattern, patlen, dest);
#else

    for (size_t n = 0; n <= (siglen - patlen); n++)
    {
        float k_corr = 0;
        for (size_t m = 0; m < patlen; m++)
        {
            k_corr += Signal[n + m] * Pattern[m];
        }
        dest[n] = k_corr;
    }

#endif

    return TINY_OK;
}

描述: 计算信号和模式之间的相关性。

特点

支持平台加速

参数:

Signal: 输入信号数组
siglen: 信号数组的长度
Pattern: 输入模式数组
patlen: 模式数组的长度
dest: 输出数组，用于存储相关性结果

返回值: 返回成功或错误代码。

交叉相关函数¶

数学原理¶

互相关计算公式为：

\[ R_{xy}[n] = \sum_{k} x[k] \cdot y[k + n] \]

其中：

\( x \) 为信号序列，长度为 \( L_x \)
\( y \) 为卷积核（Kernel），长度为 \( L_y \)
\( n \in [0, L_x + L_y - 2] \)

输出长度计算：

\[ L_{\text{out}} = L_x + L_y - 1 \]

tiny_ccorr_f32¶

/**
 * @name: tiny_ccorr_f32
 * @brief Cross-correlation function
 *
 * @param Signal: input signal array
 * @param siglen: length of the signal array
 * @param Kernel: input kernel array
 * @param kernlen: length of the kernel array
 * @param corrvout: output array for the cross-correlation result
 *
 * @return tiny_error_t
 */
tiny_error_t tiny_ccorr_f32(const float *Signal, const int siglen, const float *Kernel, const int kernlen, float *corrvout)
{
    if (NULL == Signal || NULL == Kernel || NULL == corrvout)
    {
        return TINY_ERR_DSP_NULL_POINTER;
    }

    float *sig = (float *)Signal;
    float *kern = (float *)Kernel;
    int lsig = siglen;
    int lkern = kernlen;

    // swap signal and kernel if needed
    if (siglen < kernlen)
    {
        sig = (float *)Kernel;
        kern = (float *)Signal;
        lsig = kernlen;
        lkern = siglen;
    }

#if MCU_PLATFORM_SELECTED == MCU_PLATFORM_ESP32
    dsps_ccorr_f32(Signal, siglen, Kernel, kernlen, corrvout);
#else
    // stage I
    for (int n = 0; n < lkern; n++)
    {
        size_t k;
        size_t kmin = lkern - 1 - n;
        corrvout[n] = 0;

        for (k = 0; k <= n; k++)
        {
            corrvout[n] += sig[k] * kern[kmin + k];
        }
    }

    // stage II
    for (int n = lkern; n < lsig; n++)
    {
        size_t kmin, kmax, k;

        corrvout[n] = 0;

        kmin = n - lkern + 1;
        kmax = n;
        for (k = kmin; k <= kmax; k++)
        {
            corrvout[n] += sig[k] * kern[k - kmin];
        }
    }

    // stage III
    for (int n = lsig; n < lsig + lkern - 1; n++)
    {
        size_t kmin, kmax, k;

        corrvout[n] = 0;

        kmin = n - lkern + 1;
        kmax = lsig - 1;

        for (k = kmin; k <= kmax; k++)
        {
            corrvout[n] += sig[k] * kern[k - kmin];
        }
    }
#endif
    return TINY_OK;
}

描述: 计算信号和卷积核之间的互相关性。

特点

支持平台加速

参数:

Signal: 输入信号数组
siglen: 信号数组的长度
Kernel: 输入卷积核数组
kernlen: 卷积核数组的长度
corrvout: 输出数组，用于存储互相关性结果

返回值: 返回成功或错误代码。