• 数学之路-python计算实战(21)-机器视觉-拉普拉斯线性滤波


    拉普拉斯线性滤波,.边缘检測

      Laplacian

    Calculates the Laplacian of an image.

    C++: void Laplacian(InputArray src, OutputArray dst, int ddepth, int ksize=1, double scale=1, double delta=0, int borderType=BORDER_DEFAULT )
    Python: cv2.Laplacian(src, ddepth[, dst[, ksize[, scale[, delta[, borderType]]]]]) → dst
    C: void cvLaplace(const CvArr* src, CvArr* dst, int aperture_size=3 )
    Python: cv.Laplace(src, dst, apertureSize=3) → None
    Parameters:
    • src – Source image.
    • dst – Destination image of the same size and the same number of channels as src .
    • ddepth – Desired depth of the destination image.
    • ksize – Aperture size used to compute the second-derivative filters. See getDerivKernels() for details. The size must be positive and odd.
    • scale – Optional scale factor for the computed Laplacian values. By default, no scaling is applied. See getDerivKernels() for details.
    • delta – Optional delta value that is added to the results prior to storing them in dst .
    • borderType – Pixel extrapolation method. SeeborderInterpolate() for details.

    The function calculates the Laplacian of the source image by adding up the second x and y derivatives calculated using the Sobel operator:

    	exttt{dst} =  Delta 	exttt{src} =  frac{partial^2 	exttt{src}}{partial x^2} +  frac{partial^2 	exttt{src}}{partial y^2}

    This is done when ksize > 1 . When ksize == 1 , the Laplacian is computed by filtering the image with the following 3 	imes 3 aperture:

    vecthreethree {0}{1}{0}{1}{-4}{1}{0}{1}{0}


    Laplace

    计算图像的 Laplacian 变换

    void cvLaplace( const CvArr* src, CvArr* dst, int aperture_size=3 );
    src
    输入图像.
    dst
    输出图像.
    aperture_size
    核大小 (与 cvSobel 中定义一样).

    函数 cvLaplace 计算输入图像的 Laplacian变换,方法是先用 sobel 算子计算二阶 x- 和 y- 差分,再求和:


    对 aperture_size=1 则给出最快计算结果,相当于对图像採用例如以下内核做卷积:




    本博客全部内容是原创,假设转载请注明来源

    http://blog.csdn.net/myhaspl/


    # -*- coding: utf-8 -*-   
    #线性锐化滤波,拉普拉斯图像变换
    #code:myhaspl@myhaspl.com
    import cv2
    
    fn="test6.jpg"
    myimg=cv2.imread(fn)
    img=cv2.cvtColor(myimg,cv2.COLOR_BGR2GRAY)
    
    jgimg=cv2.Laplacian(img,-1)
    cv2.imshow('src',img)
    cv2.imshow('dst',jgimg)
    cv2.waitKey()
    cv2.destroyAllWindows()


    本博客全部内容是原创,假设转载请注明来源

    http://blog.csdn.net/myhaspl/

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  • 原文地址:https://www.cnblogs.com/mthoutai/p/6881554.html
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