解决cv::dilate处理后的图像边缘像素出现异常值的问题

cv::dilate处理后的图像莫名出现黑边或者白边.最后发现是borderType参数不合适导致的.
通过将第六个参数(borderType)改成cv::BORDER_ISOLATED解决问题.
如下:

int kernelSize = 3;  // 可以根据需要调整，如5,7等
cv::Mat kernel = cv::getStructuringElement(cv::MORPH_RECT, 
                                          cv::Size(kernelSize, kernelSize));
cv::dilate(src, dst, kernel, cv::Point(-1, -1), 1, cv::BORDER_ISOLATED);

此API的参数说明:

/** @brief Dilates an image by using a specific structuring element.

The function dilates the source image using the specified structuring element that determines the
shape of a pixel neighborhood over which the maximum is taken:
\f[\texttt{dst} (x,y) =  \max _{(x',y'):  \, \texttt{element} (x',y') \ne0 } \texttt{src} (x+x',y+y')\f]

The function supports the in-place mode. Dilation can be applied several ( iterations ) times. In
case of multi-channel images, each channel is processed independently.

@param src input image; the number of channels can be arbitrary, but the depth should be one of
CV_8U, CV_16U, CV_16S, CV_32F or CV_64F.
@param dst output image of the same size and type as src.
@param kernel structuring element used for dilation; if elemenat=Mat(), a 3 x 3 rectangular
structuring element is used. Kernel can be created using #getStructuringElement
@param anchor position of the anchor within the element; default value (-1, -1) means that the
anchor is at the element center.
@param iterations number of times dilation is applied.
@param borderType pixel extrapolation method, see #BorderTypes. #BORDER_WRAP is not suported.
@param borderValue border value in case of a constant border
@sa  erode, morphologyEx, getStructuringElement
 */
CV_EXPORTS_W void dilate( InputArray src, OutputArray dst, InputArray kernel,
                          Point anchor = Point(-1,-1), int iterations = 1,
                          int borderType = BORDER_CONSTANT,
                          const Scalar& borderValue = morphologyDefaultBorderValue() );