Canny边缘检测
C++代码
#include<iostream>
#include<opencv2/opencv.hpp>
#include<mex.h>
/*
nlhs 输出参数个数
plhs 输出参数指针
nrhs 输入参数个数
prhs 输入参数指针
*/
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
//获取输入矩阵的行、列
int rows = mxGetM(prhs[0]);
int cols = mxGetN(prhs[0]);
//获取输入图像的指针
unsigned char* img_ptr = (unsigned char*)mxGetPr(prhs[0]);
//实例化Mat, 注意，matlab中数据是按列存储的，但是C++ opencv中图像是按行存放的，因此
//在构造图像时候，构造为图像的转置，然后对图像进行一次转置就得到opencv中真实图像
cv::Mat image = cv::Mat(cols, rows, CV_8UC1, img_ptr);
cv::Mat image_;
cv::transpose(image, image_);
//Canny边缘检测
cv::Mat dst;
cv::Canny(image_, dst, 20, 50);
plhs[0] = mxCreateNumericMatrix_700(rows, cols, mxClassID::mxUINT8_CLASS, mxComplexity::mxREAL);
cv::Mat dst_ = cv::Mat(rows, cols, CV_8UC1, (unsigned char*)(mxGetPr(plhs[0])));
cv::transpose(dst, dst_);
//cv::imshow("canny", dst);
//cv::waitKey(0);
}
matlab测试代码
clear;
clc;
image = imread('F:\\lena\\lena_gray.jpg');
canny_img = compute_canny(image);
imshow(canny_img)
image.png
Sobel边缘检测
C++代码
#include<opencv2/opencv.hpp>
#include<mex.h>
#include<opencvmex.hpp>
//https://blog.csdn.net/shaoxiaohu1/article/details/8269690
//https://blog.csdn.net/u012978091/article/details/51138505
void mexFunction(
int nlhs, /* number of expected outputs */
mxArray *plhs[], /* array of pointers to output arguments */
int nrhs, /* number of inputs */
const mxArray *prhs[] /* array of pointers to input arguments */
) {
/*
判断matlab传入的数据类型，图像要求uint8
*/
if (!mxIsUint8(prhs[0])) {
std::runtime_error("Image data must be uint8 type!");
}
/*
将matlab中的图像转换为opencv Mat对象指针
*/
cv::Ptr<cv::Mat> image = ocvMxArrayToImage_uint8(prhs[0]);
/*
Sobel
*/
cv::Mat dx, dy;
cv::Sobel(*image.get(), dx, -1, 1, 0);
cv::Sobel(*image.get(), dy, -1, 0, 1);
/*
oepncv Mat 转换为matlab中mxArray
*/
plhs[0] = ocvMxArrayFromMat_uint8(dx);
plhs[1] = ocvMxArrayFromMat_uint8(dy);
}
matlab测试代码
clear;
clc;
image = imread('F:\\lena\\lena_gray.jpg');
[sobel_dx_img, sobel_dy_img] = compute_sobel(image);
figure(2)
subplot(1,3,1)
imshow(image)
subplot(1,3,2)
imshow(sobel_dx_img)
subplot(1,3,3)
imshow(sobel_dy_img)
image.png
