OpenCV image erosion, blur, edge detection {erode(), blur(), canny()}

1. Image Corrosion

The function is:               

CV_EXPORTS_W void erode( InputArray src, OutputArray dst, InputArray kernel,
                         Point anchor=Point(-1,-1), int iterations=1,
                         int borderType=BORDER_CONSTANT,const Scalar& borderValue=morphologyDefaultBorderValue() );  

2. The image is blurry

The function is

//! a synonym for normalized box filter
CV_EXPORTS_W void blur( InputArray src, OutputArray dst,
                        Size ksize, Point anchor=Point(-1,-1),
                        int borderType=BORDER_DEFAULT );

3. Edge detection

The function is

//! applies Canny edge detector and produces the edge map.
CV_EXPORTS_W void Canny( InputArray image, OutputArray edges,
                         double threshold1, double threshold2,
                         int apertureSize=3, bool L2gradient=false );

Fourth, the test code

#pragma once

class BaseDeal
{
public:
	BaseDeal();
	//image erosion
	void DealErode(std::string strFileName);
	//image is blurry
	void DealBlur(std::string strFileName);
	//image edge detection
	void DealCanny(std::string strFileName);
};

#include "stdafx.h"
#include "BaseDeal.h"

BaseDeal::BaseDeal()
{

}

void BaseDeal::DealErode(std::string strFileName)
{
	Mat srcMat = imread(strFileName);
	imshow("Original image", srcMat);
	Mat matElement = getStructuringElement(MORPH_RECT, Size(15,15));
	Mat destMat;
	erode (srcMat, destMat, matElement);
	imshow("腐蚀", destMat);
	waitKey(1000);
}

void BaseDeal::DealBlur(std::string strFileName)
{
	Mat srcImage = imread (strFileName);
	imshow("Mean filter{original image}", srcImage);

	Mat destImage;
	blur (srcImage, destImage, Size (7,7));

	imshow("Mean filter{effect image}", destImage);
}

void BaseDeal::DealCanny(std::string strFileName)
{
	Mat srcImage = imread (strFileName);
	imshow("Original image{edge detection}", srcImage);
	Mat matEdge; //Edge Mat
	Mat matGrayImage;//Grayscale image Mat
	//Convert original image to grayscale image
	cvtColor(srcImage, matGrayImage, CV_RGB2GRAY/*CV_BayerRG2GRAY*/);
	//Use 3*3 kernel noise reduction
	blur(matGrayImage, matEdge, Size(3,3));

	//Run CANNY operator
	Canny(matEdge, matEdge, 3,9,3);

	imshow("Edge detection renderings", matEdge);
	waitKey(1000);
}

main function

#include "stdafx.h"
#include "BaseDeal.h"

intmain()
{
	BaseDeal base;
	//base.DealErode("F:/1.jpg");
	//base.DealBlur("F:/1.jpg");
	base.DealCanny("F:/2.jpg");
	waitKey(6000);
}

result image

Image erosion:

Image is blurry:

Edge detection:

This is because

cvtColor(srcImage, matGrayImage, CV_BayerRG2GRAY); CV_BayerRG2GRAY>7, the program will crash, maybe this value is too large and the size of the image will become larger, the final result picture shows that only a small part of the edge detection is detected, and a large part is lost ;

Correct image result:

The cvtColor function has bugs in OpenCV, CV_EXPORTS_W void cvtColor( InputArray src, OutputArray dst, int code, int dstCn=0 ); The value of code cannot exceed 7, that is, the value of 8 will crash.