006】形態學開運算、閉運算、形態學梯度、頂帽、黑帽及OpenCV實現
阿新 • • 發佈：2019-01-25
一、開發環境
1、Windows 7 64位 SP1 旗艦版；
2、Qt 5.10.1；
3、OpenCV 3.4.1
二、形態學運算
2.1 開運算
腐蝕與膨脹作為形態學的基本操作，經過組合後可以很容易的實現更高一級的形態學運算。開運算即是先腐蝕後膨脹的得到的結果，即dst = open(src, element) = dilate(erode(src, element))。
開運算可以消除區域性小的白色雜點，在纖細點處分離物體，並且在平滑較大物體的邊界的同時不明顯改變其面積。
2.2 閉運算
閉運算過程與開運算過程相反，其是先膨脹後腐蝕的過程，可以消除影象中的小黑點，dst = close(src, element) = erode(dilate(src, element))。。
2.3 形態學梯度
形態學梯度是膨脹圖與腐蝕圖之差，其數學表示式為：dst = morph_grad(src, element) = dilate(src, element) - erode(src, element)。對二值影象進行形態學梯度運算，可以突出物體邊緣。通常，我們採用形態學梯度來保留物體的邊緣輪廓。2.4 頂帽
頂帽運算又常稱為禮帽運算，是原始影象與影象開運算結果之差，其數學表示式為：dst = tophat(src, element) = src - open(src, element)。頂帽運算通常用來分離比鄰近點亮一些的斑塊，在一幅影象具有大幅背景且微小細節比較有規律的情況下，頂帽運算可以用來進行背景提取。
2.5 黑帽
黑帽運算是影象閉運算結果與原始影象之差，其數學表示式為：dst = tophat(src, element) = close(src, element) - src。黑帽運算通常用來分離比鄰近點暗一些的斑塊，可以突出比原始圖輪廓周圍區域更暗的區域。
三、OpenCV實現
cv::morphologyEx()函式綜合形態學大部分運算，可以實現形態學腐蝕、膨脹、開運算、閉運算、形態學梯度、頂帽、黑帽等。cv::morphologyEx()宣告如下：
void morphologyEx( InputArray src, OutputArray dst, int op, InputArray kernel, Point anchor = Point(-1,-1), int iterations = 1, int borderType = BORDER_CONSTANT, const Scalar& borderValue = morphologyDefaultBorderValue() ); @param src Source image. The number of channels can be arbitrary. The depth should be one of CV_8U, CV_16U, CV_16S, CV_32F or CV_64F. @param dst Destination image of the same size and type as source image. @param op Type of a morphological operation, see #MorphTypes @param kernel Structuring element. It can be created using #getStructuringElement. @param anchor Anchor position with the kernel. Negative values mean that the anchor is at the kernel center. @param iterations Number of times erosion and dilation are applied. @param borderType Pixel extrapolation method, see #BorderTypes @param borderValue Border value in case of a constant border. The default value has a special meaning.
cv::morphologyEx()函式在OpenCV_3.4.1_Source\modules\imgproc\src\morph.cpp檔案中定義，其中OpenCV_3.4.1_Source為原始碼下載解壓後的資料夾。morphologyEx()函式定義如下：
static bool ocl_morphologyEx(InputArray _src, OutputArray _dst, int op,
InputArray kernel, Point anchor, int iterations,
int borderType, const Scalar& borderValue)
{
_dst.createSameSize(_src, _src.type());
bool submat = _dst.isSubmatrix();
UMat temp;
_OutputArray _temp = submat ? _dst : _OutputArray(temp);
switch( op )
{
case MORPH_ERODE:
if (!ocl_morphOp( _src, _dst, kernel, anchor, iterations, MORPH_ERODE, borderType, borderValue ))
return false;
break;
case MORPH_DILATE:
if (!ocl_morphOp( _src, _dst, kernel, anchor, iterations, MORPH_DILATE, borderType, borderValue ))
return false;
break;
case MORPH_OPEN:
if (!ocl_morphOp( _src, _temp, kernel, anchor, iterations, MORPH_ERODE, borderType, borderValue ))
return false;
if (!ocl_morphOp( _temp, _dst, kernel, anchor, iterations, MORPH_DILATE, borderType, borderValue ))
return false;
break;
case MORPH_CLOSE:
if (!ocl_morphOp( _src, _temp, kernel, anchor, iterations, MORPH_DILATE, borderType, borderValue ))
return false;
if (!ocl_morphOp( _temp, _dst, kernel, anchor, iterations, MORPH_ERODE, borderType, borderValue ))
return false;
break;
case MORPH_GRADIENT:
if (!ocl_morphOp( _src, temp, kernel, anchor, iterations, MORPH_ERODE, borderType, borderValue ))
return false;
if (!ocl_morphOp( _src, _dst, kernel, anchor, iterations, MORPH_DILATE, borderType, borderValue, MORPH_GRADIENT, temp ))
return false;
break;
case MORPH_TOPHAT:
if (!ocl_morphOp( _src, _temp, kernel, anchor, iterations, MORPH_ERODE, borderType, borderValue ))
return false;
if (!ocl_morphOp( _temp, _dst, kernel, anchor, iterations, MORPH_DILATE, borderType, borderValue, MORPH_TOPHAT, _src ))
return false;
break;
case MORPH_BLACKHAT:
if (!ocl_morphOp( _src, _temp, kernel, anchor, iterations, MORPH_DILATE, borderType, borderValue ))
return false;
if (!ocl_morphOp( _temp, _dst, kernel, anchor, iterations, MORPH_ERODE, borderType, borderValue, MORPH_BLACKHAT, _src ))
return false;
break;
default:
CV_Error( CV_StsBadArg, "unknown morphological operation" );
}
return true;
}其中，引數op用於選擇形態學運算型別，這裡用到的有下面幾個：
1）MORPH_OPEN：開運算
2）MORPH_CLOSE：閉運算
3）MORPH_GRADIENT：形態學梯度
4）MORPH_TOPHAT：頂帽
5）MORPH_BLACKHAP：黑帽
6）MORPH_ERODE：腐蝕
7）MORPH_DILATE：膨脹
四、綜合示例及演示
4.1 介面設計
介面設計如圖1所示。
圖1 介面設計
4.2 程式原始碼
1、mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include "opencv2/opencv.hpp"
using namespace cv;
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private:
Ui::MainWindow *ui;
int m_KernelValue;
bool m_isOpenFile;
int m_typeCurSel;
Mat m_srcImage;
Mat m_dstImage;
public:
void on_MorphologyEx(int typeSel);
private slots:
void on_pushButton_OpenImg_clicked();
void on_comboBox_Type_currentIndexChanged(int index);
void on_horizontalSlider_KernelValue_valueChanged(int value);
};
#endif // MAINWINDOW_H2、mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QFileDialog>
#include <QMessageBox>
#define KERNEL_MIN_VALUE 0
#define KERNEL_MAX_VALUE 40
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
setWindowTitle(tr("Qt_OpenCV形態學運算"));
//初始化變數
m_KernelValue = 15;
m_isOpenFile = false;
m_typeCurSel = 0;
//初始化控制元件
ui->horizontalSlider_KernelValue->setMinimum(KERNEL_MIN_VALUE);
ui->horizontalSlider_KernelValue->setMaximum(KERNEL_MAX_VALUE);
ui->horizontalSlider_KernelValue->setValue(m_KernelValue);
ui->label_KernelValue->setText(QString::number(m_KernelValue));
ui->comboBox_Type->insertItem(0, "膨脹");
ui->comboBox_Type->insertItem(1, "腐蝕");
ui->comboBox_Type->insertItem(2, "開運算");
ui->comboBox_Type->insertItem(3, "閉運算");
ui->comboBox_Type->insertItem(4, "形態學梯度");
ui->comboBox_Type->insertItem(5, "頂帽");
ui->comboBox_Type->insertItem(6, "黑帽");
ui->comboBox_Type->setCurrentIndex(m_typeCurSel);
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::on_pushButton_OpenImg_clicked()
{
QString fileName = QFileDialog::getOpenFileName(this,tr("Open Image"),".",tr("Image File(*.png *.jpg *.jpeg *.bmp)"));
if (fileName.isEmpty())
{
return;
}
m_srcImage = imread(fileName.toLatin1().data());//讀取圖片資料
if (!m_srcImage.data)
{
m_isOpenFile = false;
QMessageBox box(QMessageBox::Critical, "開啟影象", "讀取影象檔案失敗！請重新開啟．");
box.setStandardButtons(QMessageBox::Ok);
box.setButtonText(QMessageBox::Ok, QString("確定"));
box.exec();
return;
}
m_isOpenFile = true;//修改開啟標誌
Mat disImageTemp;
cvtColor(m_srcImage, disImageTemp, COLOR_BGR2RGB);//影象格式轉換
QImage disImage = QImage((const unsigned char*)(disImageTemp.data),disImageTemp.cols,disImageTemp.rows,QImage::Format_RGB888);
ui->label_OriginalImg->setPixmap(QPixmap::fromImage(disImage.scaled(ui->label_OriginalImg->width(), ui->label_OriginalImg->height(), Qt::KeepAspectRatio)));
on_MorphologyEx(m_typeCurSel);
}
void MainWindow::on_horizontalSlider_KernelValue_valueChanged(int value)
{
if (m_isOpenFile)
{
m_KernelValue = value;
ui->label_KernelValue->setText(QString::number(m_KernelValue));
on_MorphologyEx(m_typeCurSel);
}
}
void MainWindow::on_MorphologyEx(int typeSel)
{
//獲取核心形狀和尺寸
Mat element = getStructuringElement(MORPH_RECT, Size(m_KernelValue * 2 + 1, m_KernelValue * 2 + 1), Point(m_KernelValue, m_KernelValue));
//腐蝕操作
switch (typeSel) {
case 0:
morphologyEx(m_srcImage, m_dstImage, MORPH_DILATE, element);
break;
case 1:
morphologyEx(m_srcImage, m_dstImage, MORPH_ERODE, element);
break;
case 2:
morphologyEx(m_srcImage, m_dstImage, MORPH_OPEN, element);
break;
case 3:
morphologyEx(m_srcImage, m_dstImage, MORPH_CLOSE, element);
break;
case 4:
morphologyEx(m_srcImage, m_dstImage, MORPH_GRADIENT, element);
break;
case 5:
morphologyEx(m_srcImage, m_dstImage, MORPH_TOPHAT, element);
break;
case 6:
morphologyEx(m_srcImage, m_dstImage, MORPH_BLACKHAT, element);
break;
default:
break;
}
//顯示
cvtColor(m_dstImage, m_dstImage, COLOR_BGR2RGB);//影象格式轉換
QImage disImage = QImage((const unsigned char*)(m_dstImage.data),m_dstImage.cols,m_dstImage.rows,QImage::Format_RGB888);
ui->label_ProcessedImg->setPixmap(QPixmap::fromImage(disImage.scaled(ui->label_ProcessedImg->width(), ui->label_ProcessedImg->height(), Qt::KeepAspectRatio)));
}
void MainWindow::on_comboBox_Type_currentIndexChanged(int index)
{
m_typeCurSel = index;
if (m_isOpenFile)
{
on_MorphologyEx(m_typeCurSel);
}
}4.3 執行效果
執行效果如下：
圖2 膨脹
圖3 腐蝕
圖4 開運算
圖5 閉運算
圖6 形態學梯度（1）
圖7 形態學梯度（2）
圖8 頂帽
圖9 黑帽