叁[3]，感兴趣区域ROI

1，简介

ROI，感兴趣区域（region of interest)，截取图像

2，获取方法

方法1：使用Rect

cv::Mat src=cv::imread("*.bmp");//读取原图
cv::Mat matROI = src(cv::Rect(100,200,50,100));//截取原图，矩形区域

方法2：使用Range

cv::Mat src=cv::imread("*.bmp");//读取原图
cv::Mat matROI = src(cv::Range(100,150),cv::Range(200,300));//截取原图，矩形区域

3，图像叠加

注：Mat类型中copyTo函数和clone函数和赋值操作符操作。

3.1.1，代码1(copyTo,类型+尺寸相同)

stringstream ss;
cv::Mat src = cv::imread("BK5.jpg");//3通道彩图
cv::Mat* srcPointer = &src;
cv::Mat srcROI = src(cv::Rect(src.rows / 2 - 100, src.cols / 2 - 100, 100, 100));
ss << "src.isContinuous=" << src.isContinuous() <
ss << "src.type=" << src.type() << endl;
ss << "srcROI - Memery Address:" << &srcROI << endl;
cv::Mat srvROI_End = cv::Mat(srcROI.rows, srcROI.cols, srcROI.type(), cv::Scalar(0));
srvROI_End.copyTo(srcROI);
ss << "srcROI - Memery Address:" << &srcROI << endl;
cv::imshow("srcROI", srcROI);
cv::imshow("src-Result", src);
qDebug() << ss.str().c_str();

指针版

stringstream ss;
cv::Mat src = cv::imread("BK5.jpg");//3通道彩图
cv::Mat srcROI = src(cv::Rect(src.rows / 2 - 100, src.cols / 2 - 100, 100, 100));
cv::Mat* srcROIPointer = &srcROI;
ss << "src.isContinuous=" << src.isContinuous() <
ss << "src.type=" << src.type() << endl;
ss << "srcROI - Memery Address:" << &srcROI << endl;
cv::Mat srcROI_End = cv::Mat(srcROIPointer->rows, srcROIPointer->cols, srcROIPointer->type(), cv::Scalar(0));
srcROI_End.copyTo(*srcROIPointer);
ss << "srcROI - Memery Address:" << &srcROI << endl;
cv::imshow("srcROI", *srcROIPointer);
cv::imshow("src-Result", src);
qDebug() << ss.str().c_str();

3.1.2，打印结果

src.isContinuous=1
src.type=16
srcROI - Memery Address:000000EF810FF980
srcROI - Memery Address:000000EF810FF980

3.1.3，图片显示结果

原图的ROI区域，图片被处理。

3.1.4，结论

类型/尺寸相同，copyTo时，ROI图元修改会生效到原图中。

3.2.1，代码2(copyTo,类型不同，尺寸相同)

stringstream ss;
cv::Mat src = cv::imread("BK5.jpg");//3通道彩图
cv::Mat* srcPointer = &src;
cv::Mat srcROI = src(cv::Rect(src.rows / 2 - 100, src.cols / 2 - 100, 100, 100));
ss << "src.isContinuous=" << src.isContinuous() <
ss << "src.type=" << src.type() << endl;
ss << "srcROI - Memery Address:" << &srcROI << endl;
cv::Mat srvROI_End = cv::Mat(srcROI.rows, srcROI.cols, CV_8UC1, cv::Scalar(0));
srvROI_End.copyTo(srcROI);
ss << "srcROI - Memery Address:" << &srcROI << endl;
cv::imshow("srcROI", srcROI);
cv::imshow("src-Result", src);
qDebug() << ss.str().c_str();

3.2.2，打印结果

src.isContinuous=1
src.type=16
srcROI - Memery Address:000000EF810FF980
srcROI - Memery Address:000000EF810FF980

3.2.3，图片显示结果

原图的ROI区域，无处理效果。

3.2.4，结论

类型不同，尺寸相同，copyTo时，ROI图元不会生效到原图中。

3.3.1，代码2(copyTo,类型不同，尺寸相同)

stringstream ss;
cv::Mat src = cv::imread("BK5.jpg");//3通道彩图
cv::Mat* srcPointer = &src;
cv::Mat srcROI = src(cv::Rect(src.rows / 2 - 100, src.cols / 2 - 100, 100, 100));
ss << "src.isContinuous=" << src.isContinuous() <
ss << "src.type=" << src.type() << endl;
ss << "srcROI - Memery Address:" << &srcROI << endl;
cv::Mat srvROI_End = cv::Mat(srcROI.rows+100, srcROI.cols+100, srcROI.type(), cv::Scalar(0));
srvROI_End.copyTo(srcROI);
ss << "srcROI - Memery Address:" << &srcROI << endl;
cv::imshow("srcROI", srcROI);
cv::imshow("src-Result", src);
qDebug() << ss.str().c_str();

3.3.2，打印结果

src.isContinuous=1
src.type=16
srcROI - Memery Address:000000FC6E10F8E0
srcROI - Memery Address:000000FC6E10F8E0

3.3.3，图片显示结果

原图的ROI区域，无处理效果。

3.3.4，结论

类型相同，尺寸不同，copyTo时，ROI图元不会生效到原图中。

3.4.1，代码2(clone,类型+尺寸相同)

stringstream ss;
cv::Mat src = cv::imread("BK5.jpg");//3通道彩图
cv::Mat* srcPointer = &src;
cv::Mat srcROI = src(cv::Rect(src.rows / 2 - 100, src.cols / 2 - 100, 100, 100));
ss << "src.isContinuous=" << src.isContinuous() <
ss << "src.type=" << src.type() << endl;
ss << "srcROI - Memery Address:" << &srcROI << endl;
cv::Mat srcROI_End = cv::Mat(srcROI.rows, srcROI.cols, srcROI.type(), cv::Scalar(0));
srcROI = srcROI_End.clone();
ss << "srcROI - Memery Address:" << &srcROI << endl;
cv::imshow("srcROI", srcROI);
cv::imshow("src-Result", src);
qDebug() << ss.str().c_str();

3.4.2，打印结果

src.isContinuous=1
src.type=16
srcROI - Memery Address:00000006268FF560
srcROI - Memery Address:00000006268FF560

3.4.3，图片显示结果

原图的ROI区域，无处理效果。

3.4.4，结论

clone时，ROI图元不会生效到原图中。

4，制作掩膜

4.1.1，代码1(copyTo，mask)

绿色掩膜

    stringstream ss;
    cv::Mat src = cv::imread("BK5.jpg");//3通道彩图
    cv::Mat srcROI = src(cv::Rect(src.rows / 2 - 100, src.cols / 2 - 100, 100, 100));
    cv::Mat* srcROIPointer = &srcROI;
    ss << "src.isContinuous=" << src.isContinuous() << endl;
    ss << "src.type=" << src.type() << endl;
    ss << "srcROI - Memery Address:" << &srcROI << endl;
    cv::Mat srcROI_End = cv::Mat(srcROIPointer->rows, srcROIPointer->cols, srcROIPointer->type(), cv::Scalar(0, 255, 0));
    cv::Mat srcROI_Mask = cv::Mat(srcROIPointer->rows, srcROIPointer->cols, srcROIPointer->type(), cv::Scalar(0, 255, 0));
    srcROI_End.copyTo(*srcROIPointer, srcROI_Mask);
    ss << "srcROI - Memery Address:" << &srcROI << endl;
    cv::imshow("srcROI", *srcROIPointer);
    cv::imshow("src-Result", src);
    qDebug() << ss.str().c_str();