c++qt合并两张灰度图像

需求：将两张尺寸相同的灰度图像进行合并，合并后的图像，每个像素点灰度值为两张原图对应像素点灰度值之和。若超过255，则最大为255。

方法一：
将图像读取为cv::Mat，再调用opencv的cv::add方法，进行合并。

方法二：
不调用opencv的方法。假设两个图像数数据都为void 指针，先将其都转为unsigned char 指针，再按下标进行相加，并处理溢出情况。用一个新的unsigned char指针接收，最后再转回void指针。

配置opencv方法可参考以下文章：
https://blog.csdn.net/bangtanhui/article/details/135583311

效果如下：
两张一样的原图，合并后得到一张整体灰度值更高(更亮)的图。

在这里插入图片描述

参考代码如下：

#include "mainwindow.h"
#include "ui_mainwindow.h"#include "opencv2/core.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/imgcodecs.hpp"
#include "opencv2/highgui.hpp"//该函数用于将cv::Mat转为QImage
QImage cvMat2QImage(const cv::Mat& mat)
{// 8-bits unsigned, NO. OF CHANNELS = 1if(mat.type() == CV_8UC1) {QImage image(mat.cols, mat.rows, QImage::Format_Indexed8);// Set the color table (used to translate colour indexes to qRgb values)image.setColorCount(256);for(int i = 0; i < 256; i++) {image.setColor(i, qRgb(i, i, i));}// Copy input Matuchar *pSrc = mat.data;for(int row = 0; row < mat.rows; row ++) {uchar *pDest = image.scanLine(row);memcpy(pDest, pSrc, static_cast<size_t>(mat.cols));pSrc += mat.step;}return image;} else if(mat.type() == CV_8UC3) {      // 8-bits unsigned, NO. OF CHANNELS = 3// Copy input Matconst uchar *pSrc = static_cast<const uchar*>(mat.data);// Create QImage with same dimensions as input MatQImage image(pSrc, mat.cols, mat.rows, static_cast<int>(mat.step), QImage::Format_RGB888);return image.rgbSwapped();} else if(mat.type() == CV_8UC4) {// Copy input Matconst uchar *pSrc = static_cast<const uchar*>(mat.data);// Create QImage with same dimensions as input MatQImage image(pSrc, mat.cols, mat.rows, static_cast<int>(mat.step), QImage::Format_ARGB32);return image.copy();} else {return QImage();}
}MainWindow::MainWindow(QWidget *parent) :QMainWindow(parent),ui(new Ui::MainWindow)
{ui->setupUi(this);QString imgPath1 = "E:\\QtDemo\\ImageMerge_Demo\\img_test.bmp";QString imgPath2 = "E:\\QtDemo\\ImageMerge_Demo\\img_test_append.bmp";cv::Mat imgMat1 = cv::imread(imgPath1.toStdString(), CV_8UC1);cv::Mat imgMat2 = cv::imread(imgPath2.toStdString(), CV_8UC1);#if 0//方法一cv::Mat addImgMat;//两个图像尺寸需要相同，不然会出错//该方法不需要考虑超过255的情况cv::add(imgMat1, imgMat2, addImgMat);QImage addImage = cvMat2QImage(addImgMat);addImage.save("add.bmp");#else//方法二void* dataPtr1 = static_cast<void*>(imgMat1.data);void* dataPtr2 = static_cast<void*>(imgMat2.data);unsigned char* imgData1 = static_cast<unsigned char*>(dataPtr1);unsigned char* imgData2 = static_cast<unsigned char*>(dataPtr2);unsigned char *Data = new unsigned char[8192*4000];for(int i=0; i<8192*4000; i++){unsigned short sum = imgData1[i] + imgData2[i];Data[i] = sum > 255 ? 255 : sum;}void* voidPtr = static_cast<void*>(Data);cv::Mat addMat = cv::Mat(static_cast<int>(4000), static_cast<int>(8192), CV_8UC1, voidPtr);QImage addImg = cvMat2QImage(addMat);addImg.save("add2.bmp");#endif}MainWindow::~MainWindow()
{delete ui;
}