c语言读取bmp图像_opencv 图像处理

#include "stdafx.h"
#include <fstream>
# include <windows.h>
#include <opencv2/opencv.hpp>
using namespace std;
using namespace cv;

int _tmain(int argc, _TCHAR* argv[])
{
	BITMAPFILEHEADER fh;
	BITMAPINFOHEADER ih;
	int rows, cols;
	Mat showImg;

	ifstream src("2.bmp", ifstream::binary); //2.bmp为灰度图像
	if (!src)
	{
		cerr << "打开失败";
		return -1;
	}
	src.read((char *)&fh, sizeof(BITMAPFILEHEADER));
	if (fh.bfType != 'MB')
	{
		cerr << "这不是BMP图像";
		return -1;
	}
	src.read((char *)&ih, sizeof(BITMAPINFOHEADER));
	rows = ih.biHeight;
	cols = ih.biWidth;
	//bmp图像数据存储是4字节对齐的
	int colsDQ = (cols + 3) / 4 * 4;
	//移动到图像数据处
	src.seekg(sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER)+sizeof(RGBQUAD) * 256, ios::beg);//参数：相对位置，起点
	showImg = Mat::zeros(rows, cols, CV_8U);
	//读取图像数据
	uchar *pData = new uchar[rows*colsDQ];
	src.read((char *)pData, rows*colsDQ);
	//bmp图像数据转换到Mat图像数据（Mat图像数据非对齐）
	for (int i = rows - 1; i >= 0; --i) //bmp图像存储为行倒序
		for (int j = 0; j < cols; ++j)
		{
			showImg.ptr<uchar>(rows - 1 - i)[j] = *(pData + i*colsDQ + j);
		}
	delete[]pData;
	imshow("hi", showImg);

	waitKey();
	return 0;
}