IplImage的使用 從三通道圖中分離出三個單通道

 opncvtest.cpp : 定義控制檯應用程序的入口點。
//
#include "stdafx.h"
#include<stdio.h>

#include <opencv2/opencv.hpp>

using namespace std;
using namespace cv;

int _tmain(int argc, _TCHAR* argv[])
{
    const char* imagename = "itti.jpg";

    //從文件中讀入圖像
    IplImage * img = cvLoadImage("C:\\Users\\laicb\\Desktop\\test.jpg");

    //如果讀入圖像失敗
    IplImage * b = cvCreateImage(cvGetSize(img),IPL_DEPTH_8U,1);
    IplImage * g = cvCreateImage(cvGetSize(img),IPL_DEPTH_8U,1);
    IplImage * r = cvCreateImage(cvGetSize(img),IPL_DEPTH_8U,1);

    printf("width = %d,height = %d chanels= %d depth = %d",img->width,img->height,img->nChannels,img->depth);


    char  * data = img->imageData;
    int step = img->widthStep;
    int chanel = img->nChannels;

    char * bdata = b->imageData;
    char * gdata = g->imageData;
    char * rdata = r->imageData;

    for(int i=0;i<img->height;i++)
    {
        for(int j=0;j<img->width;j++)//這裏注意三通道的step是單通道的三倍，這裏注意除以3，否則數組越界，IPL_DEPTH_8U
        {
            bdata[i*step/3 + j] = data[i*step + j*chanel];
                        gdata[i*step/3 + j] = data[i*step + j*chanel + 1];
            rdata[i*step/3 + j] = data[i*step + j*chanel + 2];
        }
    }

    //顯示圖像
    cvNamedWindow("blue");
    cvNamedWindow("green");
    cvNamedWindow("red");

    cvShowImage("blue",b);
    cvShowImage("green",g);
    cvShowImage("red",r);

    cvNamedWindow("Window Test");
    cvShowImage("Window Test",img);

    cvWaitKey(0);

    cvReleaseImage(&img);

    cvDestroyWindow("Window Test");

    //此函數等待按鍵，按鍵盤任意鍵就返回
    waitKey();

    return 0;
}