OpenCV IplImage访问违规异常

首先，我对OpenCV还很陌生。我尝试了大约一周都没有成功，但似乎我永远也做不到。这就是为什么我必须向面临同样问题的人寻求帮助。

我想在VC#2010中构建一个非常简单的应用程序，它基本上会做以下事情：

• 读取JPEG图像并将其存储到位图变量
• 将位图变量发送到封装在VC++dll中的函数
• 在VC++dll中对图像执行简单操作（例如画一个圆圈）
• 将修改后的图像返回到VC#应用程序并在PictureBox中显示

VC#中的代码：

[DllImport("CppTestDll.dll", CallingConvention = CallingConvention.Cdecl)]
    public static extern Bitmap testImage(Bitmap img);
private void button1_Click(object sender, EventArgs e)
    {
        // read the source jpeg from disk via a PictureBox
        Bitmap bmpImage = new Bitmap(pictureBox1.Image);
       //call the function testImage from the VC++ dll
   //  and assign to another PictureBox the modified image returned by the dll
        pictureBox2.Image = (System.Drawing.Image)testImage(bmpImage);
    }

VC++dll中的代码：

#include <opencv2/highgui/highgui.hpp>
#include <opencv2/opencv.hpp>
#include <iostream>
#include <stdio.h>
using namespace cv;
using namespace std;
    __declspec(dllexport) char* testImage(char *image)
    {
        //the image is 640x480
        //read the jpeg image into a IplImage structure
       IplImage *inputImg= cvCreateImage(cvSize(640,480), IPL_DEPTH_8U, 3); 
       inputImg->imageData = (char *)image;
        // I also tried to copy the IplImage to a Mat structure
        // this way it is copying onl the header
        // if I call Mat imgMat(inputImg, true); to copy also the data, I receive an error for Memory read access
        Mat imgMat(inputImg);
        // no matter which circle drawing method I choose, I keep getting the error
        //  AccessViolationException was unhandled. Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
        cvCircle(inputImg,Point(100,100),100,cvScalar(0, 0, 255, 0),1,8,0);
        circle(imgMat,Point(100,100),100,Scalar(0, 0, 255, 0),1,8,0);
        // I tried both ways to return the image
        // If I try to modify the image I receive the above described error
        // If I don't modify the input image, I can send back the original image, but it is useless
        //return (char *)imgMat.data;
        return (char *)inputImg->imageData;
    }

你能告诉我我错在哪里吗？或者可以提供一个小的示例代码来向我展示如何做到这一点？

更新如果我在VC++dll中使用cvImageLoad从磁盘中读取jpeg文件，则绘图操作是有效的，并且我可以返回修改后的图像。问题只是以正确的方式将图像发送到dll。有什么建议吗？我该怎么做？

此外我在VC++中更改了dll，就像这个一样

__declspec(dllexport) char* testImage(uchar* image)
{
        uchar *pixels = image;
        Mat  img(480,640,CV_8UC3,pixels);
        if (!img.data)
        {
            ::MessageBox(NULL, L"no data", L"no data in imgMat mat", MB_OK);
        }
        line(img,Point(100,100),Point(200,200),Scalar(0, 0, 255, 0),1,8,0);
        return (char *)img.data;
    }

线条绘制操作失败，但如果我对线条绘制进行注释，我可以返回图像。

怎么回事？