使用openNi/NITE从Kinect生成jpeg图像

Question

我正在尝试从Kinect生成传递给人脸检测/跟踪算法的图像帧。我已经看到从openGL纹理生成jpeg图像的最好方法是通过libjpeg，但我不知道如何开始。这就是我现在在代码中的代码：

//draw image frame to texture       
    const XnRGB24Pixel* pImageRow = g_imageMD.RGB24Data();
    XnRGB24Pixel* pTexRow = g_pTexMap + g_imageMD.YOffset() * g_nTexMapX;

    for (XnUInt y = 0; y < g_imageMD.YRes(); ++y)
    {
        const XnRGB24Pixel* pImage = pImageRow;
        XnRGB24Pixel* pTex = pTexRow + g_imageMD.XOffset();

        for (XnUInt x = 0; x < g_imageMD.XRes(); ++x, ++pImage, ++pTex)
        {
            *pTex = *pImage;
        }

        pImageRow += g_imageMD.XRes();
        pTexRow += g_nTexMapX;
    }

    // Create the OpenGL texture map
    glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP_SGIS, GL_TRUE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, g_nTexMapX, g_nTexMapY, 0, GL_RGB, GL_UNSIGNED_BYTE, g_pTexMap);

那么，我如何才能将这个g_pTexMap内容保存为jpeg图像呢？

Answer 1

OpenGL不处理图像文件。如果您想要将图像存储到文件中，将其传递给OpenGL并不是正确的做法。您应该将数据传递给libjpeg或其他图像文件访问库，而不是将数据传递给glTexImage2D。

看一看imlib2 http://docs.enlightenment.org/api/imlib2/html/

Answer 2

我确实尝试过imlib2，但似乎很难将openNi XnRGB24Pixel类型转换为imlib2要查找的数据流。与内存中的数据流相比，Imlib2似乎更容易处理文件(例如imageName.jpg)。然后我开始试用openCV，下面是我从一个开放讨论页面链接中获得并编辑的代码。

void generateJpeg(const xn::ImageMetaData& g_imageMD){

    //opencv to convert image to jpeg
    printf("Converting image to jpeg.\n");
    cv::Mat colorArr[3]; 
    cv::Mat colorImage; 
    const XnRGB24Pixel* pPixel; 
    const XnRGB24Pixel* pImageRow; 
    pImageRow = g_imageMD.RGB24Data();


    colorArr[0] = cv::Mat(g_imageMD.YRes(),g_imageMD.XRes(),CV_8U); 
    colorArr[1] = cv::Mat(g_imageMD.YRes(),g_imageMD.XRes(),CV_8U); 
    colorArr[2] = cv::Mat(g_imageMD.YRes(),g_imageMD.XRes(),CV_8U); 

    for (int y=0; y<g_imageMD.YRes(); y++){ 
        pPixel = pImageRow; 
        uchar* Bptr = colorArr[0].ptr<uchar>(y); 
        uchar* Gptr = colorArr[1].ptr<uchar>(y); 
        uchar* Rptr = colorArr[2].ptr<uchar>(y); 

        for(int x=0;x<g_imageMD.XRes();++x , ++pPixel){ 
                Bptr[x] = pPixel->nBlue; 
                Gptr[x] = pPixel->nGreen; 
                Rptr[x] = pPixel->nRed; 
        } 

        pImageRow += g_imageMD.XRes(); 
    } 

    cv::merge(colorArr,3,colorImage); 
     IplImage bgrIpl = colorImage;    
    cvSaveImage("image.jpg",&bgrIpl);

}