JavaCV调用摄像头如何调节分辨率？高分 求高手

求高手！ 想用JavaCV获取摄像头图像并拍照，买的高分辨率的摄像头，可是拍出来的照片才55kb，远不及直接连电脑拍出来的效果，请教如何在java程序中调节分辨率
http://blog.csdn.net/sivyer123/article/details/22411861 这是示例程序

public class video
{

public static void main(String[] args) throws Exception
{

    final String savedImageFile = "d:\\my.jpg";   //拍摄所存储的文件
    OpenCVFrameGrabber grabber = new OpenCVFrameGrabber(0);  
    grabber.start();   //开始获取摄像头数据
    IplImage image =grabber.grab(); //将所获取摄像头数据放入IplImage

    int width = image.width();  
    int height = image.height();
    final BufferedImage bImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);  
    Graphics2D bGraphics = bImage.createGraphics();                       

    CanvasFrame canvas = new CanvasFrame("Camera",1);
    canvas.setCanvasSize(width, height);  

    canvas.getCanvas().addMouseListener(new MouseAdapter(){  
            public void mouseClicked(MouseEvent e){       
              try{
                 ImageIO.write(bImage, "jpg", new File(savedImageFile));//数据写入my.jpg
                 } 
              catch (IOException e1){
                // TODO Auto-generated catch block
                e1.printStackTrace();
                }  
           }
        });
   while(canvas.isVisible() && (image=grabber.grab()) != null){  
    canvas.showImage(image); 
    bGraphics.drawImage(image.getBufferedImage(),null,0,0); 
    }

        cvReleaseImage(image);     
        grabber.stop();  
        canvas.dispose();     
}

}

参考官方的例子：https://github.com/bytedeco/javacv/blob/master/samples/WebcamAndMicrophoneCapture.java

                int captureWidth = 1280;
        int captureHeight = 720;

        // The available FrameGrabber classes include OpenCVFrameGrabber (opencv_highgui),
        // DC1394FrameGrabber, FlyCaptureFrameGrabber, OpenKinectFrameGrabber,
        // PS3EyeFrameGrabber, VideoInputFrameGrabber, and FFmpegFrameGrabber.
        OpenCVFrameGrabber grabber = new OpenCVFrameGrabber(WEBCAM_DEVICE_INDEX);
        grabber.setImageWidth(captureWidth);
        grabber.setImageHeight(captureHeight);
        grabber.start();

啊 兄弟 真牛啊！ 这个GITHUB这么高端 我是咋搜的 我在网上找了半天没找到呢

搜索分辨率相关的是根本搜索不到这个的；
我也是抱着试试看的态度，因为搜索分辨率根本找不到有用的信息；
所以想到去JavaCV的官网看看有没有什么帮助。

我想问下，调用摄像头获取的图像全黑是怎么回事，笔记本摄像头灯亮了，摄像头应该是启动了