利用opencv改变灰度图像中每个像素值碰到的问题....? 400 报错

利用opencv改变灰度图像中每个像素值碰到的问题....? 400 报错

为什么修改失败..?

//图像像素类型IPL_DEPTH_8U
	IplImage *src = cvLoadImage("haha.jpg",CV_LOAD_IMAGE_GRAYSCALE);;
	
	for (int y = 0; y < src->height; y++)
	{
		uchar *ptr = (uchar *)(src->imageData + y*src->widthStep);
		for (int x = 0; x < src->width; x++)
		{
			
			if (ptr[x] >= 200)
			{
				ptr[x] = 255;
			}
			if (ptr[x] <= 50)
			{
				ptr[x] = 0;
			}
			//此处没有输出，说明值还是被我改了
			if (ptr[x] != 0 && ptr[x] != 255)
				cout << (int)ptr[x] << " ";
		}
	}


	cvSaveImage("456.jpg", src);
	

	IplImage *ddd = cvLoadImage("456.jpg", CV_LOAD_IMAGE_GRAYSCALE);


	for (int y = 0; y < ddd->height; y++)
	{
		uchar *ptr = (uchar *)(ddd->imageData + y*ddd->widthStep);
		for (int x = 0; x < ddd->width; x++)
		{
			//这边有输出，说明值没有被我改掉啊！
			if (ptr[x] != 0 && ptr[x] != 255)
				cout << (int)ptr[x] << " ";
		}
	}