opencv学习笔记-入门（7）单通道的图像数据访问

4） 基于指针的直接访问: (简单高效)

• 对于单通道字节型图像:

  int height     = img->height;
  int width      = img->width;
  int step       = img->widthStep;
  uchar* data    = (uchar *)img->imageData;
  data[i*step+j] = 111;</pre><br><span style="color:rgb(51,153,51)"></span>

  对于多通道字节型图像:
  

• int height     = img->height;
  int width      = img->width;
  int step       = img->widthStep;
  int channels   = img->nChannels;
  uchar* data    = (uchar *)img->imageData;
  data[i*step+j*channels+k] = 111;</pre><br><span style="color:rgb(51,153,51)"></span>

  
  

  	{
  		uchar *sptr = src->data.ptr + src->step*y;
  		uchar *pDataOutput = dst->data.ptr + src->step*y;
  		for(int x = 0; x < size.width; x++, pDataOutput++, sptr+=Nds)
  		{
  			for(int iD = 0; iD < Nds; iD++)
  			{
  				data[iD] = sqrt(float(sptr[iD]));
  		
  			}
  		}
  	}	</pre><br><br>