There is an image and it is blurred horizontally with an 11 element box filter. My question is: how can the box filter be 11 elements? And since it says horizontal direction here, could it be a kernel 11 element row vector?

CodePudding user response：

Yes, it's just a mean filter kernel. Think of it as an 11 element kernel where each coefficient is equal to 1/11. So in effect it sets each output pixel to the average value of the input pixels in the range -5 to 5 in the X axis.