error handling pictures with Simulink-Avalon

I've developped my own image processing algorithm wich is based in Avalon Edge detector example provided by ALTERA.

The model load an image from Matlab using Avalon ST, after the image is processed and finally it is sent again to matlab for viewing the effect of image processing developped.

I have detected that the image result is always 10 pixels moved to the right compared with the initial image.

I've checked the model but I couldn't find any delay, Could it be because Avalon ports?