Terry is correct...all scans will have a "texture" to some degree. That is the nature of a physical scanning probe method. Only way around that is use a laser scanner or create a model from scratch in ArtCAM, Aspire, Z-Brush, etc.
The Pattern Editor has several tools to help you smooth things out (de-noise, smooth, blur). An alternative is to save your scan as a PNG graphic, edit that in a photo editor (use smooth, blur, whatever it takes to smooth the texture out), then re-save your edited PNG and import that into the PE, then save it as an MPW (your backup) and as a PTN (for use in Designer). Experiment to see which you prefer.
EDIT: Wanted to add that the more secure the object is affixed to your sled, the less "texture" you will see. Try using wood or other solid 'wedge' super-glued under the knife blade to support it fully. Things like hot glue globs and such will allow vibration, which translates to "texture". The probe (actually the z-truck) goes up and down when following the contours of an object - slight movement of the object enhances the up/down movement yielding a greater "texture". There is nothing wrong with your probe.