region of interest

[Cameron-T]

It really depends on how close the images will be to one another. The Match Pattern is going to be looking for the template at the same size because of how it looks at the pixels. The Geometric Match will find a certain shape regardless of size. If you know that your parts will be the same distance from your camera every time, I suggest using Match Pattern.

[ayman22]

thank you
but why do you recommend match pattern in fixed distance does it has an extra advantages over geomatric one

[The_Hunt]

Ayman, 

As Cameron had mentioned, it is preferable to use Pattern Matching over Geometric Matching if the distance between the camera and the parts remain constant. The primary reason for this is performance. The execution speed of Pattern Matching is far greater than Geometric. 

You may find this post to have more information regarding the differences. 

[ayman22]

thank you my friends

[CarlosOtiniano]

another detail to consider is that if we take a matching patterns and if you set score of hits, if we move the camera either vertically or horizontally matching may perish USB cameras have this problem and even more if near or further examine the objective, it must be on a fixed support and a suitable source of illumination