Consider the following problem of locating a 2d pattern inside an image (0-255).

A match is said to be found at (x, y) if most of the elements of the bigger matrix (say > 50%) are in some range of the respective elements of the smaller matrix i.e

```
0.8*small[i][j] <= bigger[x+i][y+j] <= 1.2*smaller[i][j]

```

I remember this problem to be a standard problem in image searching, but couldn't recollect, neither find the exact name. 

I would be very grateful if someone could figure out the name of an equivalent standard problem.  

Thank you in advance.