# What is the 5×5 equivalent of the 3×3 emboss kernel?

```-2  -1  0
-1   1  1
0   1  2
```

This is 3×3 emboss kernel. How should I write this in 5×5?

As I understand, these filters take directional differences (see the wikipidea page).

We can decompose you filter into directions

```0 -1  0        0  0  0       -2  0  0

0  0  0       -1  0  1        0  0  0

0  1  0        0  0  0        0  0  2
```

So, I think you can expand it over these 3 directions giving emphasis

```0  0 -1  0  0        0  0  0  0  0       -2  0  0  0  0

0  0 -1  0  0        0  0  0  0  0        0 -2  0  0  0

0  0  0  0  0       -1 -1  0  1  1        0  0  0  0  0

0  0  1  0  0        0  0  0  0  0        0  0  0  2  0

0  0  1  0  0        0  0  0  0  0        0  0  0  0  2
```

So, the final kernel would be

```-2  0 -1  0  0

0 -2 -1  0  0

-1 -1  1  1  1

0  0  1  2  0

0  0  1  0  2
```

May be you can also try interpolating filter coefficients marked as x

```-2  x -1  0  0

x -2 -1  0  0

-1 -1  1  1  1

0  0  1  2  x

0  0  1  x  2
```