The window has stopped over one patch of a landscape photograph — bright sky across the top two rows, dark ground along the bottom.
The patch
| c1 | c2 | c3 | |
|---|---|---|---|
| r1 | 90 | 90 | 90 |
| r2 | 90 | 90 | 90 |
| r3 | 10 | 10 | 10 |
The filter sitting on top of it
| c1 | c2 | c3 | |
|---|---|---|---|
| r1 | 1 | 0 | -1 |
| r2 | 2 | 0 | -2 |
| r3 | 1 | 0 | -1 |
What single number does the convolution return at this position?
Select all that apply.