A camera watches a car park at dusk. One patch of the frame is being scored by four different filters, each holding its own learned values.
Then a street lamp switches on. To keep things clean, suppose every one of the nine pixels in that patch becomes exactly 40 brighter, and that no pixel gets anywhere near 255, so nothing is capped.
Filter P
| c1 | c2 | c3 | |
|---|---|---|---|
| r1 | -0.9 | 0.1 | 1.0 |
| r2 | -1.2 | 0.0 | 1.1 |
| r3 | -0.8 | -0.1 | 0.8 |
Filter Q
| c1 | c2 | c3 | |
|---|---|---|---|
| r1 | -1.0 | 0.2 | 1.1 |
| r2 | -0.9 | 0.0 | 1.2 |
| r3 | -1.1 | 0.1 | 1.0 |
Filter R
| c1 | c2 | c3 | |
|---|---|---|---|
| r1 | 0.0 | -1.0 | 0.1 |
| r2 | -0.9 | 5.0 | -1.1 |
| r3 | -0.1 | -1.0 | 0.0 |
Filter S — all nine values are .
Nothing is known about what the patch looked like before the lamp came on.
For which filters is the score guaranteed to be exactly the same before and after, whatever the nine original pixel values were?
Select all that apply.