![]() | 1 | initial version |
Blur the whole image with either blur (a box filter) or gaussianBlur, then do a copyTo from the original to the blurred image with a mask. The mask should be 255 where you want the copy, and 0 elsewhere.
This may leave small amounts near the edge where the inside has bled over into the rest of the image. If that's a problem, there are more complicated ways we could try.