[ximgproc] SLIC superpixels: contour mask contains {-1,1} instead of {-1,0}

[netw0rkf10w]

The mask returned by getLabelContourMask() contains -1 at the segmentation contours and 1 elsewhere, which is not a valid mask. A valid mask should contains 'a' (where a != 0) at the contours and 0 elsewhere (e.g. in the case of SEEDS: a = 255).

[cbalint13]

Thanks a lot @ehku !

PR https://github.com/Itseez/opencv_contrib/pull/483 is ongoing to address the issue. I made SLIC & LSC masks just like SEEDS one. Also matrix should be CV_8UC1 type.

[netw0rkf10w]

Thanks, @cbalint13 !!

[cbalint13]

@ehku ,

Revisitied the patch. Matrix should be 8UC1, so i corrected seeds.cpp too. See here the reason:

• https://github.com/Itseez/opencv/blob/master/modules/imgproc/src/contours.cpp#L197