I've been experimenting a bit, if you the median the image, copy the layer then use out line, auto adjust, the set to multiply it gives a pretty good effect, at least for me it did. if it is a colour image turn the top layer, the one with contours into a black and white image.
You can get rid of some of the unwanted contour lines by using pencil sketch.
example.
Original -
After -
EDIT - Soften Portrait on the contour layer and adjust the softness can also get rid of some unwanted contour lines.