add param for smoothing in segmentation meshing

src/gnomon_package_tissueimagemesh/algorithm/meshFromImage/segmentationSurfaceMesh.py

@@ -35,6 +35,7 @@ class segmentationSurfaceMesh(gnomonAbstractMeshFromImage):
         self._parameters['down_facing_threshold'] = d_real("Normal z threshold", 0, -1, 1, 2, "The z coordinate below which a normal vector is considered to face downwards")
         self._parameters['fill_holes'] = d_bool("Fill holes", False, "Whether to fill holes in the segmented image to generate the surface mesh")
         self._parameters['padding'] = d_bool("Padding", False, "Whether to pad the image with background before generating the surface mesh")
+        self._parameters['gaussian_sigma'] = d_real("Gaussian sigma", 0., 0., 10., 2, "Standard deviation of the gaussian kernel used to smooth the segmented image")
 
         self._parameter_groups = {}
 
@@ -59,6 +60,7 @@ class segmentationSurfaceMesh(gnomonAbstractMeshFromImage):
                 orientation=(1 if self['orientation']=="up" else -1),
                 surface_matching='cell',
                 padding=self['padding'],
+                gaussian_sigma=self['gaussian_sigma'],
                 down_facing_threshold=self['down_facing_threshold'],
                 fill_holes=self['fill_holes']
             )