bug fixed in ConvertScalarImageToRGB

Author: armaneshaghi

nipype/interfaces/ants/visualization.py

@@ -24,7 +24,7 @@ class ConvertScalarImageToRGBInputSpec(ANTSCommandInputSpec):
     output_image=traits.Str('rgb.nii.gz', argstr='%s', usedefault=True,
                              desc=('rgb output image'), position = 2)
     mask_image=File('none', argstr='%s', exists=True,
-                    desc = 'mask image', position = 3)
+                    desc = 'mask image', position = 3, usedefault = True)
     colormap=traits.Str(argstr='%s', usedefault=True,
             desc=('Possible colormaps: grey, red, green, '
                 'blue, copper, jet, hsv, spring, summer, '