diff --git a/convert_data.lua b/convert_data.lua
index 5375243..57b9b82 100644
--- a/convert_data.lua
+++ b/convert_data.lua
@@ -118,6 +118,10 @@ local function load_images(list)
 	       -- method == user
 	       local yy = im
 	       local xx, meta2 = image_loader.load_byte(csv_meta.x)
+	       if settings.invert_x then
+		  xx = (-(xx:long()) + 255):byte()
+	       end
+
 	       if xx then
 		  if meta2 and meta2.alpha then
 		     xx = alpha_util.fill(xx, meta2.alpha, alpha_color)
diff --git a/lib/settings.lua b/lib/settings.lua
index 88a913d..f9161a7 100644
--- a/lib/settings.lua
+++ b/lib/settings.lua
@@ -80,6 +80,7 @@ cmd:option("-padding", 0, 'replication padding size')
 cmd:option("-padding_y_zero", 0, 'zero padding y for segmentation (0|1)')
 cmd:option("-grayscale", 0, 'grayscale x&y (0|1)')
 cmd:option("-validation_filename_split", 0, 'make validation-set based on filename(basename)')
+cmd:option("-invert_x", 0, 'invert x image in convert_lua')
 
 local function to_bool(settings, name)
    if settings[name] == 1 then
@@ -101,6 +102,7 @@ to_bool(settings, "pairwise_flip")
 to_bool(settings, "padding_y_zero")
 to_bool(settings, "grayscale")
 to_bool(settings, "validation_filename_split")
+to_bool(settings, "invert_x")
 
 if settings.plot then
    require 'gnuplot'