diff --git a/pyproject.toml b/pyproject.toml
index 9a29065..d6605fa 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -46,6 +46,17 @@ dependencies = [
     "klamath~=1.4",
     ]
 
+[dependency-groups]
+dev = [
+    "pytest",
+    "masque[oasis]",
+    "masque[dxf]",
+    "masque[svg]",
+    "masque[visualize]",
+    "masque[text]",
+    "masque[manhattanize]",
+    "masque[manhattanize_slow]",
+]
 
 [tool.hatch.version]
 path = "masque/__init__.py"
@@ -56,7 +67,8 @@ dxf = ["ezdxf~=1.0.2"]
 svg = ["svgwrite"]
 visualize = ["matplotlib"]
 text = ["matplotlib", "freetype-py"]
-manhatanize_slow = ["float_raster"]
+manhattanize = ["scikit-image"]
+manhattanize_slow = ["float_raster"]
 
 
 [tool.ruff]