diff --git a/raillabel/format/intrinsics_pinhole.py b/raillabel/format/intrinsics_pinhole.py
index 380df11..6979371 100644
--- a/raillabel/format/intrinsics_pinhole.py
+++ b/raillabel/format/intrinsics_pinhole.py
@@ -10,30 +10,25 @@
 
 @dataclass
 class IntrinsicsPinhole:
-    """Intrinsic calibration for a camera sensor.
-
-    Parameters
-    ----------
-    camera_matrix: tuple of float of length 12
-        This is a 3x4 camera matrix which projects 3D homogeneous points (4x1) from a camera
-        coordinate system into the image plane (3x1). This is the usual K matrix for camera
-        projection as in OpenCV. It is extended from 3x3 to 3x4 to enable its direct utilisation to
-        project 4x1 homogeneous 3D points. The matrix is defined to follow the camera model:
-        x-to-right, y-down, z-forward. The following equation applies:
-        x_img = camera_matrix * X_ccs.
-    distortion: tuple of float of length 5 to 14
-        This is the array 1xN radial and tangential distortion coefficients.
-    width_px: int
-        Width of the image frame in pixels.
-    height_px: int
-        Height of the image frame in pixels.
+    """Intrinsic calibration for a camera sensor."""
 
-    """
+    camera_matrix: tuple[
+        float, float, float, float, float, float, float, float, float, float, float, float
+    ]
+    """This is a 3x4 camera matrix which projects 3D homogeneous points (4x1) from a camera
+    coordinate system into the image plane (3x1). This is the usual K matrix for camera projection as
+    in OpenCV. It is extended from 3x3 to 3x4 to enable its direct utilisation to project 4x1
+    homogeneous 3D points. The matrix is defined to follow the camera model: x-to-right, y-down,
+    z-forward. The following equation applies: x_img = camera_matrix * X_ccs."""
+
+    distortion: tuple[float, float, float, float, float]
+    "This is the array 1x5 radial and tangential distortion coefficients."
 
-    camera_matrix: tuple[float, ...]
-    distortion: tuple[float, ...]
     width_px: int
+    "Width of the image frame in pixel."
+
     height_px: int
+    "Height of the image frame in pixel."
 
     @classmethod
     def from_json(cls, json: JSONIntrinsicsPinhole) -> IntrinsicsPinhole: