extra line and spelling mistake

skimage/feature/blob.py

@@ -388,7 +388,7 @@ def blob_doh(image, min_sigma=1, max_sigma=30, num_sigma=10, threshold=0.01,
     """
 
     if image.ndim != 2:
-        raise ValueError("'image' must be a grayscale ")
+        raise ValueError("'image' must be grayscale ")
 
     image = img_as_float(image)
     image = integral_image(image)

skimage/feature/corner.py

@@ -190,7 +190,6 @@ def hessian_matrix_det(image, sigma, integral=True):
         not computed. If `True` the integral image is computed for `image`
         and used for finding the Hessian Determinant.
 
-
     Returns
     -------
     out : array