diff --git a/src/cristallina/utils.py b/src/cristallina/utils.py
index 6e4c152..2e429da 100644
--- a/src/cristallina/utils.py
+++ b/src/cristallina/utils.py
@@ -142,9 +142,13 @@ def process_run(run_number, rois,detector='JF16T03V01', calculate =None, only_sh
     Parallel(n_jobs=n_jobs,verbose=10)(delayed(process_step)(i) for i in range(len(scan)))
 
 class ROI:
-    """Definition of region of interest (ROI) in image coordinates.
+    """Definition of region of interest (ROI) in image coordinates. 
+       (For images from detector as 2d array with convention bottom == 0th row, left == 0th column).
 
-    Example: ROI(left=10, right=20, bottom=100, top=200)
+    Examples: 
+     - ROI(left=10, right=20, bottom=100, top=200)
+     - ROI(center_x=15, width=10, center_y=150, height=100, name='peak 1')
+    
     """
 
     def __init__(