SELECT v,  iterated_median_filter(v::double precision, 5) over() FROM generate_series(1, 10) as t(v);
 v  | iterated_median_filter 
----+------------------------
  1 |                      1
  2 |                      2
  3 |                      3
  4 |                      4
  5 |                      5
  6 |                      6
  7 |                      7
  8 |                      8
  9 |                      8
 10 |                      8
(10 rows)

SELECT v,  iterated_median_filter(v, 3) over() FROM (VALUES (1), (1.1), (0.9), (1.1), (0.95), (2.1), (1.95), (2.0), (2.05), (3.11), (2.99), (3.05), (3.0)) as t(v);
  v   | iterated_median_filter 
------+------------------------
    1 |                      1
  1.1 |                      1
  0.9 |                      1
  1.1 |                    1.1
 0.95 |                    1.1
  2.1 |                   1.95
 1.95 |                      2
  2.0 |                      2
 2.05 |                   2.05
 3.11 |                   2.99
 2.99 |                      3
 3.05 |                      3
  3.0 |                      3
(13 rows)

SELECT v,  iterated_median_filter(v, 3, 'inf'::double precision) over() FROM (VALUES (1), (1.1), (0.9), (1.1), (0.95), (2.1), (1.95), (2.0), (2.05), (3.11), (2.99), (3.05), (3.0)) as t(v);
  v   | iterated_median_filter 
------+------------------------
    1 |                      1
  1.1 |                      1
  0.9 |                    1.1
  1.1 |                   0.95
 0.95 |                    1.1
  2.1 |                   1.95
 1.95 |                      2
  2.0 |                      2
 2.05 |                   2.05
 3.11 |                   2.99
 2.99 |                   3.05
 3.05 |                      3
  3.0 |                      3
(13 rows)

SELECT v,  iterated_median_filter(v, 3) over() FROM (VALUES (1), (1.1)) as t(v);
  v  | iterated_median_filter 
-----+------------------------
   1 |                      1
 1.1 |                      1
(2 rows)

SELECT v,  iterated_median_filter(v::double precision, 3) over() FROM (VALUES (NULL), (NULL), (NULL)) as t(v);
 v | iterated_median_filter 
---+------------------------
   |                      0
   |                      0
   |                      0
(3 rows)