scipy.signal.order_filter¶
- scipy.signal.order_filter(a, domain, rank)[source]¶
Perform an order filter on an N-D array.
Perform an order filter on the array in. The domain argument acts as a mask centered over each pixel. The non-zero elements of domain are used to select elements surrounding each input pixel which are placed in a list. The list is sorted, and the output for that pixel is the element corresponding to rank in the sorted list.
- Parameters
- andarray
The N-dimensional input array.
- domainarray_like
A mask array with the same number of dimensions as a. Each dimension should have an odd number of elements.
- rankint
A non-negative integer which selects the element from the sorted list (0 corresponds to the smallest element, 1 is the next smallest element, etc.).
- Returns
- outndarray
The results of the order filter in an array with the same shape as a.
Examples
>>> from scipy import signal >>> x = np.arange(25).reshape(5, 5) >>> domain = np.identity(3) >>> x array([[ 0, 1, 2, 3, 4], [ 5, 6, 7, 8, 9], [10, 11, 12, 13, 14], [15, 16, 17, 18, 19], [20, 21, 22, 23, 24]]) >>> signal.order_filter(x, domain, 0) array([[ 0., 0., 0., 0., 0.], [ 0., 0., 1., 2., 0.], [ 0., 5., 6., 7., 0.], [ 0., 10., 11., 12., 0.], [ 0., 0., 0., 0., 0.]]) >>> signal.order_filter(x, domain, 2) array([[ 6., 7., 8., 9., 4.], [ 11., 12., 13., 14., 9.], [ 16., 17., 18., 19., 14.], [ 21., 22., 23., 24., 19.], [ 20., 21., 22., 23., 24.]])