A Morphological Filtering Method Based on Particle Swarm Optimization for Railway Vehicle Bearing Fault Diagnosis

Table 2

The construction of flat SEs.

Scale	Length	Matrix form
1	2	{0, 0}
2	3	{0, 0, 0}
3	4	{0, 0, 0, 0}
n		{0, 0, …, 0, 0}