Fig. 2
From: A demonstration of high field-of-view stability in hands-free echocardiography
Steerable pyramid using complex, oriented wavelets. a The frequency subbands extracted of the six levels, and b the corresponding extracted image structural size ranges in pixels. The pixel dimensions ranged between 0.25 and 0.37 mm, depending on the image depth of the acquisition. c An example of the decomposition of an image into six levels, each containing a specific range of image structure sizes. For simplicity, only two of the sixteen orientations are illustrated (left = 0 π and right = \(\frac {\pi }{2}\))