Characteristic matching-based adaptive fast bilateral filter for ultrasound speckle reduction

Ultrasound images show a granular pattern of noise known as speckle which diminishes their quality and results in difficulties in diagnosis. This paper presents an adaptive fast bilateral filter (AFBF) to reduce the speckle noise. The presented filter is derived from a conventional bilateral filter and is adaptively adjusted by the detection of speckle statistics. The criterion of speckle region is defined from a similarity value obtained from local characteristic matching between the processing window and a reference speckle area. The presented filter can reduce the speckle noise and, at the same time, maintain the tissue structure. Ultrasound phantom testing and in vivo imaging show that the proposed method can improve the quality of an ultrasound image in terms of tissue SNR, CNR and FOM values.

► The fast bilateral filter is derived from a conventional one to reduce speckle.
► A local histogram is introduced to speed up the bilateral filter.
► A characteristic matching technique is applied to adaptively adjusting smoothing.
► Evaluation methods are demonstrated in both phantom and in vivo testing.