Research on speckle reduction in ophthalmology high frequency ultrasound imaging / 国际生物医学工程杂志

ABSTRACT

Objective Speckle is the inherent problem exists in B-Mode ultrasound image,and effective speckle noise reduction will improve the image quality and contribute greatly to clinical doctors to diagnose,especially in fine ophthalmic examination with high frequency ultrasound.Methods This paper proposed a new speckle reduction method based on the Laplacian pyramid and multiscale analysis.In the Laplacian pyramid,true clinical features were separated from noise,according to the different bandpass ultrasound image characteristics in each layer,and the advanced eight directions speckle reduction anisotropic diffusion (SRAD)was adapted to suppressed the speckle noise,and the identified noise and the extracted features were selectively emphasized by suitable edge,coherence and contrast enhancement filtering from fine to coarse scales.The performance of the proposed method was compared to the traditional SRAD method and coherence-enhancing diffusion method by measuring the equivalent number of looks (ENL) and Time cost.Results The ENL and Time cost value of the proposed method were higher compared to the SRAD and the cedif method,i.e 1.172 3 vs 1.122 3,0.929 3 and 0.864 0 vs 1.396 0,1.468 3.Conclusions In summary,the proposed method can more effectively remove the speckle noise while preserving the edge and details of the images.