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

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.

Research and realization of signal processing algorithms based on FPGA in digital ophthalmic ultrasonography imaging / 中国医疗器械杂志

<p><b>OBJECTIVE</b>To design and improve signal processing algorithms of ophthalmic ultrasonography based on FPGA.</p><p><b>METHODS</b>Achieved three signal processing modules: full parallel distributed dynamic filter, digital quadrature demodulation, logarithmic compression, using Verilog HDL hardware language in Quartus II.</p><p><b>RESULTS</b>Compared to the original system, the hardware cost is reduced, the whole image shows clearer and more information of the deep eyeball contained in the image, the depth of detection increases from 5 cm to 6 cm.</p><p><b>CONCLUSION</b>The new algorithms meet the design requirements and achieve the system's optimization that they can effectively improve the image quality of existing equipment.</p>

A Study on Mycorrhizal Microstructure of Wild Cymbidium ensifolium / 广州中医药大学学报

The microstructure of mycorrhiza of wild Cymbidium ensifolium, collected from the mountains of north Guangdong was studied. The results showed that this species possesses the typical mycorrhizal structure of orchid plant. Mycorrhizal fungi invaded the cortex parenchyma by velamen and exodermis, and then, form pelotons and expanded part of area of cortex. The intracellular mycelium was digested and absorbed with clumps of digested material in some cells.