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Objective To study the application of laser speckle contrast algorithm in high-frequency ultrasound blood flow imaging. Methods The laser speckle contrast algorithm was extended to the field of high-frequency ultrasound blood flow imaging. The high-frequency ultrasound structure images were processed by using the classic laser speckle temporal contrast algorithm to suppress the static tissue signals, enhance the dynamic blood flow signals, and obtain the high-frequency ultrasound blood flow images. The simulation experiments on flow phantoms were conducted to verify the effectiveness of the algorithm, and then human skin tissue in vivo experiments were performed to verify the applicability of the algorithm. The performances of blood flow images which obtained from ultrasound structure images with different frames by laser speckle contrast algorithm were compared and analyzed. Results The blood flow information in a tube was clearly visible in the flow phantoms experiments. The static skin tissue signals were significantly suppressed, dynamic blood flow signals were strengthened in the human skin tissue in vivo experiments, and high-frequency ultrasound blood flow images were obtained. By comparing and analyzing the performances of blood flow images, the results showed that the best blood flow images could be obtained when the number of frame was set to 10 frames. Conclusions The speckle contrast algorithm is feasible and has good application prospects in high-frequency ultrasound blood flow imaging.
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<p><b>OBJECTIVE</b>Optical coherence tomography images may be distorted by motion artifacts in dynamic imaging, so it may lead to misdiagnosis in clinical diagnosis. Motion artifacts correction has become an urgent issue in optical coherence tomography imaging.</p><p><b>METHODS</b>Firstly, using the improved complex nonlinear diffusion preprocessing filtering reduced the noise of the sequence images, then using the image mass center aligned the distortion data in the Y direction, finally, using the method of deviation average corrected motion artifacts along the Y direction.</p><p><b>RESULTS</b>After correction, the motion artifacts in the longitudinal 2D images and the 3D image disappeared, the surface of the 2D and the 3D image became more smooth, the structure between layers of the images got clear and distinct, retinal en-face single slice image was sharp, and the fundus tissue structure could be observed.</p><p><b>CONCLUSION</b>The algorithm of correction makes the physical structure of the retinal display truly after motion artifacts correction.</p>
Subject(s)
Humans , Algorithms , Artifacts , Imaging, Three-Dimensional , Motion , Retina , Tomography, Optical CoherenceABSTRACT
<p><b>OBJECTIVE</b>Using the algorithm on the layered structure of the retina and quantitative analysis of the automatic segmentation technique is the key to the early diagnosis of glaucoma and other retinopathy on optical coherence tomography. Existing methods require high quality image and have low reliability. This paper used the improved complex nonlinear diffuse filtering and other methods to solve this problem.</p><p><b>METHODS</b>This paper includes algorithm such as automatic threshold, improved complex nonlinear diffusion filtering, morphological operations and peak detection. Use the method for the segmentation of 20 retinal layers images which acquired on the self-builder OCT system, the boundary of inner limiting membrane(ILM), outer nuclear layer(ONL), the photoreceptor segments(IS/ OS) and the RPE_ChCap layer are detected accurately. At last, the photoreceptor layer thickness is measured.</p><p><b>RESULTS</b>The results of segmentation and measurement are good corresponded with expert manual segmentation and measurements, retinal foveal measurements data is consistent with Zeiss Stratus OCT central retinal thickness 212+/-20 micro m.</p><p><b>CONCLUSION</b>The algorithm proposed is prospective applied to clinical diagnosis of retinal diseases.</p>
Subject(s)
Humans , Algorithms , Retina , Software , Tomography, Optical Coherence , MethodsABSTRACT
This investigation introduces GPU (Graphics Processing Unit)- based CUDA (Compute Unified Device Architecture) technology into signal processing of ophthalmic FD-OCT (Fourier-Domain Optical Coherence Tomography) imaging system, can realize parallel data processing, using CUDA to optimize relevant operations and algorithms, in order to solve the technical bottlenecks that currently affect ophthalmic real-time imaging in OCT system. Laboratory results showed that with GPU as a general parallel computing processor, the speed of imaging data processing using GPU+CPU mode is more than dozens times faster than traditional CPU platform based serial computing and imaging mode when executing the same data processing, which reaches the clinical requirements for two dimensional real-time imaging.
Subject(s)
Computer Graphics , Image Interpretation, Computer-Assisted , Tomography, Optical Coherence , MethodsABSTRACT
Objective To reduce the error caused by the non-linearity of headphone and device via the design of calibration algorithm for acoustic immittance.Methods Values of calibration chambers with different volumes (0.5,2.0 and 5.0 ml) were measured using the digital detection system.Then,the calibration data tables,for linearity calibration with inputting the values of acoustic immittance,were produced by means of processing the signal of acoustic immittance using the digital calibration algorithm based on the values from the calibration chambers,Results With the low frequency probe tone measurement,it was confirmed that the range of error among various calibration chambers with different volumes was 1％.Conclusion The calibration algorithm enables the improving of the detection accuracy and provides the reliable data for further clinical application.
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<p><b>OBJECTIVE</b>Developing a high-frequency ultrasonic skin imaging system to obtain the high resolution ultrasonic image of the skin. And further analyzing the ultrasonic images of skin to explore the imaging characteristics of skin structure and then explore the value of high-frequency imaging in the application of skin diagnosis.</p><p><b>METHODS</b>50 MHz single element ultrasonic transducer, mechanic linear scanning method is used in the imaging system. The resolution and the ability of recognize the skin issue is verified by linear target scanning and clinical trials.</p><p><b>RESULTS</b>Both the axial and lateral resolution of the system reaches 50 microm. The subtle structure of normal skin tissue is clearly visible. Some diseases have obvious appearance in the image.</p><p><b>CONCLUSIONS</b>50 MHz ultrasonic skin imaging system is of high resolution and is valuable to skin structure detect and disease diagnosis.</p>
Subject(s)
Humans , Skin , Diagnostic Imaging , Ultrasonography , MethodsABSTRACT
Objective To keep the intensity of sound constant and reduce the effect of ear canal difference on detection process.Methods Real-time detection of the probe tone in ear canal was carried out and by control ling the output circuit of the probe tone through the digital signal compensation algorithm,to realize real-time digital tympanometry of ear system and the function of constant pressure control.Results The results showed that the probe tone remained constant at 226 Hz for the measurement of middle ear and tympanometry was accurate.Conclusion The study simplified system configuration and provides basis for the clinical application.
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Objective To study a multiple frequency tympanometry on ear system. Methods Based on the original low frequency and single ingredient SY-IA tympanometry, the study mainly focused on such aspects as multiple frequency probe tone circuit, constant pressure sound control system, micropressor control system and multiple frequency acoustic immitance & phase angle detection circuit. Results Multiple frequency tympanometry on ear system could detect multiple frequency acoustic immitance and phase angle for normal ear, tympanum loosed ear and ossicular chain break ear under different probe tone. Conclusion Experiments show that multiple frequency tympanometry on ear system based on ARM is helpful to the diagnosis of pathological changes which are insensitive to single low frequency tympanometry.