Objective To observe the value of preoperative CT radiomics models for predicting composition of in vivo urinary calculi.Methods Totally 543 urolithiasis patients were retrospectively enrolled and divided into calcium...Objective To observe the value of preoperative CT radiomics models for predicting composition of in vivo urinary calculi.Methods Totally 543 urolithiasis patients were retrospectively enrolled and divided into calcium oxalate monohydrate stone group(group A,n=373),anhydrous uric acid stone group(group B,n=86),carbonate apatite group(group C,n=30),ammonium urate stone group(group D,n=28)and ammonium magnesium phosphate hexahydrate stone group(group E,n=26)according to the composition of calculi,also divided into training set and test set at the ratio of 7∶3.Radiomics features were extracted and screened based on plain CT images of urinary system.Five binary task models(model A—E corresponding to group A—E)and a quinary task model were constructed using least absolute shrinkage and selection operator algorithm for predicting the composition of calculi in vivo.Then receiver operating characteristic curves were drawn,and the area under the curves(AUC)were calculated to evaluate the predictive efficacy of binary task models,while the accuracy,precision,recall and F1 score were used to evaluate the predictive efficacy of the quinary task model.Results All binary task models had good efficacy for predicting the composition of urinary calculi in vivo,with AUC of 0.860—0.948 in training set and of 0.856—0.933 in test set.The accuracy,precision,recall and F1 score of the quinary task model for predicting the composition of in vivo urinary calculi was 82.25%,83.79%,46.23%and 0.596 in training set,respectively,while was 80.63%,75.26%,43.48%and 0.551 in test set,respectively.Conclusion Binary task radiomics models based on preoperative plain CT had good efficacy for predicting the composition of in vivo urinary calculi,while the quinary task radiomics model had high accuracy but relatively poor stability.展开更多
The T-joints of Ti?6Al?4V alloy were manufactured by double-sided synchronized laser beam welding with the homologous filler wire. The formation, microstructure and mechanical properties of welded joints as well as th...The T-joints of Ti?6Al?4V alloy were manufactured by double-sided synchronized laser beam welding with the homologous filler wire. The formation, microstructure and mechanical properties of welded joints as well as the correlations of each other were investigated. The results indicate that the quality of weld seams is good without defects such as discontinuity, beading, visible cracks or porosity, which is linked to the steady molten pool behavior and droplet transition. The morphologies of the heat affected zone (HAZ) located on the skin and stringer are disparate. The microstructure of the HAZ and fusion zone (FZ) is mainly comprised of acicular martensiticα′ phases. The microhardness of the HAZ and FZ is higher than that of the base metal (BM) and reaches a maximum value at the HAZ near FZ on the stringer. The tensile specimens along the skin and stringer fractured at the BM with ductile fracture surfaces.展开更多
A design strategy for a research platform of a telepresence telerobot system based on virtual reality technology is put forward. The design frame of the system is described, and its important core techniques are descr...A design strategy for a research platform of a telepresence telerobot system based on virtual reality technology is put forward. The design frame of the system is described, and its important core techniques are described. An octrees data structure is utilized to build kinematic and dynamic modeling of the virtual simulation environment, Delphi+OpenGL+3DS MAX are adopted to carry through the virtual modeling and visible simulation exploitation of the slave-robot and its environment. Photo-correction is adopted to correct positioning deviation of the virtual geometric model and modeling errors. The cost of software and hardware equipment for the research platform realized is low. The master/slave robot (manipulator) system and all software in the system were designed and manufactured by our research group. The performance of the system has reached the level required for research. An indispensable experiment base is provided for the research of a telepresence telerobot system based on virtual reality technology.展开更多
A kind of image distortion in Optical Coherence Tomography (OCT) resulted from average refractive index changes between structures of bio tissue is discussed for the first time.Analysis is given on following situation...A kind of image distortion in Optical Coherence Tomography (OCT) resulted from average refractive index changes between structures of bio tissue is discussed for the first time.Analysis is given on following situations:1) Exact refraction index changes between microstructures;2)The gradient of average refractive index change between different tissue layers is parallel to the probe beam;3) The gradient of average refractive index change is vertical to the probe beam.The results show that the image distortion of situation 1) is usually negligible;in situation 2) there is a spread or shrink effect without relative location error; however,in situation 3) there is a significant image error inducing relative location displacement between different structures.Preliminary design to eliminate the distortion is presented,the method of which mainly based on the image classification and pixel array re arrangement.展开更多
Automatic extraction of road and linear structure from remote sensing images is a very important problem. This paper analyses several existing methods of the automatic road and linear structure extraction by using som...Automatic extraction of road and linear structure from remote sensing images is a very important problem. This paper analyses several existing methods of the automatic road and linear structure extraction by using some multi-spectral remote sensing images acquired from different spatial resolutions, districts and road characteristics. Their advantages and disadvantages have been generalized.展开更多
A method for shadow detection and compensation for color aerial images is presented. It is considered that the intensity value of each image pixel is the product of illumination function and ground object reflection, ...A method for shadow detection and compensation for color aerial images is presented. It is considered that the intensity value of each image pixel is the product of illumination function and ground object reflection, and the shadowed regions on the image are mainly caused by the short of illumination, so the information compensation for the shadowed regions should concentrate on the illumination adjustment of concerned area on the basis of the analysis of whole image. The shadow detection and compensation procedure proposed by this paper consists of four steps.展开更多
Objective: To evaluate the accuracy of these two methods and focus on the analysis and management of the false-negative cases. Methods: Results of full field digital mammography (FFDM) and fine needle aspiration cytol...Objective: To evaluate the accuracy of these two methods and focus on the analysis and management of the false-negative cases. Methods: Results of full field digital mammography (FFDM) and fine needle aspiration cytology (FNAC) were obtained and analyzed from a consecutive of 102 women with palpable breast masses, results were correlated with the histopathological findings. Results: Of the 102 cases, malignancy was confirmed in 43 cases (42.16%) by final pathological examination, the sensitivity and specificity of cancer detection with FNA cytology was 90.7% (39/43) and 89.8% (53/59), re- spectively, the whole accuracy was 90.2% (92/102), with a positive predictive value of 86.7% (39/45) and a negative predictive value of 93.0% (53/57). FFDM gave a sensitivity of 88.4% (38/43), specificity of 83.1% (49/59), and whole accuracy 85.3% (87/102), the positive predictive value and negative predictive value was 79.2% (38/48) and 90.7% (49/54), respectively. All the FNAC-negative cancer cases were suggestive of malignancy by FFDM findings, however, the benign cases which present as equivocal finding by FNA cytology, could not be ruled out the presence of malignancy. Conclusion: FNAC and FFDM both are accurate, effective and economical diagnostic modalities, combined use of these two methods can reduced the misdiag- nosis rate of breast masses.展开更多
Diagnostic imaging is carried out in patients with esophageal carcinoma in order to decide on the therapeutical procedure, to control therapy, to document complications and to assess concomitant diseases. Chest X-rays...Diagnostic imaging is carried out in patients with esophageal carcinoma in order to decide on the therapeutical procedure, to control therapy, to document complications and to assess concomitant diseases. Chest X-rays and esophagograms give a 2-dimensional view of the X-ray absorption in 3-dimensional examination volumes, the diagnostic accuracy thus being limited by overshadowing. Because of the robust examination technique, the broad availability and the low costs chest X-rays are usually used for short-term controls under therapy and follow-up. Esophagography is carried out in order to asses the exact location and length of a known esophageal carcinoma prior to therapy and in order to assess peristaltic disturbances and ?stulas. CT and MRI provide tomographic images with a spatial resolution of up to 1 mm3 allowing the reconstruction of high-resolution images not only in the transversal but also in any other plain. The diagnostic accuracy of esophagography is comparatively high in T1–T3 stages (80%–90%). T1 and T2 tumors cannot be diagnosed by CT and MRI, because both methods do not visualize the mucosa (unlike esophagography and endoscopy) and the esophageal wall layers (unlike EUS). In?ltration depth tends to be overestimated in T1 and T2 carcinomas and to be underestimated in T3 and T4 cancers. CT and MRI cannot detect metastases in normally sized lymph nodes and cannot accurately di?erentiate between benign and malignant lymphadenopathy in enlarged nodes with a reported sensitivities and speci?ties of 60% and 74%, respectively. However, further prospective studies using up to date CT and MR technology are needed to assess the present diagnostic situation. CT and MRI do not only visualize the mediastinum, but also the lungs, the pleura and the skeleton as well as the neck and the abdomen thus providing a comprehensive overview of the TNM stage in 3 body regions.展开更多
An easy-to-implement yet practical single-camera microscopic stereo-digital image correlation(stereo-DIC) technique is proposed for surface three-dimensional(3D) deformation measurement of singe lap joint(SLJ) samples...An easy-to-implement yet practical single-camera microscopic stereo-digital image correlation(stereo-DIC) technique is proposed for surface three-dimensional(3D) deformation measurement of singe lap joint(SLJ) samples subjected to mechanical loads. The basic principles, optical configurations and implementation procedures of the proposed technique are described in detail. Compared with existing single-camera 2D-DIC technique, which has been regularly used for in-plane deformation measurement of a SLJ specimen, the proposed technique offers the special merit of simultaneously determining all the three displacement components by simply adding two additional optical elements to existing single-camera 2D-DIC systems. The accuracy and effectiveness of the proposed technique is demonstrated by measuring the 3D deformation of a SLJ specimen subjected to quasi-static tensile loads.展开更多
Monitoring and control of combustion flames in utility boilers are required in order to optimize combustion conditions.This paper presents an instrumentation system for the concurrent measurement of the temperature di...Monitoring and control of combustion flames in utility boilers are required in order to optimize combustion conditions.This paper presents an instrumentation system for the concurrent measurement of the temperature distributionand soot concentration of flames developed on the two-color principle. This system consists of an endoscope,an optical assembly with optical filters, a CCD camera, a frame grabber and associated image processingsoftware. Experiments are performed on a methane-air combustor and the temperature fields and the soot concentrationscorresponding to the flame images are obtained. The results have demonstrated that the system is capableof performing on-line measurement of flame and temperature distribution, providing temporal and spatial characterizationof the combustion process. In addition, the combination of advanced optical sensing and digital imageprocessing technique can help to define the threshold by the analysis of the background noise. Furthermore, theutilization of the filter technique can enhance the image presentation effect to an extent.展开更多
文摘Objective To observe the value of preoperative CT radiomics models for predicting composition of in vivo urinary calculi.Methods Totally 543 urolithiasis patients were retrospectively enrolled and divided into calcium oxalate monohydrate stone group(group A,n=373),anhydrous uric acid stone group(group B,n=86),carbonate apatite group(group C,n=30),ammonium urate stone group(group D,n=28)and ammonium magnesium phosphate hexahydrate stone group(group E,n=26)according to the composition of calculi,also divided into training set and test set at the ratio of 7∶3.Radiomics features were extracted and screened based on plain CT images of urinary system.Five binary task models(model A—E corresponding to group A—E)and a quinary task model were constructed using least absolute shrinkage and selection operator algorithm for predicting the composition of calculi in vivo.Then receiver operating characteristic curves were drawn,and the area under the curves(AUC)were calculated to evaluate the predictive efficacy of binary task models,while the accuracy,precision,recall and F1 score were used to evaluate the predictive efficacy of the quinary task model.Results All binary task models had good efficacy for predicting the composition of urinary calculi in vivo,with AUC of 0.860—0.948 in training set and of 0.856—0.933 in test set.The accuracy,precision,recall and F1 score of the quinary task model for predicting the composition of in vivo urinary calculi was 82.25%,83.79%,46.23%and 0.596 in training set,respectively,while was 80.63%,75.26%,43.48%and 0.551 in test set,respectively.Conclusion Binary task radiomics models based on preoperative plain CT had good efficacy for predicting the composition of in vivo urinary calculi,while the quinary task radiomics model had high accuracy but relatively poor stability.
基金Project supported by Science and Technology on Power Beam Processes Laboratory at Beijing Aeronautical Manufacturing Technology Research Institute,China
文摘The T-joints of Ti?6Al?4V alloy were manufactured by double-sided synchronized laser beam welding with the homologous filler wire. The formation, microstructure and mechanical properties of welded joints as well as the correlations of each other were investigated. The results indicate that the quality of weld seams is good without defects such as discontinuity, beading, visible cracks or porosity, which is linked to the steady molten pool behavior and droplet transition. The morphologies of the heat affected zone (HAZ) located on the skin and stringer are disparate. The microstructure of the HAZ and fusion zone (FZ) is mainly comprised of acicular martensiticα′ phases. The microhardness of the HAZ and FZ is higher than that of the base metal (BM) and reaches a maximum value at the HAZ near FZ on the stringer. The tensile specimens along the skin and stringer fractured at the BM with ductile fracture surfaces.
文摘A design strategy for a research platform of a telepresence telerobot system based on virtual reality technology is put forward. The design frame of the system is described, and its important core techniques are described. An octrees data structure is utilized to build kinematic and dynamic modeling of the virtual simulation environment, Delphi+OpenGL+3DS MAX are adopted to carry through the virtual modeling and visible simulation exploitation of the slave-robot and its environment. Photo-correction is adopted to correct positioning deviation of the virtual geometric model and modeling errors. The cost of software and hardware equipment for the research platform realized is low. The master/slave robot (manipulator) system and all software in the system were designed and manufactured by our research group. The performance of the system has reached the level required for research. An indispensable experiment base is provided for the research of a telepresence telerobot system based on virtual reality technology.
文摘A kind of image distortion in Optical Coherence Tomography (OCT) resulted from average refractive index changes between structures of bio tissue is discussed for the first time.Analysis is given on following situations:1) Exact refraction index changes between microstructures;2)The gradient of average refractive index change between different tissue layers is parallel to the probe beam;3) The gradient of average refractive index change is vertical to the probe beam.The results show that the image distortion of situation 1) is usually negligible;in situation 2) there is a spread or shrink effect without relative location error; however,in situation 3) there is a significant image error inducing relative location displacement between different structures.Preliminary design to eliminate the distortion is presented,the method of which mainly based on the image classification and pixel array re arrangement.
文摘Automatic extraction of road and linear structure from remote sensing images is a very important problem. This paper analyses several existing methods of the automatic road and linear structure extraction by using some multi-spectral remote sensing images acquired from different spatial resolutions, districts and road characteristics. Their advantages and disadvantages have been generalized.
文摘A method for shadow detection and compensation for color aerial images is presented. It is considered that the intensity value of each image pixel is the product of illumination function and ground object reflection, and the shadowed regions on the image are mainly caused by the short of illumination, so the information compensation for the shadowed regions should concentrate on the illumination adjustment of concerned area on the basis of the analysis of whole image. The shadow detection and compensation procedure proposed by this paper consists of four steps.
文摘Objective: To evaluate the accuracy of these two methods and focus on the analysis and management of the false-negative cases. Methods: Results of full field digital mammography (FFDM) and fine needle aspiration cytology (FNAC) were obtained and analyzed from a consecutive of 102 women with palpable breast masses, results were correlated with the histopathological findings. Results: Of the 102 cases, malignancy was confirmed in 43 cases (42.16%) by final pathological examination, the sensitivity and specificity of cancer detection with FNA cytology was 90.7% (39/43) and 89.8% (53/59), re- spectively, the whole accuracy was 90.2% (92/102), with a positive predictive value of 86.7% (39/45) and a negative predictive value of 93.0% (53/57). FFDM gave a sensitivity of 88.4% (38/43), specificity of 83.1% (49/59), and whole accuracy 85.3% (87/102), the positive predictive value and negative predictive value was 79.2% (38/48) and 90.7% (49/54), respectively. All the FNAC-negative cancer cases were suggestive of malignancy by FFDM findings, however, the benign cases which present as equivocal finding by FNA cytology, could not be ruled out the presence of malignancy. Conclusion: FNAC and FFDM both are accurate, effective and economical diagnostic modalities, combined use of these two methods can reduced the misdiag- nosis rate of breast masses.
文摘Diagnostic imaging is carried out in patients with esophageal carcinoma in order to decide on the therapeutical procedure, to control therapy, to document complications and to assess concomitant diseases. Chest X-rays and esophagograms give a 2-dimensional view of the X-ray absorption in 3-dimensional examination volumes, the diagnostic accuracy thus being limited by overshadowing. Because of the robust examination technique, the broad availability and the low costs chest X-rays are usually used for short-term controls under therapy and follow-up. Esophagography is carried out in order to asses the exact location and length of a known esophageal carcinoma prior to therapy and in order to assess peristaltic disturbances and ?stulas. CT and MRI provide tomographic images with a spatial resolution of up to 1 mm3 allowing the reconstruction of high-resolution images not only in the transversal but also in any other plain. The diagnostic accuracy of esophagography is comparatively high in T1–T3 stages (80%–90%). T1 and T2 tumors cannot be diagnosed by CT and MRI, because both methods do not visualize the mucosa (unlike esophagography and endoscopy) and the esophageal wall layers (unlike EUS). In?ltration depth tends to be overestimated in T1 and T2 carcinomas and to be underestimated in T3 and T4 cancers. CT and MRI cannot detect metastases in normally sized lymph nodes and cannot accurately di?erentiate between benign and malignant lymphadenopathy in enlarged nodes with a reported sensitivities and speci?ties of 60% and 74%, respectively. However, further prospective studies using up to date CT and MR technology are needed to assess the present diagnostic situation. CT and MRI do not only visualize the mediastinum, but also the lungs, the pleura and the skeleton as well as the neck and the abdomen thus providing a comprehensive overview of the TNM stage in 3 body regions.
基金supported by the National Natural Science Foundation of China(Grant Nos.1127203211322220 and 11427802)+2 种基金the Program for New Century Excellent Talents in University(Grant No.NCET-12-0023)the Science Fund of State Key Laboratory of Automotive Safety and Energy(Grant No.KF14032)Beijing Nova Program(Grant No.xx2014B034)
文摘An easy-to-implement yet practical single-camera microscopic stereo-digital image correlation(stereo-DIC) technique is proposed for surface three-dimensional(3D) deformation measurement of singe lap joint(SLJ) samples subjected to mechanical loads. The basic principles, optical configurations and implementation procedures of the proposed technique are described in detail. Compared with existing single-camera 2D-DIC technique, which has been regularly used for in-plane deformation measurement of a SLJ specimen, the proposed technique offers the special merit of simultaneously determining all the three displacement components by simply adding two additional optical elements to existing single-camera 2D-DIC systems. The accuracy and effectiveness of the proposed technique is demonstrated by measuring the 3D deformation of a SLJ specimen subjected to quasi-static tensile loads.
基金the National High Technology Research and Development of China (863 Program) (2006AA05A103)the National Natural Science Fund (grant No. 40501017, grant No. 50706053)
文摘Monitoring and control of combustion flames in utility boilers are required in order to optimize combustion conditions.This paper presents an instrumentation system for the concurrent measurement of the temperature distributionand soot concentration of flames developed on the two-color principle. This system consists of an endoscope,an optical assembly with optical filters, a CCD camera, a frame grabber and associated image processingsoftware. Experiments are performed on a methane-air combustor and the temperature fields and the soot concentrationscorresponding to the flame images are obtained. The results have demonstrated that the system is capableof performing on-line measurement of flame and temperature distribution, providing temporal and spatial characterizationof the combustion process. In addition, the combination of advanced optical sensing and digital imageprocessing technique can help to define the threshold by the analysis of the background noise. Furthermore, theutilization of the filter technique can enhance the image presentation effect to an extent.
