According to the characteristics of dynamic firing in pulse coupled neural network (PCNN) and regional configuration in retinal blood vessel network, a new method combined with simplified PCNN and fast 2D-Otsu algorit...According to the characteristics of dynamic firing in pulse coupled neural network (PCNN) and regional configuration in retinal blood vessel network, a new method combined with simplified PCNN and fast 2D-Otsu algorithm was proposed for automated retinal blood vessels segmentation. Firstly, 2D Gaussian matched filter was used to enhance the retinal images and simplified PCNN was employed to segment the blood vessels by firing neighborhood neurons. Then, fast 2D-Otsu algorithm was introduced to search the best segmentation results and iteration times with less computation time. Finally, the whole vessel network was obtained via analyzing the regional connectivity. Experiments implemented on the public Hoover database indicate that this new method gets a 0.803 5 true positive rate and a 0.028 0 false positive rate on an average. According to the test results, compared with Hoover algorithm and method of PCNN and 1D-Otsu, the proposed method shows much better performance.展开更多
Intussusception is rare in adults. We describe a 47-year-old man with ileal schwannoma that led to ileocolic intussusception. Abdominal ultrasonography,abdominal CT scan and barium enema confirmed an ileal tumor. Colo...Intussusception is rare in adults. We describe a 47-year-old man with ileal schwannoma that led to ileocolic intussusception. Abdominal ultrasonography,abdominal CT scan and barium enema confirmed an ileal tumor. Colonoscopy revealed a peduncular submucosal tumor (SMT) 75 mm long with an ulcerated apex at the ascending colon. The provisional diagnosis was a gastrointestinal stromal tumor of the terminal ileum. Ileocecal resection was carried out and the tumor was histologically diagnosed as schwannoma. Abdominal pain resolved postoperatively. This case reminds us that ileal schwannoma should be included in the differential diagnosis of intussusception caused by an SMT in the intestine.展开更多
New adaptive preprocessing algorithms based on the polar coordinate system were put forward to get high-precision corneal topography calculation results. Adaptive locating algorithms of concentric circle center were c...New adaptive preprocessing algorithms based on the polar coordinate system were put forward to get high-precision corneal topography calculation results. Adaptive locating algorithms of concentric circle center were created to accurately capture the circle center of original Placido-based image, expand the image into matrix centered around the circle center, and convert the matrix into the polar coordinate system with the circle center as pole. Adaptive image smoothing treatment was followed and the characteristics of useful circles were extracted via horizontal edge detection, based on useful circles presenting approximate horizontal lines while noise signals presenting vertical lines or different angles. Effective combination of different operators of morphology were designed to remedy data loss caused by noise disturbances, get complete image about circle edge detection to satisfy the requests of precise calculation on follow-up parameters. The experimental data show that the algorithms meet the requirements of practical detection with characteristics of less data loss, higher data accuracy and easier availability.展开更多
This paper presented an individual recognition algorithm for human iris using fractal dimension of grayscale extremums for feature extraction.Firstly,iris region was localized from an eye image with modified circle de...This paper presented an individual recognition algorithm for human iris using fractal dimension of grayscale extremums for feature extraction.Firstly,iris region was localized from an eye image with modified circle detector stemmed from Daugman’s integro-differential operator.Then,segmentation was used to extract the iris and to exclude occlusion from eyelids and eyelashes.The extracted iris was normalized and mapped to polar coordinates for matching.In feature encoding,a new approach based on fractal dimension of grayscale extremums was designed to extract textural features of iris.Finally,a normalized correlation classifier was employed to determine the agreement of two iris feature templates,and the feature template was rotated left and right to avoid the interference from rotation of eyes and tilting of head.The experimental results show that fractal dimension of grayscale extremums can extract textural features from iris image effectively,and the proposed recognition algorithm is accurate and efficient.The proposed algorithm was tested on CASIA-IrisV3-Interval iris database and the performance was evaluated based on the analysis of both False Accept Rate(FAR)and False Reject Rate(FRR)curves.Experimental results show that the proposed iris recognition algorithm is effective and efficient.展开更多
Objective. To investigate the magnetic resonance (MR) features of meningeal carcinomatosis, and to improve the ability in understanding and diagnosing meningeal carcinomatosis by MR findings.Methods. Eleven cases with...Objective. To investigate the magnetic resonance (MR) features of meningeal carcinomatosis, and to improve the ability in understanding and diagnosing meningeal carcinomatosis by MR findings.Methods. Eleven cases with proven meningeal carcinomatosis were studied by conventional and Gd - DTPA enhanced MR imaging. The enhancement patterns and features, as well as the types of meningeal involvement, were retrospectively analyzed.Results. Conventional MR imaging showed no evident meningeal abnormalities. After the administration of Gd - DTPA, abnormal pia mater enhancement was detected in 9 cases, demonstrating as the continuous, thin, and lineal high signal intensity on the brain surface that could descend into the sulci. The abnormal pial enhancement occurred on the cortical surfaces of cerebellum, brainstem, and cerebrum. No abnormal enhancement in the subarach-noid space was found. Abnormal dura - arachnoid enhancement was seen in 3 cases, showing as the continuous, thick, and curvilineal high signal intensity over the convexities or in the tentorium without extension into the cortical sulci. Cerebral dura - arachnoid involvement was found in all 3 cases and one of them also showed abnormal enhancement in cerebellar dura - arachnoid and tentorium. Of the 11 cases, 9 with pial involvement had abnormal cerebrospinal fluid (CSF) results, 2 involving only the dura - arachnoid had normal CSF results.Conclusion. Meningeal carcinomatosis could be well demonstrated by Gd - DTPA enhanced MR imaging, and its type could be differentiated by the enhancement features. Combined with the clinical information, Gd - enhanced MR imaging may lead to the diagnosis and guide the therapy of meningeal carcinomatosis.展开更多
To meet the needs in the fundus examination,including outlook widening,pathology tracking,etc.,this paper describes a robust feature-based method for fully-automatic mosaic of the curved human retinal images photograp...To meet the needs in the fundus examination,including outlook widening,pathology tracking,etc.,this paper describes a robust feature-based method for fully-automatic mosaic of the curved human retinal images photographed by a fundus microscope. The kernel of this new algorithm is the scale-,rotation-and illumination-invariant interest point detector & feature descriptor-Scale-Invariant Feature Transform. When matched interest points according to second-nearest-neighbor strategy,the parameters of the model are estimated using the correct matches of the interest points,extracted by a new inlier identification scheme based on Sampson distance from putative sets. In order to preserve image features,bilinear warping and multi-band blending techniques are used to create panoramic retinal images. Experiments show that the proposed method works well with rejection error in 0.3 pixels,even for those cases where the retinal images without discernable vascular structure in contrast to the state-of-the-art algorithms.展开更多
Intravascular ultrasound (IVUS) is a new technology for the diagnosis of coronary artery disease, and for the support of coronary intervention. IVUS image segmentation often encounters difficulties when plaque and aco...Intravascular ultrasound (IVUS) is a new technology for the diagnosis of coronary artery disease, and for the support of coronary intervention. IVUS image segmentation often encounters difficulties when plaque and acoustic shadow are present A novel approach for hard plaque recognition and media-adventitia border detection of IVUS images is presented in this paper. The IVUS images were first enhanced by a spatial-frequency domain filter that was constructed by the directional filter and histogram equalization. Then, the hard plaque was recognized based on the intensity variation within different regions that were obtained using the k-means algorithm. In the next step, a cost matrix representing the probability of the media-adventitia border was generated by combining image gradient, plaque location and image intensity. A heuristic graph-searching was applied to find the media-adventitia border from the cost matrix.Experiment results showed that the accuracy of hard plaque recognition and media-adventitia border detection was 89.94% and 95.57%, respectively. In conclusion,using hard plaques recognition could improve media-adventitia border detection in IVUS images.展开更多
Pneumocephalus is the presence of air in the cranial vault. The common etiologies of pneumocephalus are brain trauma and cranial surgery. We report a case of a 26-year-old man with brain trauma who developed diffuse p...Pneumocephalus is the presence of air in the cranial vault. The common etiologies of pneumocephalus are brain trauma and cranial surgery. We report a case of a 26-year-old man with brain trauma who developed diffuse pneumocephalus after sneezing. CT scan was performed on arrival, and the image showed subarach- noid hemolxhage without pneumocephalus. On the seventh day after a big sneeze brain CT scan was re-performed, which showed pneumocephalus. After another ten days of treatment, the patient was discharged without any symptoms.展开更多
Complementary metal oxide semiconductor(CMOS) image sensors(CIS) are being widely used in digital video cameras, web cameras, digital single lens reflex camera(DSLR), smart phones and so on, owing to their high level ...Complementary metal oxide semiconductor(CMOS) image sensors(CIS) are being widely used in digital video cameras, web cameras, digital single lens reflex camera(DSLR), smart phones and so on, owing to their high level of integration, random accessibility, and low-power operation. It needs to be installed with the cover glass in practical applications to protect the sensor from damage, mechanical issues,and environmental conditions, which, however, limits the accuracy and usability of the sensor due to the reflection in the optical path from air-to-cover glass-to-air. In this work, the flexible 3D nanocone anti-reflection(AR) film with controlled aspect ratio was firstly employed to reduce the light reflection at air/cover glass/air interfaces by directly attaching onto the front and rear sides of the CIS cover glass.As both the front and rear sides of cover glass were coated by the AR film, the output image quality was found to be improved with external quantum efficiency increased by 7%, compared with that without AR film. The mean digital data value, root-mean-square contrast, and dynamic range are increased by45.14%, 38.61% and 57, respectively, for the output image with AR films. These results provide a novel and facile pathway to improve the CIS performance and also could be extended to rational design of other image sensors and optoelectronic devices.展开更多
Objective： To evaluate the sensitivity and specificity of CT scan findings in patients with blunt abdominal trauma admitted to the university hospital. Methods： All the patients with blunt abdominal trauma admitted ...Objective： To evaluate the sensitivity and specificity of CT scan findings in patients with blunt abdominal trauma admitted to the university hospital. Methods： All the patients with blunt abdominal trauma admitted at a tertiary teaching trauma center in Iran between 2005 and 2007 were enrolled in this study. In the absence of any clinical manifestations, the patients underwent a diagnostic CT scan. Laparatomy was performed in those with positive CT results. Others were observed for 48 hours and discharged in case no problem was reported; otherwise they underwent laparatomy. Information on patients＇ demographic data, mechanism of trauma, indication for CT scan, CT scan findings, results of laparotomy were gathered. The sensitivity, specificity and accuracy of the CT-scan images in regard with the organ injured were calculated. The sensitivity, specificity and accuracy of the CT scan were calculated in each case. Results： CT scan had the highest sensitivity for detecting the injuries to liver （100%） and spleen （86.6%）. The specificity of the method for detecting retroperitoneal hematoma （100%） and injuries to kidney （93.5%） was higher than other organs. The accuracy of CT images to detect the injuries to spleen, liver, kidney and retroperitoneal hematoma was reported to be 96.1%, 94.4%, 91.6% and 91.6% respectively. Conclusion： The findings of the present study reveal that CT scan could be considered as a good choice, especially for patients with blunt abdominal trauma in teaching hospitals where the radiologic academic staff is not present in the hospital in the night shifts.展开更多
基金Project (60872081) supported by the National Natural Science Foundation of ChinaProject (50051) supported by the Program for New Century Excellent Talents in UniversityProject (4092034) supported by the Natural Science Foundation of Beijing
文摘According to the characteristics of dynamic firing in pulse coupled neural network (PCNN) and regional configuration in retinal blood vessel network, a new method combined with simplified PCNN and fast 2D-Otsu algorithm was proposed for automated retinal blood vessels segmentation. Firstly, 2D Gaussian matched filter was used to enhance the retinal images and simplified PCNN was employed to segment the blood vessels by firing neighborhood neurons. Then, fast 2D-Otsu algorithm was introduced to search the best segmentation results and iteration times with less computation time. Finally, the whole vessel network was obtained via analyzing the regional connectivity. Experiments implemented on the public Hoover database indicate that this new method gets a 0.803 5 true positive rate and a 0.028 0 false positive rate on an average. According to the test results, compared with Hoover algorithm and method of PCNN and 1D-Otsu, the proposed method shows much better performance.
文摘Intussusception is rare in adults. We describe a 47-year-old man with ileal schwannoma that led to ileocolic intussusception. Abdominal ultrasonography,abdominal CT scan and barium enema confirmed an ileal tumor. Colonoscopy revealed a peduncular submucosal tumor (SMT) 75 mm long with an ulcerated apex at the ascending colon. The provisional diagnosis was a gastrointestinal stromal tumor of the terminal ileum. Ileocecal resection was carried out and the tumor was histologically diagnosed as schwannoma. Abdominal pain resolved postoperatively. This case reminds us that ileal schwannoma should be included in the differential diagnosis of intussusception caused by an SMT in the intestine.
基金Project(20120321028-01)supported by Scientific and Technological Key Project of Shanxi Province,ChinaProject(20113101)supported by Postgraduate Innovative Key Project of Shanxi Province,China
文摘New adaptive preprocessing algorithms based on the polar coordinate system were put forward to get high-precision corneal topography calculation results. Adaptive locating algorithms of concentric circle center were created to accurately capture the circle center of original Placido-based image, expand the image into matrix centered around the circle center, and convert the matrix into the polar coordinate system with the circle center as pole. Adaptive image smoothing treatment was followed and the characteristics of useful circles were extracted via horizontal edge detection, based on useful circles presenting approximate horizontal lines while noise signals presenting vertical lines or different angles. Effective combination of different operators of morphology were designed to remedy data loss caused by noise disturbances, get complete image about circle edge detection to satisfy the requests of precise calculation on follow-up parameters. The experimental data show that the algorithms meet the requirements of practical detection with characteristics of less data loss, higher data accuracy and easier availability.
基金supported by the Independent Innovation Foundation of Shandong University(No.2009JC004)the Program of Development of Science and Technology of Shandong(No.2010GSF10243)
文摘This paper presented an individual recognition algorithm for human iris using fractal dimension of grayscale extremums for feature extraction.Firstly,iris region was localized from an eye image with modified circle detector stemmed from Daugman’s integro-differential operator.Then,segmentation was used to extract the iris and to exclude occlusion from eyelids and eyelashes.The extracted iris was normalized and mapped to polar coordinates for matching.In feature encoding,a new approach based on fractal dimension of grayscale extremums was designed to extract textural features of iris.Finally,a normalized correlation classifier was employed to determine the agreement of two iris feature templates,and the feature template was rotated left and right to avoid the interference from rotation of eyes and tilting of head.The experimental results show that fractal dimension of grayscale extremums can extract textural features from iris image effectively,and the proposed recognition algorithm is accurate and efficient.The proposed algorithm was tested on CASIA-IrisV3-Interval iris database and the performance was evaluated based on the analysis of both False Accept Rate(FAR)and False Reject Rate(FRR)curves.Experimental results show that the proposed iris recognition algorithm is effective and efficient.
文摘Objective. To investigate the magnetic resonance (MR) features of meningeal carcinomatosis, and to improve the ability in understanding and diagnosing meningeal carcinomatosis by MR findings.Methods. Eleven cases with proven meningeal carcinomatosis were studied by conventional and Gd - DTPA enhanced MR imaging. The enhancement patterns and features, as well as the types of meningeal involvement, were retrospectively analyzed.Results. Conventional MR imaging showed no evident meningeal abnormalities. After the administration of Gd - DTPA, abnormal pia mater enhancement was detected in 9 cases, demonstrating as the continuous, thin, and lineal high signal intensity on the brain surface that could descend into the sulci. The abnormal pial enhancement occurred on the cortical surfaces of cerebellum, brainstem, and cerebrum. No abnormal enhancement in the subarach-noid space was found. Abnormal dura - arachnoid enhancement was seen in 3 cases, showing as the continuous, thick, and curvilineal high signal intensity over the convexities or in the tentorium without extension into the cortical sulci. Cerebral dura - arachnoid involvement was found in all 3 cases and one of them also showed abnormal enhancement in cerebellar dura - arachnoid and tentorium. Of the 11 cases, 9 with pial involvement had abnormal cerebrospinal fluid (CSF) results, 2 involving only the dura - arachnoid had normal CSF results.Conclusion. Meningeal carcinomatosis could be well demonstrated by Gd - DTPA enhanced MR imaging, and its type could be differentiated by the enhancement features. Combined with the clinical information, Gd - enhanced MR imaging may lead to the diagnosis and guide the therapy of meningeal carcinomatosis.
基金Program for NewCentury Excellent Talents in UniversityGrant number:50051+1 种基金The Key Project for Technology Research of Ministry Education of ChinaCrant number:106030
文摘To meet the needs in the fundus examination,including outlook widening,pathology tracking,etc.,this paper describes a robust feature-based method for fully-automatic mosaic of the curved human retinal images photographed by a fundus microscope. The kernel of this new algorithm is the scale-,rotation-and illumination-invariant interest point detector & feature descriptor-Scale-Invariant Feature Transform. When matched interest points according to second-nearest-neighbor strategy,the parameters of the model are estimated using the correct matches of the interest points,extracted by a new inlier identification scheme based on Sampson distance from putative sets. In order to preserve image features,bilinear warping and multi-band blending techniques are used to create panoramic retinal images. Experiments show that the proposed method works well with rejection error in 0.3 pixels,even for those cases where the retinal images without discernable vascular structure in contrast to the state-of-the-art algorithms.
文摘Intravascular ultrasound (IVUS) is a new technology for the diagnosis of coronary artery disease, and for the support of coronary intervention. IVUS image segmentation often encounters difficulties when plaque and acoustic shadow are present A novel approach for hard plaque recognition and media-adventitia border detection of IVUS images is presented in this paper. The IVUS images were first enhanced by a spatial-frequency domain filter that was constructed by the directional filter and histogram equalization. Then, the hard plaque was recognized based on the intensity variation within different regions that were obtained using the k-means algorithm. In the next step, a cost matrix representing the probability of the media-adventitia border was generated by combining image gradient, plaque location and image intensity. A heuristic graph-searching was applied to find the media-adventitia border from the cost matrix.Experiment results showed that the accuracy of hard plaque recognition and media-adventitia border detection was 89.94% and 95.57%, respectively. In conclusion,using hard plaques recognition could improve media-adventitia border detection in IVUS images.
文摘Pneumocephalus is the presence of air in the cranial vault. The common etiologies of pneumocephalus are brain trauma and cranial surgery. We report a case of a 26-year-old man with brain trauma who developed diffuse pneumocephalus after sneezing. CT scan was performed on arrival, and the image showed subarach- noid hemolxhage without pneumocephalus. On the seventh day after a big sneeze brain CT scan was re-performed, which showed pneumocephalus. After another ten days of treatment, the patient was discharged without any symptoms.
基金financially supported by the National Natural Science Foundation of China(61474128,21503261,61504155and 61404145)Youth Innovation Fund for Interdisciplinary Research of SARI(Y526453233,141004)+2 种基金Science & Technology Commission of Shanghai Municipality(14JC1492900,14511102302,15DZ1100502)Youth Innovation Promotion Association,CAS(2013302)Development Fund for Information communication and integrated circuit technology public service platform(No.2016-14)supported by Zhangjiang Adminstrative Committee
文摘Complementary metal oxide semiconductor(CMOS) image sensors(CIS) are being widely used in digital video cameras, web cameras, digital single lens reflex camera(DSLR), smart phones and so on, owing to their high level of integration, random accessibility, and low-power operation. It needs to be installed with the cover glass in practical applications to protect the sensor from damage, mechanical issues,and environmental conditions, which, however, limits the accuracy and usability of the sensor due to the reflection in the optical path from air-to-cover glass-to-air. In this work, the flexible 3D nanocone anti-reflection(AR) film with controlled aspect ratio was firstly employed to reduce the light reflection at air/cover glass/air interfaces by directly attaching onto the front and rear sides of the CIS cover glass.As both the front and rear sides of cover glass were coated by the AR film, the output image quality was found to be improved with external quantum efficiency increased by 7%, compared with that without AR film. The mean digital data value, root-mean-square contrast, and dynamic range are increased by45.14%, 38.61% and 57, respectively, for the output image with AR films. These results provide a novel and facile pathway to improve the CIS performance and also could be extended to rational design of other image sensors and optoelectronic devices.
文摘Objective： To evaluate the sensitivity and specificity of CT scan findings in patients with blunt abdominal trauma admitted to the university hospital. Methods： All the patients with blunt abdominal trauma admitted at a tertiary teaching trauma center in Iran between 2005 and 2007 were enrolled in this study. In the absence of any clinical manifestations, the patients underwent a diagnostic CT scan. Laparatomy was performed in those with positive CT results. Others were observed for 48 hours and discharged in case no problem was reported; otherwise they underwent laparatomy. Information on patients＇ demographic data, mechanism of trauma, indication for CT scan, CT scan findings, results of laparotomy were gathered. The sensitivity, specificity and accuracy of the CT-scan images in regard with the organ injured were calculated. The sensitivity, specificity and accuracy of the CT scan were calculated in each case. Results： CT scan had the highest sensitivity for detecting the injuries to liver （100%） and spleen （86.6%）. The specificity of the method for detecting retroperitoneal hematoma （100%） and injuries to kidney （93.5%） was higher than other organs. The accuracy of CT images to detect the injuries to spleen, liver, kidney and retroperitoneal hematoma was reported to be 96.1%, 94.4%, 91.6% and 91.6% respectively. Conclusion： The findings of the present study reveal that CT scan could be considered as a good choice, especially for patients with blunt abdominal trauma in teaching hospitals where the radiologic academic staff is not present in the hospital in the night shifts.
