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find Keyword "视觉" 118 results
  • Research on pulmonary nodule recognition algorithm based on micro-variation amplification

    Objective To develop an innovative recognition algorithm that aids physicians in the identification of pulmonary nodules. MethodsPatients with pulmonary nodules who underwent thoracoscopic surgery at the Department of Thoracic Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School in December 2023, were enrolled in the study. Chest surface exploration data were collected at a rate of 60 frames per second and a resolution of 1 920×1 080. Frame images were saved at regular intervals for subsequent block processing. An algorithm database for lung nodule recognition was developed using the collected data. ResultsA total of 16 patients were enrolled, including 9 males and 7 females, with an average age of (54.9±14.9) years. In the optimized multi-topology convolutional network model, the test results demonstrated an accuracy rate of 94.39% for recognition tasks. Furthermore, the integration of micro-variation amplification technology into the convolutional network model enhanced the accuracy of lung nodule identification to 96.90%. A comprehensive evaluation of the performance of these two models yielded an overall recognition accuracy of 95.59%. Based on these findings, we conclude that the proposed network model is well-suited for the task of lung nodule recognition, with the convolutional network incorporating micro-variation amplification technology exhibiting superior accuracy. Conclusion Compared to traditional methods, our proposed technique significantly enhances the accuracy of lung nodule identification and localization, aiding surgeons in locating lung nodules during thoracoscopic surgery.

    Release date:2025-02-28 06:45 Export PDF Favorites Scan
  • Recent advance on photosensitive occipital lobe epilepsy

    Photosensitive occipital lobe epilepsy (POLE) is a rare idiopathic reflex focal epilepsy that can occur in all age groups. It is characterized by occipital lobe seizures induced by flashing stimuli (flashing sunlight, video games, TV commercials and programs, etc.). Photoparoxysmal response on EEG is induced by intermittent photic stimulation; Ictal EEG shows rapid spike rhythms are originated from the occipital region. There are no obvious abnormalities in brain image. POLE responds well to anti-seizure medications and has a good prognosis. This article reviews the research progress on POLE in order to improve the clinician’s understanding and reduce the rates of missed diagnosis and misdiagnosis.

    Release date:2024-07-03 08:46 Export PDF Favorites Scan
  • The effect of electrode positions on multifocal visual evoked potential

    Objective To compare the effect of electrode positions on multifocal visual evoked potential(mf-VEP). Methods Ten healthy individuals were tested with RETIscan multifocal VEP system 3.20, each individual was tested with four electrode positions: the active and reference electrode were placed 2.0 cm above and below the inion in Ch1;3.0 cm above and 4.5 cm below the inion in Ch2;2.0 cm on both right and left side of the inion in Ch3 and 4.0 cm on both right and left side of the inion in Ch4. The summed amplitudes of hemifield mf-VEP were analyzed and compared according to different electrode positions. Results The difference among summed amplitudes of the upper or lower hemifield mf-VEP recorded with Ch1、Ch2、Ch3 and Ch4 was statistically significant;and the difference between Ch2 and the other channels was statistically significant too. The difference among summed amplitudes of the horizontal sites whose amplitudes were small when recorded with Ch2 and summed amplitudes of the corresponding sites recorded with Ch3 and Ch4 were statistically significant;and the difference between Ch4 and the other channels was statistically significant too. Conclusions compared to Ch1、Ch3 and Ch4, Ch2 can make a better recording of mf-VEP. As for some sites, especially those along horizontal line, horizontal electrodes could improve the amplitudes of mf-VEP recorded with vertical electrodes,and Ch4 could do better to improve the mf-VEP recorded with Ch2 than Ch3. (Chin J Ocul Fundus Dis,2004,20:346-348)

    Release date:2016-09-02 05:58 Export PDF Favorites Scan
  • THE ANALYSIS OF DIAPARITY EVOKED POTENTIALS BY A NEW FORM OF STATIC RANDOM-DOT STEREOGRAMS

    A new form of static random-dot stereograms free of monocular clues was designed as stimulus to elicit disparity evoked potentials in 40 normal subjects.A characteristic wide positive wave at about 250ms was consistently recorded in disparity stimulation,which may be regard as evdence of the presence of stereopsis.In constrast,recordings for monocular stimulus all demonstrated a relatively smaller and sharper positive wave with a markedly shortened latency. (Chin J Ocul Fundus Dis,1993,9:214-217)

    Release date:2016-09-02 06:35 Export PDF Favorites Scan
  • The detection of disparity evoked potentials in ametropes.

    Purpose To investigate the influence of ametropia on stereopsis and its mechanism by using the disparity evoked potential testing. Methods A new set of static random dot stereograms was utilized as a stimulation to elicit the disparity evoked potentials in 21 ametropes and 40 stereo normal subjects. Rezults The P250 wave,which was related to stereoscopic stimulation in ametropes,was recorded in both the ametropes and emetropic stereo normal persons in this series,and the characteristic changes of P250 wave with increasing visual disparity in ametropes were similar to those in normal subjects.The differences of mean amplitudes and latencies of P250 waves between myopes and hyperopes were not significant. Conclusion Ametropia in full correction dose not significanly affect the function of stereopsis. (Chin J Ocul Fundus Dis,1998,14:225-227)

    Release date:2016-09-02 06:11 Export PDF Favorites Scan
  • The Application of Multifocal Visual Evoked Potentials in Cerebral Palsy Children

    ObjectiveTo evaluate the differences of visual evoked potentials (amplitudes and latency) between cerebral palsy (CP) children and normal children. MethodsThis study involved fourteen children aged from 4 to 7 years with CP (monoplegia) between 2009 and 2013. Another 14 normal children aged from 5 to 9 years treated in the Department of Ophthalmology in West China Hospital during the same period were regarded as the control group. Both eyes of all the participants were examined by multifocal visual evoked potential (mfVEP). The mfVEP examination results were recorded, and amplitude and latency were analyzed. First, we analyzed the differences of amplitudes and latency time between monoplegia children and children in the control group. Second, gross motor function classification system (GMFCS) was used to classify the fourteen monoplegia children among whom there were five GMFCS Ⅰ patients and nine GMFCS Ⅱ patients. The differences of mfVEP were analyzed between the two GMFCS groups. ResultsThe amplitude and latency of mfVEP in children with CP showed gradual changes similar to those in the normal children. The amplitudes were decreasing and the latencies were delaying from the first eccentricity to the sixth eccentricity. The amplitudes in children with CP were lower than those in the control group in the first to the third eccentricities for both eyes (P<0.05), and latency of left eye was delayed in the first eccentricity in children with CP (P=0.045). No difference was found between the two GMFCS groups (P>0.05) except the amplitude of the first eccentricity (P=0.043). ConclusionsThe results of mfVEP show significant differences of amplitude and latency between CP and normal children, suggesting the existence of visual pathway impairments in cerebral palsy children. The results of mfVEP can provide an objective basis of visual impairments for cerebral palsy children.

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  • Magnetic resonance diffusion tensor imaging for optic nerves and optic radiation in blind patients

      Objective To observe the characteristics of magnetic resonance diffusion tensor imaging(MR-DTI)for optic nerves and optic radiation in blind patients.Methods The optic nerves and optic radiation of 20 blind patients(blind group)and 20 controls(control group) were scanned by MR-DTI. Fractional anisotropy (FA) and directional encoded color (DEC) maps were acquired through postprocessing with the aid of volumeone 1.72 software. The signal intensity of optic nerves and optic radiation were then observed. The FA, mean diffusivity (MD), lambda;∥ and lambda;perp; value of bilateral optic nerves and optic radiation in two groups were measured in the DEC maps.Results While the high signal intensity was found in bilateral optic nerves in FA and DEC maps in control group,the signal decreased markedly in the blind group. The FA and lambda;∥ value of optic nerves in the blind group were declined obviously compared to that in the control group. The difference was statistically significant (t=16.294, 14.660;P=0.000). The MD and lambda;perp; value of optic nerves in the blind group were increased obviously compared to that in the control group, the difference was also statistically significant (t=8.096, 8.538; P=0.000). The high signal intensity was found in bilateral optic radiation in FA and DEC maps in both the blind and control groups. There were no statistic differences in FA and MD value in bilateral optic radiation between the blind and control groups (Left:t=1.456,1.811;P=0.152,0.076. Right:t=0.779,0.073;P=0.440,0.942). Conclusion A low signal intensity of bilateral optic nerves and a high signal intensity of bilateral optic radiation were found in blind patients.

    Release date:2016-09-02 05:41 Export PDF Favorites Scan
  • Application of real visual experience in optometry teaching

    Optometry involves knowledge from multiple fields such as biology, physics, chemistry, psychophysics, and medicine. Traditional undergraduate education in optometry mainly focuses on knowledge transmission and lacks interaction, resulting in low student interest and unsatisfactory teaching outcomes. In order to improve this situation, the teaching team of Department of Optometry and Visual Science, West China School of Medicine, Sichuan University proposed a method of integrating real visual experiences into teaching. By combining multimedia tools and existing methods, real visual phenomena and personal visual experiences are integrated into the curriculum. This new teaching method stimulates students’ interest in learning, increases classroom interaction, promotes knowledge understanding and application through vivid visual phenomena and students’ own visual experiences. This article will introduce the above teaching method.

    Release date:2025-01-23 08:44 Export PDF Favorites Scan
  • The effect of form deprivation on the morphology of retinal ganglion cells in mice

    ObjectiveTo investigate the effects of form deprivation on the morphology of different types of RGC in mice.MethodsSixty B6.Cg-Tg (Thy1-YFP) HJrs/J transgenic mice were randomly assigned to form-deprived group (n=28) and control group (n=32). The right eyes of mice in the form-deprived group were covered by an occluder for 2 weeks as experimental eyes. The right eyes of mice in the control group were taken as control eyes. Before and 2 weeks after form deprivation, the refraction and ocular biometrics were measured; RGC were stained with Bra3a antibody and counted; the morphology of RGC was reconstructed with Neuroexplore software after immunohistochemical staining. The data was compared among experimental eyes, fellow eyes and control eyes by one-way analysis of variance.ResultsTwo weeks after form deprivation, the axial myopia was observed in the experimental eyes (refraction: F=15.009, P<0.001; vitreous chamber depth: F=3.360, P=0047; ocluar axial length: F=5.011, P=0013). The number of RGC in central retina of the experimental eyes was decreased compared with the fellow eyes and the control eyes (F=4.769, P=0.035). The reconstructed RGC were classified into 4 types according to their dendritic morphology. Form deprivation affected all 4 types of RGC but in a different way. Among them, 3 types of RGC were likely contribute to form vision perception. Form deprivation increased the dendrite branches in these types of ganglion cells. However, form deprivation decreasd dendrite segment numbers in both eyes and the intersection and length insholl analyse type 4 ganglion cells which were morphologically identified as ipRGC.ConclusionForm deprivation distinguishingly affects the morphology of different types of RGC, indicating that form vision and non-form vision play different role in myopia development.

    Release date:2019-11-19 09:24 Export PDF Favorites Scan
  • A review of researches on decoding algorithms of steady-state visual evoked potentials

    Brain-computer interface (BCI) systems based on steady-state visual evoked potential (SSVEP) have become one of the major paradigms in BCI research due to their high signal-to-noise ratio and short training time required by users. Fast and accurate decoding of SSVEP features is a crucial step in SSVEP-BCI research. However, the current researches lack a systematic overview of SSVEP decoding algorithms and analyses of the connections and differences between them, so it is difficult for researchers to choose the optimum algorithm under different situations. To address this problem, this paper focuses on the progress of SSVEP decoding algorithms in recent years and divides them into two categories—trained and non-trained—based on whether training data are needed. This paper also explains the fundamental theories and application scopes of decoding algorithms such as canonical correlation analysis (CCA), task-related component analysis (TRCA) and the extended algorithms, concludes the commonly used strategies for processing decoding algorithms, and discusses the challenges and opportunities in this field in the end.

    Release date:2022-06-28 04:35 Export PDF Favorites Scan
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