Simultaneous Localization and Mapping (SLAM) is a crucial technology for intelligent mobile robots to operate successfully in unknown environments. While many excellent SLAM systems have been ...developed in recent years, most assume that the environment is static, resulting in poor performance in dynamic environments. To address this limitation, we propose multiview stereo (MVS)‐SLAM (MVS‐SLAM), a real‐time semantic RGBD SLAM system with improved‐multiview geometry, built on the RGBD mode of ORB‐SLAM3. MVS‐SLAM tightly integrates semantic and geometric information to tackle the challenges posed by dynamic scenes. To meet the real‐time requirements, the semantic module leverages the latest and fastest object detection network, YOLOv7, to provide semantic prior knowledge for the geometric module. We introduce a novel geometric constraint method that capitalizes on depth images and semantic information to recover three‐dimensional (3D) feature points and initial camera pose. We use a 3D coordinate error threshold to identify dynamic points and remove them using the K‐means clustering algorithm. This approach effectively reduces the impact of dynamic points. We validate MVS‐SLAM using challenging dynamic sequences from the TUM data set, demonstrating that it significantly improves localization accuracy and system robustness in all types of dynamic environments.
Using satellite-based SAR (Synthetic Aperture Radar) imagery to detect and track ships is a formidable challenge. However, accurate analysis is hampered by inherent difficulties such as obscured ...edges, multiple targets, varying dimensions and complex backgrounds. These factors contribute to a poor signal-to-noise ratio. Various artificial intelligence models have been developed to improve these problems, especially with YOLO-based models. To overcome the above challenges and achieve robust performance, this study presents a model called SwinYOLOv7, a novel fusion of the YOLOv7 framework with the Features Pyramid Network and the Swin Transformer using ground-breaking anchor-free detection algorithms. This innovative method aims to increase the accuracy of vessel detection while reducing the impact of background clutter. The proposed model improved by YOLOv7 examined three different datasets in detail: SRSDD-v1.0, HRSID, and SSDD to optimize the performance of the model. The training process was consistently verified using superior recall, precision, and F1-score values, which can be easily compared with previous studies. The results show that the model using the Swin Transformer attention mechanism and using an image size of 640×640 achieves the highest accuracy of 96.59%. Alternative attention mechanisms, including the Squeeze-and-Excitation Network (SEnet), the Convolutional Block Attention Module (CBAM), Channel Attention (CA) and Efficient Channel Attention (ECA), deliver poorer accuracy rates. The combination of YOLOv7 and Swin Transformer yielded encouraging results that enabled the proposed model to outperform the current benchmarking models. Therefore, the proposed model provides a compelling solution to ensure accurate vessel identification in complex search and rescue scenarios.
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•A new version of YOLOv7 model was developed based on Swin Transformer.•Different data sources were used for training and testing new model for ship detection.•The performance of new model was compared with other 18 older models.•The new YOLOv7 model boosts the detection performance better than previous ones.•Model using 640×640 image size achieved the highest accuracy of 96.59%.
We explore the tilted-pulse-front excitation technique to control the superradiant emission of terahertz (THz) pulses from large-area photonconductive semiconductor switches. Two cases are studied. ...First, a photoconductive antenna emitting into free space, where the propagation direction of the optically generated THz beam is controlled by the choice of the tilt angle of the pump pulse front. Second, a THz waveguide structure with an integrated photoconductive window for the generation of THz radiation, where the injection of the THz radiation into a waveguide mode is optimized by the pulse front tilt. By providing long interaction lengths, such a waveguide-based optical-pump/THz-probe set-up may provide a new platform for the study of diverse short-lived optically induced excitations.
To compare the mean change in Corneal Endothelial cell Density (CED), from baseline (pre-operative value), two months after phacoemulsification cataract surgery between type II diabetic patients and ...non-diabetic patients.
This prospective stratified controlled study was conducted at PNS Shifa Hospital, Karachi. 80 eyes of 72 type II diabetic patients and 80 eyes of 77 non diabetic controls, having Nuclear Opalescence (NO) grades 2 and 3 on slit lamp examination underwent phacoemulsification surgery. CED was measured in cells/mm
, of concerned eye of each subject preoperatively and 2 months post operatively using specular microscope. The difference in mean CED change between the two groups after surgery was analyzed.
Mean age of study population was 61.41± 6.76 years. Out of study population, 92 (57.5%) were males and 68 (42.5%) were females. There was a statistically significant difference between both groups in terms of mean post-operative CED, mean change in CED and mean frequency change in CED (p <0.05). There was no statistically significant difference between both groups in age, gender, laterality of eyes and mean pre-operative CED, (p >0.05). Difference of pre-operative CED from post-operative CED in each group was statistically significant.
There is a significant difference between diabetic population and normal population in terms of corneal endothelial loss after uneventful phacoemulsification cataract surgery.
To compare the difference in peripapillary Retinal Nerve Fibre Layer (RNFL) thickness between normal population and Type-II diabetic patients without diabetic retinopathy using Spectral Domain ...Optical Coherence Tomography (SD OCT).
This cross sectional study was carried out at PNS Shifa Naval Hospital, from May 2017 to November 2017. Out of 200 eyes, 100 eyes were of normal individuals and 100 eyes were of Type-II diabetic patients without diabetic retinopathy. Both groups were age and gender matched. Average RNFL thickness, along with RNFL of each quadrant of individuals was noted using SD OCT, and compared between two groups.
Mean age of study population was 44.63 ± 4.30 years. Mean axial length was 23.46 ± 0.59 mm. Mean peripapillary RNFL thickness was 126.98 ± 10.07 µm in Group-A (normal individuals), and 120.77 ± 5.41 µm in Group-B (Type-II diabetics). Difference in mean RNFL thickness, as well as RNFL thicknesses of each quadrant was statistically significant between both groups (p-value < 0.001).
Diabetic patients have thin RNFL as compared to normal individuals, and must be taken in account while making diagnosis of any disease based on thinning of RNFL.
Solid lipid nanoparticles (SLNs) have several potential applications in the topical drug delivery. The current project aimed to prepare and characterize SLNs loaded with vitamin E for topical ...administration and incorporating the prepared SLNs in a cream base. Further, the permeation of prepared SLNs was studied through a synthetic membrane and the release profiles were compared with vitamin E cream. The prepared SLNs were subjected to stability studies at two different temperatures. Hot homogenization followed by dilution technique was used for the preparation of SLNs. In this project, PDMS membrane was used to mimic the skin for permeation studies. From the results of this study, it can be concluded that prepared SLNs had enhanced the permeation of vitamin E as compared to vitamin E cream.
Primary open angle glaucoma (POAG) is worldwide prevalent ailment, affecting millions, and leading irreversible cause of blindness. The treatment strategies revolve around one modifiable factor, ...elevated intraocular pressure (IOP), despite POAG presenting with normal IOP. Emphasis is put forth in recent past detecting structural elements of glaucoma; lamina cribrosa (LC) is found to be a promising prospect. Morphological alterations of LC are implicated as early sign before onset of glaucomatous optic neuropathy (GON). In this review, the authors explored scientific works from 1976 till 2018 through Google, Google Scholar, PubMed, HEC Digital Library, Springerlink, and PakMedinet in four months’ time, extracted structural features of LC, its measurable attributes, fresh innovations employed for in-vivo visualization and clinical signs aiding in establishing diagnosis of glaucoma which will assist as a prophylactic measure against GON. No such work has ever been done in South-East Asia including our country. So LC opens a new horizon for research in Pakistan.
doi: https://doi.org/10.12669/pjms.35.6.568
How to cite this:Saba A, Usmani A, Qamar-Ul-Islam, Assad T. Unfolding the enigma of lamina cribrosa morphometry and its association with glaucoma. Pak J Med Sci. 2019;35(6):1730-1735. doi: https://doi.org/10.12669/pjms.35.6.568
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
This study aims to explore the factors contributing mental health of Afghan migrants residing in Iran during the COVID-19 pandemic. With a deep understanding of the unique challenges encountered by ...migrants, especially during times of crisis, this research delves into the influential factors of experienced anxiety, social cohesion, and stress and their significant contribution to the development of depression among Afghan migrants. The study included a sample of 469 individuals from the Afghan migrant community, aged 15 to 80 years. Data collection took place from December to March 2022 in Iran. The study revealed that anxiety and the burden of the COVID-19 pandemic significantly influenced the occurrence of depression among Afghan migrants. Furthermore, the relationship between these factors and depression was mediated by the experience of stress. Conversely, higher levels of perceived social cohesion in the host country were linked to reduced stress and depression among the migrants. As Afghan migrants in Iran face a heightened risk of developing depression, the importance of social support and integration is underscored by the association between higher levels of perceived social cohesion in the host country and reduced levels of stress and depression. Recognizing the vulnerabilities of this population, it becomes evident that fostering social support networks and promoting integration can play a crucial role in mitigating the negative impact of migration-related stressors and enhancing mental wellbeing among this population.
To compare corneal morphological parameters between diabetics and age matched non-diabetic control subjects and to evaluate the correlation of these parameters in relation to duration of diabetes ...mellitus (DM), glycemic status and severity of diabetic retinopathy.(DR).
This cross sectional comparative study was conducted at the Department of Ophthalmology, PNS Shifa Karachi from February 2016 to January 2017. Patients with ages between 10 to 80 years of either gender who were diagnosed to have DM were recruited in the study. Control group comprised of age matched healthy volunteers who did not have DM. Corneal morphological parameters (CED, Average cell size, CV of cell size and hexagonality) was evaluated in each subject with non-contact specular microscope and findings were endorsed on a pre devised proforma.
Data of 298 eyes (149 diabetic patients and 149 healthy controls) was evaluated. Mean corneal endothelial cell density (CED) of diabetic population was 2494.47 ± 394.10 cells/mm
, while mean CED of control group was 2574.46 ± 279.97 cells/mm
p = 0.04. Between group differences in mean average cell size, CV of cell size and hexagonality was statistically not significant. Analysis of corneal endothelial parameters among subgroups of patients with no DR, with NPDR and PDR did not show statistically significant difference. Moreover, patients with diabetes of more than 10 years duration had significantly lower CED (p <0.01) and larger average cell size (p= 0.03). Duration of DM was significantly correlated with type of DR, HbA1c level, CED, polymegethism and hexagonality.
Mean corneal endothelial cell density (CED) was found to be significantly lower in diabetic population as compared to healthy controls.
Objective: To compare the frequency of depression in low vision and normal vision patients.
Study Design: Comparative cross-sectional study.
Place and Duration of Study: Eye Department, Combined ...Military Hospital, Malir Cantt, Karachi Pakistan, from Dec 2017 to May 2019.
Methodology: Patients with low vision and normal vision were evaluated for depression. Initially, each patient underwent a complete Outpatient ophthalmological workup. Then, the patients were assigned to the low vision and normal vision groups,and after informed consent, each patient was to complete Patient Health Questionnaire-9 (PHQ-9).
Result: Two hundred and sixty-nine patients with low vision and 275 patients with normal vision were included in the study.One hundred and eighty-two (67.66%) patients with low vision and 71(25.82%) patients with normal vision were found to have significant depression (PHQ-9 score≥5). Depression was significantly more prevalent in the Low Vision-Group (p=<0.01).
Conclusion: Significantly high level of depression in the Low Vision-Group needs to be taken care of in ophthalmology departments. The ophthalmologist should not look into the eyes but treat the patients as human beings.
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