The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform

Henrik Lundandersen - One of the best experts on this subject based on the ideXlab platform.

  • optos wide field imaging versus Conventional Camera imaging in danish patients with type 2 diabetes
    Acta Ophthalmologica, 2019
    Co-Authors: Stine Byberg, Dorte Vistisen, Lars Jorge Diaz, Morten Charles, Javad Nouri Hajari, Marianne Valerius, Ellen Juul, Marit E Jorgensen, Henrik Lundandersen
    Abstract:

    PURPOSE Diabetic retinopathy (DR) screening methods are costly, requiring specialized personnel and patient mydriasis. The Optos apparatus can be operated by nonspecialists and provides ultra-wide-field imaging, with 200° views of the retina in a single image. We compared DR grading obtained from Optos imaging with DR grading from Conventional Topcon imaging. METHODS We conducted a cross-sectional study of 101 persons with diabetes who participated in the Addition-DK 10-year follow-up study. Retina fundus photos using both Optos and Topcon imaging were taken for both eyes. All photos were graded by specialist ophthalmologic nurses, using a modified version of the 'Proposed International Clinical DR severity scale'. We constructed frequency tables and assessed levels of agreement between Optos and Topcon gradings using weighted Kappa statistics, separately for peripheral and macular grading. We tested if the agreements between the two Cameras were significantly different using a stratified Wilcoxon test. RESULTS Significantly, more lesions in the periphery were identified by Optos compared with Topcon (p < 0.01), resulting in a fair Kappa agreement of 0.21. We saw no significant differences in the grading of the macula region (p = 0.97) between the two Cameras. Although only 7% of the macula image gradings differed between the Cameras, the Kappa agreement of macula grading was only moderate (Kappa = 0.52). CONCLUSION The inter-Camera agreement was acceptable for macula image grading, but only fair for peripheral grading, with Optos identifying more microvascular changes in the periphery. The clinical significance and impact on screening modality and frequency remain to be explored.

Paul M Simon - One of the best experts on this subject based on the ideXlab platform.

  • single shot high dynamic range imaging with Conventional Camera hardware
    International Conference on Computer Vision, 2011
    Co-Authors: Keigo Hirakawa, Paul M Simon
    Abstract:

    A combination of photographic filter placed over the lens and the color filter array on image sensor induces differences in red, green, and blue channel sensitivities. Spectrally selective single-shot HDR (S4HDR) imaging treats this as an exposure bracketing. Optimally exposed regions of low dynamic range red/green/blue color components are merged in a principled manner to yield a single HDR color image. Though not expected to yield results superior to the traditional time multiplexing counterparts, the single-shot HDR solution we propose is a robust alternative that can be realized with Conventional Camera hardware.

Marit E Jorgensen - One of the best experts on this subject based on the ideXlab platform.

  • optos wide field imaging versus Conventional Camera imaging in danish patients with type 2 diabetes
    Acta Ophthalmologica, 2019
    Co-Authors: Stine Byberg, Dorte Vistisen, Lars Jorge Diaz, Morten Charles, Javad Nouri Hajari, Marianne Valerius, Ellen Juul, Marit E Jorgensen, Henrik Lundandersen
    Abstract:

    PURPOSE Diabetic retinopathy (DR) screening methods are costly, requiring specialized personnel and patient mydriasis. The Optos apparatus can be operated by nonspecialists and provides ultra-wide-field imaging, with 200° views of the retina in a single image. We compared DR grading obtained from Optos imaging with DR grading from Conventional Topcon imaging. METHODS We conducted a cross-sectional study of 101 persons with diabetes who participated in the Addition-DK 10-year follow-up study. Retina fundus photos using both Optos and Topcon imaging were taken for both eyes. All photos were graded by specialist ophthalmologic nurses, using a modified version of the 'Proposed International Clinical DR severity scale'. We constructed frequency tables and assessed levels of agreement between Optos and Topcon gradings using weighted Kappa statistics, separately for peripheral and macular grading. We tested if the agreements between the two Cameras were significantly different using a stratified Wilcoxon test. RESULTS Significantly, more lesions in the periphery were identified by Optos compared with Topcon (p < 0.01), resulting in a fair Kappa agreement of 0.21. We saw no significant differences in the grading of the macula region (p = 0.97) between the two Cameras. Although only 7% of the macula image gradings differed between the Cameras, the Kappa agreement of macula grading was only moderate (Kappa = 0.52). CONCLUSION The inter-Camera agreement was acceptable for macula image grading, but only fair for peripheral grading, with Optos identifying more microvascular changes in the periphery. The clinical significance and impact on screening modality and frequency remain to be explored.

Paul J M Wijsman - One of the best experts on this subject based on the ideXlab platform.

  • efficiency in image guided robotic and Conventional Camera steering a prospective randomized controlled trial
    Surgical Endoscopy and Other Interventional Techniques, 2021
    Co-Authors: Paul J M Wijsman, F J Voskens, Lennert Molenaar, C D P Van T Hullenaar, E C J Consten, Werner A Draaisma, I A M J Broeders
    Abstract:

    Robotic Camera steering systems have been developed to facilitate endoscopic surgery. In this study, a randomized controlled trial was conducted to compare Conventional human Camera control with the AutoLap™ robotic Camera holder in terms of efficiency and user experience when performing routine laparoscopic procedures. Novelty of this system relates to the steering method, which is image based. Patients undergoing an elective laparoscopic hemicolectomy, sigmoid resection, fundoplication and cholecystectomy between September 2016 and January 2018 were included. Stratified block randomization was used for group allocation. The primary aim of this study was to compare the efficiency of robotic and human Camera control, measured with surgical team size and total operating time. Secondary outcome parameters were number of cleaning moments of the laparoscope and the post-study system usability questionnaire. A total of 100 patients were randomized to have robotic (50) versus human (50) Camera control. Baseline characteristics did not differ significantly between groups. In the robotic group, 49/50 (98%) of procedures were carried out without human Camera control, reducing the surgical team size from four to three individuals. The median total operative time (60.0 versus 53.0 min, robotic vs. control) was not significantly different, p = 0.122. The questionnaire showed a positive user satisfaction and easy control of the robotic Camera holder. Image-based robotic Camera control can reduce surgical team size and does not result in significant difference in operative time compared to human Camera control. Moreover, robotic image-guided Camera control was associated with positive user experience.

N. Ahuja - One of the best experts on this subject based on the ideXlab platform.

  • An Omnidirectional Stereo Vision System Using a Single Camera
    18th International Conference on Pattern Recognition (ICPR'06), 2006
    Co-Authors: Sooyeong Yi, N. Ahuja
    Abstract:

    We describe a new omnidirectional stereo imaging system that uses a concave lens and a convex mirror to produce a stereo pair of images on the sensor of a Conventional Camera. The light incident from a scene point is split and directed to the Camera in two parts. One part reaches Camera directly after reflection from the convex mirror and forms a single-viewpoint omnidirectional image. The second part is formed by passing a subbeam of the reflected light from the mirror through a concave lens and forms a displaced single viewpoint image where the disparity depends on the depth of the scene point. A closed-form expression for depth is derived. Since the optical components used are simple and commercially available, the resulting system is compact and inexpensive. This, and the simplicity of the required image processing algorithms, make the proposed system attractive for real-time applications, such as autonomous navigation and object manipulation. The experimental prototype we have built is described