1,720,976 research outputs found
Development of a surgical stereo endoscopic image dataset for validating 3D stereo reconstruction algorithms
Get PDFIn the last decades, endoscopic stereo images have been exploited to retrieve tissue surface information of the surgical site using 3D reconstruction algorithms. The application of such algorithms in Computer Assisted Surgery (CAS) tools for Minimally Invasive Surgery (MIS) requires a robust validation process in order to guarantee reliability and safety. 3D reconstruction algorithms are commonly evaluated comparing their result with respect to a reference Ground Truth (GT). However, few datasets providing endoscopic images and GT are openly available.
Considering the increasing necessity of surgical datasets, the aim of this work is the generation of an Endoscopic Abdominal Stereo (EndoAbS) dataset composed of stereo-images with associated GT for 3D stereo-reconstruction algorithm validation. To recreate the surgical scenario, a polyurethane surgical phantom abdomen was built. Images were captured with a stereo-endoscope, while for acquiring the GT a laser scanner (calibrated with respect to the stereoendoscope) was used. This dataset is openly available on-line for the benefit of the CAS community
Label-based Optimization of Dense Disparity Estimation for Robotic Single Incision Abdominal Surgery
Get PDFMinimally invasive surgical techniques have led to novel approaches such as Single Incision Laparoscopic Surgery (SILS), which allows the reduction of post-operative infections and patient recovery time, improving surgical outcomes. However, the new techniques pose also new challenges to surgeons: during SILS, visualization of the surgical field is limited by the endoscope field of view, and the access to the target area is limited by the fact that instruments have to be inserted through a single port.
In this context, intra-operative navigation and augmented reality based on pre-operative images have the potential to enhance SILS procedures by providing the information necessary to increase the intervention accuracy and safety. Problems arise when structures of interest change their pose or deform with respect to pre-operative planning, as usually happens in soft tissue abdominal surgery. This requires online estimation of the deformations to correct the pre-operative plan, which can be done, for example, through methods of depth estimation from stereo endoscopic images (3D reconstruction). The denser the reconstruction, the more accurate the deformation identification can be.
This work presents an algorithm for 3D reconstruction of soft tissue, focusing on the refinement of the disparity map in order to obtain an accurate and dense point map. This algorithm is part of an assistive system for intra-operative guidance and safety supervision for robotic abdominal SILS .
Results show that comparing our method with state-of-the-art CPU implementations, the percentage of valid pixel obtained with our method is 24% higher while providing comparable accuracy. Future research will focus on the development of a real-time implementation of the proposed algorithm, potentially based on a hybrid CPU-GPU processing framework
Virtual Assistive System for Robotic Single Incision Laparoscopic Surgery
Get PDFSingle Incision Laparoscopic Surgery (SILS) reduces
the trauma of large wounds decreasing the post-operative infections,
but introduces technical difficulties for the surgeon, who has
to deal with at least three instruments in a single incision. These
drawbacks can be overcome with the introduction of robotic
arms inside the abdominal cavity, but still remain difficulties in
the surgical field vision, limited by the endoscope field of view.
This work is aimed at developing a system to improve the information
required by the surgeon and enhance the vision during
a robotic SILS. In the pre-operative phase, the segmentation and
surface rendering of organs allow the surgeon to plan the surgery.
During the intra-operative phase, the run-time information (tools
and endoscope pose) and the pre-operative information (3D
models of organs) are combined in a virtual environment. A
point-based rigid registration of the virtual abdomen on the real
patient creates a connection between reality and virtuality. The
camera-image plane calibration allows to know at run-time the
pose of the endoscopic view.
The results show how using a small set of 4 points (the minimal
number of points that would be used in a real procedure) for the
camera-image plane calibration and for the registration between
real and virtual model of the abdomen, is enough to provide a
calibration/registration accuracy within the requirements
Dense soft tissue 3D reconstruction refined with super-pixel segmentation for robotic abdominal surgery
Get PDFPurpose: Single-incision laparoscopic surgery decreases postoperative infections, but introduces limitations in the surgeon’s maneuverability and in the surgical field of view. This work aims at enhancing intra-operative surgical visualization by exploiting the 3D information about the surgical site. An interactive guidance system is proposed wherein the pose of preoperative tissue models is updated online. A critical process involves the intra-operative acquisition of tissue surfaces. It can be achieved using stereoscopic imaging and 3D reconstruction techniques. This work contributes to this process by proposing new methods for improved dense 3D reconstruction of soft tissues, which allows a more accurate deformation identification and facilitates the registration process.
Methods: Two methods for soft tissue 3D reconstruction are proposed: Method 1 follows the traditional approach of the block matching algorithm. Method 2 performs a nonparametric modified census transform to be more robust to illumination variation. The simple linear iterative clustering (SLIC) super-pixel algorithm is exploited for disparity refinement by filling holes in the disparity images.
Results: The methods were validated using two video datasets from the Hamlyn Centre, achieving an accuracy of 2.95 and 1.66 mm, respectively. A comparison with ground-truth data demonstrated the disparity refinement procedure: (1) increases the number of reconstructed points by up to 43% and (2) does not affect the accuracy of the 3D reconstructions significantly.
Conclusion: Both methods give results that compare favorably with the state-of-the-art methods. The computational time constraints their applicability in real time, but can be greatly improved by using a GPU implementation
Enhanced Vision to Improve Safety in Robotic Surgery
Get PDFIn the last few decades, major complications in surgery have emerged as a significant public health issue, and so the practical implementation of safety measures to prevent injuries and deaths in different phases of surgery is required. The introduction of novel technologies in the operating theater, such as surgical robotic systems, opens new questions on how much and in which way safety can be further improved. Computer-assisted surgery, in combination with robotic systems, can greatly help in enhancing the surgeons’ capabilities providing direct patient- and process-specific support to surgeons with different degrees of experience. In particular, the application of augmented reality (AR) tools could represent a significant step toward safer clinical procedures, improving the quality of health care. This chapter describes the main areas involved in an AR system, such as computer vision methods for identification of areas of interest, surgical scene description, and safety warning methods. Recent advances in the field are also presented, providing as an example the Enhanced Vision System for Robotic Surgery: an AR system to provide assistance in the protection of vessels from injury during the execution of surgical procedures with a commercial robotic surgical system
Enhanced Vision System to improve safety in Robotic Single Incision Laparoscopic Surgery
Get PDFMinimally invasive abdominal surgery can reduce the trauma of large wound to a minimum, but introduces technical difficulties for the surgeon, who has to deal with at least three instruments in a single incision. These drawbacks can be overcome with the introduction of robotic arms inside the abdominal cavity. In this work we propose an architecture to increase the safety during intra-operative robotic Single Incision Laparoscopic Surgery (SILS) based on intraoperative registration of pre-operative images and dynamic active constraints. In the pre-operative phase the surface rendering of organs allows the surgeon to identify important structures to be protected during the surgery. A subsequent step consists in registering these images to the intraoperative images acquired using on board stereo-cameras. The precision of this latter step is highly dependent on the stereo vision calibration of the imaging system.
We present the evaluation of the accuracy of our stereo imaging system. Preliminary results show that the number of frames for high quality stereo camera calibration is 35. In this case, the camera calibration accuracy satisfies the clinical requirements for organ motion tracking
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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