LiDAR-assisted Large-scale Privacy Protection in Street-view Cycloramas

Recently, privacy has a growing importance in several domains, especially in street-view images. The conventional way to achieve this is to automatically detect and blur sensitive information from these images. However, the processing cost of blurring increases with the ever-growing resolution of images. We propose a system that is cost-effective even after increasing the resolution by a factor of 2.5. The new system utilizes depth data obtained from LiDAR to significantly reduce the search space for detection, thereby reducing the processing cost. Besides this, we test several detectors after reducing the detection space and provide an alternative solution based on state-of-the-art deep learning detectors to the existing HoG-SVM-Deep system that is faster and has a higher performance.Comment: Accepted at Electronic Imaging 201

Aggregated Deep Local Features for Remote Sensing Image Retrieval

Remote Sensing Image Retrieval remains a challenging topic due to the special nature of Remote Sensing Imagery. Such images contain various different semantic objects, which clearly complicates the retrieval task. In this paper, we present an image retrieval pipeline that uses attentive, local convolutional features and aggregates them using the Vector of Locally Aggregated Descriptors (VLAD) to produce a global descriptor. We study various system parameters such as the multiplicative and additive attention mechanisms and descriptor dimensionality. We propose a query expansion method that requires no external inputs. Experiments demonstrate that even without training, the local convolutional features and global representation outperform other systems. After system tuning, we can achieve state-of-the-art or competitive results. Furthermore, we observe that our query expansion method increases overall system performance by about 3%, using only the top-three retrieved images. Finally, we show how dimensionality reduction produces compact descriptors with increased retrieval performance and fast retrieval computation times, e.g. 50% faster than the current systems.Comment: Published in Remote Sensing. The first two authors have equal contributio

Bootstrapped CNNs for Building Segmentation on RGB-D Aerial Imagery

Detection of buildings and other objects from aerial images has various applications in urban planning and map making. Automated building detection from aerial imagery is a challenging task, as it is prone to varying lighting conditions, shadows and occlusions. Convolutional Neural Networks (CNNs) are robust against some of these variations, although they fail to distinguish easy and difficult examples. We train a detection algorithm from RGB-D images to obtain a segmented mask by using the CNN architecture DenseNet.First, we improve the performance of the model by applying a statistical re-sampling technique called Bootstrapping and demonstrate that more informative examples are retained. Second, the proposed method outperforms the non-bootstrapped version by utilizing only one-sixth of the original training data and it obtains a precision-recall break-even of 95.10% on our aerial imagery dataset.Comment: Published at ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Science

Temperature dependent graphene suspension due to thermal Casimir interaction

Thermal effects contributing to the Casimir interaction between objects are usually small at room temperature and they are difficult to separate from quantum mechanical contributions at higher temperatures. We propose that the thermal Casimir force effect can be observed for a graphene flake suspended in a fluid between substrates at the room temperature regime. The properly chosen materials for the substrates and fluid induce a Casimir repulsion. The balance with the other forces, such as gravity and buoyancy, results in a stable temperature dependent equilibrium separation. The suspended graphene is a promising system due to its potential for observing thermal Casimir effects at room temperature.Comment: 5 pages, 4 figures, in APL production 201

Minimally invasive osteosynthesis of fractures of the tibial condyles

ОСТЕОСИНТЕЗ ПЕРЕЛОМАПЕРЕЛОМА ИММОБИЛИЗАЦИЯ ВНУТРЕННЯЯХИРУРГИЧЕСКИЕ ОПЕРАЦИИ МАЛОИНВАЗИВНЫЕБОЛЬШЕБЕРЦОВОЙ КОСТИ ПЕРЕЛОМЫ /ХИРКОНЕЧНОСТИ НИЖНЕЙ ТРАВМЫ /ХИРПЕРЕЛОМЫ /ХИРЦель. Провести сравнительный анализ результатов малоинвазивного и традиционного открытого остеосинтеза у пациентов с переломами мыщелков большеберцовой кости. Материал и методы. В зависимости от проводимого метода хирургического лечения переломов мыщелков большеберцовой кости пациенты были разделены на две группы. В первой группе (n=70) применялась открытая репозиция перелома с внутренней фиксацией. Во второй группе (n=70) применены малоинвазивные методы лечения: закрытая репозиция и чрескожная фиксация канюлированными вин- тами, репозиция через трепанационное окно c фиксацией винтами/пластиной, малоинвазивный остеосинтез пластинами, артроскопически ассистированный остеосинтез. В сравниваемых группах оценивали следующие показатели: длительность операции, рентгенологический результат лечения, функциональное состояние нижней конечности, длительность временной нетрудоспособности. Результаты. Установлено, что применение малоинвазивных хирургических методов лечения переломов мыщелков большеберцовой кости позволяет сократить длительность операции c 100 (90-120) до 70 (60-90) минут (Me (25%-75%), однако не влияет на качество репозиции и количество инфекционных осложнений. Также отмечено, что использование малоинвазивных методов остеосинтеза переломов мыщелков большеберцовой кости позволяет сократить время временной нетрудоспособности c 24 (22-41) недель до 21 (17-33,5) (Me (25%-75%)) и достичь лучших функциональных результатов по сравнению с традиционными открытыми методами лечения. Изучение отдаленных рентгенологических результатов лечения показало, что оба метода лечения позволяют достичь удовлетворительной репозиции костных фрагментов. При переломах типа Schatzker 1 и 2 выявлены преимущества малоинвазивных методов лече- ния. Качество репозиции переломов типа Schatzker 3-6 в обеих группах сопоставимо. Следует отметить, что независимо от примененного метода лечения репозиция бикондилярных переломов (Schatzker 5, 6) сопровождалась худшим рентгенологическим результатом по сравнению с результатами одномыщелко- вых повреждений. Заключение. Проведенное исследование подтвердило эффективность применения малоинвазивных хирургических методов в лечении пациентов с переломами мыщелков голени.Objectives. To carry out a comparative analysis of the results of minimally invasive and traditional open osteosynthesis in patients with fractures of the tibial condyles. Methods. The patients were divided into two groups depending on the performed surgical treatment method of the fractures of the tibial condyles. In the first group (n=70) the open reposition of the fracture with the internal fixation was applied. In the second group (n=70) minimally invasive treatment methods were used: the closed reposition and percutaneous fixation with cannulated screws, reposition through the trepanation window with screws/plate fixation, minimally invasive osteosynthesis by plates, arthroscopically-assisted osteosynthesis. The following parameters were evaluated in the compared groups: the duration of the operation, the radiographic result of the treatment, the functional condition of the lower limb and the duration of temporary work incapacity. Results. It has been found out that use of minimally invasive surgical treatment of fractures of the tibial condyles reduces the operative time from 100 (90-120) to 70 (60-90) minutes, but does not affect the quality of the reposition, and the number of infectious complications. It is also noted that the use of minimally invasive osteosynthesis of fractures of the tibial condyles permits to reduce the time of temporary disability from 24 (22-41) weeks to 21 (17-33,5) and achieve better functional outcomes compared with traditional open procedures. The study of long-term radiographic results of treatment showed that both methods of treatment permit to achieve a satisfactory reposition of bone fragments. In Schatzker type I and II fracture the advantages of minimally invasive treatment methods have been determined. The quality of reposition of Schatzker type III and VI fracture in both groups is comparable. It should be pointed out that regardless of the treatment technique used, reposition of the bicondylar fractures (Schatzker type V and VI) was accompanied by worse radiological outcomes in comparison with the results of single condyle damage. Conclusion. The performed research has proved the efficacy of minimally invasive surgical procedures for the treatment of patients with tibial condylar fractures

Symbolic-numeric approach for solving linear differential equations of the fourth order

This paper presents a symbolic-numeric approach for solving linear differential equations of the fourth order in the form of generalized power series. The working program allows to find solutions to differential equations of the fourth order in the form of power series, generally, of any order, but is limited by capabilities of a given computer. Some examples of solving differential equations of the fourth order are presented, which show the efficiency of the developed progra