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Mark I Abrahams, Carlos A Peres, Hugo C M Costa
The degree to which terrestrial vertebrate populations are depleted in tropical forests occupied by human communities has been the subject of an intense polarising debate that has important conservation implications. Conservation ecologists and practitioners are divided over the extent to which community-based subsistence offtake is compatible with ecologically functional populations of tropical forest game species. To quantify depletion envelopes of forest vertebrates around human communities, we deployed a total of 383 camera trap stations and 78 quantitative interviews to survey the peri-community areas controlled by 60 semi-subsistence communities over a combined area of over 3...
2017: PloS One
Orhan Ozturan, Alper Yenigun, Fadlullah Aksoy, Burak Ertas
Endoscopic ear surgery (EES) is increasingly a preferred technique in otologic society. It offers excellent visualization of the anatomical structures directly and behind the corners with variable angled telescopes. It also provides reduced operative morbidity due to being able to perform surgical interventions with less invasive approaches. Operative preparation and setup time and cost of endoscopy system are less expensive compared with surgical microscopes. On the other hand, the main disadvantage of EES is that the surgery has to be performed with 1 single hand...
October 16, 2017: Journal of Craniofacial Surgery
Khalil M Ahmad Yousef, Bassam J Mohd, Khalid Al-Widyan, Thaier Hayajneh
Extrinsic calibration of a camera and a 2D laser range finder (lidar) sensors is crucial in sensor data fusion applications; for example SLAM algorithms used in mobile robot platforms. The fundamental challenge of extrinsic calibration is when the camera-lidar sensors do not overlap or share the same field of view. In this paper we propose a novel and flexible approach for the extrinsic calibration of a camera-lidar system without overlap, which can be used for robotic platform self-calibration. The approach is based on the robot-world hand-eye calibration (RWHE) problem; proven to have efficient and accurate solutions...
October 14, 2017: Sensors
Sebastián Bronte, Luis M Bergasa, Daniel Pizarro, Rafael Barea
This paper presents a sequential non-rigid reconstruction method that recovers the 3D shape and the camera pose of a deforming object from a video sequence and a previous shape model of the object. We take PTAM (Parallel Mapping and Tracking), a state-of-the-art sequential real-time SfM (Structure-from-Motion) engine, and we upgrade it to solve non-rigid reconstruction. Our method provides a good trade-off between processing time and reconstruction error without the need for specific processing hardware, such as GPUs...
October 14, 2017: Sensors
Jakob Rodseth, Edward P Washabaugh, Chandramouli Krishnan
BACKGROUND: Transcranial magnetic stimulation (TMS) is commonly used for assessing or modulating brain excitability. However, the credibility of TMS outcomes depends on accurate and reliable coil placement during stimulation. Navigated TMS systems can address this issue, but these systems are expensive for routine use in clinical and research environments. OBJECTIVE: The purpose of this study was to provide a high-quality open source framework for navigated TMS and test its reliability and accuracy using standard TMS procedures...
October 9, 2017: Restorative Neurology and Neuroscience
Bradley L Preece, George Nehmetallah
Multifunctional cameras capable of performing a wide variety of nearly simultaneous imaging tasks are expected to play a major role in the near future. Computational imaging (CI) systems will serve as one of the main enabling technologies for multifunctional cameras, especially due to the abundance of low-cost, high-speed computational processing available today. An important aspect of these systems is to be able to quantify their performance with respect to specific imaging tasks. However, the non-traditional design of CI systems, both available and proposed, presents a considerable challenge to modeling, comparing, specifying, and measuring their performance...
September 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Morteza Maali Amiri, Mark D Fairchild
There have been numerous methods for accessing the reflectance spectra; some methods enable one to obtain the spectra directly, such as using a spectrophotometer, hyper-spectral camera, and so forth. Even though the accuracy by which the spectra are obtained can be very high, the high price of these methods could pose an obstacle. On the other hand, there has been an interest in estimation of the spectral reflectance from colorimetric information that is more easily attainable; the accuracy in this case might not be as high but these methods are the most cost efficient...
July 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Haris Ahmad Khan, Jean-Baptiste Thomas, Jon Yngve Hardeberg, Olivier Laligant
With the advancement in sensor technology, the use of multispectral imaging is gaining wide popularity for computer vision applications. Multispectral imaging is used to achieve better discrimination between the radiance spectra, as compared to the color images. However, it is still sensitive to illumination changes. This study evaluates the potential evolution of illuminant estimation models from color to multispectral imaging. We first present a state of the art on computational color constancy and then extend a set of algorithms to use them in multispectral imaging...
July 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Lee Streeter
Time-of-flight range imaging is analyzed using stochastic calculus. Through a series of interpretations and simplifications, the stochastic model leads to two methods for estimating linear radial velocity: maximum likelihood estimation on the transition probability distribution between measurements, and a new method based on analyzing the measured correlation waveform and its first derivative. The methods are tested in a simulated motion experiment from (-40)-(+40)  m/s, with data from a camera imaging an object on a translation stage...
July 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Shao-Bing Gao, Ming Zhang, Chao-Yi Li, Yong-Jie Li
It is an ill-posed problem to recover the true scene colors from a color biased image by discounting the effects of scene illuminant and camera spectral sensitivity (CSS) at the same time. Most color constancy (CC) models have been designed to first estimate the illuminant color, which is then removed from the color biased image to obtain an image taken under white light, without the explicit consideration of CSS effect on CC. This paper first studies the CSS effect on illuminant estimation arising in the inter-dataset-based CC (inter-CC), i...
August 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Byeongho Moon, Soohwan Yu, Seungyong Ko, Seonhee Park, Joonki Paik
This paper presents a digital zooming method using a super-resolution (SR) algorithm based on the local self-similarity between the wide- and tele-view images acquired by an asymmetric dual camera system. The proposed SR algorithm consists of four steps: (i) registration of an optically zoomed image to the wide-view image, (ii) restoration of the central region of the zoomed wide-view image, (iii) restoration of the boundary region of the zoomed wide-view image, and (iv) fusion of the results from steps (ii) and (iii)...
June 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Jun Wu, Zhijing Yu, Tao Wang, Jingchang Zhuge, Yue Ji, Bin Xue
Airplane wing deformation is an important element of aerodynamic characteristics, structure design, and fatigue analysis for aircraft manufacturing, as well as a main test content of certification regarding flutter for airplanes. This paper presents a novel real-time detection method for wing deformation and flight flutter detection by using three-dimensional speckle image correlation technology. Speckle patterns whose positions are determined through the vibration characteristic of the aircraft are coated on the wing; then the speckle patterns are imaged by CCD cameras which are mounted inside the aircraft cabin...
June 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Maryam Ghaneizad, Zahra Kavehvash, Hamid Aghajan
In this paper, a novel approach for foreground extraction has been proposed based on a popular three-dimensional imaging technique in optics, called integral imaging. In this approach, multiple viewpoint images captured from a three-dimensional scene are used to extract range information of the scene and effectively extract an object or a person, even in the presence of heavy occlusion. The algorithm consists of two parts: depth estimation and reconstruction of the targeted object at the estimated depth distance...
June 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Jose M Sotoca, Pedro Latorre-Carmona, Filiberto Pla, Xin Shen, Satoru Komatsu, Bahram Javidi
In this work, a 3D reconstruction approach for flexible sensing inspired by integral imaging techniques is proposed. This method allows the application of different integral imaging techniques, such as generating a depth map or the reconstruction of images on a certain 3D plane of the scene that were taken with a set of cameras located at unknown and arbitrary positions and orientations. By means of a photo-consistency measure proposed in this work, all-in-focus images can also be generated by projecting the points of the 3D plane into the sensor planes of the cameras and thereby capturing the associated RGB values...
October 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Kazutaka Kamiya, Hidenaga Kobashi, Masahide Takahashi, Nobuyuki Shoji, Kimiya Shimizu
SIGNIFICANCE: The progressive accumulation of the calcification may deteriorate corneal transparency, especially in the interpalpebral area, and subsequent visual performance for patients with band keratopathy. However, the detailed quantitative analysis of light scattering or higher-order aberrations on visual performance for these patients so far has not been elucidated. PURPOSE: The aim of this study was to assess the relationship of intraocular forward scattering, corneal backward scattering, and corneal higher-order aberrations with visual acuity in eyes with band keratopathy...
October 13, 2017: Optometry and Vision Science: Official Publication of the American Academy of Optometry
Rafael Vivacqua, Raquel Vassallo, Felipe Martins
Autonomous driving in public roads requires precise localization within the range of few centimeters. Even the best current precise localization system based on the Global Navigation Satellite System (GNSS) can not always reach this level of precision, especially in an urban environment, where the signal is disturbed by surrounding buildings and artifacts. Laser range finder and stereo vision have been successfully used for obstacle detection, mapping and localization to solve the autonomous driving problem...
October 16, 2017: Sensors
Bolin Cai, Yuwei Wang, Keyi Wang, Mengchao Ma, Xiangcheng Chen
Camera parameters can't be estimated accurately using traditional calibration methods if the camera is substantially defocused. To tackle this problem, an improved approach based on three phase-shifting circular grating (PCG) arrays is proposed in this paper. Rather than encoding the feature points into the intensity, the proposed method encodes the feature points into the phase distribution, which can be recovered precisely using phase-shifting methods. The PCG centers are extracted as feature points, which can be located accurately even if the images are severely blurred...
October 16, 2017: Sensors
Jing Li, Fangbing Zhang, Lisong Wei, Tao Yang, Zhaoyang Lu
Pedestrian detection is among the most frequently-used preprocessing tasks in many surveillance application fields, from low-level people counting to high-level scene understanding. Even though many approaches perform well in the daytime with sufficient illumination, pedestrian detection at night is still a critical and challenging problem for video surveillance systems. To respond to this need, in this paper, we provide an affordable solution with a near-infrared stereo network camera, as well as a novel three-dimensional foreground pedestrian detection model...
October 16, 2017: Sensors
Ajad Chhatkuli, Daniel Pizarro, Toby Collins, Adrien Bartoli
We present a global and convex formulation for the templateless 3D reconstruction of a deforming object with the perspective camera. We show for the first time how to construct a Second-Order Cone Programming (SOCP) problem for Non-Rigid Structure-from-Motion (NRSfM) using the Maximum-Depth Heuristic (MDH). In this regard, we deviate strongly from the general trend of using affine cameras and factorization-based methods to solve NRSfM, which do not perform well with complex nonlinear deformations. In MDH, the points' depths are maximized so that the distance between neighbouring points in camera space are upper bounded by the geodesic distance...
October 13, 2017: IEEE Transactions on Pattern Analysis and Machine Intelligence
Simone Cappelletti, Edoardo Bottoni, Paola Antonella Fiore, Marco Straccamore, Claus Henssge, Costantino Ciallella
We report a case of a double homicide in which the victims, a man and his daughter, were simultaneously killed by a single gunshot. The temperature-based nomogram method for estimation of the time since death was used to ascertain the reliability of the method in a case of simultaneous demise, where the exact time of death was obtained from the analysis of security cameras.In the case presented, the victims differed for a great number of parameters (e.g., atmospheric conditions, thermal insulation of lower trunk, and, above all, body weight), except for the time of death, that was simultaneous...
October 15, 2017: International Journal of Legal Medicine
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