Depth sensor

Because of its importance in pathogen removal and algal productivity in waste stabilization ponds, sunlight penetration was measured in microcosms and in situ under Sahelian climatic conditions. The different wavelengths were detected using a submersible radiometer equipped with three sensors: UV-B (311 nm), UV-A (369 nm) and photosynthetically available radiation (PAR, 400-700 nm). UV-B was more attenuated than UV-A and PAR. Facultative pond was more light-attenuating than maturation pond. The mean euphotic depths for UV-B were 0...

Any processing delay between the two eyes can result in illusory 3D percepts for moving objects because of either changes in the pure disparities over time for disparity sensors or by changes to sensors that encode motion/disparity conjointly. This is demonstrated by viewing a fronto-parallel pendulum through a neutral density (ND) filter placed over one eye, resulting in the illusory 3D percept of the pendulum following an elliptical orbit in depth, the so-called Pulfrich phenomenon. Here we use a paradigm where a cylinder rotating in depth, defined by moving Gabor patches is presented at different interocular phases, generating strong to ambiguous depth percepts...

Hardness, dimensions, and location of biological tissues are important parameters for electronic palpation protocols with standardized performance. This study presents a novel fluid-type tactile sensor able to measure size and depth of heterogeneous substances in elastic bodies. The new sensor is very simple and can be easily fabricated. It consists of an image sensor, LED lights, and a touchpad filled with translucent water. The intensity field of the light traveling in the touchpad is analyzed to estimate the touchpad shape which conforms to the shape of an object in contact...

We reconstructed the three-dimensional (3D) surface displacement field of the 24 August 2014 M6.0 South Napa earthquake using SAR data from the Italian Space Agency's COSMO-SkyMed and the European Space Agency's Sentinel-1A satellites. Along-track and cross-track displacements produced with conventional SAR interferometry (InSAR) and multiple-aperture SAR interferometry (MAI) techniques were integrated to retrieve the east, north, and up components of surface deformation. The resulting 3D displacement maps clearly delineated the right-lateral shear motion of the fault rupture with a maximum surface displacement of approximately 45 cm along the fault's strike, showing the east and north components of the trace particularly clearly...

Fish are able to sense water flow velocities relative to their body with their mechanoreceptive lateral line organ. This organ consists of an array of flow detectors distributed along the fish body. Using the excitation of these individual detectors, fish can determine the location of nearby moving objects. Inspired by this sensory modality, it is shown here how neural networks can be used to extract an object's location from simulated excitation patterns, such as can be measured along arrays of stationary artificial flow velocity sensors...

A hypodermic needle has been introduced incorporating an electrical impedance spectroscopy (EIS) sensor, called micro-EIS-on-a-needle for depth profiling (μEoN-DP). The μEoN-DP can locate endophytic renal tumors as well as determine tumor margins by detecting the impedance difference between normal and cancer tissues. To evaluate the μEoN-DP as a novel tool to determine the optimal surgical margin during partial nephrectomy (PN), the electrical impedance differences between renal parenchymal tissues and renal cell carcinoma (RCC) tumors are investigated with regard to the distance from the tumors...

We present a practical and inexpensive method to reconstruct 3D scenes that include transparent and mirror objects. Our work is motivated by the need for automatically generating 3D models of interior scenes, which commonly include glass. These large structures are often invisible to cameras. Existing 3D reconstruction methods for transparent objects are usually not applicable in such a room-sized reconstruction setting. Our simple hardware setup augments a regular depth camera with a single ultrasonic sensor, which is able to measure the distance to any object, including transparent surfaces...

BACKGROUND AND OBJECTIVES: Automatic detection of human fall is a key problem in video surveillance and home monitoring. Existing methods using unimodal data (RGB / depth / skeleton) may suffer from the drawbacks of inadequate lighting condition or unreliability. Besides, most of proposed methods are constrained to a small space with off-line video stream. METHODS: In this study, we overcome these encountered issues by combining multi-modal features (skeleton and RGB) from Kinect sensor to take benefits of each data characteristic...

Separate sewer systems are sensitive to illegal or mis-connections. Several techniques (including the Distributed Temperature Sensor) are now available to identify and locate those connections. Based on thermal fingerprints, DTS allows the localization of each lateral connection along a reach. The use of Infra-Red camera has been investigated with 748 laboratory experiments (artificial connections along a flume). The tested connections vary in diameters (from 75 to 200 mm), lengths of intrusion (from 0 to 200 m), shapes (circular or linear i...

In this paper, we report the design and experimental validation of a novel optical sensor for radial artery pulse measurement based on fiber Bragg grating (FBG) and lever amplification mechanism. Pulse waveform analysis (PWA) is a diagnostic tool for clinical examination and disease diagnosis. High fidelity radial artery pulse waveform has been investigated in clinical studies for estimating central aortic pressure which is proved to be predictors of cardiovascular diseases. As a three-dimensional cylinder, the radial artery needs to be examined from different locations to achieve optimal pulse waveform for estimation and diagnosis...

The current communication signifies the effect of oxygen vacancies (OVs) both qualitatively and quantitatively in multiferroic BiFe0.83Ni0.17O3 by an in-depth atomic-level investigation of its electronic structure and magnetization properties, and these materials have a variety of applications in spintronics, optoelectronics, sensors and solar energy devices. Depending on the precise location of OVs, all the three types of spintronic material namely half-metallic, spin gapless semiconductor and bipolar magnetic conductor have been established in a single material for the first time and both super-exchange and double-exchange interactions are possible in accordance with the precise location of OVs...

We demonstrate a fast and cost-effective technique to perform three dimensional (3D) scanning and replication of large paleontological specimens, in this case the entire skull of a Tyrannosaurus rex (T.rex) with a volume in the range of 2 m3. The technique involves time-of-flight (TOF) depth sensing using the Kinect scanning module commonly used in gesture recognition in gaming. Raw data from the Kinect sensor was captured using open source software and the reconstruction was done rapidly making this a viable method that can be adopted by museums and researchers in paleontology...

Understanding how aquatic species respond to extremes of DO and temperature is crucial for determining how they will be affected by climate change, which is predicted to increasingly expose them to levels beyond their optima. In this study we used novel animal-borne DO, temperature and depth sensors to determine the effect of extremes of DO and temperature on the vertical habitat use of Atlantic salmon Salmo salar in aquaculture cages. Salmon showed a preference for temperatures around 16.5 to 17.5 °C, however, selection of preferred temperatures was trumped by active avoidance of low DO (<35% saturation) at the bottom of the cage...

Studies on depth images containing three-dimensional information have been performed for many practical applications. However, the depth images acquired from depth sensors have inherent problems, such as missing values and noisy boundaries. These problems significantly affect the performance of applications that use a depth image as their input. This paper describes a depth enhancement algorithm based on a combination of color and depth information. To fill depth holes and recover object shapes, asynchronous cellular automata with neighborhood distance maps are used...

To efficiently inspect surface defects on steel ball bearings, a new method based on a circumferential eddy current array (CECA) sensor was proposed here. The best probe configuration, in terms of the coil quality factor (Q-factor), magnetic field intensity, and induced eddy current density on the surface of a sample steel ball, was determined using 3-, 4-, 5-, and 6-coil probes, for analysis and comparison. The optimal lift-off from the measured steel ball, the number of probe coils, and the frequency of excitation current suitable for steel ball inspection were obtained...

Fiber-optic endomicroscopes open new avenues for the application of non-linear optics to novel in vivo applications. To achieve focus scanning in vivo, shape memory alloy (SMA) wires have been used to move optical elements in miniature endomicroscopes. However, this method has various limitations, making it difficult to achieve accurate and reliable depth scanning. Here we present a feedback-controlled SMA depth scanner. With a Hall effect sensor, contraction of the SMA wire can be tracked in real time, rendering accurate and robust control of motion...

In this paper we present a method for autofocusing images of sputum smears taken from a microscope which combines the finding of the optimal focus distance with an algorithm for extending the depth of field (EDoF). Our multifocus fusion method produces an unique image where all the relevant objects of the analyzed scene are well focused, independently to their distance to the sensor. This process is computationally expensive which makes unfeasible its automation using traditional embedded processors. For this purpose a low-cost optimized implementation is proposed using limited resources embedded GPU integrated on cutting-edge NVIDIA system on chip...

Visual activity recognition plays a fundamental role in several research fields as a way to extract semantic meaning of images and videos. Prior work has mostly focused on classification tasks, where a label is given for a video clip. However, real life scenarios require a method to browse a continuous video flow, automatically identify relevant temporal segments and classify them accordingly to target activities. This paper proposes a knowledge-driven event recognition framework to address this problem. The novelty of the method lies in the combination of a constraint-based ontology language for event modeling with robust algorithms to detect, track and re-identify people using color-depth sensing (Kinect(®) sensor)...

The high precision and scalable technology offered by atom interferometry has the opportunity to profoundly affect gravity surveys, enabling the detection of features of either smaller size or greater depth. While such systems are already starting to enter into the commercial market, significant reductions are required in order to reach the size, weight and power of conventional devices. In this article, the potential for atom interferometry based gravimetry is assessed, suggesting that the key opportunity resides within the development of gravity gradiometry sensors to enable drastic improvements in measurement time...

Falls are a major source of death and disability in older adults; little data, however, are available about the etiology of falls in community-dwelling older adults. Sensor systems installed in independent and assisted living residences of 105 older adults participating in an ongoing technology study were programmed to record live videos of probable fall events. Sixty-four fall video segments from 19 individuals were viewed and rated using the Falls Video Assessment Questionnaire. Raters identified that 56% (n = 36) of falls were due to an incorrect shift of body weight and 27% (n = 17) from losing support of an external object, such as an unlocked wheelchair or rolling walker...