Laser Distance Meter Research Articles

Chest Compression Depth Targets in Critically Ill Infants and Children Measured With a Laser Distance Meter: Single-Center Retrospective Study From Japan, 2019-2022.

Current resuscitation guidelines recommend target chest compression depth (CCd) of approximately 4cm for infants and 5cm for children. Previous reports based on chest CT suggest these recommended CCd targets might be too deep for younger children. Our aim was to examine measurements of anterior-posterior chest diameter (APd) with a laser distance meter and calculate CCd targets in critically ill infants and children. A retrospective descriptive study. Single-center PICU, using data from May 2019 to May 2022. All critically ill children admitted to PICU and under 8 years old were eligible to be included in the retrospective cohort. None. The chest APd measurements using a laser distance meter are part of our usual practice on the PICU. Target CCd and the over-compression threshold CCd for each age group was calculated as 1/3 and 1/2 of APd, respectively. In 555 patients, the median (interquartile range) of the calculated target CCd for each age group was: 2.7 cm (2.5-2.9 cm), 2.9 cm (2.7-3.2 cm), 3.2 cm (3-3.5 cm), 3.4 cm (3.2-3.6 cm), 3.4 cm (3.2-3.6 cm), 3.6 cm (3.4-3.8 cm), 3.6 cm (3.4-4 cm), and 4 cm (3.5-4.2 cm), for 0, 2, 3-5, 6-8, 9-11, 12-17, 18-23, 24 to less than 60, and 60 to less than 96 months, respectively. Using guideline-recommended absolute CCd targets, 4 cm for infants and 5 cm for children, 49% of infants between 0 and 2 months, and 45.5% of children between 12 and 17 months would be over-compressed during cardiopulmonary resuscitation. In our cohort, the 1/3 CCd targets calculated from APd measured by laser meter were shallower than the guideline-recommended CCd. Further studies including evaluating hemodynamics during cardiopulmonary resuscitation with these shallower CCd targets are needed.

PRACTICAL EXPLORATION OF LOW-COST YET HIGHLY ACCURATE 3D MAPPING TECHNIQUES FOR DOCUMENTATION AND CONSERVATION OF AN EGYPTIAN TOMB (THEBAN TOMB 45)

Abstract. This research presents the initial endeavour to perform geo-referenced 3D reconstruction of an ancient Egyptian tomb located on the West Bank of the Nile in Luxor, evaluating low-cost techniques. This study uses low-cost equipment in conjunction with simple geodetical principles to accurately map a tomb in 3D to empower archaeological teams with limited budgets to efficiently and effectively map their projects. Emphasizing the project goals of both high detail and high accuracy, one of our chosen techniques is photogrammetry with a standard system camera. Additionally, 3D mapping with a modern smartphone was explored in the tomb and was compared with results from the photogrammetry process. Geo-referencing the underground map in a global grid was also part of the project goals. This research shows that, within certain reasonable constraints, the chosen low-cost techniques successfully achieved all goals of producing a highly detailed, highly accurate, and georeferenced 3D map of the selected tomb (Theban Tomb 45). In this first season of mapping the tomb in 3D, various mapping methods were used and tried and where possible compared. Digitally mapping an ancient, underground Egyptian tomb requires a planned approach. In order to better plan when using low-cost scanning equipment, preliminary research was done for mapping a mostly underground, relatively small but complex to survey ancient Egyptian tomb. Data have been collected with the use of both devices and also with a total station, a laser distance meter and a GNSS (Global Navigation Satellite System) datalogger.

Aerial Imaging-Based Fuel Information Acquisition for Wildfire Research in Northeastern South Korea

Tree detection and fuel amount and distribution estimation are crucial for the investigation and risk assessment of wildfires. The demand for risk assessment is increasing due to the escalating severity of wildfires. A quick and cost-effective method is required to mitigate foreseeable disasters. In this study, a method for tree detection and fuel amount and distribution prediction using aerial images was proposed for a low-cost and efficient acquisition of fuel information. Three-dimensional (3D) fuel information (height) from light detection and ranging (LiDAR) was matched to two-dimensional (2D) fuel information (crown width) from aerial photographs to establish a statistical prediction model in northeastern South Korea. Quantile regression for 0.05, 0.5, and 0.95 quantiles was performed. Subsequently, an allometric tree model was used to predict the diameter at the breast height. The performance of the prediction model was validated using physically measured data by laser distance meter triangulation and direct measurement from a field survey. The predicted quantile, 0.5, was adequately matched to the measured quantile, 0.5, and most of the measured values lied within the predicted quantiles, 0.05 and 0.95. Therefore, in the developed prediction model, only 2D images were required to predict a few of the 3D fuel details. The proposed method can significantly reduce the cost and duration of data acquisition for the investigation and risk assessment of wildfires.

The reliability of clinical tools with and without ultrasound guidance to measure leg-length inequality.

To determine and compare the reliability and efficiency of various methods of leg-length measurement. A total of 88 leg-lengths were measured among 50 subjects (79%-84% female, mean age = 30-33 years). Leg-lengths were measured in both supine and standing positions using multiple devices, including a tape measure, a LASER distance meter, and diagnostic ultrasound. All methods of leg-length measurement using the middle of the femoral head as a reference point, identified via ultrasound, demonstrated excellent reliability (intraclass correlation coefficient = 0.95-1.00). Measurements performed in supine, using the anterior superior iliac spine as a reference point, with a tape measure, demonstrated good-to-excellent reliability (intraclass correlation coefficient = 0.86-0.95, standard error of the measurement = 16.1-19.9 cm). Standing measurements using the anterior superior iliac spine as a reference point, using a tape measure, demonstrated fair-to-excellent reliability (intraclass correlation coefficient = 0.71-0.95). Ultrasound-guided landmark identification appear to be a more reliable method compared to palpation of the anterior superior iliac spine for measurement of leg-length using clinical tools. When coupled with ultrasound guidance, a hand-held LASER distance meter/pitch locator apparatus or a retractable tape measure appears to be acceptable alternatives to a fixed LASER distance meter on a linear actuator for leg-length measurement.

Observing Near-Real-Time Volcanoes Deformation Using InSAR – Time Series of LiCSBAS in Indonesia

The Synthetic Aperture Radar (SAR) sensors onboard satellites are leading in advance to monitor physical changes of volcano edifices such as deformation. A few days of temporal resolution imageries provided by Sentinel-1 SAR make it possible to monitor volcanoes worldwide in near-real-time monitoring. The Sentinel-1 constellation produces a large amount of SAR images valuable for monitoring volcano deformation and hazard mitigation. However, processing the Interferometric SAR (InSAR) for a large SAR dataset is time-consuming and requires high-performance computers. Overcoming the problem, the Center for Observation & Modelling of Earthquakes, Volcanoes & Tectonics (COMET) created a program called Looking Inside the Continents from Space of Sentinel Aperture Radar (LiCSAR) integrated to InSAR time-series analysis of LiCSBAS InSAR to process and calculate the interferogram deformation in time series efficiently. This study presents the LiCSBAS observation for volcanic activities at Mts. Sinabung and Agung in North Sumatra and Bali, respectively. We have observed the activities of both volcanoes from 2015 to 2022. We have analyzed 1824 and 848 interferograms of Mt. Sinabung and Mt. Agung, respectively. The LiCSBAS InSAR time-series analysis was successfully processed for Mts. Sinabung and Agung despite being located under tropics. Velocity deformation of Mt. Sinabung is dominated by uplift around the summit, consistent with measurement by the Center for Volcanology and Geological Hazard Mitigation (CVGHM). In the period of January to March 2017, the lava dome measurement using laser distance meter showed an increase from 1.2 Mm3 to 1.7 Mm3, while LiCSBAS detected an uplift movement of 14 mm. On the contrary, the deformation of Mt. Agung at the summit of lava dome is 3 mm/yr indicate uplift, while subsidence is observed around the crater.

A Tailor-Made, Mirror-Based Infrared Scanner for the Reflectography of Paintings: Development, Features, and Applications.

Since infrared reflectography was first applied in the 1960s to visualize the underdrawings of ancient paintings, several devices and scanning techniques were successfully proposed both as prototypes and commercial instruments. In fact, because of the sensors' small dimension, typically ranging from 0.1 to 0.3 megapixels, scanning is always required. Point, line, and image scanners are all viable options to obtain an infrared image of the painting with adequate spatial resolution. This paper presents a newly developed, tailormade scanning system based on an InGaAs camera equipped with a catadioptric long-focus lens in a fixed position, enabling all movements to occur by means of a rotating mirror and precision step motors. Given the specific design of this system, as the mirror rotates, refocus of the lens is necessary and it is made possible by an autofocus system involving a laser distance meter and a motorized lens. The system proved to be lightweight, low cost, easily portable, and suitable for the examination of large-scale painting surfaces by providing high-resolution reflectograms. Furthermore, high-resolution images at different wavelengths can be obtained using band-pass filters. The in-situ analysis of a 16th-century panel painting is also discussed as a representative case study to demonstrate the effectiveness and reliability of the system described herein.

A real-time fire evacuation system based on the integration of Building Information Modeling and Augmented Reality

In the past decade, the drawings in construction projects' standard fire evacuation routes are usually guided in two-dimensional (2-D) views to explain hazardous areas and evacuation routes. Common users cannot interpret the drawings quickly, understand their exact position within the building, and select appropriate evacuation routes. Thus, when fires occur, the construction project's fire can cause damages, and the number of dead or injured workers involved can be high. Nowadays, Building Information Modeling (BIM) and Augmented Reality (AR) are used in construction projects to create construction in a three-dimensional (3-D) visualization. This study aims to create a prototype application that combines Building Information Modeling (BIM) and Augmented Reality (AR) to improve the fire evacuation system and provide real-time access to information for evacuating from hazardous locations. A marker-based location system was implemented, using a marker as a spatial index to link the physical location and virtual information. The system was tested for accuracy using the proposed system and the MATALL Laser Distance Meter on the 4th floor of the Department of Civil Engineering Building at Chulalongkorn University. The results showed that the average percentage difference from the current location to the exit measured by the proposed system was lower than that measured by the MATALL Laser Distance meter, with an average percentage difference of less than 2.2%. Therefore, the proposed system effectively provides real-time access to information such as the current location, exit, distance of the shortest route from the current location to the destination, and virtual green line, voice, and arrow direction for evacuation guidance. It is convenient for decision-making and helps users find destinations quickly and efficiently.

Sensores ultrassônicos de baixo custo para coleta de dados em experimentação a campo

ABSTRACT Surface runoff monitoring is important for the sustainable management of global water resources. Obtaining a practical and inexpensive method for collecting data in the field can help to better understand surface runoff and its effects, necessary for the management of watersheds. This study sought to elaborate the calibration curves of the ultrasonic sensor due to temperature variability, verifying the inaccuracy of the distance between objects and the sensor, and determining the feasibility of using low-cost sensors in an in-loco experiment installed on Parshall flumes. The experiment was conducted on the Experimental Farm of the Federal University of Grande Dourados, Dourados, MS, Brazil. The data were collected by twelve HC-SR04 ultrasonic distance sensors , which were coupled to a data acquisition system composed of an expansion board connected to a Raspberry minicomputer. Sensor calibration using temperature data resulted in the error correction of ± 8.0 mm of distance reading. On the other hand, the R2 of the comparison curves between sensor and control system (laser distance meter and ruler in the flume) resulted in high values (above 0.95), showing the feasibility of its use and meeting the specifications for use in the field subject to weather conditions. This study demonstrates the performance of ultrasonic sensors as a potential for new application to evaluate surface runoff aiming to propose new runoff coefficients.

Effect of a constrictor plate on behavior of a model steel pipe pile driven in dense sand

This study investigates the effect of a constrictor plate on the drivability and load-carrying capacity of open-ended pipe piles via a series of model pile tests. The model pile had an outer diameter of 88.9 mm and was driven in a dense sand to a depth of 670 mm using an impact hammer. Soil plug lengths were measured using a laser distance meter for the entire process of the pile driving. The model pile further employed a double-wall system to separately measure the annulus resistance, soil plug resistance, and outer shaft resistance. Two tests with a constrictor plate located at 98.4 mm and 200 mm above the pile base and one test without a constrictor plate were performed. The piles with a constrictor plate required about 15–20% more pile driving energy than the pile without a constrictor plate. Results from static load tests showed that the piles with a constrictor plate were able to resist more axial loads than the pile without a constrictor plate by about 25–38%.

Flatness and Thickness Measurements of Circular Plate Component Using Laser Distance Meter

Flatness and Thickness Measurements of Circular Plate Component Using Laser Distance Meter

A fully functional palmtop microchip electrophoresis analyzer with laser-induced fluorescence detection

Microchip electrophoresis (MCE) is an ideal tool for rapid on-site analysis of multiple components, therefore the demand for portable MCE devices is increasing. In this work, a fully functional palmtop MCE analyzer was built, integrating units of sample injection, laser-induced fluorescence (LIF) detection, high-voltage (HV), imaging and data acquisition. Frames were fabricated with 3D printing to encapsulate miniaturized components selected with balanced consideration on size, cost and performance. The LIF unit contains a laser diode as the excitation light source, a collimating lens used in the commercial laser diode as the focusing lens and an avalanche photodiode (APD) for the laser distance meter as the photoelectric converter. The sample injection was achieved by negative pressure induced pinching. The total cost of the device is approximately $600 with a size of 89 × 98 × 98 mm3 and a weight of 350 g. It can be powered by a laptop or a mobile power bank. The limit of detection (LOD) measured under a typical MCE condition for sodium fluorescein could be 110 pM. The applicability of the device was demonstrated with the detection of rhodamines and DNA fragments.

Free-Surface Velocity Measurement Using Direct Sensor Orientation-Based STIV.

Particle image velocimetry (PIV) is a quantitative flow visualization technique, which greatly improves the ability to characterize various complex flows in laboratory and field environments. However, the deployment of reference objects or ground control points (GCPs) for velocity calibration is still a challenge for in situ free-surface velocity measurements. By combining space-time image velocimetry (STIV) with direct sensor orientation (DSO) photogrammetry, a laser distance meter (LDM)-supported photogrammetric device is designed, to realize the GCPs-free surface velocity measurement under an oblique shooting angle. The velocity calibration with DSO is based on the collinear equation, while the lens distortion, oblique shooting angle, water level variation, and water surface slope are introduced to build an imaging measurement model with explicit physical meaning for parameters. To accurately obtain the in situ position and orientations of the camera utilizing the LDM and its embedded tilt sensor, the camera’s intrinsic parameters and relative position within the LDM are previously calibrated with a planar chessboard. A flume experiment is designed to evaluate the uncertainty of optical flow estimation and velocity calibration. Results show that the proposed DSO-STIV has good transferability and operability for in situ measurements. It is superior to propeller current meters and surface velocity radars in characterizing shallow free-surface flows; this is attributed to its non-intrusive, whole-field, and high-resolution features. In addition, the combined uncertainty of free-surface velocity measurement is analyzed, which provides an alternative solution for error assessment when comparing measurement failures.

IMPROVING THE PARAMETERS OF A PHOTOAMPLIFIER OF LASER DISTANCE METER BY APPLYING THE BESSEL FILTER

The existing laser distance meters are studied, and a comparative analysis is carried out. For improving the parameters, UNI-T laser distance meter was chosen. Electrical signal types are distinguished in the main nodes. It is recommended to add the Bessel 4-th order filter in the receiving nodes, which increases sensitivity, distance measurement and energy saving of the laser distance meter.

An anthropometric-based method for the assessment of pelvis position in three-dimensional space

Determining the pelvis position remains a challenge for clinical therapists and researchers mainly due to the difficulty in assessing its potential triaxial rotations in the upright standing posture. The method described in this study aims to determine the position of the pelvis in the upright standing posture by calculating the Euler/Cardan angles of pelvic rotations based on the triaxial coordinates of the anterior superior iliac spines and the pubic symphysis. The coordinates of these bony landmarks were determined with two laser distance meters and a standard metric ruler, all mounted on a custom-made structure. The calculations of all Euler/Cardan angle rotation sequences for both the internal and external rotations of the pelvis were performed by developing an algorithm that executed via a computer program specifically designed for the purpose of this study. The validity of the algorithm was tested by comparing the actual angles of known positions at which an anatomical model of the pelvis was placed with the calculated angles. Our findings revealed <1° differences between the actual and the calculated angles of pelvis rotations regardless of the axis around which it was rotated suggesting that the proposed method can be used for clinical and research purposes.•The triaxial coordinates of pelvis bony landmarks can be measured anthropometrically using simple measuring instruments•Pelvis posture can be determined in 3D space with great accuracy by means of the Euler/Cardan angles

Mangrove condition at Selayar Island based on field data and NDVI

Mangrove monitoring in Selayar is part of Reef Health Monitoring which starts from 2015 to 2019 as a result of collaboration between Coremap CTI and Hasanuddin University. The results of satellite image analysis show that the estimated mangrove area in Selayar is 695 hectares, spatially distributed over 9 islands and 24 villages. This study aims to map the condition of mangroves in Selayar and Pasi Island based on canopy cover and NDVI. There were six mangrove locations visited on the field, four locations at Selayar Island, and two locations at Pasi Island. Each station was divided into three observation plots where positions are determined as detail as possible using GNSS, laser distance meter, and compass. There were 18 observed plots. The canopy cover was measure using the hemispherical photo method. Sentinel 2A satellite image was use to mapping NDVI and mangrove condition based on its canopy cover. The correlation between canopy cover and NDVI was 0.96. The coefficient of determination of the regression was 91.3%, and the RMSE value was 5.3%. Referring to KLH standards, mangroves in Selayar and Pasi Island classified as dense, moderate and sparse was 34%, 39%, and 27% recpectively of the total 274 hectares. Mangroves in damaged condition are about 75 hectares scattered on Selayar Island. These results are expected to become a benchmark to monitor mangrove conditions in the Selayar Islands and its vicinity.

Design Characteristic of Static Fishing Boat on Sunda Strait

Fishing vessels operating static fishing gear in the Sunda Strait and based at the Coastal Fishing Port (PPP) Labuan are dominated by gillnets and hook and line. Even though they use the same operating method, the boat designs used can be different. This study aims to determine the characteristics of the static fishing boat that operating in the Sunda Strait. Data collection was conducted in October-December 2008 around PPP Labuan using a laser distance meter. The ships that were sampled were 8 units of gillnet boat and 5 units of hook and line fishing boats. The results showed that the ratio of the main dimensions of the static fishing boat in the Sunda Strait was still by the reference value with the overall shape of the bow is rake bow. The hull shape of the gillnet fishing boat consists of a u-bottom and a round flat bottom, while the hook and line fishing boat is entirely u-bottom. The design of the static fishing vessel in the Sunda Strait is following the basic needs of the static gear fleet, which prioritizes high stability and a large work area compared to the speed of the ship.

Improvement of analysis results from the GAGG scintillator Compton camera operated on an unmanned helicopter by selecting stable flight conditions

ABSTRACT A Compton camera system for use on an unmanned helicopter was previously developed to characterize the distribution of radioactive materials in highly contaminated areas. For this study, a Compton camera system was equipped with a small camera, laser distance meter, an attitude angle sensor, temperature sensors, and real-time monitoring software for better measurement of flight parameters and more precise detection of hot spot locations. To confirm whether the detection results were improved by the modifications, ground-level ambient dose equivalent rate distributions were derived from hovering and programmed flights over a field in Okuma, Fukushima Prefecture (Japan) and compared against readings from survey meters taken at the ground level. For one hovering flight, the correlation between the datasets was improved by selecting a period of stable flight position and attitude and restricting the deviation of the attitude angles. Between 6.0% and 7.6% improvement in the position resolution was achieved using the data from stable flight periods, even when only 1-minute data windows were used. The precision of hot spot detections and ambient dose equivalent rate distributions obtained from the Compton camera were thus improved by the aforementioned modifications to the system.

Complementing Digital Image Analysis and Laser Distance Meter in Beer Foam Stability Determination

The aim of this research is to investigate the possibility of applying a laser distance meter (LDM) as a complementary measurement method to image analysis during beer foam stability monitoring. The basic optical property of foam, i.e., its high reflectivity, is the main reason for using LDM. LDM measurements provide relatively precise information on foam height, even in the presence of lacing, and provide information as to when foam is no longer visible on the surface of the beer. Sixteen different commercially available lager beers were subjected to analysis. A camera and LDM display recorded the foam behavior; the LDM display which was placed close to the monitored beer glass. Measurements obtained by the image analysis of videos provided by the visual camera were comparable to those obtained independently by LDM. However, due to lacing, image analysis could not accurately detect foam disappearance. On the other hand, LDM measurements accurately detected the moment of foam disappearance since the measurements would have significantly higher values due to multiple reflections in the glass.

TLS AND SHORT-RANGE PHOTOGRAMMETRIC DATA FUSION FOR BUILDINGS 3D MODELING

Abstract. The adoption of 3D survey techniques is essential to promote efficient and timely information acquisition on constructed buildings. This article addresses terrestrial LiDAR (TLS) and close-range photogrammetric data fusion for the 3D modeling of a building in Level of Detail (LoD) 3. The selected building presents challenging elements for modeling, such as extended curved slabs, external glass walls, recessed facades and diverse roof pitches. It is located on the campus of the Federal University of Paraná (UFPR) in Curitiba, Brazil. The accuracy of the data integration was obtained through the analysis of deviations between the clouds of primary points. The accuracy of the point cloud model was verified by comparing its dimensions with the real dimensions of the building, obtained by means of a handheld laser distance meter (EDM). The results demonstrate that there was a correspondence between the EDM measures and the model, with a satisfactory statistical agreement between the estimated and reference values and a general maximum absolute error of 4.5 cm. The article focuses on the accuracy of point cloud models for the cadastral updating of buildings, providing information for decision making in projects documentation and interventions.

Validation of a real-time location system for zone assignment and neighbor detection in dairy cow groups

Tracking data are increasingly used for studying social behavior in dairy cows but guidelines are not available regarding the appropriate system setup and data quality. In this study, we investigated the effects of system calibration, as well as data filtering and smoothing methods on the detection of the location and neighbor preferences of dairy cows in a barn using an ultra-wideband real-time location system (RTLS). We followed a group of 15 or 14 cows during two periods: period 1 with RTLS calibration using a laser distance meter; and period 2 with RTLS calibration using professional surveying technology. During both periods, tracking data were collected every 1.73 s for 3 days for all cows in the group together with data from an electronic feeder system. We performed continuous video analysis of cow locations for 1 day in both periods. We compared the effects of four different filtering and smoothing methods (i.e., Kalman filter, sliding window, jump filter, and median filter) on data preparation using raw tracking data. We assigned specific areas (i.e., lying stalls, walking alley, brush area, feed, and water bins) to the measured X-Y coordinates and compared them with the video-based zone assignments. Sensitivity and precision were calculated to evaluate the quality of the zone assignments corresponding to the different RTLS calibration setups and the effects of filtering and smoothing methods. When the RTLS was accurately calibrated these methods did not result in further improvements. The zone assignments agreed well for the video and all of the prepared tracking data at the lying stalls in both periods, and the agreement was good during period 2 at the feed bunk (sensitivity and precision >0.85). When using zone-based and distance-based approaches for detecting neighbors at the lying stalls and feed bunk based on the prepared tracking data we found high correlations (>0.9) with the neighbor information based on video and electronic bin data in period 2. However, the zone-based approach resulted in the lowest mean absolute error. The quality of the tracking data appeared to be especially important when detecting cows in small areas and with short visit durations (e.g., feed bunk). Our results highlight the importance of accurate RTLS calibration setup and the quality of tracking data when inferring dairy cow behavior based on it.