Simple Distance Measurement Research Articles

Surface Tracking Controls of an Unmanned Underwater Vehicle with Fixed Sonar Ray Measurements in Tunnel-Like Environments

This paper introduces 3-D surface tracking control of an Unmanned Underwater Vehicle (UUV) in tunnel-like environments. Consider the case where a sonar transducer in the UUV does not rotate, and it only emits fixed sonar ray reporting a simple distance measurement. This reduces the power consumption of the UUV, while reducing the UUV’s size and price. The UUV is controlled to proceed in tunnel-like environments, while maintaining a predefined distance from the tunnel boundaries. For maintaining a predefined distance from tunnel boundaries, the UUV uses fixed sonar rays surrounding it. As far as we know, our article is novel in developing 3-D surface tracking controls of tunnel-like environments utilizing an UUV with fixed sonar rays surrounding it. MATLAB simulations are used for demonstrating the performance of the proposed tracking controls.

Diagnosing Extrusion Process Based on Displacement Signal and Simple Decision Tree Classifier.

The article presents an extensive analysis of the literature related to the diagnosis of the extrusion process and proposes a new, unique method. This method is based on the observation of the punch displacement signal in relation to the die, and then approximation of this signal using a polynomial. It is difficult to find in the literature even an attempt to solve the problem of diagnosing the extrusion process by means of a simple distance measurement. The dominant feature is the use of strain gauges, force sensors or even accelerometers. However, the authors managed to use the displacement signal, and it was considered a key element of the method presented in the article. The aim of the authors was to propose an effective method, simple to implement and not requiring high computing power, with the possibility of acting and making decisions in real time. At the input of the classifier, authors provided the determined polynomial coefficients and the SSE (Sum of Squared Errors) value. Based on the SSE values only, the decision tree algorithm performed anomaly detection with an accuracy of 98.36%. With regard to the duration of the experiment (single extrusion process), the decision was made after 0.44 s, which is on average 26.7% of the extrusion experiment duration. The article describes in detail the method and the results achieved.

Optical Distance Measurement Based on Induced Nonlinear Photoresponse of High-Performance Organic Near-Infrared Photodetectors

Extraction barriers are usually undesired in organic semiconductor devices since they lead to reduced device performance. In this work, we intentionally introduce an extraction barrier for holes, leading to nonlinear photoresponse. The effect is utilized in near-infrared (NIR) organic photodetectors (OPDs) to perform distance measurements, as delineated in the focus-induced photoresponse technique (FIP). The extraction barrier is introduced by inserting an anodic interlayer with deeper highest occupied molecular orbital (HOMO), compared to the donor material, into a well-performing OPD. With increasing irradiance, achieved by decreasing the illumination spot area on the OPD, a higher number of holes pile up at the anode, counteracting the built-in field and increasing charge-carrier recombination in the bulk. This intended nonlinear response of the photocurrent to the irradiance allows determining the distance between the OPD and the light source. We demonstrate fully vacuum-deposited organic NIR optical distance photodetectors with a detection area up to 256 mm2 and detection wavelengths at 850 and 1060 nm. Such NIR OPDs have a high potential for precise, robust, low-cost, and simple optical distance measurement setups.

Intuitionistic Fuzzy C-Means Algorithm Based on Membership Information Transfer-Ring and Similarity Measurement.

The fuzzy C-means clustering (FCM) algorithm is used widely in medical image segmentation and suitable for segmenting brain tumors. Therefore, an intuitionistic fuzzy C-means algorithm based on membership information transferring and similarity measurements (IFCM-MS) is proposed to segment brain tumor magnetic resonance images (MRI) in this paper. The original FCM lacks spatial information, which leads to a high noise sensitivity. To address this issue, the membership information transfer model is adopted to the IFCM-MS. Specifically, neighborhood information and the similarity of adjacent iterations are incorporated into the clustering process. Besides, FCM uses simple distance measurements to calculate the membership degree, which causes an unsatisfactory result. So, a similarity measurement method is designed in the IFCM-MS to improve the membership calculation, in which gray information and distance information are fused adaptively. In addition, the complex structure of the brain results in MRIs with uncertainty boundary tissues. To overcome this problem, an intuitive fuzzy attribute is embedded into the IFCM-MS. Experiments performed on real brain tumor images demonstrate that our IFCM-MS has low noise sensitivity and high segmentation accuracy.

Frequency selection for reconstruction of fringe envelope using the stability of position on optical axis direction of the phase minimum values of different frequencies

We investigated applying the stability of the position on the optical axis direction corresponding to the phase minimum values of different frequencies for signal processing in multiple pulse-train interferometry. We calculated the position on the optical axis direction corresponding to the phase minimum value of different frequencies and obtained accurate peak position measurements of the fringe envelope using our selected frequency components. We chose this method because matching phases of frequencies means that these frequencies are less affected by measurement noise. We used an unbalanced Michelson interferometer with a fixed mirror position measurement to evaluate the performance of our proposed system. This method is expected to be useful for simple and long-range absolute distance measurements.

A simple distance measurement instrument based on the law of light reflection

Measurement instruments of physics, especially those dedicated as teaching aids in physics classroom are improving. These measuring instruments are not only used for measurement purposes, but also to apply theoretical concept into the real world, thus making it easier for students to comprehend. Therefore, this study aims to design, construct, and test a distance-measuring instrument based on the law of light reflection, especially for teaching physics. The method used in this study is quantitative-descriptive method, with the stages of designing, constructing, developing, and testing the distance-measuring instrument. The measuring instrument is constructed from simple, inexpensive, and easily obtained tools and materials, and it is an improvement version of a similar instrument previously developed. The testing stage of this instrument shows that the distance measurement results using the instrument is in good agreement with the results using a ruler depending upon the fixed flat mirror angle of the instrument.

ABSOLUTE DISTANCE MEASUREMENT USING FREQUENCY SCANNING INTERFEROMETRY

Absolute distance measurement is necessary for many applications where the distance to a fixed-target is required. In this paper, frequency scanning interferometry is implemented with an external cavity tunable diode laser, which has a wavelength scanning range of (665-675 nm), to measure distances up to 5 m absolutely (achieved by multi-reflection system). An ultra-low expansion (ULE) Fabry-Perot (FP) cavity has been used as a reference to measure the tunable-laser scanning range. Absolute distance is determined by counting the synthetic fringes and FP peaks simultaneously while scanning the laser frequency. A fringe processing technique is developed to perform online distance measurement even though the tunable laser is not mode-hop free. This fringe processing method enables simple, fast and accurate distance measurements with repeatability ±3.9×10-6 L and combined uncertainty ±38.9×10-6 L which is limited by the calibration system used.

A simple method of measuring tibial tubercle to trochlear groove distance on MRI: description of a novel and reliable technique.

Tibial tubercle-trochlear groove (TT-TG) distance is a variable that helps guide surgical decision-making in patients with patellar instability. The purpose of this study was to compare the accuracy and reliability of an MRI TT-TG measuring technique using a simple external alignment method to a previously validated gold standard technique that requires advanced software read by radiologists. TT-TG was calculated by MRI on 59 knees with a clinical diagnosis of patellar instability in a blinded and randomized fashion by two musculoskeletal radiologists using advanced software and by two orthopaedists using the study technique which utilizes measurements taken on a simple electronic imaging platform. Interrater reliability between the two radiologists and the two orthopaedists and intermethods reliability between the two techniques were calculated using interclass correlation coefficients (ICC) and concordance correlation coefficients (CCC). ICC and CCC values greater than 0.75 were considered to represent excellent agreement. The mean TT-TG distance was 14.7mm (Standard Deviation (SD) 4.87mm) and 15.4mm (SD 5.41) as measured by the radiologists and orthopaedists, respectively. Excellent interobserver agreement was noted between the radiologists (ICC 0.941; CCC 0.941), the orthopaedists (ICC 0.978; CCC 0.976), and the two techniques (ICC 0.941; CCC 0.933). The simple TT-TG distance measurement technique analysed in this study resulted in excellent agreement and reliability as compared to the gold standard technique. This method can predictably be performed by orthopaedic surgeons without advanced radiologic software. II.

Quantitative metrics in clinical radiology reporting: a snapshot perspective from a single mixed academic-community practice

Quantitative imaging has emerged as a leading priority on the imaging research agenda, yet clinical radiology has traditionally maintained a skeptical attitude toward numerical measurement in diagnostic interpretation. To gauge the extent to which quantitative reporting has been incorporated into routine clinical radiology practice, and to offer preliminary baseline data against which the evolution of quantitative imaging can be measured, we obtained all clinical computed tomography (CT) and magnetic resonance imaging (MRI) reports from two randomly selected weekdays in 2011 at a single mixed academic-community practice and evaluated those reports for the presence of quantitative descriptors. We found that 44% of all reports contained at least one “quantitative metric” (QM), defined as any numerical descriptor of a physical property other than quantity, but only 2% of reports contained an “advanced quantitative metric” (AQM), defined as a numerical parameter reporting on lesion function or composition, excluding simple size and distance measurements. Possible reasons for the slow translation of AQMs into routine clinical radiology reporting include perceptions that the primary clinical question may be qualitative in nature or that a qualitative answer may be sufficient; concern that quantitative approaches may obscure important qualitative information, may not be adequately validated, or may not allow sufficient expression of uncertainty; the feeling that “gestalt” interpretation may be superior to quantitative paradigms; and practical workflow limitations. We suggest that quantitative imaging techniques will evolve primarily as dedicated instruments for answering specific clinical questions requiring precise and standardized interpretation. Validation in real-world settings, ease of use, and reimbursement economics will all play a role in determining the rate of translation of AQMs into broad practice.

Optimization and Falsification in Empirical Agent-Based Models

The pioneering works in Agent-Based Modeling (ABM) - notably Schelling (1969) and Epstein and Axtell (1996) - introduced the method for testing hypotheses in "complex thought experiments" (Cederman 1997, 55). Although purely theoretical experiments can be important, the empirical orientation of the social sciences demands that the gap between modeled "thought experiments" and empirical data be as narrow as possible. In an ideal setting, an underlying theory of real-world processes would be tested directly with empirical data, according to commonly accepted technical and methodological standards. A possible procedure for narrowing the gap between theoretical assumptions and empirical data comparison is presented in this paper. It introduces a two-stage process of optimizing a model and then reviewing it critically, both from a quantitative and qualitative point of view. This procedure systematically improves a model's performance until the inherent limitations of the underlying theory become evident. The reference model used for this purpose simulates air traffic movements in the approach area of JFK International Airport in New York. This phenomenon was chosen because it provides a testbed for evaluating an empirical ABM in an application of sufficient complexity. The congruence between model and reality is expressed in simple distance measurements and is visually contrasted in Google Earth. Context knowledge about the driving forces behind controlled approaches and genetic optimization techniques are used to optimize the results within the range of the underlying theory. The repeated evaluation of a model's 'fitness' - defined as the ability to hit a set of empirical data points - serves as a feedback mechanism that corrects its parameter settings. The successful application of this approach is demonstrated and the procedure could be applied to other domains.

SU‐GG‐I‐07: Evaluation of Cine‐CT for Quantifying Respiratory Displacement of Lung Tumors Without a Respiratory Surrogate

Purpose: The conventional approach to measuring tumor displacement, the net movement of its geometric center, is to use 4D‐CT with a respiratory surrogate. We propose using the MIP, average CT and new Max‐Min projection CT images from cine‐CT without a respiratory surrogate as a method of evaluating respiratory displacement of lung tumors. We evaluate the reliability of this method in producing accurate displacement quantification. Method and Materials: We design a new Max‐Min projection CT image, which is the pixel‐by‐pixel average of the maximum intensity projection (MIP) and minimum intensity projection (mip.) The Max‐Min directly shows the displacement volume of a tumor. A simple distance measurement on Max‐Min yields the tumor displacement. Max‐Min, cine‐MIP and cine‐ACT are obtained on a scanner with the cine‐CT capability without using a respiratory surrogate. The average CT (ACT) images are derived from averaging the cine CT images at the same slice location. All cine‐CT images are acquired on a GE 8‐slice CT. We use Max‐Min, cine‐MIP and cine‐ACT images to measure the tumor displacement for 38 4D‐CT simulation patients with lung tumors. For comparison, the 4D‐CT scan of each patient is also used to measure displacement. Results: The Max‐Min images show a clear displacement volume and yield a measurable displacement in 76.3% of cases. The Max‐Min method works best for tumors with reasonably smooth boundaries and displacements less than the tumor size. With 4D‐CT as a gold standard, Max‐Min measures displacement accurately to within one CT voxel (2.5 mm). In the other 23.7% of cases, cine‐MIP and cine‐ACT are used to quantify the displacement with 5 mm accuracy (2 CT voxels). Conclusion: Use of the Max‐Min, cine‐MIP and cine‐ACT images is a reliable method of quickly quantifying tumor respiratory displacement without a respiratory surrogate.

Gis supported hedonic model for assessing property value in west Oakland, California

A hedonic linear regression model is constructed in this paper to estimate property value. In our model, the property value (sales price) is a function of several selected variables such as the property characteristics, social neighborhoods, level of neighborhood environmental contaminations, level of neighborhood crimes, and locational accessibility to jobs or services. Definitions and calculation of these variables are approached by using Geographic Information System tools. For improving estimation, gravity model is employed to measure both levels of neighborhood toxic sites and crimes; and a time-based method is used to measure the locational accessibility rather than simple straight-line distance measurement. This study discovers that the relationship between house value and its nearby highway is nonlinear. The methodology could help policy makers assess the external effects of a property. Our model also could be used potentially to identify the current and historic trends of development caused by neighborhood or environments change in the study area.

Characteristic of Self-Coupling Distance Meter using VCSEL

In developing an automation in processes, a demand for compact and simple distance measurement is increasing. A compact distance meter based on self-coupling effect of semiconductor laser has been studied. It is a compact and simple sensor with high accuracy as it consists of only a laser and a lens. However, a measurement error of this distance meter increases due to mode hop of FP type semiconductor laser. In this paper, a distance meter based on self-coupling effect using VCSEL is studied. It is confirmed that the mode hop for VCSEL does not happen and the distance meter using VCSEL can measure a distance. Furthermore, the distance meter using VCSEL with less optical output power can measure longer distance than that using FP laser.

An Inquiry Lab on Inclined Planes

This paper describes an open-ended inquiry lab exercise dealing with inclined planes that I have used in my introductory high school physics classes. It involves making some simple force and distance measurements, calculating the work done by various forces, analyzing results, and explaining them in a conceptual way. The laboratory exercise is adaptable to various levels of instruction, from guided inquiry and conceptual explanations to complete inquiry with mathematical derivations.

A pilot study on ultrasonic sensor-based measurement of head movement

In this paper, we propose a high-performance, ultrasonic sensor-based head movement detection system, which can be easily applied as an eye tracking device by rotating a mirror set in front of a video camera in a head-free video-based eye-gaze detection system. We propose a simple distance measurement method that uses an A-D converter and an envelope detection method. Experimental results indicate small standard deviations of 0.4-0.8 mm (0.10% S.D.) when the distance between the transmitter and the receiver is within the range of 40-80 cm. In addition, we arranged three transmitters on the apices of a triangle to simulate the head of the user. The receivers were arranged on the apices of a larger triangle. The coordinates of each transmitter were determined using the measured distances from the transmitter to the three receivers. The center of gravity of the three transmitters and the normal vector of the plane that includes the three transmitters were calculated based on the estimated coordinates of the three transmitters. The results indicate sufficiently high precision and measuring frequency for our purpose. The proposed method would be useful for adjusting the focus of a zoom lens to the eye, as well as adjusting the direction of the mirror to the eye.

Opto-electronic displacement gauge based on speckle interferometer

Modern technology demands precise distance measurements. People have used many phenomena for this purpose but there is always a need for less expensive and more reliable devices. In this paper we present a simple opto-electronic distance measurement gauge based on the phenomenon of speckling phenomenon. In the proposed setup we substitute diffraction gratings, which are commonly used in displacement gauges, with a rough surface. When illuminated by a coherent and monochromatic beam the surface scatters light to form a speckle field, whose intensity variations are read by one or more detectors. These changes are related to displacement of the rough surface and, therefore, can be utilized for displacement measurements. The presented setup has some important advantages over the grating approach: lower mechanical tolerances on parts and being based directly on the wavelength of light instead of the period of a grating. Also, it is less expensive, so can offer a viable solution for medium accuracy distance measurements.

Thiol-Reactive, Luminescent Europium Chelates: Luminescence Probes for Resonance Energy Transfer Distance Measurements in Biomolecules

Lanthanide chelates have recently been shown to be extremely promising luminescence probes for distance measurements in biomolecules using luminescence resonance energy transfer measurements [P. R. Selvin, T.M. Rana, and J.E. Hearst (1994)J. Am. Chem. Soc.116, 6029–6030; P.R. Selvin, and J.E. Hearst (1994)Proc. Natl. Acad. Sci. USA91, 10024–10028]. In this work we describe simple procedures for preparing highly fluorescent thiol-reactive europium chelates. These new compounds contain a uv-absorbing coumarin group which sensitizes europium emission, diethylenetriaminepentaacetic acid or triethylenetetraaminehexaacetic acid groups which provide europium chelating function, and a pyridyl disulfide group which allows specific modification of thiol groups. These reagents can be used to label proteins at Cys residues or synthetic oligonucleotides which contain thiol groups. Modification can be reversed easily by treatment with a reducing agent (dithiothreitol). Luminescence energy transfer between these new chelates and CY5 fluorochrome attached to the opposite ends of 15-bp double-stranded DNA was measured to test their usefulness for distance measurements in macromolecules. The distance measured between the chelate (donor) and CY5 (acceptor) was in the range expected for the length of 15-bp DNA. The stability of europium chelates and their conjugates with a protein, the precision of distance measurements using these chelates, possible errors due to intramolecular energy transfer, and the modulation of theR0value with deuterium oxide were tested. The results obtained fully confirmed the great potential of these new probes for sensitive, simple, and precise distance measurements in biomolecules using luminescence resonance energy transfer.

Modern radiographic methods in the diagnosis of periodontal disease.

For many years, radiographs have been a valuable aid in the diagnosis of periodontal disease and the evaluation of treatment effects. Computer-based image acquisition and processing techniques will now further increase the importance of radiography in periodontal diagnosis. Temporal changes of lesions can be made easily visible by means of subtraction radiography based on digital images. This process requires a pair of images with identical gray-level distributions and projection geometry. The gray-level distribution and perspective projection of images can be corrected by means of digital image processing. A pair of identical images can thus be obtained without mechanical alignment of patient, film, and x-ray source. Algorithms have been developed for automatical determination of the borders of lesions and can subsequently produce quantitative information ranging from simple distance measurements to advanced multidimensional quantitation of image parameters. Accurate volume measurements can be carried out by the utilization of calibration wedges in the image. Image reconstruction procedures, such as tomosynthesis, provide information about the third dimension, which is normally lost in conventional radiographic projections. The buccal and lingual sites of the alveolar crest can be inspected separately. The progress of computer-aided procedures as discussed in this paper appears to have great potential for the improvement of the radiographic diagnosis of periodontal lesions. Especially, the benefits of reproducibility and quantitative evaluation of treatment effects will greatly improve the role of radiography in periodontics.

Using Low Cost Piezoelectric Ultrasonic Sensors for 3D Measurement in Robots

The problem of measuring the distance between a robot gripper and an object has been treated. A design, experimental verification and experience of alternate solutions using pulsed ultrasonics are reported. Ultrasonics is often superior to optical methods in a rough robot environment and has a relatively low cost. The developed sensor and methodology offers not only distance measurement capabilities but also space orientation and an object identification among a limited number of possible forms. The feedback potential is apparent. Contrary to liquid environment, ultrasound in free air is significantly absorbed. This is part of the reasons why several frequencies have been used, 40 kHz for distances up to about one meter and 200 kHz for small distances. A sensor device has been designed with four 40 kHz transducers mounted around one 200 kHz transducer. Simple distance measurements are made by a pulse echo method. More advanced measurements use the responses from all the microphones. Also, the angle of a surface can be determined. By changing the frequency between 40 and 200 kHz for the ultrasonic excitation the range of the distance measurements is significantly increased while the accuracy is maintained. It is not trivial to estimate the front of the reflected echo of the ultrasonic transducers, since the echo is a harmonic sinusoidal oscillation with growing amplitude, corrupted by noise. Particular algorithms have been developed to detect the front. The ultrasonic device requires fast sampling, and a special computer interface has been designed. The system has been built around a laboratory robot platform. Experimental experiences of both object identification and sensor based feedback are described.