Optical Distance Sensor Research Articles

Metal Detector Signal Imprints of Detected Objects

Humanitarian demining missions are activities in which an operator safety and time consumption are key issues. To increase a discrimination ability of ATMID metal detector, which we have been using, we extended the capability of the detector with mounting inertial measurement unit (IMU) supplemented by two optical distance sensors on the detector head. That enabled us to perform dead reckoning based on accelerations and angular rates measured by IMU in all three axes. Optical distance sensors have been used for compensation purposes and an initial distance measurement. Our main aim was to interconnect magnetic imprint sensed by the detector with precise localization of its head, which led to imprint size estimation as well as its position. Due to low-cost micro-electro-mechanical system (MEMS) based IMU implementation we have had to deal with unstable dead reckoning outcomes. For this reason we used our designed complex magnetic markers (CMMs) which demarked a searched area plus provided us with precise positioning at its both edges. The main contribution of this paper is in the study and identification of CMM magnetic imprints characteristics and their differences related to various aspects of CMM usage during demining procedure and its conditions. The characteristics of CMMs have been studied and analyzed according to several laboratory experiments and results are presented.

Low Cost 3D Scanner by Means of a 1D Optical Distance Sensor

Nowadays, 3D scanners have become widely used tools in different disciplines, such as robotics, medicine and manufacturing. These devices are capable of representing virtual 3D objects with extremely good accuracy, but they are very expensive, making them not affordable for research institutions with low economical resources. Because of that, many authors have been worked on projects to develop low cost 3D scanners implementing different methodologies and technologies. This article shows a methodology to develop a prototype of a 3D scanner device that can represent virtual 3D objects from distance measurements obtained by a 1D optical distance sensor. Essentially, the device consists of three elements, an electromechanical platform, a data acquisition hardware (controlled by the PIC18F4550 microcontroller) and a graphical user interface, programmed in Matlab language.The results obtained by scanning different solid objects are very promising and show the effectiveness of the presented approach and good functionality of the device.

Motion compensated fiber-optic confocal microscope based on a common-path optical coherence tomography distance sensor

A motion compensated fiber-optic confocal microscope system is demonstrated by utilizing a Fourier domain common-path optical coherence tomography (FD-CP-OCT) distance sensor and a high-speed linear motor at the distal end of a fiber-optic confocal microscope imaging probe. The fiber-optic confocal microscope is based on a 460 μm diameter imaging bundle with 10 K cores. The fiber bundle was terminated with a gradient index lens system. Using one-dimensional A-scan data of CP-OCT, the distance deviation of the target from the focal plane of the probe was monitored and motion compensated at the rate of 840 Hz, for a confocal microscopic imaging frame rate of 1fps and was 200 × 200 pixels in size, with a distance error less than 5 μm.

Metrological performance verification of coordinate measuring systems with optical distance sensors

Optical coordinate measuring systems are gaining increasing interest in production quality control, due to their rapidity and other advantages with respect to traditional measuring techniques using contact probes. This paper presents an experimental investigation on procedures and standards for testing coordinate measuring systems equipped with optical distance sensors. Particular attention is given to methods for testing two of the most important specifications of optical coordinate measuring system: the probing error and the error of indication for size measurement. The investigation is aimed at improving the performance verification methods employed at the state of the art. This will help the industrial users in the selection process of those systems, with an improvement of measurement precision in manufacturing.

Position feedback tracking of the Acrobot walking-like trajectory based on the reduced velocity observer

This paper provides the algorithm how to exponentially track any trajectory of the Acrobot based on the knowledge of two position variables only. Namely, it aims to design a special reduced observer for the Acrobot angular velocities based on the respective angles measurements and then to combine this observer with the earlier developed full state feedback controllers. For the Acrobot with point feet it is not an easy task to measure the angle between its stance leg and the surface. This paper suggests to measure instead of this angle a certain distance using a laser beam sensor and then to compute the stance angle from that distance. For this purpose, the optical laser distance sensor was selected, purchased and analyzed. Remarkably, the corresponding computations maintain basically the same order of precision for the computed angle as achieved for that measured distance. The stability of both the reduced observer and the overall output feedback tracking is demonstrated as well. Both of them are based on the Acrobot's model partial exact feedback linearization of order 3. The developed algorithm is then applied to the position feedback tracking of the walking-like trajectory of the Acrobot during a swing phase of a single step. Besides the theoretical analysis, the approach is demonstrated via numerical simulations.

High Throughput System for Geometry Inspection of Large-Size Distributed Objects

he article presents a measurement system designed for “on-line” high throughput simultaneous optical inspection of large set of geometrical parameters (more than 1000 points) defining geometry of some complex surface. The measurement system is based on the distributed network of optical distance sensors. Specialized optical sensor as basic system element was developed for this purpose. Among its features are the following: non-contact measurement, high optical and electromagnetic noise immunity, small footprint, and mass-production oriented. The system allows us to measure up to 1700 linear distance parameters simultaneously in the range of 40mm, with accuracy (3σ) of 0.1 mm and sampling rate of at least 103 Hz.

Compact optical fiber whitelight interferometric distance sensor for arbitrary small distance measurement

A compact optical fiber distance sensor that is capable of measuring arbitrary small distance is produced by fabricating a microsized polymer core at the end of a single mode fiber. The polymer core introduces an additional reflective interface to a conventional Fabry-Perot cavity. As such, sufficient fringes are presented in the whitelight reflectance spectrum of the distance sensor so that arbitrary small distances can be demodulated using the Fourier transformation technique. The performance of the distance sensor is verified experimentally.

胸腔鏡下手術のための位相差強調型腫瘍イメージャ

This paper discusses an availability of proposed Non-Contact Phase Difference type Imager capable of detecting a lung tumor based on phase differential technique for Video-Assisted Thoracic Surgery called VATS. The developed sensor is composed of an air supply system and an optical fiber distance sensor next to the air nozzle. A removed human lung is used to verify the performance of the developed sensor. Toward clinical application, it is confirmed that both a tumor detection capability and a safety to the lung tissues of the developed sensor through in vivo experiments by using pig lungs. Finally, we also show a newly sensing system for clinical application.

KOMEKAMI Switch: A Novel Wearable Input Device Using Movement of Temple

A wearable computing system plays a leading role in the ubiquitous computing era, in which computers are used at any place and at any time. Now the mobile multimedia communication technology based devices, such as mobile phone, handy-type PC, etc., have come to be used in such a broad range of areas, the features of wearable hands-free computing system, which people can constantly use in their daily life or workplace while doing some other job, are highly valued more than ever. However, the wearable computing system has not yet spread so widely owing to various factors. Among such factors is the delay in the development of human machine interface, which is applicable to the wearable computing system. Conventional technologies that require either manual manipulation of keyboard, mouse, touch panel, etc., or a large equipment to make use of electroencephalogram, eyeball movements, etc. for realizing hands-free interface, are not suitable for the wearable computing system. We, therefore, developed a human-machine interface for the wearable computing system. This interface makes it easy to manipulate machine with intentional movements of temple. User can constantly use machine with no interference, as well as with hands free. It is compact and lightweight, permitting ease of manufacturing at a low cost. It does not react to daily actions like conversation, diet, etc., other than movements intended to control the machine. This interface consists of one optical distance sensor mounted in the vicinity of the left and right temples each and of one single-chip microcomputer.

Simulation, implementation, and analysis of an optical fiber bundle distance sensor with single mode illumination

A simulation model for an optical fiber bundle distance sensor with a single mode fiber as the illumination fiber and a multimode fiber as the receiving fiber is presented. Approximating the illumination light exiting the single mode fiber as having a Gaussian intensity profile, a closed-form solution of the reflected light coupled into the receiving fiber was derived. A distance sensor was implemented and the measured sensor outputs were compared with the simulation data to verify the theoretical model. The performance of the distance sensor with different design parameters was analyzed. Design guidelines for achieving desired sensor performances are suggested.

Performance analysis of an optical distance sensor for roll angle estimation in sport motorcycles

The roll angle is a crucial parameter for motorcycle dynamics. The ability of measuring it reliably in real time is an enabling technology for active control systems design for two-wheeled vehicles and for tire performance assessment. Nonetheless, it is quite difficult to devise the best trade-off between cost and precision and to choose the most appropriate sensor technology and lay-out. This paper analyzes if low-cost non contact optical distance sensors are a viable solution for measuring the roll angle. To use this method in sport applications some basic requirements must be satisfied, first of all the distance measurement must be reliable even at very high speed and under different lighting conditions. Our aim is to test a low cost optical triangulator with a single LED emitter and to show how the interference due to asphalt roughness in a condition of solar lighting and high speed affects the quality of its output.

106 光学式距離センサを用いたエスカレータ用警告発生装置の開発

106 光学式距離センサを用いたエスカレータ用警告発生装置の開発

Compact Triangulation Sensor Array Constructed by Wafer Bending

An optical triangulation distance sensor array was constructed by bending a silicon wafer. Since bending is the final process in the fabrication sequence, planar photolithography can be included in the fabrication sequence. The elements on the Si wafer are all prealigned under a planar condition, and the position-sensitive detector, mirror, and alignment pit for the collimation ball lens are prepared before bending the wafer. The size of the optical bench produced by the sensor substrate is 1.4 mm deep. By batch fabrication, a 2×2 sensor array was produced. A dynamic range of 4 mm and a noise level of ±1% was confirmed by testing.

An Optical Distance sensor Fabricated by Micromachining Technology

A micro-optical distance sensor by a combination of LIGA technology and Si micromachining is proposed. The function of the distance sensor is based on the triangulation principle. This sensor consists of optical components made by the LIGA process, i.e. a free space micro-optical system and micro-cylindrical lenses, and an electrical base with opto-electrical devices.In this paper, two prototype sensors are described, which have measurement ranges of 1 mm (Type1) and 10mm (Type2). The dimensions of the pure sensor chip are 7 mm (W) × 7 mm (L) × 3 mm (H). The repeatability error of Type1 and Type2 are ±3 μm and ±80 μm, respectively.

Novel Optical Distance Sensor Based on MSM Technology

This paper describes a novel distance-sensor concept based on photodiodes in metal-semiconductor-metal technology (MSM). MSM photodiodes can be operated as electrooptical mixers functioning similar to the so-called photonic mixing device (PMD). This paper employs the correlation techniques previously used with the PMD to the MSM. First, experimental results obtained with the MSM inserted into the authors' standard laboratory setup are provided. Additionally, different configurations well suited for mixer operation of the MSM are pointed out. Throughout this paper, similarities between the PMD and MSM are pointed out, as well as key differences.

Identification of timber deformations

A system to assess timber deformations has been developed using an array of optical distance sensors (ODS), each of which controls a strip of the timber determining how it deviates from flatness. The main characteristics of the ODS system are compactness, modularity and real-time elaboration software. The shape of the timber is reconstructed by sampling the distance between the timber and the ODS while the timber is running in the wood plant. The working principle of the ODS is based on the triangulation of a light spot. A low-power laser diode projects a light spot on the timber surface. The image of the spot moves on a position-sensitive detector (PSD) according to the distance between the optical system and the timber. Suitable software for computer-aided operation was developed at an industrial plant producing wood cutting systems. A prototype of the ODS system has been constructed and tested under real operating conditions.

An optical probe based on spherical aberration for surface figure testing

An optical distance sensor is presented that utilizes longitudinal spherical aberration to probe and monitor the height distribution of a reflecting sample. The surface shape parameters are recovered after scanning. The working principle is discussed in terms of optical design data, and the actual performance of a laboratory setup is demonstrated accordingly.

Development of an Optical Distance Sensor for Robots

A description is given of the development of an optical distance sensor for robots. The surface of an object is illuminated by light coming through a pinhole, and the light reffected on the surface is guided into a photosensor array by another pinhole. Based on the position of the photosensor unit that detects a magnitude greater than that detected by any other unit, the distance between the surface and the sensor head is determined geometrically, without influence from circumferential illumination or other conditions of an object such as irregularity, reflectivity, and orientation. This sensor is quite powerful and should have a wide variety of practical uses. Both analytic and experimental results are presented.