A near-field modeling technique was applied to modeling of a halogen extended light source. The modeling was performed to create a continuous set of rays which can then be used in raytracing for the purpose of designing a reflector. The near- field modeling was implemented by acquiring a series of images of the source using CCD camera with wide-angle lens focused at infinity. Optical ray model, which involved geometrical and ray modeling of the source to match its measured luminous intensity distribution, was also developed. Luminous intensity distribution as well as illuminance pattern from a reflector/source combination, calculated using near-field and optical ray models, were compared. It is demonstrated, in this paper, that near-field modeling technique has several advantages over the optical ray modeling technique when used for computer design of reflectors.
Results of a new noninvasive technique for pulp detection that is based on monitoring the time variations in the laser speckle pattern from a human tooth are presented. The paper also contains preliminary results of experiments and attempts at mathematical modeling of multiple scattering of a laser beam from a solid cylinder.
Techniques for measuring time-varying biospeckle of botanical specimens are investigated. Experimental evidence on the probability density function is presented. Several applicable techniques, such as power spectral density and correlation, are used for measuring and analyzing the temporal speckle intensity variations. These techniques are shown to exhibit information about the shelf life and aging of some botanical specimens used in our study. We also present a new phenomena related to the spatial properties of time-varying speckles. Theoretical and experimental results on the size of a speckle in a speckle pattern and its relation to the temporal intensity variation are also detailed.
Described in this paper is a compact phase measuring ESPI system that incorporates single mode fiber and diode laser. The single mode fiber along with diode laser provides ease of system arrangement but also causes wavelength fluctuation and instability. The wavelength instability was reduced to an acceptable level with an optical isolator. Experimental studies on wavelength stability of the diode laser, the back-reflection intensity from the fiber ends, and their influence on the system are presented.
In this paper a comparison of different techniques to obtain vibration patterns by phase stepping on an electronic speckle pattern interferometer (ESPI) is made. The theoretical evaluation of the contrast of the fringes shows that the (pi) phase step method gives good contrast; however, the four step method gives the same contrast along with better pictorial representation. Speckle averaging on the other hand also increases the contrast of the fringes apart from smoothing of speckles. Experimental results corroborating the theoretical predictions are also presented.
To understand the involvement of the State of Indiana with the Center for Applied Optics at Rose-Hulman Institute of Technology, it is best to start with an explanation of the Indiana Corporation for Science and Technology (CST), its basic charter and its programs. Established in 1982 as a private not-for-profit corporation, CST was formed to promote economic development within the State of Indiana. Two programs that were initially a part of CST's charter and supported with state dollars were a seed capital investment program, aimed at developing new products and processes, and the establishment of university centers of technology development. The former was conceived to create jobs and new, technologically advanced industries in Indiana. The latter was an attempt to encourage technology transfer from the research laboratories of the state universities to the production lines of Indiana industry. Recently, CST has undergone a name change to the Indiana Business Modernization and Technology Corporation (BMT) and adopted an added responsibility of proactive assistance to small- and medium-sized businesses in order to enhance the state's industrial competitiveness.
An approach that has proved effective for preparing optics graduates for their first job in the industry, is presented.
A growing number of universities and colleges are offering coursework in optics and optics related fields at the graduate as well as undergraduate level. Some of these are part of degree programs in optics/optics related field, some are a part of a concentration or area minor program in optics and in other cases these courses are just stand alone courses. Some of these courses also have a lab component. Some of the optics graduates go on to pursue doctorate degree and some seek employment in the industry upon completion of their B.S. or M.S. degree. Optical engineering/science is being recognized more and more as a discipline in its own right and the demand in the industry for such graduates has grown and is expected to continue to grow.
The preparation of the optic graduates, based only on coursework, for a job in the industry is considered adequate but can be enhanced substantially by including some experience which is as close as possible to the work experience at a typical first job in the industry.Some of the degree programs achieve this through a "Co-Op program" in which a student spends one/two semesters at the college/university taking courses, followed by a semester as an intern in the industry. Another approach is to provide to the students, while they are in school taking courses, an experience which is similar to what they will encounter at their first job in the industry. We have used this latter approach effectively for our M.S. (Applied Optics) students.
Our Center for Applied Optics Studies works with businesses, industries, and government agencies in helping solve some of their problems. This usually involves developing a new or improved product or process, or doing a feasibility/evaluation study. The M.S. (Applied Optics) students are required to do a thesis and, whenever possible, we have required them to use one of these problems as the focus of their M.S. thesis project. The following list of Master's thesis of recent graduates provides an indication of the variety and type of problems:
1. "Prototype Right Angle Fiber Optic Connector and Bend Loss of Optical Fibers"
2. "Optical Nondestructive Testing of Meltalic Honeycomb Bonding"
3. "Measurements of Static Displacements Using Digital Speckle Pattern Interferometry and Image Processing"
4. "Studies of Wavelength-Dependent Loss Effects in Optical Fiber Components and Sensors"
5. "Lens for Microlithography"
6. "Non-invasive Study of Human Cardiac Cycle Using Holographic Interferometry"
7. "Veiling Glare in the F4111 Image Intensifier"
8. "Characterization of a Heat-Treated Photoretractive Crystal, Barium Titante"
9. "Phase-Conjugate Shear-Interferometer"
10. "Forward Light Scattering from Optical Fibers"
Most of these thesis projects were driven by industrial interaction and
involved a close liaison with an engineer/scientist from the
organization that had a vested interest in the solution of the problem. Examples of other industrially driven projects where M.S. (Applied Optics) students as well as undergraduate students gained useful experience, though not reflected in the list of thesis, are:
1. Development of a New Brightness Meter for the Paper and Pulp Industry;
2. Feasibility Study and Subseguent
Development of a Vision Inspection
The progress on many of these projects is measured by the satisfactory completion of well defined milestones on a pre-set project schedule. By participating in these type of industrially driven projects, the students get exposed to some of the concepts of project management as well.
A phase-measuring fiber optic electronic speckle pattern interferometer (ESPI) was recently constructed and demonstrated. In this arrangement, phase stepping is introduced by stretching the fiber wrapped around a piezoelectric transducer. Calibration of the phase step is critical in phase measurement techniques for obtaining good phase plots. Methods used for calibrating the stretcher are outlined and the drifts in the phase caused by fluctuations in temperature and mechanical stresses are discussed. Ways to minimize this drift are also presented.
In this paper we discuss a fiber optic electronic speckle pattern interferometer (ESPI) for obtaining 3D information about surface deformation. Phase stepping is introduced by stretching the fiber wrapped around a piezo-electric transducer. Two schemes to stretch the fiber are discussed. Also calibration of the phase step is critical in phase measurement techniques for obtaining good phase plots. In this paper we outline a method used for calibrating the stretcher. We also discuss the error in the phase caused by temperature changes.
Fiber optic Mach-Zehnder interferometric sensors for the measurement of various physical parameters such as pressure temperature and magnetic fields are well known and documented. This paper deals with the construction of a fiber optic sensor incorporating He-Ne and diode lasers. Preliminary experimental results for temperature sensing are reported.
In this paper we discuss a fiber optic phase measuring Electronic Speckle Pattern Interferometer. The phase stepping is obtained by stretching the reference arm fiber. We also outline briefly the theory of determining the phase by differentiating the interferogram. Preliminary results obtained with four bucket and differentiation algorithms are presented. 2.
A machine vision systelu has been developed to size and count ore as it passes down a conveyor belt. The imaging system consists of a line scan camera a zoom lens and a structured lighting arrangenient. The structured lighting produces a line of light which is projected onto the conveyor belt at an angle with respect to the caniera. When a piece of ore is present the line of light covering the piece is displaced out of the field of view of the camera. This method is used to overcome the poor contrast between the ore and the conveyor belt. Iniages are acquired using an iiaage processor which performs real-tiiae thresholding of the iraage before it is passed to a frame buffer. A coniputer progrant locates the ore pieces in the image and identifies the boundaries between those pieces which are touching. Chords corresponding to the approximate major and minor axes of each piece are calculated. Using these measurements the size distribution for a population of ore is determined. 1.