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Vinod Karar

Bio: Vinod Karar is an academic researcher from Central Scientific Instruments Organisation. The author has contributed to research in topics: Surface roughness & Polishing. The author has an hindex of 10, co-authored 126 publications receiving 525 citations. Previous affiliations of Vinod Karar include Academy of Scientific and Innovative Research & Council of Scientific and Industrial Research.


Papers
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Journal ArticleDOI
TL;DR: A generalised contrast enhancement algorithm is proposed which is independent of parameter setting for a given dynamic range of the input image and uses the modified histogram for spatial transformation on grey scale to render a better quality image irrespective of the image type.
Abstract: Histogram equalisation has been a much sought-after technique for improving the contrast of an image, which however leads to an over enhancement of the image, giving it an unnatural and degraded appearance. In this framework, a generalised contrast enhancement algorithm is proposed which is independent of parameter setting for a given dynamic range of the input image. The algorithm uses the modified histogram for spatial transformation on grey scale to render a better quality image irrespective of the image type. Added to this, two variants of the proposed methodology are presented, one of which preserves the brightness of original image while the other variant increases the image brightness adaptively, giving it a better look. Qualitative and quantitative assessments like degree of entropy un-preservation, edge-based contrast measure and structure similarity index measures are then applied to the 500 image data set for comparing the proposed algorithm with several existing state-of-the-art algorithms. Experimental results show that the proposed algorithm produces better or comparable enhanced images than several algorithms.

87 citations

Journal ArticleDOI
TL;DR: In this paper, the linear complementary filters are used as elementary blocks in the multiple model adaptive estimation (MMAE) structure and their weights are modified probabilistically to obtain an accurate orientation estimate.

51 citations

Journal ArticleDOI
TL;DR: In this article, the results of an experimental study performed for full aperture polishing of BK7 optical glass are reported, where flat samples of borosilicate (BK7) glass are polished using an optical pitch polisher and cerium oxide (CeO2) slurry.
Abstract: It has been a challenge to finish optical glass surfaces due to their hard and brittle nature. Moreover, tight tolerances of surface figure and finish make polishing a more critical operation. This work reports the results of an experimental study performed for full aperture polishing of BK7 optical glass. Flat samples of borosilicate (BK7) glass are polished using an optical pitch polisher and cerium oxide (CeO2) slurry. Taguchi's L9 orthogonal array is used for the design of experiments. Abrasive concentration, pressure and overarm speed are considered as variable process parameters. Polishing is performed for duration of 120 minutes for each combination of parameters. Material removal is measured using the precision weighing balance. Surface roughness was measured using a Form Talysurf PGI 120 profiler. Abrasive slurry concentration is observed to be one of the most significant parameters in the optical polishing process. It affects both the material removal rate (MRR) and the surface roughness. Pressu...

48 citations

Posted Content
TL;DR: An attempt is made to introduce this topic for beginners covering different aspects of vision based motion estimation task and a list of different datasets for visual odometry and allied research areas are provided for a ready reference.
Abstract: With rapid advancements in the area of mobile robotics and industrial automation, a growing need has arisen towards accurate navigation and localization of moving objects. Camera based motion estimation is one such technique which is gaining huge popularity owing to its simplicity and use of limited resources in generating motion path. In this paper, an attempt is made to introduce this topic for beginners covering different aspects of vision based motion estimation task. The evolution of VO schemes over last few decades is discussed under two broad categories, that is, geometric and non-geometric approaches. The geometric approaches are further detailed under three different classes, that is, feature-based, appearance-based, and a hybrid of feature and appearance based schemes. The non-geometric approach is one of the recent paradigm shift from conventional pose estimation technique and is thus discussed in a separate section. Towards the end, a list of different datasets for visual odometry and allied research areas are provided for a ready reference.

23 citations

Journal ArticleDOI
11 Feb 2019-Energies
TL;DR: The optimum scheduling of hydro and thermal units is proposed, where these units are acting as a relay unit, and the efficiency of the proposed hybrid algorithm is established by comparing it to these two hybrid algorithms.
Abstract: The main objective of short-term hydrothermal scheduling is the optimal allocation of the hydro and thermal generating units, so that the total cost of thermal plants can be minimized. The time of operation of the functioning units are considered to be 24 h. To achieve this objective, the hybrid algorithm combination of Artificial Bee Colony (ABC) and the BAT algorithm were applied. The swarming behavior of the algorithm searches the food source for which the objective function of the cost is to be considered; here, we have used two search algorithms, one to optimize the cost function, and another to improve the performance of the system. In the present work, the optimum scheduling of hydro and thermal units is proposed, where these units are acting as a relay unit. The short term hydrothermal scheduling problem was tested in a Chilean system, and confirmed by comparison with other hybrid techniques such as Artificial Bee Colony–Quantum Evolutionary and Artificial Bee Colony–Particle Swarm Optimization. The efficiency of the proposed hybrid algorithm is established by comparing it to these two hybrid algorithms.

22 citations


Cited by
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Journal ArticleDOI
01 Jul 1968-Nature
TL;DR: The Thermophysical Properties Research Literature Retrieval Guide as discussed by the authors was published by Y. S. Touloukian, J. K. Gerritsen and N. Y. Moore.
Abstract: Thermophysical Properties Research Literature Retrieval Guide Edited by Y. S. Touloukian, J. K. Gerritsen and N. Y. Moore Second edition, revised and expanded. Book 1: Pp. xxi + 819. Book 2: Pp.621. Book 3: Pp. ix + 1315. (New York: Plenum Press, 1967.) n.p.

1,240 citations

Journal Article
TL;DR: The OPTO-MECHANICAL DESIGN PROCESS as discussed by the authors is a process for measuring and measuring the performance of an instrument by measuring its parameters, such as the instrument's weight and center of gravity.
Abstract: THE OPTO-MECHANICAL DESIGN PROCESS Introduction Conceptualization Performance Specifications and Design Constraints Preliminary Design Design Analysis and Computer Modeling Error Budgets and Tolerances Experimental Modeling Finalizing the Design Design Reviews Manufacturing the Instrument Evaluating the End Product Documenting the Design References ENVIRONMENTAL INFLUENCES Introduction Parameters of Concern Environmental Testing of Optics References OPTO-MECHANICAL CHARACTERISTICS OF MATERIALS Introduction Materials for Refracting Optics Materials for Reflecting Optics Materials for Mechanical Components Adhesives Sealants Special Coatings for Opto-Mechanical Materials Techniques for Manufacturing Opto-Mechanical Parts References MOUNTING INDIVIDUAL LENSES Introduction Considerations of Centered Optics Cost Impacts of Fabrication Tolerances Lens Weight and Center of Gravity Location Mounting Individual Low-Precision Lenses Mountings for Lenses with Curved Rims Mountings Interfacing with Spherical Surfaces Elastomeric Mountings for Lenses Mounting Lenses on Flexures Alignment of the Individual Lens Mounting Plastic Lenses References MOUNTING MULTIPLE LENSES Introduction Multielement Spacing Considerations Examples of Lens Assemblies with No Moving Parts Examples of Lens Assemblies Containing Moving Parts Lathe Assembly Techniques Microscope Objectives Assemblies Using Plastic Parts Liquid Coupling of Lenses Catadioptric Assemblies Alignment of Multi-Lens Assemblies Alignment of Reflecting Telescope Systems References MOUNTING WINDOWS AND FILTERS Introduction Conventional Window Mounts Special Window Mounts Mounts for Shells and Domes Conformal Windows Filter Mounts Windows Subject to a Pressure Differential References DESIGNING AND MOUNTING PRISMS Introduction Geometric Relationships Designs for Typical Prisms Kinematic and Semikinematic Prism Mounting Principles Mounting Prisms by Clamping Mounting Prisms by Bonding Flexure Mounts for Prisms References DESIGN AND MOUNTING SMALL, NONMETALLIC MIRRORS, GRATINGS, AND PELLICLES Introduction General Considerations Semikinematic Mountings for Small Mirrors Mounting Mirrors by Bonding Flexure Mounts for Mirrors Multiple-Mirror Mounts Mountings for Gratings Pellicle Design and Mounting References LIGHTWEIGHT NONMETALLIC MIRROR DESIGN Introduction Material Considerations Core Cell Configurations Cast Ribbed Substrates Slotted-Strut and Fused Monolithic Substrates Frit-Bonded Substrates Low-Temperature Bonded Substrates Machined-Core Substrates Contoured-Back Solid Mirror Configurations Thin Face Sheet Mirror Configurations Scaling Relationships for Lightweight Mirrors References MOUNTING LARGE, HORIZONTAL-AXIS MIRRORS Introduction General Considerations of Gravity Effects V-Type Mounts Multipoint Edge Supports The Ideal Radial Mount Mercury Tube Mounts Strap and Roller-Chain Mounts Push-Pull Mounts Comparison of Dynamic Relaxation and Finite-Element Analysis Techniques References MOUNTING LARGE VERTICAL-AXIS MIRRORS Introduction Ring Mounts Air Bag (Bladder) Mounts Multiple-Point Supports Metrology Mounts References MOUNTING LARGE, VARIABLE-ORIENTATION MIRRORS Introduction Mechanical Flotation Mounts Hydraulic/Pneumatic Mounts Center-Mounted Mirrors Mounts for Double-Arch Mirrors Bipod Mirror Mounts Thin Face Sheet Mirror Mounts Mounts for Large Space-Borne Mirrors References DESIGN AND MOUNTING OF METALLIC MIRRORS Introduction General Considerations of Metal Mirrors Aluminum Mirrors Beryllium Mirrors Mirrors Made from Other Metals Mirrors with Foam and Metal Matrix Cores Plating of Metal Mirrors Single-Point Diamond Turning of Metal Mirrors Conventional Mountings for Metal Mirrors Integral Mountings for Metal Mirrors Flexure Mountings for Larger Metal Mirrors Interfacing Multiple SPDT Components to Facilitate Assembly and Alignment References OPTICAL INSTRUMENT STRUCTURAL DESIGN Introduction Rigid Housing Configurations Modular Design Principles and Examples A Structural Design for High Shock Loading Athermalized Structural Designs Geometries for Telescope Tube Structures References ANALYSIS OF THE OPTO-MECHANICAL DESIGN Introduction Failure Predictions for Optics Stress Generation at Opto-Mechanical Interfaces Parametric Comparisons of Annular Interface Types Bending Effects Due to Offset Annular Contacts Effects of Temperature Changes Effects of Temperature Gradients Stresses in Cemented and Bonded Optics Due to Temperature Changes Some Effects of Temperature Changes on Elastomerically Mounted Lenses References APPENDIX A: UNITS AND THEIR CONVERSION APPENDIX B: SUMMARY OF METHODS FOR TESTING OPTICAL COMPONENTS AND OPTICAL INSTRUMENTS UNDER ADVERSE ENVIRONMENTAL CONDITIONS APPENDIX C: HARDNESS OF MATERIALS APPENDIX D: GLOSSARY INDEX

219 citations