A5063471945- Optical measurement and interference techniques
- Advanced Measurement and Metrology Techniques
- Visual Attention and Saliency Detection
- Advanced Image and Video Retrieval Techniques
- Image Enhancement Techniques
- Advanced Vision and Imaging
- Surface Roughness and Optical Measurements
- Image and Signal Denoising Methods
- Advanced Image Processing Techniques
- Photonic and Optical Devices
- Advanced Image Fusion Techniques
- Image and Video Quality Assessment
- Image Retrieval and Classification Techniques
- Image Processing Techniques and Applications
- Medical Image Segmentation Techniques
- Optical Polarization and Ellipsometry
- Advanced Fiber Optic Sensors
- Video Analysis and Summarization
- Physics of Superconductivity and Magnetism
- Industrial Vision Systems and Defect Detection
- Visual perception and processing mechanisms
- Video Surveillance and Tracking Methods
- Digital Holography and Microscopy
- Optical Coatings and Gratings
- Advanced Optical Imaging Technologies
Indian Institute of Technology Kharagpur
2016-2025
Tufts University
2019
Stanford University
2019
Indian Institute of Technology Delhi
1990-2018
Institute of Post Graduate Medical Education and Research
2014-2016
Indian Institute of Technology Roorkee
2016
National University of Singapore
1988-2015
Indian Statistical Institute
2006-2013
Concordia University
2005-2007
University West
2006
Hazy images suffer from low visibility since the light gets scattered as it passes through various atmospheric particles. Moreover, such are prone to color distortion, particularly in real weather conditions like sandstorms. In this letter, an effective dehazing technique is proposed using weighted least squares filtering on dark channel prior and correction that involves automatic detection of cast images. We show spread hue a hazy image can differentiate non-cast one. propose measure same...
A new type of wave front shearing interferometer is described in which two images the under test are different sizes made to interfere. When centres coincide, this results effectively shear along radial direction. It shown that interpretation resulting interferogram comparatively easy. In addition, instrument extremely convenient handle, since all adjustments can be with a white light source.
Real-world image degradation due to light scattering can be described based on the Koschmieder’s model. Training deep models restore such degraded images is challenging as real-world paired data scarcely available and synthetic may suffer from domain-shift issues. In this paper, a zero-shot single restoration model proposed leveraging theoretically deduced property of through Our network estimates parameters model, which describes in input image, perform restoration. We show that suitable...
Quantifying ambiguities in images using fuzzy set theory has been of utmost interest to researchers the field image processing. In this paper, we present use rough and its certain generalizations for quantifying compare it theory. We propose classes entropy measures based on generalizations, perform rigorous theoretical analysis provide some properties which they satisfy. Grayness spatial are then quantified proposed measures. demonstrate utility effectiveness by considering elementary...
Histogram equalization, which aims at information maximization, is widely used in different ways to perform contrast enhancement images. In this paper, an automatic exact histogram specification technique proposed and for global local of The desired obtained by first subjecting the image a modification process then maximizing measure that represents increase decrease ambiguity. A new method measuring based upon band-limited approach center-surround retinal receptive field model also devised...
A wavefront shearing interferometer is described which can be conveniently used for routine tests of optical systems with relative apertures f/6 or less. The necessity equalizing the two paths has been eliminated in this instrument, making it extremely easy to adjust and handle. At same time, shear continuously varied, so that zonal errors easily identified.
This paper presents a novel histogram thresholding methodology using fuzzy and rough set theories. The strength of the proposed lies in fact that it does not make any prior assumptions about unlike many existing techniques. For bilevel thresholding, every element is associated with one two regions by comparing corresponding errors association. are considered ambiguous nature, and, hence, error measures based on fuzziness or roughness regions. Multilevel carried out method tree structured...
When the rays emerging from a conventional two-beam interferometer are reflected back through instrument, fringes similar in appearance and behavior to three-beam obtained. Extremely accurate measurements possible with help of these fringes, using photometric setting criterion. The mode formation as well theoretical intensity distribution them under various conditions, discussed.
A noise-suppressing low-light image enhancement approach is proposed in this paper based on the extent of exposedness at each pixel. To end, a progressive, structure-aware estimation procedure presented that quantifies local and global exposedness. These values are leveraged to produce locally smooth pixel-level map signifies required degrees pixels. This subsequently used an function, which satisfies few important properties, generate enhanced image. Before enhancement, inherent noise...
In the instrument described, collimated light from lens which is being tested directed into a triangular path interferometer in two beams are sheared by tilting single, parallel plate, while difference between them varied linearly with time, over range of one wavelength, means polarizing system. The modulus and argument frequency response obtained directly amplitude phase resultant sinusoidal variation total flux interference pattern.
The instrument described utilizes a beam dividing system similar to that used in the Jamin interferometer, but employs three interfering beams instead of two. This permits determination fractional fringe order with an extremely high degree accuracy. It can be for studying very small changes refractive index gases and liquids, and, slightly modified form, as auto-collimating interferometer precise measurement thickness evaporated films.
A triangular path shearing interferometer is described which can be used for the examination of large transparent objects. It has advantage that it conveniently adapted to an existing schlieren system, affording possibility quantitative measurements. The additional optical elements required are only comparatively small aperture and therefore quite inexpensive.
Summary In a study of placentae from 3000 consecutive deliveries nearter were the extrachorial type. All forms placenta extrachorialis associated with high maternal parity. The totally circumvallate is accompanied by an unduly incidence threatened abortion, premature labour and fetal hypoxia, excessive proportion infants either partially or show intrauterine growth retardation. Circummarginate are no clinical significance.
A pyrophoric technique using an explosive exothermic reaction has been developed to yield calcined and microscopically homogeneous (0.3 μm size) powders of multicomponent cuprate systems. The used synthesize superconducting materials variable composition the type M1M2⋅⋅⋅MnOx. bulk prepared from these show sharp (1 K) transitions nearly ideal Meissner effect.
Abstract An arrangement using a radial shearing interferometer is described with which quantitative measurement of the aberration coefficients microscope objectives can be conveniently made. Measurements made at an angle to axis as well on axis, and for various wavelengths. The apparatus relatively simple, stable easy handle. In addition, since tests are carried out under conditions approximating those actually used, effect changes in parameters studied quite readily. Some results obtained...
Increased contrast and resolution can be obtained with the Fabry-Perot interferometer by reflecting transmitted beams back through instrument. An arrangement for this purpose is described in which double-passed interference pattern isolated means of a simple polarizing system.