Azimuthal Walsh Functions can be utilized to obtain an orthogonal set of Azimuthal Walsh Filters where the transmission values of +1 and -1 are achieved by using 0 and pi phase respectively. The inherent asymmetry in the azimuthal Walsh filters leads to asymmetrical Point Spread Function (PSF) in the far field diffraction pattern. This report presents results of our preliminary investigation on the effects of phase asymmetry in the filters on the PSF in the Far-field patterns. © 2015 IEEE.

INDRANI BHATTACHARYA

Museology

A SAHA

L HAZRA

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Asymmetrical PSF by Azimuthal Walsh filters

2015 2nd International Conference on Opto-Electronics and Applied Optics: Advances in Optical Sciences and Engineering II, IEM OPTRONIX 2015

Binary polar Walsh filters derived from two dimensional polar Walsh functions provides an effective tool for tailoring the three dimensional intensity distributions of a point spread function (PSF) in the pupil plane in a diffraction limited imaging system. This paper reports the study of radial as well as azimuthally variant polar Walsh filters and observation on their imaging characteristics near the focal plane of a rotationally symmetric imaging system. © Springer India 2015.

Springer Proceedings in Physics

Point spread function of apertures masked by two-dimensional polar walsh filters

Pupil plane filtering by radial Walsh filters is a convenient technique for tailoring the axial intensity distribution near the focal plane of a rotationally symmetric imaging system. Radial Walsh filters, derived from radial Walsh functions, form a set of orthogonal phase filters that take on values either 0 or p phase, corresponding to 1 or -1 values of the radial Walsh functions over prespecified annular regions of the circular filter. Order of these filters is given by the number of zero-crossings, or equivalently phase transitions within the domain over which the set is defined. In general, radial Walsh filters are binary phase zone plates, each of them demonstrating distinct focusing characteristics. The set of radial Walsh filters can be classified into distinct groups, where the members of each group possess self-similar structures. Self-similarity can also be observed in the corresponding axial intensity distributions. These observations provide valuable clues in tackling the inverse problem of synthesis of phase filter in accordance with prespecified axial intensity distributions. This paper reports our observations on self-similarity in radial Walsh filters of various orders and corresponding axial intensity distributions. © 2014 Optical Society of America.

Journal of the Optical Society of America A: Optics and Image Science, and Vision

Self-similarity in radial Walsh filters and axial intensity distributions in the far-field diffraction pattern

Walsh functions form a complete set of normal orthogonal functions that take on values either +1 or -1 over a prespecified domain. Corresponding filters can be synthesized as phase filters that take on values either 0 or π phase. This paper presents different types of Walsh functions in one and two dimensions to demonstrate that a large class of pupil filters can be synthesized from them to cater to the various needs of diffraction pattern for tailoring transverse and/or axial resolution in microscopic applications. Illustrative numerical results are presented. © 2006.

Micron

Walsh filters for tailoring of resolution in microscopic imaging

Radial Walsh functions form a closed set of orthogonal functions over a given finite interval, each function taking merely one constant value (either +1 or -1) in each of a finite number of subintervals into which the entire interval is divided. This set provides a remarkable set of orthogonal radial filters for the pupil of an imaging system. We report analytical expressions for members of the set and their Hankel transforms of order zero. Far-field diffraction characteristics, namely, the far-field amplitude distribution and the optical transfer functions, are presented for the first eight members of the set. © 1986 Optical Society of America.

Journal	Data powered by Typeset2015 2nd International Conference on Opto-Electronics and Applied Optics: Advances in Optical Sciences and Engineering II, IEM OPTRONIX 2015
Publisher	Data powered by TypesetInstitute of Electrical and Electronics Engineers Inc.