Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Dihan Md. Nuruddin Hasan is active.

Publication


Featured researches published by Dihan Md. Nuruddin Hasan.


Photonics Letters of Poland | 2010

A Highly Nonlinear Spiral Photonic Crystal Fiber for Tailoring Two Zero Dispersion Wavelengths in the Visible Region

Muhammad Nazmul Hossain; M. Shah Alam; Dihan Md. Nuruddin Hasan; K. M. Mohsin

The paper presents the way that colour can serve solving the problem of calibration points indexing in a camera geometrical calibration process. We propose a technique in which indexes of calibration points in a black-and-white chessboard are represented as sets of colour regions in the neighbourhood of calibration points. We provide some general rules for designing a colour calibration chessboard and provide a method of calibration image analysis. We show that this approach leads to obtaining better results than in the case of widely used methods employing information about already indexed points to compute indexes. We also report constraints concerning the technique. Nowadays we are witnessing an increasing need for camera geometrical calibration systems. They are vital for such applications as 3D modelling, 3D reconstruction, assembly control systems, etc. Wherever possible, calibration objects placed in the scene are used in a camera geometrical calibration process. This approach significantly increases accuracy of calibration results and makes the calibration data extraction process easier and universal. There are many geometrical camera calibration techniques for a known calibration scene [1]. A great number of them use as an input calibration points which are localised and indexed in the scene. In this paper we propose the technique of calibration points indexing which uses a colour chessboard. The presented technique was developed by solving problems we encountered during experiments with our earlier methods of camera calibration scene analysis [2]-[3]. In particular, the proposed technique increases the number of indexed points points in case of local lack of calibration points detection. At the beginning of the paper we present a way of designing a chessboard pattern. Then we describe a calibration point indexing method, and finally we show experimental results. A black-and-white chessboard is widely used in order to obtain sub-pixel accuracy of calibration points localisation [1]. Calibration points are defined as corners of chessboard squares. Assuming the availability of rough localisation of these points, the points can be indexed. Noting that differences in distances between neighbouring points in calibration scene images differ slightly, one of the local searching methods can be employed (e.g. [2]). Methods of this type search for a calibration point to be indexed, using a window of a certain size. The position of the window is determined by a vector representing the distance between two previously indexed points in the same row or column. However, experiments show that this approach has its disadvantages, as described below. * E-mail: [email protected] Firstly, there is a danger of omitting some points during indexing in case of local lack of calibration points detection in a neighbourhood (e.g. caused by the presence of non-homogeneous light in the calibration scene). A particularly unfavourable situation is when the local lack of detection effects in the appearance of separated regions of detected calibration points. It is worth saying that such situations are likely to happen for calibration points situated near image borders. Such points are very important for the analysis of optical nonlinearities, and a lack of them can significantly influence the accuracy of distortion modelling. Secondly, such methods may give wrong results in the case of optical distortion with strong nonlinearities when getting information about the neighbouring index is not an easy task. Beside this, the methods are very sensitive to a single false localisation of a calibration point. Such a single false localisation can even result in false indexing of a big set of calibration points. To avoid the above-mentioned problems, we propose using a black-and-white chessboard which contains the coded index of a calibration point in the form of colour squares situated in the nearest neighbourhood of each point. The index of a certain calibration point is determined by colours of four nearest neighbouring squares (Fig.1). An order of squares in such foursome is important. Because the size of a colour square is determined only by the possibility of correct colour detection, the size of a colour square can be smaller than the size of a black or white square. The larger size of a black or white square is determined by the requirements of the exact localisation step which follows the indexing of calibration points [3]. In this step, edge information is extracted from a blackand-white chessboard. This edge information needs larger Artur Nowakowski, Wladyslaw Skarbek Institute of Radioelectronics, Warsaw University of Technology, Nowowiejska 15/19, 00-665 Warszawa, [email protected] Received February 10, 2009; accepted March 27, 2009; published March 31, 2009 http://www.photonics.pl/PLP


ieee region 10 conference | 2009

Design of some quaternary combinational logic blocks using a new logic system

Ifat Jahangir; Dihan Md. Nuruddin Hasan; Md. Shamim Reza

A new scheme for quaternary logic is proposed. The logic system is based on the extension of Boolean algebra, instead of conventional Fuzzy logic or Galois Field theory. This logic mainly focuses on the capability of handling coupled-binary input, where binary operands are coupled in pairs to form multivalued entities. Several operators are defined and a fully operational algebra is developed. To make it compatible with other quaternary logic systems, a method for expressing arbitrary functions in sum-of-product forms is also developed. Finally, using these operators and functions, combinational blocks like adder, multiplexer, demultiplexer, decoder and encoder are designed and their generalized equations are presented.


Applied Optics | 2011

Dispersion and nonlinearity properties of a chalcogenide As 2 Se 3 suspended core fiber

K. M. Mohsin; M. Shah Alam; Dihan Md. Nuruddin Hasan; Muhammad Nazmul Hossain

A highly nonlinear suspended core fiber (SCF) has been proposed, where a geometrical design parameter called suspension factor (SF) has been used for dispersion tailoring in the infrared region (1.2 μm to 2.8 μm). We have investigated the effect of different suspended conditions of the SCF core on group velocity dispersion, fiber nonlinearity, and power distributions. Peak effective nonlinearity (∼500 W−1 m−1 at 1200 nm with eight air holes) can be varied significantly with SF. The effect of SF on tailoring the zero dispersion wavelengths has been observed. The SF can also be utilized to control mode overlap between core mode and air hole mode for different sensing applications.


annual conference on computers | 2009

Development of a novel quaternary algebra with the design of some useful logic blocks

Ifat Jahangir; Dihan Md. Nuruddin Hasan; Shajid Islam; Nahian Alam Siddique; Md. Mehedi Hasan

A completely new scheme for quaternary logic is proposed. Instead of conventional Fuzzy logic or Galois Field theory, the logic system is based on the extension of Boolean algebra. The logic is capable of handling both quaternary and coupled-binary inputs, where binary operands are coupled in pairs to form quaternary entities. All necessary operators are defined and several theorems and properties are derived to develop a way of expressing arbitrary truth tables with sum-of-product functions. To demonstrate the functionality of this novel logic scheme, some useful logic blocks such as decoder, multiplexer, and half-adder are designed.


Optical Engineering | 2011

Design of a spiral silica photonic crystal fiber for nonlinear applications in visible region

Md. Nazmul Hossain; M. Shah Alam; Dihan Md. Nuruddin Hasan; K. M. Mohsin

A silica spiral photonic crystal fiber is presented here for tailoring two zero dispersion wavelengths (ZDWs) in the visible region. The proposed fiber has two ZDWs (523.1 and 716.8 nm) along with a very high nonlinearity parameter (1060 W−1 km−1 at 500 nm) around the visible region. The proposed design shows improvement over the group dispersion control and air holes collapsibility of highly air filled hexagonal photonic crystal fiber (HPCF), and low damage threshold of the soft glass photonic crystal fiber. Besides, the low air filling fraction (≈43%) of the proposed design reduces the probability of sustaining higher order modes in the fiber and also ensures easy fabrication due to fewer air holes.


annual conference on computers | 2009

Design of quaternary sequential circuits using a newly proposed quaternary algebra

Ifat Jahangir; Dihan Md. Nuruddin Hasan; Nahian Alam Siddique; Shajid Islam; Md. Mehedi Hasan

Using a novel quaternary algebra, several sequential circuits are designed. The quaternary logic scheme used here is obtained by extending Boolean algebra into quaternary domain. A set of operators capable of handling both coupled-binary and ordinary inputs are used to design the sequential circuit elements such as latches, flip-flops, registers and counters. Sufficient conditions for stable operation of the sequential blocks are derived mathematically and demonstrated graphically using simulated timing diagrams.


ieee region 10 conference | 2010

Optical characterization of a chalcogenide glass nanophotonic device

Dihan Md. Nuruddin Hasan; Muhammad Nazmul Hossain; K. M. Mohsin; M. Shah Alam

In this paper, we have proposed a nonlinear photonic device and characterized linear and nonlinear optical properties from 1.5 µm to 5 µm using full vector finite element method. A sub-wavelength photonic wire inside a silica glass photonic crystal structure with an average index contrast ≈ 1.4 is found to maintain tight optical confinement at the peak operating wavelength. We have obtained a highly anomalous dispersion region starting from 1.76 µm to a maximum of 4.6 µm. A method to tune the upper zero GVD wavelength has been explored. Again, high anomalous dispersion of pure silica at longer wavelengths has been investigated for the first time. A nonlinearity parameter within the order of 105 W−1 Km−1 also confirms low power mid-IR supercontinuum generation for a pumping wavelength in the short-wavelength infrared band.


international conference on electrical and control engineering | 2010

Design and characterization of a novel spiral photonic crystal fiber nanowire for visible range applications

Dihan Md. Nuruddin Hasan; M. Shah Alam; Muhammad Nazmul Hossain; K. M. Mohsin

In this paper, we have proposed a novel nanophotonic device for nonlinear applications in the visible range. The proposed device is a photonic crystal fiber nanowire composed of highly transparent silica with a germania doped silica as core material. Numerical analysis has confirmed that the proposed nonlinear device has a maximum Raman gain coefficient of 1324 W<sup>−1</sup>km<sup>−1</sup> with a nonlinearity parameter of 1144 W<sup>−1</sup>km<sup>−1</sup>. Again, the ultra-flattened dispersion slope of −0.0038 ps/nm<sup>2</sup>-km obtained at wavelength ≈ 584 nm has also validated the efficiency of dispersion control mechanism of the newly proposed spiral photonic crystal fiber structure for nonlinear applications. Later, tunability of Raman effective area and Raman interaction length has been investigated for the proposed nanowire based device in the flat dispersion region.


international conference on electrical and control engineering | 2010

Comparative analysis of propagation characteristics of two triangular lattice photonic crystal fibers in the middle infrared spectrum

Dihan Md. Nuruddin Hasan; M. Shah Alam; K. M. Mohsin; Muhammad Nazmul Hossain

In this paper, a numerical comparison of optical performances of chalcogenide based PCFs with hexagonal and octagonal symmetry has been performed in the mid-IR spectrum for the first time. A tapering factor has been introduced to investigate the effects of core size for both the cases. Qualitative analysis of group velocity dispersion has been presented for a bandwidth of 3500 nm. Later, air filling fraction has been considered to shift the dispersion profile to anomalous region for the two cases. Finally, effective area method has been applied to find the cut-off region in the phase diagram. It has been found that improvement of bandwidth in O-PCF over H-PCF is subject to air filling fraction and operating wavelength.


conference on optoelectronic and microelectronic materials and devices | 2010

Analysis of dispersion and nonlinear loss characteristics of silica clad silicon nanowire

Dihan Md. Nuruddin Hasan; M. Shah Alam; K. M. Mohsin; Muhammad Nazmul Hossain

An analytic equation has been proposed to realize propagation characteristics for different geometrical patterns of silicon nanowire using full vector FEM. Analysis of mode dependent nonlinear loss has revealed that attenuation of signal power is less for higher order modes than for the fundamental modes excited in the nanowire.

Collaboration


Dive into the Dihan Md. Nuruddin Hasan's collaboration.

Top Co-Authors

Avatar

M. Shah Alam

Bangladesh University of Engineering and Technology

View shared research outputs
Top Co-Authors

Avatar

K. M. Mohsin

Bangladesh University of Engineering and Technology

View shared research outputs
Top Co-Authors

Avatar

Muhammad Nazmul Hossain

Bangladesh University of Engineering and Technology

View shared research outputs
Top Co-Authors

Avatar

Ifat Jahangir

Bangladesh University of Engineering and Technology

View shared research outputs
Top Co-Authors

Avatar

Md. Nazmul Hossain

Bangladesh University of Engineering and Technology

View shared research outputs
Top Co-Authors

Avatar

Nahian Alam Siddique

Bangladesh University of Engineering and Technology

View shared research outputs
Top Co-Authors

Avatar

Md. Mehedi Hasan

Military Institute of Science and Technology

View shared research outputs
Top Co-Authors

Avatar

Shajid Islam

Military Institute of Science and Technology

View shared research outputs
Top Co-Authors

Avatar

Md. Shamim Reza

Bangladesh University of Engineering and Technology

View shared research outputs
Researchain Logo
Decentralizing Knowledge