Deep underwater image enhancement through colour cast removal and optimization algorithm

ABSTRACT

Blue–green colour cast effect and low contrast are common problems suffered by deep underwater images. This paper introduces a new method which consists of two major steps: red channel correction based on green and blue channels (RCCGB), and simultaneous contrast stretching and mean pixel enhancement (SCSMPE). The RCCGB is designed to minimize the effect of blue–green illumination. This step considers the differences between the red channel and other channels in terms of total pixel values. The second major step, SCSMPE is specifically designed to perform contrast stretching and improve the mean pixel value simultaneously through particle swarm optimization (PSO). Based on the visual observation, the proposed method significantly reduces the effect of the blue–green colour cast and improves the image contrast. Furthermore, the average quantitative values for 300 underwater images also demonstrate the superiority of the proposed method.     

An Iterative Multiuser Detector for Overloaded LDPC Coded CDMA Systems

Maximum number of users in a Code Division Multiple Access (CDMA) system, disregarding the type of used signature sequences, is equal to the processing gain; but in overloaded CDMA systems, it is tried to use some special methods of applying signature sequences so that the number of users exceeds the processing gain of the system. This growth in capacity is gain at the cost of decrease in performance of the conventional systems; and usually it is tried to use channel coding methods or multi-user detectors to compensate this decrease. Because of advantages of using coding methods joined with multiuser detectors in achieving better performance and also because of some benefits of using (Low Density Parity Check) LDPC method in comparison with similar capacity achieving coding methods, in this article, an iterative multi-user detector for an overloaded LDPC Coded CDMA system is proposed. This receiver consists of a combination of matched filters in the first stage and a linear (Minimum Mean Square Error) MMSE detector and an Interference Cancellation (IC) scheme in the successive stages. In the suggested method, a bank of LDPC decoders gives the soft information to the IC blocks, which help for the better interference cancellation. Comparing the performance of the proposed system with that of Turbo coded system shows that the proposed system, in addition to advantages of using LDPC codes instead of Turbo codes, has better bit error rate performance.     

DETERMINATION OF THE EFFECT OF LEMON ADDITION UPON ELEMENT CONCENTRATIONS IN TEA

Consumption of tea is a popular tradition in Turkey. In this article, non essential and toxic element concentrations were determined in infusions and lemon added infusions in widely consumed Turkish teas (black, earl grey, and green tea). Element concentrations were found to be in the order of aluminum > nickel > barium in black and earl grey teas. In green tea, the order was changed to aluminum > nickel > lead > barium. The concentrations of arsenic and antimony were below the detection limit of the inductively coupled plasma optical emission spectrometry method employed. The addition of lemon increased aluminum, cadmium, and lead concentrations in all teas whereas nickel concentration increased in black and green tea but decreased in earl grey. The barium concentration was same at all tea samples. In comparison with the recommended daily allowance ratios, the amount of aluminum consumed is between 13.167–24.396% in males and 17.556–32.528% in females for people who consume 200 mL of teas daily. Other elements (cadmium, lead, nickel, barium) which are a concern for tea consumption were determined and the hazard index of daily tea drinking was found to be in the safe range except for green tea with lemon addition.     

Use of a Reflectance Spectroscopy Accessory for Optical Characterization of ZnO-Bi(2)O(3)-TiO(2) Ceramics

The optical band-gap energy (E(g)) is an important feature of semiconductors which determines their applications in optoelectronics. Therefore, it is necessary to investigate the electronic states of ceramic ZnO and the effect of doped impurities under different processing conditions. E(g) of the ceramic ZnO + xBi(2)O(3) + xTiO(2), where x = 0.5 mol%, was determined using a UV-Vis spectrophotometer attached to a Reflectance Spectroscopy Accessory for powdered samples. The samples was prepared using the solid-state route and sintered at temperatures from 1140 to 1260 °C for 45 and 90 minutes. E(g) was observed to decrease with an increase of sintering temperature. XRD analysis indicated hexagonal ZnO and few small peaks of intergranular layers of secondary phases. The relative density of the sintered ceramics decreased and the average grain size increased with the increase of sintering temperature.     

Proposal of an alternating bending technique for evaluating low‐to‐high cycle fatigue of structural steels

This paper proposes an alternating bending technique for evaluating fatigue life in the low‐to‐high cycle fatigue regime. A method was developed for estimating the stress, elastic strain, and plastic strain ranges of a plastically deformed specimen subjected to alternating bending with consideration of stress and strain distributions. To evaluate its effectiveness, fatigue testing was conducted using a specimen made of a steel used for pressure vessels. The stress, elastic strain, and plastic strain ranges could be obtained during cyclic bending. The elastic strain amplitude life and plastic strain amplitude life curves were linear in a log–log plot in the low‐to‐high cycle fatigue regime. Hence, the fatigue life under alternating bending could be evaluated using the proposed strain‐based approach. However, these curves could not be predicted using equations with parameters obtained from tensile testing, such as the universal slope method, due to the strain gradient in the specimen.     

超音速火焰喷涂与激光重熔Al0.2CrFeNi(Co,Cu)合金的干滑动磨损及氧化性能对比研究

用超音速火焰喷涂(HVOF)法在316L不锈钢基体上沉积Al0.2CrFeNiCo和Al0.2CrFeNiCu两种高熵合金涂层,然后对涂层进行激光重熔(LR)以改善其显微组织.研究LR工艺对涂层干滑动磨损和氧化行为的影响.结果表明,将粉末与单体元素混合导致HVOF涂层中形成内氧化物.LR消除了氧化物和气孔.LR后,两种...     

Developing flow of Newtonian fluids over superhydrophobic transverse grooves in circular tube

Journal of Mechanical Science and Technology - In this paper, the effects of dimensionless gas area fraction (δ) and normalized groove-rib periodic spacing (Λ) on developing flow for...     

Hybrid multi-verse optimizer with grey wolf optimizer for power scheduling problem in smart home using IoT

The Journal of Supercomputing - The power scheduling problem in smart home (PSPSH) is one of the complex NP-hard scheduling problems, where it has a deep and rugged search space due to the high...     

Thermal analysis of a constructal T-shaped porous fin with simultaneous heat and mass transfer

The present work establishes an analytical model for computing the temperature distribution,fin efficiency and optimum design parameters of a constructal T-shaped porous fin operating in fully wet condition.For more practical results,this study considers a cubic polynomial relationship between the humidity ratio of saturated air and the corresponding fin surface temperature.The temperature distribution has been determined by solving the highly non-linear governing equations using a semi-analytical transformation technique called Differential Transform Method.A comparison of the results with that of a numerical model shows that this transformation method is a very efficient and convenient tool for solution of non-linear problems.The effects of various geometric,thermo-physical and psychometric parameters on the temperature distribution,fin efficiency and optimum design condition have been investigated.Also,a comparison has been presented between solid and porous fins and the results point out that by selecting an appropriate value of porosity,the heat transfer rate can be increased than the corresponding solid fin.