Mohd Zaid Abdullah

Automated inspection system for colour and shape grading of starfruit (Averrhoa carambola L.) using machine vision sensor

A prototype machine vision station was developed for quality grading of the unique star shape and rich golden colour carambola fruits (Averrhoa carambola L.). The grading criteria were based on the Malaysia’s Federal Agriculture Marketing Authority standards for starfruits export. A Fourier-based shape separations method was developed for shape grading, whereas colour recognition was established using multivariate discriminant analysis. The Wilks’ lambda analysis was invoked to transform and compress the data set comprising of large number of interconnected variates to a reduced set of variates. A robust scaling normalization was introduced in order to achieve invariant to geometrical transformations. Over 200 starfruit samples were inspected by the machine vision system and the results were compared to human judgement. Overall, the vision system was able to classify correctly 100% of the starfruits for shape and 92% for colour. Since the algorithms were implemented in software, the system could be programmed to inspect other fruits and agriculture commodities.

A Novel 5.8 GHz High Gain Array Dielectric Resonator Antenna

In this paper, a novel nine elements array dielectric resonator antenna (DRA) is presented. The DRA was excited by a microstrip feeder with a rectangular aperture coupled slots. The slot positions were determined based on the characteristic of standing wave ratio over a short ended microstrip. The measured gain of the array DRA operating at 5.84 GHz was about 10 dBi having impedance bandwidth of 60MHz. The proposed DRA exhibits an enhancement of the gain in comparison with a single pellet DRA. The size of the whole antenna structure is about 60 mm× 40mm and potentially can be used in wireless systems.

Antenna in LTCC Technologies: A Review and the Current State of the Art

This paper presents a chronological review of the research carried out on antennas in low-temperature cofired ceramics (LTCC) technology over the last ten years or so. Major breakthroughs in LTCC technologies and its shortcomings are highlighted. The current state of the art of LTCC-technology-based antennas is then evaluated. All realizable features of the LTCC-based antennas, which are compact and of light weight and offer high-speed functionality for portable electronic devices, are illustrated. Different techniques used by researchers for broadbanding, multiband designs, and fabrication of LTCC-based antennas are also presented. This paper ends with some recommendations and concluding remarks.

RADAR SENSING FEATURING BICONICAL ANTENNA AND ENHANCED DELAY AND SUM ALGORITHM FOR EARLY STAGE BREAST CANCER DETECTION

A biconical antenna has been developed for ultra- wideband sensing. A wide impedance bandwidth of around 115% at bandwidth 3.73{14GHz is achieved which shows that the proposed antenna exhibits a fairly sensitive sensor for microwave medical imaging applications. The sensor and instrumentation is used together with an improved version of delay and sum image reconstruction algorithm on both fatty and glandular breast phantoms. The relatively new imaging set-up provides robust reconstruction of complex permittivity proflles especially in glandular phantoms, producing results that are well matched to the geometries and composition of the tissues. Respectively, the signal-to-clutter and the signal-to-mean ratios of the improved method are consistently higher than 5dB and 10dB, corresponding to an average increase in image fldelity of more than 140% compared to conventional radar focusing technique.

Discrimination and classification of Eurycoma longifolia Jack in medicinal foods by means of a DSP-based electronic taste sensor

Eurycoma longifolia Jack (ELJ), better known as Malaysian Ginseng, is fast becoming popular due to its efficacy as a general health and testosterone booster, and for its known aphrodisiac properties. With the growing popularity of ELJ, together with the increasing consumer demand for healthy foods, it is expected that the number of healthy food suppliers boasting claims that their products are enriched with this medicinal herb will also increase. It is, therefore, important to device a strategy that can rapidly provide corroborating evidence in order to assess the authenticity of such a claim onsite. A portable electronic taste sensor employing digital signal processing (DSP) technology was developed to meet this objective. The sensor was constructed from eight kinds of lipid membranes forming the multichannel artificial taste-sensing equipment. The system was trained to detect ELJ into four different concentrations: 0.01%, 0.03%, 0.05% and 0.08%. Over 100 samples were tested, from which the taste system was able to correctly classify the test mixtures at a greater than 90% success rate. This classification success rate, however, dropped to well below 50% when data from multichannel were used independently, indicating the between-channel variations were relatively small. Data fusion via principal component analysis helped enlarge the variation with the first and second principal components, contributed nearly 92% of the total variance. Equipped with 32-bit state-of-the-art DSPs, the taste system allowed both training and testing schemes to be implemented directly onboard.

Unimodal thresholding for Laplacian-based Canny-Deriche filter

A unimodal thresholding method for the Laplacian-based Canny-Deriche edge detector featuring a double-thresholding approach and reconstruction strategy was proposed. In this method, an improved image segmentation technique derived from an image histogram was developed. The accuracy of the segmentation was compared with the Otsu, Rosin, and Canny-hysteresis techniques. It was shown that the proposed method is more robust and accurate in detecting edges, resulting in a sensitivity of consistently more than 17.1%, with a standard deviation of less than 0.087, and a figure of merit (FOM) greater than 0.787 for all images tested in this study.

NOVEL MODELING AND DESIGN OF CIRCULARLY POLARIZED DIELECTRIC RESONATOR ANTENNA ARRAY

This paper presents a design of circularly polarized dielectric resonator antenna (DRA) array. The dielectric resonators (DRs) were excited by rectangular aperture coupling slots feed with a linear microstrip. The slot positions were determined based on the characteristic of standing wave ratio over a short ended microstrip to deliver the maximum amount of coupling power to the DRs, in order to improve the array gain Each DR element was rotated 45 - with respect to the sides of the exciting slot to generate circular polarization pattern. The DRA array was modeled and simulated as a parallel RLC input impedance component using Agilent (ADS) software, since that will ensure the resonant frequency of the antenna as primary design step before simulating in (CST) software and doing the measurements. The results of the return loss, gain radiation and pattern axial ratio are shown. The gain of the proposed array in X band was about 8.5dBi, while the 3dB axial ratio bandwidth started from 8.14 to 8.24GHz. The impedance bandwidths started from 8.14GHz to 8.26GHz. The proposed DRA exhibited an enhancement of the gain in comparison to a single pellet DRA. The size of the whole antenna structure is about 40mm £ 50mm and can potentially be used in wireless systems.

Automatic detection of micro-crack in solar wafers and cells: a review

This paper presents a review of the machine detection systems for micro-crack inspection of solar wafers and cells. To-date, there are various methods and procedures that have been developed at various laboratories around the world to inspect solar wafers and solar cells for manufacturing defects. This paper on micro-crack detection offers a comprehensive and an up-to-date review of different detection strategies, describing the main features of each technique together with its strengths as well as weaknesses. This paper will benefit researchers and practitioners, especially those who want to develop automatic inspection systems for inspecting solar wafers or solar cells for micro-cracks.

Shape and weight grading of mangoes using visible imaging

Automatic grading of Harumanis mangoes by its shape and weight analysis.The Fourier descriptor method was developed to grade the shape of Harumanis mango.The cylinder method was developed to grade the weight of Harumanis mango.Multi-classification using Support Vector Machine and Discriminant analysis. This paper presents the work on the use of visible imaging as a tool in grading the mangoes. A Fourier-descriptor method was applied on mango images acquired by a CCD camera, to grade the fruits by their shapes. The method was able to correctly classify 98.3% using DA and 100% using SVM. It is also possible to estimate the weight of the mangoes from their images by applying the Cylinder approximation analysis method. The scatter plot between the estimated and actual values of the weight shows high correlation, with R2 equal to 94.0%. The high prediction accuracy obtained shows that this simple formula is adequate for the prediction of fruit weight and volume (measured volume using the cylinder method). The correlation formula derived based on the collected data is determined as w=2.256V-157.7 where w is estimated weight in grams and V is estimated volume. Overall result for weight grading using our proposed method yields 95% accuracy.

Development of a Compact Wide-Slot Antenna for Early Stage Breast Cancer Detection Featuring Circular Array Full-View Geometry

A novel planar type antenna printed on a high permittivity Rogers’ substrate is proposed for early stage microwave breast cancer detection. The design is based on a p-shaped wide-slot structure with microstrip feeding circuit to eliminate losses of transmission. The design parameters are optimized resulting in a good reflection coefficient at −10 dB from 4.5 to 10.9 GHz. Imaging result using inhomogeneous breast phantom indicates that the proposed antenna is capable of detecting a 5 mm size cancerous tumor embedded inside the fibroglandular region with dielectric contrast between the target and the surrounding materials ranging from 1.7 : 1 to 3.6 : 1.