Ahmad Husni Mohd Shapri
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Preferred name
Ahmad Husni Mohd Shapri
Official Name
Ahmad Husni, Mohd Shapri
Alternative Name
Mohd Shapri, Ahmad Husni
Mohd. Shapri, Ahmad Husni
Shapri, Ahmad Husni Mohd
Shapri, Ahmad H.M.
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Scopus Author ID
55533640800
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DTB-1911-2022

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Enhancing fractal image compression speed using peer adjacent mapping with sum of absolute difference for computed radiography images

2020 , N. A. Z. Rahman , Rizalafande Che Ismail , Ahmad Husni Mohd Shapri , Mohd Nazrin Md Isa

The encoding phase in full-search fractal image compression (FIC) is time-intensive as a sequential search must be performed through a massive domain pool to find the best-matched domain for each block of ranges. In this paper, a peer adjacent with the sum of absolute difference (SAD) mapping has been suggested to enhance the FIC speed while retaining the reconstructed image quality. The SAD similarity measure applied in searching the most matching domain between domain pool for a range before transformation in order to shorten the mapping process. Therefore, instead of performing a complete search in the next level, one requires to only search a close neighbourhood of the region computed from the previous search. The efficiency of the proposed method is evaluated using standard test image, SMPTE test pattern and standard computed radiography digital images from JSRT database, from which the peak signal-to-noise ratio (PSNR), compression time and compression ratio are calculated. The experimental results validate the effectiveness of the proposed method.

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An Improved Irreversible Fractal Scheme for Medical Image Compression

2020-12-18 , Norazeani Abdul Rahman , Rizalafande Che Ismail , Ahmad Husni Mohd Shapri

In this paper, an improved fractal image compression (FIC) based on peer adjacent scheme and domain classification was proposed. The proposed method has low computation cost since it contains no search operations, thus becoming fast irreversible fractal scheme. Comprehensive experiments on a standard test image and several types of digital radiology images revealed that the proposed method is competitive when compared to established quadtree-based FIC techniques. The novelty of the proposed method lies in the use of this improved domain classification and mapping strategy for accurate and more precise FIC encoding. The empirical result of standard test image suggests that the proposed method is more competitive compared to the established schemes and achieves better performance in terms the peak signal-to-noise ratio (PSNR) and compression time averaging at 27.27 dB and 6.88 s, respectively. Also, the proposed method obtains an efficient compression ratio with 16.13 compared to others. Additionally, experiments involving various medical image modalities confirmed the superiority of the proposed method for practical applications of medical image compression.

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Peer adjacent mapping with optimum parameters for fractal image compression on medical images

2020 , Norazeani Abdul Rahman , Rizalafande Che Ismail , Ahmad Husni Mohd Shapri , Mohd Nazrin Md Isa

In order to reduce fractal image compression (FIC) computational complexity, this paper presents a novel approach based on peer adjacent and mean difference method in mapping the domain and range blocks. It allows the substitution of the costly process of the domain and range mapping with straight-forward peer adjacent schemes. The optimum parameters are suggested in terms of quadtree threshold, range sizes and number of iterations to fine-tune the output. Simulations on real computed radiography images show that the proposed method with optimum parameters yields a considerable peak signal-to-noise ratio (PSNR) value above 48 dB, reducing the runtime by as much as 19.32 s with the highest compression ratio is 20.03. Comparison with the standard FIC method confirms that our method not only accelerated the domain-range mapping procedure but also provided a high compression ratio with remarkable visual quality.

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Enhancing efficiency and stability in CPT systems: a state feedback controller approach

2025-03 , Ahmed Al-Hattami. , Shakir Saat , Yusmarnita Yusop , Md Rabiul Awal , Ahmad Husni Mohd Shapri , Huzaimah Husin

This work aims to present an innovative design and simulation of an autotuning capacitive power transfer (CPT) system. The system utilizes a Class-E converter, renowned for its exceptional efficiency. Challenges arise when trying to regulate the output voltage of a Class-E converter in the presence of load fluctuations, leading to an escalation in switching losses. By employing first harmonic approximation (FHA) and generalized state space averaging (GSSA), a state-space model of the system is constructed to effectively address this problem. The output voltage is regulated by a state feedback controller developed using the Lyapunov approach. This paper presents a comparative analysis of a traditional PID controller and a recently suggested state feedback controller, with a primary emphasis on system stabilization. The study examines the similarities and differences between the two controllers. The efficacy of the proposed controller design is demonstrated through the utilization of simulation data. Furthermore, these results confirm the validity of the comparative study, making it a substantial contribution to the field of CPT systems.

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Improved edge refinement filter with entropy feedback measurement for retrieving region of interest and blind image deconvolution

2020-02-01 , Ahmad Husni Mohd Shapri , Abdullah M.Z.

This study proposes an improved edge refinement filter with entropy feedback measurement for locating an optimal region of interest (ROI) in blurry images. This technique is inspired by He et al.'s algorithm and enhanced by introducing a suitable filter to obtain smooth unwanted pixels whilst retaining important and significant edges. This approach led to an accurate retrieval of ROI and a considerably precise image restoration within a blind deconvolution framework. Results show that the proposed method is more competitive than existing techniques and achieves better performance in terms of peak signal-to-noise ratio, kernel similarity index and error ratio.

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The design of inductive power transfer system for fish aquarium using class-E inverter and LCCL impedance matching

2023-06-01 , Saat S. , Yusop Y. , Husin S.H. , Awal M.R. , Ahmad Husni Mohd Shapri

Nowadays, the accessories in fish aquarium systems such as water pump, inter-nal filter, and LED light are powered using cables. This will cause to safety issue such as tangled wire, and risk of electric shock. Therefore, this work aims to design a wireless power transfer system to power up the fish aquarium’ accessories wirelessly without require any physical connection between source and loads. To be more specific, inductive power transfer (IPT) is used instead of capaci-tive power transfer (CPT) due to high efficiency ability owned by IPT. Class-E inverter circuit is proposed in this paper to convert DC to AC at nearly 100% efficiency. The inverter provides a low switching loss which is important as the circuit operates at high frequency, 1 MHz operating frequency. Furthemore, LCCL impedance matching circuit is added into receiver part of the system to enhance the efficiency of overall circuit. The analyses were done based on the distance between the coils and the misalignment of the coils against the output power and efficiency. The developed prototype is supplied by 24 V DC and ca-pable to deliver 5 W power. The overall efficiency of the prototype is 87.81%.

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Publication

Enhancing fractal image compression speed using peer adjacent mapping with sum of absolute difference for computed radiography images

2020 , Norazeani Abdul Rahman , Rizalafande Che Ismail , Ahmad Husni Mohd Shapri , Mohd Nazrin Md Isa

The encoding phase in full-search fractal image compression (FIC) is time-intensive as a sequential search must be performed through a massive domain pool to find the best-matched domain for each block of ranges. In this paper, a peer adjacent with the sum of absolute difference (SAD) mapping has been suggested to enhance the FIC speed while retaining the reconstructed image quality. The SAD similarity measure applied in searching the most matching domain between domain pool for a range before transformation in order to shorten the mapping process. Therefore, instead of performing a complete search in the next level, one requires to only search a close neighbourhood of the region computed from the previous search. The efficiency of the proposed method is evaluated using standard test image, SMPTE test pattern and standard computed radiography digital images from JSRT database, from which the peak signal-to-noise ratio (PSNR), compression time and compression ratio are calculated. The experimental results validate the effectiveness of the proposed method. © 2020 Author(s).

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