Removal of ring artifacts in CT imaging through detection and correction of stripes in the sinogram

Anas, Emran Mohammad Abu,Lee, Soo Yeol,Hasan, Md. Kamrul Institute of Physics in association with the Ameri 2010 Physics in medicine & biology Vol.55 No.22

<P>Due to malfunctioning and mis-calibration of cells in digital x-ray detectors as well as impurities on the scintillator screens, stripe artifacts arise in the sinogram which in turn generate ring artifacts in the reconstructed x-ray computed tomography images. In this paper, a novel technique is proposed for the detection and removal of stripe artifacts in a sinogram with a view to suppress the ring artifacts from the tomographic images. To accurately detect the stripe creating pixels using a derivative-based algorithm, at first the sinogram is windowed to create a sub-sinogram by keeping the pixel of examination at the center position in the sub-sinogram. The other pixels in the sub-sinogram are selected from a polyphase component of the sinogram. A new mathematical index is proposed here to isolate the strong and weak ring-generating stripes from the good ones. For the correction of strong ring artifacts resulting from the defective detector elements and dusty scintillator crystals, 2D variable window moving average and weighted moving average filters are proposed in this work. On the other hand, a conventionally trusted constant bias correction scheme is adopted to correct the responses of the mis-calibrated detector elements. To evaluate and compare the performance of the proposed algorithm, real micro-CT images acquired from two flat panel detectors under different operating conditions are used. Experimental results show that the proposed method can remove ring artifacts more effectively without imparting noticeable distortion in the image as compared to a recently reported technique in the literature.</P>

Assessing the Phonological Abilities of Jordanian Arabic-speaking Children with Phonological Disorders

Anas al Huneety,Moh’d Ahmad Khaled Al-omari,Bassil Mashaqba,Mohammed Nour Abu Guba,Anas al Huneety 한국언어청각임상학회 2024 Communication Sciences and Disorders Vol.29 No.1

Objectives: This study investigated the validity of four language measures, i.e., phonological mean length of utterance (PMLU), the proportion of whole-word proximity (PWP), the proportion of whole-word correctness (PWC), and percentage of correct consonants, in assessing phonological development in Jordanian Arabic (JA) speaking children with phonological disorders in comparison with typically developing (TD) children. Methods: The study involved 88 monolingual JA-speaking children within the age range of 5 to 6 years, with 44 children diagnosed with phonological disorders and 44 TD children. Each group was further categorized into two age groups, namely 5;0-5;6 and 5,7-6,0. Data were gathered by observing the interactions between the children and their caregivers or parents using age-appropriate toys. A minimum of 100 utterances were collected from each participant. Results: The study found that TD children performed better than the children with phonological disorders on all measures, indicating delayed phonological performance in the phonological disorders group. Positive correlations between the measures were also observed, indicating their ability to provide significant information about children’s phonological abilities. Specific speech sound errors and substitution patterns exhibited by children with phonological disorders were identified, highlighting the motor control and articulatory challenges experienced by this group. Age was found to be a significant factor in the development of TD children, while children with phonological disorders showed similar scores across different age groups. Conclusion: These findings support the usage of the four measures for understanding phonological development in children with phonological disorders, accurately diagnosing them and tracking their progress.

The Relationship between Accounting Conservatism and Earning Management in Emerging Markets: The Moderating Role of Size

Anas Ghazalat,Jamal Abu-Serdaneh,Haifa Majaly 대한산업공학회 2023 Industrial Engineeering & Management Systems Vol.22 No.2

Direct and gradient-based average strain estimation by using weighted nearest neighbor cross-correlation peaks

Hussain, Mohammad,Abu Anas, Emran,Alam, S.,Lee, Soo,Hasan, Md. IEEE 2012 and Frequency Control Vol.59 No.8

<P>In this paper, two novel approaches, gradientbased and direct strain estimation techniques, are proposed for high-quality average strain imaging incorporating a cost function maximization. Stiffness typically is a continuous function. Consequently, stiffness of proximal tissues is very close to that of the tissue corresponding to a given data window. Hence, a cost function is defined from exponentially weighted neighboring pre- and post-compression RF echo normalized cross-correlation peaks in the lateral (for displacement estimation) or in both the axial and the lateral (for direct strain estimation) directions. This enforces a controlled continuity in displacement/strain and average displacement/strain is calculated from the corresponding maximized cost function. Axial stress causes lateral shift in the tissue. Therefore, a 1-D post-compression echo segment is selected by incorporating Poisson's ratio. Two stretching factors are considered simultaneously in gradient-based strain estimation that allow imaging the lesions properly. The proposed time-domain gradient-based and direct-strain-estimation-based algorithms demonstrate significantly better performance in terms of elastographic signal-to-noise ratio (SNRe), elastographic contrast-to-noise ratio (CNRe), peak signal-to-noise ratio (PSNR), and mean structural similarity (MSSIM) than the other reported time-domain gradientbased and direct-strain-estimation techniques in finite element modeling (FEM) simulation and phantom experiments. For example, in FEM simulation, it has been found that the proposed direct strain estimation method can improve up to approximately 2.49 to 8.71, 2.2 to 6.63, 1.5 to 5, and 1.59 to 2.45 dB in the SNRe, CNRe, PSNR, and MSSIM compared with the traditional direct strain estimation method, respectively, and the proposed gradient-based algorithm demonstrates 2.99 to 16.26, 18.74 to 23.88, 3 to 9.5, and 0.6 to 5.36 dB improvement in the SNRe, CNRe, PSNR, and MSSIM, respectively, compared with a recently reported time-domain gradient-based technique. The range of improvement as noted above is for low to high applied strains. In addition, the comparative results using the in vivo breast data (including malignant or benign masses) also show that the lesion size is better defined by the proposed gradient-based average strain estimation technique.</P>

Investigation of DPD transport properties in modeling bioparticle motion under the effect of external forces: Low Reynolds number and high Schmidt scenarios

Waheed, Waqas,Alazzam, Anas,Al-Khateeb, Ashraf N.,Sung, Hyung Jin,Abu-Nada, Eiyad American Institute of Physics 2019 The Journal of chemical physics Vol.150 No.5

Direct Mean Strain Estimation for Elastography Using Nearest-Neighbor Weighted Least-Squares Approach in the Frequency Domain

Hasan, Md. Kamrul,Anas, Emran Mohammad Abu,Alam, S. Kaisar,Lee, Soo Yeol Elsevier 2012 Ultrasound in medicine & biology Vol.38 No.10

<P>Ultrasound elastography is emerging with enormous potential as a medical imaging modality for effective discrimination of pathological changes in soft tissue. It maps the tissue elasticity or strain due to a mechanical deformation applied to it. The strain image most often calculated from the derivative of the local displacement field is highly noisy because of the de-correlation effect mainly due to unstable free-hand scanning and/or irregular tissue motion; consequently, improving the SNR of the strain image is still a challenging problem in this area. In this paper, a novel approach using the nearest-neighbor weighted least-squares is presented for direct estimation of the 'mean' axial strain for high quality strain imaging. Like other time/frequency domain reported schemes, the proposed method exploits the fact that the post-compression rf echo signal is a time-scaled and shifted replica of the pre-compression rf echo signal. However, the elegance of our technique is that it directly computes the mean strain without explicitly using any post filter and/or previous local displacement/strain estimates as is usually done in the conventional approaches. It is implemented in the short-time Fourier transform domain through a nearest-neighbor weighted least-squares-based Fourier spectrum equalization technique. As the local tissue strain is expected to maintain continuity with its neighbors, we show here that the mean strain at the interrogative window can be directly computed from the common stretching factor that minimizes a cost function derived from the exponentially weighted windowed pre- and post-compression rf echo segments in both the lateral and axial directions. The performance of our algorithm is verified for up to 8% applied strain using simulation and experimental phantom data and the results reveal that the SNR of the strain image can be significantly improved compared to other reported algorithms in the literature. The efficacy of the algorithm is also tested with in vivo breast data known to have malignant or benign masses from histology.</P>

Acquisition of Syllable Structure in Jordanian Arabic

Bassil M. Mashaqba,Khalid G. Al-Shdifa,Anas I. Al Huneety,Mais Abu Alhala 한국언어청각임상학회 2019 Communication Sciences and Disorders Vol.24 No.4

Objectives: The aim of this research was to investigate the early word syllable structure and notable phonological processes in the speech of Jordanian Arabic (JA)-speaking children. Methods: Elicited and spontaneous speech productions of 20 children were transcribed and analyzed by syllable structure. The ages of the participants ranged from 1 to 3 years, divided into four age groups: 1;0-1;6, 1;7-2;0, 2;1-2;6, and 2;7-3;0. Then, the data was analyzed according to ten phonological processes influencing word syllable structure and number. Results: CVC was found to be the most prevalent syllable structure used across all age groups. In terms of syllable number, disyllabic words were the most frequently used. Onomatopoeia, weak syllable deletion, and closed syllable CVVC reduction to CVV were noticed in the productions of children in the first age group. Cluster reduction and onset/ coda deletion occurred the most with the age group 2;1-2;6, while syllable deletion was evident until age 3. Conclusion: It appears that JA-speaking children use CVC syllable structure heavily in bisyllabic and polysyllabic words in their early speech; they avoid monosyllabic CV or CVC syllables to preserve the minimal bimoraic weight of Arabic phonological words. Onomatopoeia is noticed beyond the age of 1 with syllable deletion in the speech of children up to 3. The results are discussed within the context of the current literature.