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Tomography ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 158-174
Author(s):  
Xue Ren ◽  
Ji Eun Jung ◽  
Wen Zhu ◽  
Soo-Jin Lee

In this paper, we present a new regularized image reconstruction method for positron emission tomography (PET), where an adaptive weighted median regularizer is used in the context of a penalized-likelihood framework. The motivation of our work is to overcome the limitation of the conventional median regularizer, which has proven useful for tomographic reconstruction but suffers from the negative effect of removing fine details in the underlying image when the edges occupy less than half of the window elements. The crux of our method is inspired by the well-known non-local means denoising approach, which exploits the measure of similarity between the image patches for weighted smoothing. However, our method is different from the non-local means denoising approach in that the similarity measure between the patches is used for the median weights rather than for the smoothing weights. As the median weights, in this case, are spatially variant, they provide adaptive median regularization achieving high-quality reconstructions. The experimental results indicate that our similarity-driven median regularization method not only improves the reconstruction accuracy, but also has great potential for super-resolution reconstruction for PET.


2022 ◽  
Vol 40 (2) ◽  
pp. 619-628
Author(s):  
Mustafa Youldash ◽  
Saleh Al-Dossary ◽  
Lama AlDaej ◽  
Farah AlOtaibi ◽  
Asma AlDubaikil ◽  
...  

Author(s):  
Christos Baloglou ◽  

This paper deals with those aspects of Byzantine intellectual heritage, which belong to the Bessarion’s thought and writing. Bessarion, Cardinal of the Roman-Catholic Church, proposed specific, systematic and analytical measures for a re-organization and recovery of the Despotate of Mistra, while, as it is known, he lived there from the end of 1431 until the end of 1436. Then Вessarion, in his capacity as cardinal, showed his continual and undiminished interest to the advancement of Greek nation, as proven by three famous memoranda of scholar. These are appeals to Constantine Palaiologos, Despot of Mistra, as well as to the doge of Venice. Dated July 13, 1453 the letter to the doge informed him on the Fall of Constantinople and the sufferings of Greek nation! Especially noteworthy is the third (and only surviving) letter of Вessarion, addressed to his friend, Despot Constantine Palaiologos in the spring of 1444. Here Вessarion proposes a specific, specialized program for the economic restructure, social reorganization and military strengthening of the Despotate. The intellectual associates education with economy. Sharing the economic philosophy of ancient Greeks on self-sufficiency and utilization of local means, Вessarion became a forerunner of mercantilism, while also acknowledging the productive contribution of education. The proposal of Вessarion for the transfer of the Despotate’s capital closer to the Isthmus was of great geopolitical importance since, when the guarding of the Hexamilion Wall would be reconstructed and constant and properly updated. These proposals, having been so important for the evolution of Byzantine economic thought, took an appropriate place in its development.


2021 ◽  
Vol 7 ◽  
pp. e611
Author(s):  
Zengguo Sun ◽  
Guodong Zhao ◽  
Marcin Woźniak ◽  
Rafał Scherer ◽  
Robertas Damaševičius

The GF-3 satellite is China’s first self-developed active imaging C-band multi-polarization synthetic aperture radar (SAR) satellite with complete intellectual property rights, which is widely used in various fields. Among them, the detection and recognition of banklines of GF-3 SAR image has very important application value for map matching, ship navigation, water environment monitoring and other fields. However, due to the coherent imaging mechanism, the GF-3 SAR image has obvious speckle, which affects the interpretation of the image seriously. Based on the excellent multi-scale, directionality and the optimal sparsity of the shearlet, a bankline detection algorithm based on shearlet is proposed. Firstly, we use non-local means filter to preprocess GF-3 SAR image, so as to reduce the interference of speckle on bankline detection. Secondly, shearlet is used to detect the bankline of the image. Finally, morphological processing is used to refine the bankline and further eliminate the false bankline caused by the speckle, so as to obtain the ideal bankline detection results. Experimental results show that the proposed method can effectively overcome the interference of speckle, and can detect the bankline information of GF-3 SAR image completely and smoothly.


2021 ◽  
Vol 8 (6) ◽  
pp. 1287
Author(s):  
Adam Syarif Hidayatullah ◽  
Fitra Abdurrachman Bachtiar ◽  
Imam Cholissodin

<p class="Abstrak">Keberhasilan sebuah perusahaan terjadi karena dapat mengelola sumber daya manusianya dengan baik begitu juga sebaliknya. Salah satu instansi yang mengelola sumber daya manusia menggunakan Manajemen Talenta adalah Badan Kepegawaian Daerah (BKD) kota Malang, dengan mengevaluasi pegawainya setiap tahunnya setelah pekerjaan selesai dilakukan. Hal ini menyebabkan hasil pekerjaan yang telah dilakukan tidak optimal, sehingga perlu identifikasi dini pegawai yang memiliki kinerja dibawah rata – rata sehingga dapat dievaluasi dan meminimalisir hasil pekerjaan yang tidak optimal dengan menggunakan teknik klasifikasi. Penelitian ini menggunakan teknik klasifikasi <em>Nearest Centroid Neighbor Classifier Based on K Local Means Using Harmonic Mean Distance</em> (LMKHNCN). Metode ini merupakan metode modifikasi dari metode <em>K-Nearest Neighbor</em> (KNN) dan dibuktikan memiliki performa lebih baik dibandingkan dengan metode aslinya KNN. Dilakukan pengujian <em>F1-Score</em> dan akurasi menggunakan <em>K-Fold Cross Validation</em> untuk mengetahui persebaran akurasi dan juga pengujian mengenai pengaruh normalisasi karena tidak ada informasi normalisasi pada penelitian sebelumnya. Metode pada kasus ini menghasilkan performa klasifikasi yang baik, dibuktikan bahwa hasil akurasi dan <em>F1-Score</em> oleh metode ini berturut – turut ialah mencapai 98,8% dan 98,1%.</p><p class="Abstrak"> </p><p class="Judul2"><strong><em>Abstract</em></strong></p><p><em>The success of company occurs because is manage human resources well and vice versa. One of institute that mange human resource using Talent Management is Malang city Badan Kepegawaian Daerah (BKD), which evaluates its employee annually after the work is completed. This can cause not optimal work result, so it necessary to early identification of employees who have performance below average performance so that can be evaluated and minimize not optimal result. This study is use classification technique Nearest Centroid Neighbor Classifier Based on K Local Means Using Harmonic Mean Distance (LMKHNCN). This method is modified base algorithm of K-Nearest Neighbor (KNN). F1-Score and Accuracy using K-Fold Cross Validation to measure performance of this method and normalization testing due to no any information about that in previous study. This method is proven to have better performance compared to it original algorithm KNN. The method in this study has produced good classification performance. The result of classification accuracy and F1-Score by this method reach </em><em>98,8% dan 98,1%</em>.</p>


2021 ◽  
Author(s):  
Jianjian Cao ◽  
Wenjie Cai ◽  
Shuaicong Hu ◽  
Jingying Yang ◽  
Yufeng Ji ◽  
...  

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2097
Author(s):  
Chengcai Fu ◽  
Fengli Lu ◽  
Xiaoxiao Zhang ◽  
Guoying Zhang

Affected by the uneven concentration of coal dust and low illumination, most of the images captured in the top-coal caving face have low definition, high haze and serious noise. In order to improve the visual effect of underground images captured in the top-coal caving face, a novel single-channel Retinex dedusting algorithm with frequency domain prior information is proposed to solve the problem that Retinex defogging algorithm cannot effectively defog and denoise, simultaneously, while preserving image details. Our work is inspired by the simple and intuitive observation that the low frequency component of dust-free image will be amplified in the symmetrical spectrum after adding dusts. A single-channel multiscale Retinex algorithm with color restoration (MSRCR) in YIQ space is proposed to restore the foggy approximate component in wavelet domain. After that the multiscale convolution enhancement and fast non-local means (FNLM) filter are used to minimize noise of detail components while retaining sufficient details. Finally, a dust-free image is reconstructed to the spatial domain and the color is restored by white balance. By comparing with the state-of-the-art image dedusting and defogging algorithms, the experimental results have shown that the proposed algorithm has higher contrast and visibility in both subjective and objective analysis while retaining sufficient details.


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