6 results on '"Lakpa Dorje Tamang"'
Search Results
2. Super-resolution Ultrasound Imaging Scheme Based on a Symmetric Series Convolutional Neural Network
- Author
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Lakpa Dorje Tamang
- Subjects
Series (mathematics) ,Kernel (image processing) ,Feature (computer vision) ,business.industry ,Computer science ,Feature extraction ,Feed forward ,Medical imaging ,Pattern recognition ,Artificial intelligence ,business ,Convolutional neural network ,Image (mathematics) - Abstract
In this paper, we propose a symmetric series convolutional neural network (SS-CNN), which is a novel deep convolutional neural network (DCNN)-based super-resolution (SR) technique for ultrasound medical imaging. The proposed model comprises two parts: a feature extraction network (FEN) and an up-sampling layer. In the FEN, the low-resolution (LR) counterpart of the ultrasound image passes through a symmetric series of two different DCNNs. The low-level feature maps obtained from the subsequent layers of both DCNNs are concatenated in a feed forward manner, aiding in robust feature extraction to ensure high reconstruction quality. Subsequently, the final concatenated features serve as an input map to the latter 2D convolutional layers, where the textural information of the input image is connected via skip connections. The second part of the proposed model is a sub-pixel convolutional (SPC) layer, which up-samples the output of the FEN by multiplying it with a multi-dimensional kernel followed by a periodic shuffling operation to reconstruct a high-quality SR ultrasound image. We validate the performance of the SS-CNN with publicly available ultrasound image datasets. Experimental results show that the proposed model achieves an exquisite reconstruction performance of ultrasound image over the conventional methods in terms of peak signal-to-noise ratio (PSNR), and structural similarity index (SSIM), while providing compelling SR reconstruction time.
- Published
- 2021
3. Exponential Data Embedding Scheme for Display to Camera Communications
- Author
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Byung Wook Kim and Lakpa Dorje Tamang
- Subjects
Orientation (computer vision) ,Computer science ,business.industry ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Visible light communication ,02 engineering and technology ,01 natural sciences ,Signal ,Display device ,010309 optics ,020210 optoelectronics & photonics ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Discrete cosine transform ,Bit error rate ,Embedding ,Computer vision ,Artificial intelligence ,business ,Data transmission - Abstract
Digital displays and off-the-shelf smartphone cameras are the most common and promptly available electronic devices which have also been recently applied for data transmission and reception through optical medium in a wireless manner. In this paper, we propose a data embedding technique in display to camera communication (D2C) where the data is inserted into the mid-frequency region of a discrete cosine transform (DCT) domain image. The intended data in the form of modulated symbols are first multiplied with the predetermined embedding factor and then exponentially multiplied with the vector coefficients of the selected region. Extensive experiments considering receiver orientation, capture distance and angle were conducted in a real-world environment with the help of off-the-shelf smartphone camera and a digital display. We showed that the proposed technique offers fair peak signal to average ratio (PSNR) with robust bit error rate (BER) performance, while the data embedded on the image was not perceptible to human vision.
- Published
- 2020
4. Deep Learning Approaches to Colorectal Cancer Diagnosis: A Review
- Author
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Lakpa Dorje Tamang and Byung Wook Kim
- Subjects
Technology ,medicine.medical_specialty ,QH301-705.5 ,Computer science ,Colorectal cancer ,QC1-999 ,Colonoscopy ,colorectal cancer ,Health care ,medicine ,General Materials Science ,Medical physics ,Use case ,Biology (General) ,QD1-999 ,Instrumentation ,Fluid Flow and Transfer Processes ,medicine.diagnostic_test ,business.industry ,Physics ,Process Chemistry and Technology ,Deep learning ,General Engineering ,deep learning ,Digital pathology ,Cancer ,Engineering (General). Civil engineering (General) ,medicine.disease ,Computer Science Applications ,Chemistry ,Computer-aided diagnosis ,computer-aided diagnosis ,Artificial intelligence ,TA1-2040 ,digital pathology ,business - Abstract
Unprecedented breakthroughs in the development of graphical processing systems have led to great potential for deep learning (DL) algorithms in analyzing visual anatomy from high-resolution medical images. Recently, in digital pathology, the use of DL technologies has drawn a substantial amount of attention for use in the effective diagnosis of various cancer types, especially colorectal cancer (CRC), which is regarded as one of the dominant causes of cancer-related deaths worldwide. This review provides an in-depth perspective on recently published research articles on DL-based CRC diagnosis and prognosis. Overall, we provide a retrospective synopsis of simple image-processing-based and machine learning (ML)-based computer-aided diagnosis (CAD) systems, followed by a comprehensive appraisal of use cases with different types of state-of-the-art DL algorithms for detecting malignancies. We first list multiple standardized and publicly available CRC datasets from two imaging types: colonoscopy and histopathology. Secondly, we categorize the studies based on the different types of CRC detected (tumor tissue, microsatellite instability, and polyps), and we assess the data preprocessing steps and the adopted DL architectures before presenting the optimum diagnostic results. CRC diagnosis with DL algorithms is still in the preclinical phase, and therefore, we point out some open issues and provide some insights into the practicability and development of robust diagnostic systems in future health care and oncology.
- Published
- 2021
5. Deep D2C-Net: deep learning-based display-to-camera communications
- Author
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Lakpa Dorje Tamang and Byung Wook Kim
- Subjects
Channel (digital image) ,Artificial neural network ,Computer science ,Image quality ,business.industry ,Deep learning ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Convolutional neural network ,Atomic and Molecular Physics, and Optics ,Display device ,Optics ,Bit error rate ,Computer vision ,Artificial intelligence ,business ,Decoding methods - Abstract
In this paper, we propose Deep D2C-Net, a novel display-to-camera (D2C) communications technique using deep convolutional neural networks (DCNNs) for data embedding and extraction with images. The proposed technique consists of fully end-to-end encoding and decoding networks, which respectively produce high-quality data-embedded images and enable robust data acquisition in the presence of optical wireless channel. For encoding, Hybrid layers are introduced where the concurrent feature maps of the intended data and cover images are concatenated in a feed-forward fashion; for decoding, a simple convolutional neural network (CNN) is utilized. We conducted experiments in a real-world environment using a smartphone camera and a digital display with multiple parameters, such as transmission distance, capture angle, display brightness, and resolution of the camera. Experimental results prove that Deep D2C-Net outperforms the existing state-of-the-art algorithms in terms of peak signal-to-noise ratio (PSNR) and bit error rate (BER), while the data-embedded image displayed on the screen yields high visual quality for the human eye.
- Published
- 2021
6. Spectral Domain-Based Data-Embedding Mechanisms for Display-to-Camera Communication
- Author
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Byung Wook Kim and Lakpa Dorje Tamang
- Subjects
visible light communication ,Computer Networks and Communications ,Computer science ,Image quality ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,lcsh:TK7800-8360 ,Visible light communication ,02 engineering and technology ,Communications system ,Display device ,data embedding ,display-to-camera communication ,0202 electrical engineering, electronic engineering, information engineering ,Discrete cosine transform ,Computer vision ,Electrical and Electronic Engineering ,business.industry ,lcsh:Electronics ,020206 networking & telecommunications ,Hardware and Architecture ,Control and Systems Engineering ,Signal Processing ,Bit error rate ,Embedding ,020201 artificial intelligence & image processing ,Artificial intelligence ,discrete cosine transform ,business ,Data transmission - Abstract
Recently, digital displays and cameras have been extensively used as new data transmission and reception devices in conjunction with optical camera communication (OCC) technology. This paper presents three types of frequency-based data-embedding mechanisms for a display-to-camera (D2C) communication system, in which a commercial digital display transmits information and an off-the-shelf smartphone camera receives it. For the spectral embedding, sub-band coefficients obtained from a discrete cosine transform (DCT) image and predetermined embedding factors of three embedding mechanisms are used. This allows the data to be recovered from several types of noises induced in wireless optical channels, such as analog-to-digital (A/D) and digital-to-analog (D/A) conversion, rotation, scaling, and translation (RST) effects, while also maintaining the image quality to normal human eyes. We performed extensive simulations and real-world D2C experiments using several performance metrics. Through the analysis of the experimental results, it was shown that the proposed method can be considered as a suitable candidate for the D2C system in terms of the achievable data rate (ADR), peak signal-to-noise ratio (PSNR), and the bit error rate (BER).
- Published
- 2021
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