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Medical image magnification based on original and estimated pixel selection models
, Article Journal of Biomedical Physics and Engineering ; Volume 10, Issue 3 , 2020 , Pages 357-366 ; Khosravi, M. R ; Khosravi, B ; Halvaee, P ; Sharif University of Technology
Shiraz University of Medical Sciences
2020
Abstract
Background: The issue of medial image resolution enhancement is one of the most important topics for medical imaging that helps improve the performance of many post-processing aspects like classification and segmentation towards medical diagnosis. Objective: Our aim in this paper is to evaluate different types of pixel selection models in terms of pixel originality in medical image reconstruction problems. A previous investigation showed that selecting far original pixels has highly better performance than using near unoriginal/estimated pixels while magnifying some benchmarks in digital image processing. Material and Methods: In our technical study, we apply two classical inter-polators,...
Coupling reduction of printed yagi antenna arrays for millimeter-wave imaging applications
, Article 2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, APSURSI 2019, 7 July 2019 through 12 July 2019 ; 2019 , Pages 1767-1768 ; 9781728106922 (ISBN) ; Fakharzadeh, M ; Ranjbar Naeini, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this paper, methods for reduction of coupling between receiving and transmitting antenna arrays are proposed and tested. Coupling between RX and TX causes saturation and a higher noise level in IF. So, coupling reduction improves image quality of system. Antenna element of arrays are printed antipodal Yagi-Uda antenna with greater than 8 dBi gain and higher than 4 GHz bandwidth. Frequency bandwidth of this imaging system is 27 to 30.5 GHz. Half power beamwidth of this antenna element is larger than 90 dB. Front to back ratio of this antenna is improved in this paper to 30 dB at 29 GHz. © 2019 IEEE
A novel image hiding scheme using content aware seam carving method
, Article ARES 2010 - 5th International Conference on Availability, Reliability, and Security, 15 February 2010 through 18 February 2010 ; Feb , 2010 , Pages 702-707 ; 9780769539652 (ISBN) ; Jamzad, M ; Sharif University of Technology
2010
Abstract
In image hiding we embed a secret image into a cover image. In order to minimize the distortion of secret image, we presented a novel steganographic method based on content-aware seam carving. In this paper, we propose a new image hiding method in which, the secret image is initially classified based on image complexity measure. Then it is resized to an appropriate smaller size, but for having the important objects of the image in resized image we use seam carving method that resizes an image whereas the important content of it remains. By applying the seam carving, we have an image that is smaller than the original one, and then we hide it in a cover image. Obviously hiding a smaller secret...
Human detection in occluded scenes through optically inspired multi-camera image fusion
, Article Journal of the Optical Society of America A: Optics and Image Science, and Vision ; Volume 34, Issue 6 , 2017 , Pages 856-869 ; 10847529 (ISSN) ; Kavehvash, Z ; Aghajan, H ; Sharif University of Technology
Abstract
In this paper, a novel approach for foreground extraction has been proposed based on a popular three-dimensional imaging technique in optics, called integral imaging. In this approach, multiple viewpoint images captured from a three-dimensional scene are used to extract range information of the scene and effectively extract an object or a person, even in the presence of heavy occlusion. The algorithm consists of two parts: depth estimation and reconstruction of the targeted object at the estimated depth distance. Further processing of the resulting reconstructed image can lead to the detection of a face or a pedestrian in the scene, which may not otherwise be detectable due to partial...
Field-of-view extension using code-division-multiple-access technique: Numerical analysis
, Article Computational Optical Sensing and Imaging, COSI 2011, Toronto, 10 July 2011 through 14 July 2011 ; April , 2011 ; 21622701 (ISSN) ; 9781557529145 (ISBN) ; Mehranya, K ; Bagherib, S ; Sharif University of Technology
2011
Abstract
We discuss the use of code-division-multiple-access technique for enhancing the field-of-view in 3D imaging and display. This approach is numerically analyzed and simulations show measurable improvements in the quality of final 3D image
Implementation of absolute quantification in small-animal SPECT imaging: Phantom and animal studies
, Article Journal of Applied Clinical Medical Physics ; Volume 18, Issue 4 , 2017 , Pages 215-223 ; 15269914 (ISSN) ; Vosoughi, N ; Tanha, K ; Assadi, M ; Ghafarian, P ; Rahmim, A ; Ay, M. R
John Wiley and Sons Ltd
2017
Abstract
Purpose: Presence of photon attenuation severely challenges quantitative accuracy in single-photon emission computed tomography (SPECT) imaging. Subsequently, various attenuation correction methods have been developed to compensate for this degradation. The present study aims to implement an attenuation correction method and then to evaluate quantification accuracy of attenuation correction in small-animal SPECT imaging. Methods: Images were reconstructed using an iterative reconstruction method based on the maximum-likelihood expectation maximization (MLEM) algorithm including resolution recovery. This was implemented in our designed dedicated small-animal SPECT (HiReSPECT) system. For...
Effective Implementation of Image Reconstruction Algorithms for Millimeter-Wave Imaging Applications
, M.Sc. Thesis Sharif University of Technology ; Shabany, Mahdi (Supervisor) ; Kavehvash, Zahra (Co-Supervisor)
Abstract
Millimeter waves provide an effective opportunity to improve vision and imaging in addition to systems based on visible light, X-rays, and infrared, and researchers have paid special attention to the field of millimeter waves to develop imaging. The spectrum of millimeter waves is in the frequency between 30GHz and 300GHz, which is equivalent to the wavelength in free space, between 1 and 10mm. The advantage of millimeter waves is that it works well in different weather conditions. Also, these millimeter waves have the ability to pass through clothing and provide a suitable level of resolution in reconstructed images and provide a suitable ability to separate different materials from each...
Effect of surface stresses on elastic behavior of a screw dislocation inside the wall of a nanotube
, Article Physica Status Solidi (B) Basic Research ; Volume 248, Issue 6 , 2011 , Pages 1437-1441 ; 03701972 (ISSN) ; Gutkin, M. Y ; Moeini Ardakani, S. S ; Sharif University of Technology
Abstract
Behavior of a screw dislocation inside a nanotube (NT) is considered in the context of surface elasticity. The elastic fields as well as the image force acting over the dislocation are derived and analyzed in detail. In contrast with the result of classical elasticity, the screw dislocation is shown to be repelled by free surfaces and occupy two stable equilibrium positions near them. The image force strongly depends on the NT's inner and outer radii as well as surface elastic characteristics
Quality improvement of digitized radiographs by filtering technique development based on morphological transformations
, Article 2004 Nuclear Science Symposium, Medical Imaging Conference, Symposium on Nuclear Power Systems and the 14th International Workshop on Room Temperature Semiconductor X- and Gamma- Ray Detectors, Rome, 16 October 2004 through 22 October 2004 ; Volume 3 , 2004 , Pages 1845-1849 ; 10957863 (ISSN) ; Taheri, M ; Kargarnovin, M. H ; Ghasemi, F ; Rokrok, B ; Seiedi, M ; Edaalati, K ; Kermani, A ; Rastkhah, N ; Sharif University of Technology
2004
Abstract
Radiographic inspection is the most appreciated technique among the other non-destructive testing methods due to producing unique finger print record as the film. Converting of radiographs to a digital format and further digital image processing is the best method of enhancing the image quality and assisting the interpreter on his evaluation. In this research, different algorithms were used for image enhancement and radiograph interpretation in MATLAB environment. A graphical user interface (GUI) was created for implementation of different algorithms. Both spatial and frequency (wavelet) domains techniques were used for image enhancement. Results showed that the defect recognition...
Compressed sensing and multiple image fusion: An information theoretic approach
, Article Iranian Conference on Machine Vision and Image Processing, MVIP ; 2013 , Pages 339-342 ; 21666776 (ISSN) ; 9781467361842 (ISBN) ; Mashhadi, S ; Engineers (IEEE) Antennas and Propagation Society; The Institute of Electrical and Electronics ; Sharif University of Technology
IEEE Computer Society
2013
Abstract
In this paper, we propose an information theoretic approach to fuse images compressed by compressed sensing (CS) techniques. The goal is to fuse multiple compressed images directly using measurements and reconstruct the final image only once. Since the reconstruction is the most expensive step, it would be a more economic method than separate reconstruction of each image. The proposed scheme is based on calculating the result using weighted average on the measurements of the inputs, where weights are calculated by information theoretic functions. The simulation results show that the final images produced by our method have higher quality than those produced by traditional methods, especially...
Fourier optics approach in evaluation of the diffraction and defocus aberration in three-dimensional integral imaging
, Article Computational Modelling of Objects Represented in Images: Fundamentals, Methods and Applications III - Proceedings of the International Symposium, CompIMAGE 2012 ; 2012 , Pages 81-84 ; 9780415621342 (ISBN) ; Kavehvash, Z ; Mehrany, K ; Sharif University of Technology
CRC
2012
Abstract
The unwanted effects of diffraction and defocus aberration in three-dimensional integral imaging are taken into account by using the Fourier optics approach. The concepts of point spread function and optical transfer function widely in use for conventional two-dimensional imaging are generalized and applied to three-dimensional integral imaging systems. The effects of diffraction and defocus aberration are then studied and the performance of the conventional single lens imaging system is compared against that of the integral imaging
Intelligent classification of web pages using contextual and visual features
, Article Applied Soft Computing Journal ; Volume 11, Issue 2 , 2011 , Pages 1638-1647 ; 15684946 (ISSN) ; Fotouhi, M ; Khaleghi, M ; Sharif University of Technology
Abstract
In this paper we address classification of Web content and in particular its application in the detection of pornographic Web pages. Filtering of undesirable Web content is mainly achieved based on blocking a specific Web address via searching it in a reference list of black URLs or doing a plain contextual analysis on the page by searching special keywords in the text. The main problem with current filtering methods is the requirement for instantly update of the URL list and also the high rate of over-blocking the usual pages. In this paper, we propose an intelligent approach which is based on using textual, profile, and visual features in a hierarchical structure classifier. Textual...
A high capacity image hiding method based on fuzzy image coding/decoding
, Article 2009 14th International CSI Computer Conference, CSICC 2009, 20 October 2009 through 21 October 2009 ; 2009 , Pages 518-523 ; 9781424442621 (ISBN) ; Sajedi, H ; Jamzad, M ; Sharif University of Technology
Abstract
Recently, a technique has been proposed for image hiding, that is based on block texture similarity where, blocks of secret image are compared with blocks of a set of cover images and the cover image with the most similar blocks to those of the secret image is selected as the best candidate cover image to conceal the secret image. In this paper, we propose a new image hiding method in which, the secret image is initially coded using a fuzzy coding/decoding method. By applying the fuzzy coder, each block of the secret image is compressed to a smaller block. In this way, after compressing the secret image to a smaller one, we hide it in a cover image. Obviously hiding a smaller secret image...
Efficient millimetre-wave imaging structure for detecting axially rotated objects
, Article IET Microwaves, Antennas and Propagation ; Volume 12, Issue 3 , 2018 , Pages 416-424 ; 17518725 (ISSN) ; Kavehvash, Z ; Shabany, M ; Sharif University of Technology
Institution of Engineering and Technology
2018
Abstract
An efficient multi-static millimetre-wave (MMW) imaging system is proposed with the aim of obtaining the information of an axially tilted object. It is known that a multi-static structure performs better than a mono-static array in detecting the reflected signal from axially tilted surfaces due to the specular reflection. Still, no efficient multi-static structure for the purpose of imaging tilted objects in view of the computational time, cost and image quality is proposed till now. The authors propose an efficient multi-static MMW imaging system tackle this issue with the minimum number of antennae. Furthermore, the small number of antennae in the proposed design and the proposed fast...
An image annotation rectifying method based on deep features
, Article 2nd International Conference on Digital Signal Processing, ICDSP 2018, 25 February 2018 through 27 February 2018 ; 2018 , Pages 88-92 ; 9781450364027 (ISBN) ; Jamzad, M ; Sharif University of Technology
Association for Computing Machinery
2018
Abstract
Automatic image annotation methods generate a list of tags for each test image and present it in a matrix structure. To achieve a more accurate annotation, we propose a method with the aim of correcting the tag list. In our method, we detect an indicator for each group of tags and use it to rectify the annotation results. To find a correct indicator, we apply a deep feature vector generated by the “AlexNet” model. Using this indicator, we determine the suitable tags for an image. The purposed method is independent of feature vector, dataset, and annotation method. It can be applied to the currently available annotation methods. Our experiments showed improvement in all annotation methods...
Architecture to improve the accuracy of automatic image annotation systems
, Article IET Computer Vision ; Volume 14, Issue 5 , August , 2020 , Pages 214-223 ; Jamzad, M ; Sharif University of Technology
Institution of Engineering and Technology
2020
Abstract
Automatic image annotation (AIA) is an image retrieval mechanism to extract relative semantic tags from visual content. So far, the improvement of accuracy in newly developed such methods have been about 1 or 2% in the F1-score and the architectures seem to have room for improvement. Therefore, the authors designed a more detailed architecture for AIA and suggested new algorithms for its main parts. The proposed architecture has three main parts: feature extraction, learning, and annotation. They designed a novel learning method using machine learning and probability bases. In the annotation part, they suggest a novel method that gains the maximum benefit from the learning part. The...
Chromosome image contrast enhancement using adaptive, iterative histogram matching
, Article 2011 7th Iranian Conference on Machine Vision and Image Processing, MVIP 2011 - Proceedings, 16 November 2011 through 17 November 2011 ; 2011 ; 9781457715358 (ISBN) ; Mousavi, H. S ; Khalaj, B. H ; Sharif University of Technology
2011
Abstract
Vivid banding patterns in medical images of chromosomes are a vital feature for karyotyping and chromosome classification. The chromosome image quality may be degraded by many phenomenon such as staining, sample defectness and imaging conditions. Thus, an image enhancement processing algorithm is needed before classification of chromosomes. In this paper, we propose an adaptive and iterative histogram matching (AIHM) algorithm for chromosome contrast enhancement especially in banding patterns. The reference histogram, with which the initial image needs to be matched, is created based on some processes on the initial image histogram. Usage of raw information in the histogram of initial image...
An efficient down-sampling method for multiresolution image completion
, Article 2011 7th Iranian Conference on Machine Vision and Image Processing, MVIP 2011 - Proceedings ; 2011 ; 9781457715358 (ISBN) ; Kasaei, S ; Mahdavi Amiri, N ; Sharif University of Technology
Abstract
Image completion is an active subject in image and video processing, which deals with recovering the missing or removed parts of a given 2-D or 3-D data. Here, we present a method to efficiently build the multiresolution pyramid for a partially-missing image, by which, multiresolution image completion can be efficiently initialized and performed. Using this approach, we improve our previous algorithm for multiresolution image completion, especially when the inputs suffer spread missing areas. In comparison with the overall process of image completion, the computational and space complexity of the proposed method for building multiresolution pyramid is eligible. The obtained results of our...
Structural image representation for image registration
, Article 2015 International Symposium on Artificial Intelligence and Signal Processing, AISP 2015, 3 March 2015 through 5 March 2015 ; March , 2015 , Pages 95-100 ; 9781479988174 (ISBN) ; Shirpour, M ; Manzuri, M. T ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Image registration is an important task in medical image processing. Assuming spatially stationary intensity relation among images, conventional area based algorithms such as CC (Correlation Coefficients) and MI (Mutual Information), show weaker results alongside spatially varying intensity distortion. In this research, a structural representation of images is introduced. It allows us to use simpler similarity metrics in multimodal images which are also robust against the mentioned distortion field. The efficiency of this presentation in non-rigid image registration in the presence of spatial varying distortion field is examined. Experimental results on synthetic and real-world data sets...
Medical images stabilization using sparse-induced similarity measure
, Article 2015 2nd International Conference on Pattern Recognition and Image Analysis, IPRIA 2015, 11 March 2015 through 12 March 2015 ; March , 2015 ; 9781479984459 (ISBN) ; Arabshahi, S ; Ghafari, A ; Fatemizadeh, E ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Medical image stabilization has been widely used for clinical imaging modalities. Registration is a conspicuous stage for stabilizing dynamic medical images. Some of regular methods are sensitive to bias field distortion. Sparse-induced similarity measure (SISM) is a robust registering method against spatially-varying intensity distortions which is not evitable on clinical imaging instruments. This paper presents a method for registering medical images to average of captured images using SISM method to avoid spatially-varying intensity distortions like Bias field. Proposed method is compared with SSD and MI similarity measure based registrations. Results show enhancement in stabilizing...