Magnification Technique Research Articles

May predictors of difficulty in thyroid surgery increase the incidence of complications? Prospective study with the proposal of a preoperative score

BackgroundAlthough thyroidectomy is one of the most common surgical procedures performed worldwide, some permanent complications, despite the considerably reducing incidence, may affect dramatically the patients quality of life. The purpose of this study is to evaluate whether factors identified preoperatively and expressed in a score could be predictors of major surgical difficulty during total thyroidectomy and influence the incidence of complications.MethodsA total of 164 patients who underwent total thyroidectomy were examined. For each patient we calculated a preoperative score, including seven parameters, which we evaluated to be predictors of difficulty in thyroid surgery, that is, sex, body mass index (BMI), neck length, neck extension, thyroid gland volume, thyroiditis, and increased parenchymal vascularization. The overall score was also compared with peri- and post-operative factors describing objectively the difficulty in thyroid surgery. These factors are the duration of the operation, the length of hospitalization, the incidence of complications such as hemorrhage, hypoparathyroidism, and recurrent laryngeal nerve injuries.ResultsThere was no statistically significant association between our score and either the percentage of postoperative complications or the length of hospitalization. The operative time was the only variable remarkably associated with the score value (p < 0.00001). Comparing the duration of the operation with each of the preoperative predictive factors, we found that none of the factors reached the value of statistical significance, but a close association could be noted with the thyroid volume and the BMI.ConclusionsIn our study, predictors of difficulty in thyroidectomy did not affect morbidity rates, as suggested by previous studies, but only operative times, which were significantly increased in patients with higher score. Although our results have limited statistical significance, they allow us to confirm the fundamental role of a systematic use of optical magnification and microsurgical technique in thyroidectomy. Further studies, with a larger cohort of patients, are needed to validate our results and to formulate a universally accepted predictive score of difficulty in thyroidectomy preoperatively.

Radiation Dose Practice Audit of 6,234 Fluoroscopically-Guided Spinal Injections

Background: Fluoroscopic imaging guidance is frequently used in performing spinal interventional techniques. Reference level standards are a quality improvement tool to help reduce radiation dose and serve as benchmarks for physicians and their technologists to achieve reasonable radiation exposure while performing fluoroscopically-guided spinal procedures. There are limited data describing radiation dose for musculoskeletal injections - in particular, spinal injections without any published reference standards. Objective: The purpose of this study is to perform a practice audit of radiation doses of fluoroscopically-guided spinal injections to establish preliminary reference levels as a quality improvement tool for potential use in future radiation reduction measures. Study Design: Retrospective, observational study. Settings: An academic-based subspecialty, high volume pain medicine practice. Methods: A retrospective analysis of 6,234 spinal injections of 9 different types performed by experienced practitioners between January and December 2012 was conducted under an institutional review board’s approval with HIPAA compliance and waiver of informed consent. Cumulative radiation dose (in mGy) and exposure time (in seconds) distributions (percentiles) as displayed on the C-arm were calculated per injection for each type of fluoroscopically-guided spinal injection. Confidence intervals for the dose distributions were determined by using bootstrap resampling and were used to determine preliminary reference levels. Results: Proposed preliminary reference levels of cumulative radiation dose (in mGy) and exposure time (in seconds) for fluoroscopically-guided spinal interventional procedures are provided for lumbar transforaminal (13 mGy, 30 s), cervical transforaminal (6 mGy, 49 s), caudal epidural (12 mGy, 23s), cervical facet injection (3 mGy, 36 s), lumbar facet injection (9 mGy, 20s), interlaminar (13mGy, 39s), lumbar radiofrequency denervation (7 mGy, 17s), lumbar sympathetic block (21 mGy, 39s), cervical medial branch block (2 mGy, 25 s), lumbar medial branch block (4 mGy, 12s) and sacroiliac joint injections (18 mGy, 37s). Limitations: Study performed at a single subspecialty institution using only one type of C-arm which limits generalizability. Conclusions: Radiation doses and preliminary reference levels of fluoroscopically-guided interventional spine procedures performed by experienced practitioners are made available without correction for body habitus or field of view, magnification or subtraction techniques or continuous vs pulsed mode. A registry of radiation-dose data for fluoroscopically-guided interventional spine procedures would be the next step to refine this data. Key Words: Spinal procedures, radiation dose, patient safety

Ru(dcbpy)2 dppz]2+ /Fullerene Cosensitized PTB7-Th for Ultrasensitive Photoelectrochemical MicroRNA Assay.

A new cosensitization photoelectrochemical (PEC) strategy was established by using a donor-acceptor-type photoactive material, poly{4,8-bis[5-(2-ethylhexyl)thiophen-2-yl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophene-4,6-diyl} (PTB7-Th), as a signal indicator, which was cosensitized with bis(4,4'dicarboxyl-2,2'-bipyridyl)(4,5,9,14-tetraazabenzo[b]triphenylene)ruthenium(II) ([Ru(dcbpy)2 dppz]2+ ) embedded in the grooves of the DNA duplex and fullerene (nano-C60 ) immobilized on the surface of DNA nanoflowers for microRNA assay. [Ru(dcbpy)2 dppz]2+ and nano-C60 could effectively enhance the photoelectric conversion efficiency (PCE) of PTB7-Th as a result of well-matched energy levels among nano-C60 , [Ru(dcbpy)2 dppz]2+ and PTB7-Th, leading to a clearly enhanced photocurrent signal. Meanwhile, a target recycling magnification technique based on duplex-specific nuclease was applied in this work to obtain higher detection sensitivity. The proposed biosensor demonstrated excellent analytical properties within a linear detection range of 2.5 fm to 2.5 nm and a limit of detection down to 0.83 fm. Impressively, this cosensitization PEC strategy offers an effective and convenient avenue to significantly improve the PCE of a photoactive material, resulting in a remarkably improved photocurrent signal for ultrasensitive and highly accurate detection of various targets.

Auxiliary techniques for the diagnosis of incipient interproximal caries, in deciduous molars of children from 4 to 10 years old

Objective: The incipient carious lesion known for their clinical characteristics like white opaque after drying shows a rough surface, this is the first evidence of caries which is actively and visible on the surface of the dental tissue observed in a pit and fissure, proximal surfaces near the contact point along the gingival margin, in relation to the proximal surfaces by having a difficult accessibility, just by visual inspection is a big obstacle, so the objective of this study is identify the auxiliary a proximal decay incipient technique with improved an outcome to diagnosis in primary molars. Materials and Methods: A transversal and descriptive study was performed. The sample was composed by 50 children from 4-10 years old. A medical history was applied, which recorded all the dental information about the diagnosis, taking into account the criteria according to ICDAS in 2005. The examination was took place various sessions, a prophylaxis was previously performed, for this study we used an oral mirror, magnifying glass, a type of viscera which increased (3.5X), LED lamp and per apical bitewing x-rays. Results: A significant difference in efficacy for detection of interproximal caries lesions among emerging techniques evaluated were found. Conclusion: A 3.5X magnification technique made it possible to detect more caries lesions in primary molars with a total of 69. Followed by visual and radiographic being Trans illuminations which had the lowest levels of effectiveness.

Dermoscopy, with and without visual inspection, for diagnosing melanoma in adults.

Dermoscopy, with and without visual inspection, for diagnosing melanoma in adults.

The contribution of use -wear for stone tool identification at the Upper Paleolithic site Shuidonggou Locality 2, North China

In North China, the archaeology of the Late Pleistocene is characterized by the persistence of flake-based lithic assemblages. Little is known about the use of stone tools and the reasons behind the success of a relatively simple core and flake technology are unclear. Most lithic studies in the region are traditionally based on a typological categorization of assemblages with the frequencies of cores and tool-types playing a significant role in the characterization of the site (e.g. residential vs. more logistical occupation). Hence, to discriminate stone tool from byproduct is essential to better understand variables such as site function or mobility but it remains particularly challenging in poorly standardized lithic assemblages. Here we present preliminary results of a study on the newly excavated material from cultural layer 2 and 3 at Shuidonggou Locality 2 (32.6–29.9 ka cal BP). We analyze use-wears on a sample of retouched and unretouched blanks using the low magnification technique and we compared our observations with several experimental referential. Our results can be summarized in two main points. First, we observe a similar frequency of use-wear on retouched tools and unretouched blanks. Second, differences in tool types do not match our basic identification of the working motions. Our results suggest that in Shuidonggou Locality 2, using retouch as a predictor for tool use is problematic (especially with regards to tool functions). Given that tool frequencies and tool diversity are data used to model site function, tool curation and hunter-gatherer mobility, we suggest that this issue should be further investigated in the context of ‘core and flakes’ assemblage.

Defect detection in FRP-bonded structural system via phase-based motion magnification technique

Defect detection in FRP-bonded structural system via phase-based motion magnification technique

Frequency-based damage detection in cantilever beam using vision-based monitoring system with motion magnification technique

This article proposes a method for damage detection using vision-based monitoring with motion magnification technique. The methods based on the vibration characteristics of structures such as natural frequency, mode shapes, and modal damping have been applied to structural damage detection. However, the conventional methods have limitations for practical applications. Vision-based monitoring system can be employed as a new structural monitoring system because of its simplicity, potentially low cost, and unique capability of collecting high-resolution data. A methodology called video motion magnification has been developed to amplify non-visible small motions in a video to reveal the dynamic response. The video motion magnification method can be applied to measure small displacements to calculate the natural frequencies and the operational deflection shapes of the structures. Unlike conventional optimization methods, a genetic algorithm explores the entire solution space and can obtain the global optimum. In this article, identification of the location and magnitude of damage in a cantilever beam is formulated as an optimization problem using a real-value genetic algorithm by minimizing the objective function, which directly compares the first three natural frequencies changes from the phase-based motion magnification measurement and from the analytical model of a damaged cantilever beam.

Subtle Changes of Basketball Player in Video Based Euler Method

Analysing basketball player movement is not performed conventionally recently. Combining science and technology in sport has made a great impact. Basketball player movement analysis using latest technology can achieved by many ways such as retrieving information from video. A video that contains basketball match can be valuable resource to be analysed by computer vision technique. Player movement estimation can be separated into two categories such explicitly or implicitly. Player movement estimation that is performed implicitly is assumed more efficient than explicitly one, but in consequent, it has exploiting series computation like Lagrangian or Eulerian to the pixel color value and it is not easy to be seen by human visual system. This paper uses Eulerian series because of its succest in the previous research activity that called eluerian video magnification technique. That technique is implemented to basketball player in the field and it is not easy task because it is the object is formed as group in certain environment.

A new video magnification technique using complex wavelets with Radon transform application

Magnifying micro-movements of natural videos that are undetectable by human eye has recently received considerable interests, due to its impact in numerous applications. In this paper, we use dual tree complex wavelet transform (DT-CWT), to analyze video frames in order to detect and magnify micro-movements to make them visible. We use DT-CWT, due to its excellent edge-preserving and nearly-shift invariant features. In order to detect any minor change in object’s spatial position, the paper proposes to modify the phases of the CWT coefficients decomposition of successive video frames. Furthermore, the paper applies Radon transform to track frame micro-movements without any temporal band-pass filtering. The paper starts by presenting a simple technique to design orthogonal filters that construct this CWT system. Next, it is shown that modifying the phase differences between the CWT coefficients of arbitrary frame and a reference one results in image spatial magnification. This in turn, makes these micro-movements seen and observable. Several simulation results are given, to show that the proposed technique competes very well to the existing micro-magnification approaches. In fact, as it manages to yield superior video quality in far less computation time.

Analysis of Soot Propensity in Combustion Processes Using Optical Sensors and Video Magnification.

Industrial combustion processes are an important source of particulate matter, causing significant pollution problems that affect human health, and are a major contributor to global warming. The most common method for analyzing the soot emission propensity in flames is the Smoke Point Height (SPH) analysis, which relates the fuel flow rate to a critical flame height at which soot particles begin to leave the reactive zone through the tip of the flame. The SPH and is marked by morphological changes on the flame tip. SPH analysis is normally done through flame observations with the naked eye, leading to high bias. Other techniques are more accurate, but are not practical to implement in industrial settings, such as the Line Of Sight Attenuation (LOSA), which obtains soot volume fractions within the flame from the attenuation of a laser beam. We propose the use of Video Magnification techniques to detect the flame morphological changes and thus determine the SPH minimizing observation bias. We have applied for the first time Eulerian Video Magnification (EVM) and Phase-based Video Magnification (PVM) on an ethylene laminar diffusion flame. The results were compared with LOSA measurements, and indicate that EVM is the most accurate method for SPH determination.

Detection of human vital signs in hazardous environments by means of video magnification.

In cases of natural disasters, epidemics or even in dangerous situations like an act of terrorism, battle fields, a shooting or a mountain accident, finding survivors is a challenge. In these kind of situations it is sometimes critical to know if a person has vital signs or not, without the need to be in contact with the victim, thus avoiding jeopardizing the lives of the rescue workers. In this work, we propose the use of video magnification techniques to detect small movements in human bodies due to breathing that are invisible to the naked eye. Two different video magnification techniques, intensity-based and phase-based, were tested. The utility of these techniques to detect people who are alive but injured in risk situations was verified by simulating a scene with three people involved in an accident. Several factors such as camera stability, distance to the object, light conditions, magnification factor or computing time were analyzed. The results obtained were quite positive for both techniques, intensity-based method proving more adequate if the interest is in almost instant results whereas the phase-based method is more appropriate if processing time is not so relevant but the degree of magnification without excessive image noise.

PCA-based magnification method for revealing small signals in video

Video magnification techniques are useful for visualizing small changes in videos. Current methods are mainly applied for two aspects: motion amplification and color amplification. For instance, Eulerian video magnification (EVM) has shown impressive results in the context of color of human face and subtle head motion caused by the influx of blood at each beat. Such visual results have possible applications in non-contact human physiological parameter measurement, such as heart rate estimation. Unfortunately, the linear EVM is sensitive to noise and frequencies of the changes should be customized, which generates a limitation of applications. This paper presents an advanced EVM for magnifying the signal amplitude in the presence of relatively high noise as well as unknown the frequencies of changes in video. Principal component analysis (PCA) is performed to decompose the frames and the component whose spatial variation best matches small changes to be magnified. The advantage of PCA-based method is that it can select the subtle signals with a denoising process like spatial filtering. Experimental results show that the PCA-based EVM can support larger amplification factors for small changes visualization as well as less noise and artifacts.

An efficient motion magnification system for real-time applications

The human eye cannot see subtle motion signals that fall outside human visual limits, due to either limited resolution of intensity variations or lack of sensitivity to lower spatial and temporal frequencies. Yet, these invisible signals can be highly informative when amplified to be observable by a human operator or an automatic machine vision system. Many video magnification techniques have recently been proposed to magnify and reveal these signals in videos and image sequences. Limitations, including noise level, video quality and long execution time, are associated with the existing video magnification techniques. Therefore, there is value in developing a new magnification method where these issues are the main consideration. This study presents a new magnification method that outperforms other magnification techniques in terms of noise removal, video quality at large magnification factor and execution time. The proposed method is compared with four methods, including Eulerian video magnification, phase-based video magnification, Riesz pyramid for fast phase-based video magnification and enhanced Eulerian video magnification. The experimental results demonstrate the superior performance of the proposed magnification method regarding all video quality metrics used. Our method is also 60–70% faster than Eulerian video magnification, whereas other competing methods take longer to execute than Eulerian video magnification.

Euler Renk ve Hareket Büyütme Yöntemlerinin Performans Analizi

Bu calismasinda, insan gozu tarafindan algilanmasi zor olan bir goruntudeki, gizli renk ve hareket degisimlerini aciga cikarmada kullanilan goruntu buyutme yontemlerinin performans analizi yapilmistir. Bu analiz isleminde, goruntu buyutme yontemi olarak Euler renk buyutme ve Euler hareket buyutme yontemleri kullanilmistir. Her iki goruntu buyutme yonteminde, goruntu ayristirma yontemi olarak hem Laplace piramidi hem de Gauss piramidi kullanilmis ve bu piramitlerin performanslari karsilastirilmistir. Tum piramit ayristirmalarindan elde edilen cikis goruntuleri hesapsal olarak analiz edilir ve PSNR (En Buyuk Isaret-Gurultu Orani) ve SSIM (Yapisal Benzerlik Indeksi Olcumu) degerleri uzerinden birbirleriyle karsilastirilir. Goruntu isleme zamani, goruntu ayristirma yontemlerini karsilastirmada kullanilan bir parametredir. Goruntu ayristirma yontemleriyle yapilan deneylerin sonuclari goruntu isleme zamani acisindan incelendiginde, Gauss piramit ayristirmasiyla goruntu buyutmenin daha iyi bir performansa sahip oldugu gorulmustur. Bu yontemler goruntu kalitesi olarak PSNR degerleri acisindan incelendiginde, Gauss piramidinin renk buyutme isleminde daha iyi sonuclar verdigi Laplace piramidinin ise hareket buyutme isleminde daha iyi sonuclar verdigi gorulmustur.

Feasibility of extracting operating shapes using phase-based motion magnification technique and stereo-photogrammetry

Optically-based vibration measurements can be used to determine the full-field dynamic response of structures without the need of mounted transducers (e.g. accelerometers, strain gages, and LVDTs) that can add cost, have wiring, power signal transmission issues, and may affect the dynamic characteristics by adding mass or stiffness. The three-dimensional digital image correlation (3D DIC) and three-dimensional point tracking (3DPT) methods based on a stereo-vision system can provide the full-field dynamic displacements of a structure with sub-pixel accuracy. However, stereo-photogrammetry systems are limited by camera resolution and intrinsic noise of the acquired images. Moreover, exciting a structure with only a small amount of energy may result in a subtle mechanical response that is not perceptible by observing the raw data of the conventional optical measurement systems (i.e. 3D DIC and 3DPT). Thus, in order to use the optical-sensing techniques to identify dynamic characteristics of a structure at high frequencies, the signal-to-noise ratio (SNR) in the sequence of images captured with a stereo-vision system needs to be improved. Within this paper, phase-based video magnification in conjunction with the stereo-photogrammetry techniques are used to measure the higher-frequency operating shapes of a cantilever beam and a 2.3-m long Skystream 4.7 wind turbine blade. The phase-based motion estimation method uses complex steerable pyramids to decompose the original sequence of images to amplitude and phase at different spatial resolutions (subsampled images). Motion information is conserved within the phase values which can be filtered in the time domain and amplified to detect the subtle motions. The magnified sequence of images using the motion magnification technique are post-processed using 3D DIC or 3DPT to quantify infinitesimal deformations that are not recognizable using only the traditional stereo-photogrammetry methods. The results obtained within this paper reveal the great potential of motion magnification in conjunction with stereo-photogrammetry techniques in detecting small motions of structures and extracting 3D operating shapes from the optically measured data with low SNR. Compared to traditional stereo-photogrammetry, additional modes of the test structures are obtainable by means of combining the phase based motion magnification and conventional image-sensing techniques (i.e. 3D DIC and 3DPT). The proposed methodology could be used to enhance the established procedure to extract more information about the dynamic characteristics of structures (only once effectively calibrated), compared to existing image-sensing techniques and contact measurement sensors.

Advancement of thyroid surgery video recording: A comparison between two full HD head mounted video cameras

BackgroundThe aim of this study was to test two different video cameras and recording systems used in thyroid surgery in our Department. This is meant to be an attempt to record the real point of view of the magnified vision of surgeon, so as to make the viewer aware of the difference with the naked eye vision. Materials and methodsIn this retrospective study, we recorded and compared twenty thyroidectomies performed using loupes magnification and microsurgical technique: ten were recorded with GoPro® 4 Session action cam (commercially available) and ten with our new prototype of head mounted video camera. ResultsSettings were selected before surgery for both cameras. The recording time is about from 1 to 2 h for GoPro® and from 3 to 5 h for our prototype. The average time of preparation to fit the camera on the surgeon's head and set the functionality is about 5 min for GoPro® and 7–8 min for the prototype, mostly due to HDMI wiring cable. Videos recorded with the prototype require no further editing, which is mandatory for videos recorded with GoPro® to highlight the surgical details. Conclusionthe present study showed that our prototype of video camera, compared with GoPro® 4 Session, guarantees best results in terms of surgical video recording quality, provides to the viewer the exact perspective of the microsurgeon and shows accurately his magnified view through the loupes in thyroid surgery. These recordings are surgical aids for teaching and education and might be a method of self-analysis of surgical technique.

Remote sensing of physiological signs using a machine vision system

The aim of this work is to remotely measure heart rate (HR) and respiratory rate (RR) using a video camera from long range (> 50 m). The proposed system is based on imperceptible signals produced from blood circulation, including skin colour variations and head motion. As these signals are not visible to the naked eye and to preserve the signal strength in the video, we used an improved video magnification technique to enhance these invisible signals and detect the physiological activity within the subject. The software of the proposed system was built in a graphic user interface (GUI) environment to easily select a magnification system to use (colour or motion magnification) and measure the physiological signs independently. The measurements were performed on a set of 10 healthy subjects equipped with a finger pulse oximeter and respiratory belt transducer that were used as reference methods. The experimental results were statistically analysed by using the Bland–Altman method, Pearson's correlation coefficient, Spearman correlation coefficient, mean absolute error, and root mean squared error. The proposed system achieved high correlation even in the presence of movement artefacts, different skin tones, lighting conditions and distance from the camera. With acceptable performance and low computational complexity, the proposed system is a suitable candidate for homecare applications, security applications and mobile health devices.

Linear sampling and magnification technique based on phase modulators and dispersive elements: The temporal lenticular lens

In this work, we exploit the space/time duality in optics to implement a temporal lenticular lens allowing to simultaneously sample and magnify an arbitrary-shaped optical signal. More specifically, by applying a sinusoidal phase-modulation, the signal under test is propagated through a discrete dispersive element that samples and magnifies its initial waveform. Thanks to this temporal lenticular lens, optical sampling associated to an intensity magnification factor of 3.6 is experimentally demonstrated at a repetition rate of 10 GHz.

Quality index evaluation of videos based on fuzzy interface system

Objective image quality assessment (IQA) is a challenge facing digital image and video processing systems because image quality is distorted during various applications, including restoration, compression, storage and transmission. Therefore, this study proposes a new methodology based on a fuzzy interface system called quality evaluation system (QES) to measure the total quality index (TQI) of input videos with many distorted situations. Nine quality metrics [peak signal-to-noise ratio, visual signal-to-noise ratio, weighted signal-to-noise ratio, structural similarity (SSIM), multi-scale SSIM, universal image quality index, visual information fidelity, information fidelity criterion and noise quality measure] were used as inputs for three fuzzy logic controller systems, and their outputs were set as inputs to another fuzzy logic controller system to obtain the TQI of the input video. This process contributes to obtain clear performance of the quality index of the input video despite the failure of some IQA methods in providing quality performance of the input video in some situations. The proposed QES is tested on four videos captured with different digital cameras under different noise levels. Furthermore, the authors evaluated the proposed QES on three databases (TID2008, TID2013 and LIVE) to improve the experimental results. In addition, the authors used wavelet decomposition and image de-noising to enhance the standard Eulerian video magnification technique. The proposed QES was also used to prove that the authors' magnification system has better magnification quality index than other magnification techniques.