Multi-Modal Rigid Image Registration and Segmentation Using Multi-Stage Forward Path Regenerative Genetic Algorithm

Multi-modal image registration has significant meanings in clinical diagnosis, treatment planning, and image-guided surgery. Since different modalities exhibit different characteristics, finding a fast and accurate correspondence between images of different modalities is still a challenge. In this paper, we propose an image synthesis-based multi-modal registration framework. Image synthesis is performed by a ten-layer fully convolutional network (FCN). The network is composed of 10 convolutional layers combined with batch normalization (BN) and rectified linear unit (ReLU), which can be trained to learn an end-to-end mapping from one modality to the other. After the cross-modality image synthesis, multi-modal registration can be transformed into mono-modal registration. The mono-modal registration can be solved by methods with lower computational complexity, such as sum of squared differences (SSD). We tested our method in T1-weighted vs T2-weighted, T1-weighted vs PD, and T2-weighted vs PD image registrations with BrainWeb phantom data and IXI real patients' data. The result shows that our framework can achieve higher registration accuracy than the state-of-the-art multi-modal image registration methods, such as local mutual information (LMI) and α-mutual information (α-MI). The average registration errors of our method in experiment with IXI real patients' data were 1.19, 2.23, and 1.57 compared to 1.53, 2.60, and 2.36 of LMI and 1.34, 2.39, and 1.76 of α-MI in T2-weighted vs PD, T1-weighted vs PD, and T1-weighted vs T2-weighted image registration, respectively. In this paper, we propose an image synthesis-based multi-modal image registration framework. A deep FCN model is developed to perform image synthesis for this framework, which can capture the complex nonlinear relationship between different modalities and discover complex structural representations automatically by a large number of trainable mapping and parameters and perform accurate image synthesis. The framework combined with the deep FCN model and mono-modal registration methods (SSD) can achieve fast and robust results in multi-modal medical image registration. Graphical abstract The workflow of proposed multi-modal image registration framework.

BackgroundInformation transmission and processing in the nervous system has stochastic nature. Multiple factors contribute to neuronal trial-to-trial variability. Noise and variations are introduced by the processes at the molecular and cellular level (thermal noise, channel current noise, membrane potential variations, biochemical and diffusion noise at synapses etc). The stochastic processes are affected by different physical (temperature, electromagnetic field) and chemical (drugs) factors. The aim of this study was experimental investigation of hypotheses that increase in the noise level in the brain affects processing of visual information. Change in the noise level was introduced by an external factor producing excess noise in the brain.MethodsAn exposure to 450 MHz low-frequency modulated microwave radiation was applied to generate excess noise. Such exposure has been shown to increase diffusion, alter membrane resting potential, gating variables and intracellular Calcium efflux. Nine healthy volunteers passed the experimental protocol at the lower (without microwave) and the higher (with microwave) noise level. Two photos (visual stimuli) of unfamiliar, young male faces were presented to the subjects, one picture after another. The task was to identify later the photos from a group of six photos and to decide in which order they were presented. Each subject had a total of eight sessions at the lower and eight at the higher noise level. Each session consisted of 50 trials; altogether a subject made 800 trials, 400 at the lower and 400 at the higher noise level. Student t-test was applied for statistical evaluation of the results.ResultsCorrect recognition of both stimuli in the right order was better at the lower noise level. All the subjects under investigation showed higher numbers of right answers in trials at the lower noise level. Average number of correct answers from n=400 trials with microwave exposure was 50.3, without exposure 54.4, difference 7.5%, p<0.002. No difference between results at the lower and the higher noise level was revealed in the case of only partly correct or incorrect answers.ConclusionsOur experimental results showed that introduced excess noise reduced significantly ability of the nervous system in correct processing of visual information.

To assess acoustic noise levels for ambient noise and magnetic resonance (MR) imaging at 1.5 T during use of six "worst-case" pulse sequences. Acoustic noise measurements were obtained at the entrance, center, and exit of the magnet bore of the MR system by means of a specially modified device that is unaffected by electromagnetic radiation. The highest ambient noise level was 73 dB at both the entrance and exit of the magnet bore (A-weighted scale). The highest noise levels during MR imaging occurred during use of a gradient-echo (GRE) pulse sequence and was 102 dB at the entrance and exit of the magnet bore and 103 dB at the center (A-weighted scale). MR imaging performed with the worst-case pulse sequences did not produce noise levels that exceeded federal guidelines. Noise levels were, however, high enough to impair oral communication and annoy patients. Thus, techniques to attenuate acoustic noise and allow improved operator-patient communication should be used during MR imaging, especially during use of GRE pulse sequences.

Sleep fragmentation and deprivation in critically ill patients – Is noise a factor?

The transport sector has been moving toward electrification due to the significant advancement in E-mobility technology. This prioritizes reliable and safe battery energy storage system (BESS) operation. Therefore, accurate battery state-of-charge (SoC) estimation is essential in effectively monitoring and controlling the BESS stability. Many studies have been conducted to estimate the BESS SoC and improve the estimation accuracy. Nevertheless, considering system complexity and computational efforts, the suggested SoC estimate techniques fall short of providing optimal filtering performance with high noise levels. In this regard, this article introduces SoC estimation using the triple forgetting factor adaptive extended Kalman filter (TFF-AEKF) to provide better SoC estimation accuracy and faster convergence considering the high measurement noise levels and environmental circumstances encountered by the operation of electric buses (EBs). The performance of the proposed TFF-AEKF is evaluated and compared to the conventional adaptive extended Kalman filter (AEKF) and the dual forgetting factor AEKF (DFF-AEKF), considering low and high measurement noise levels. It has been validated that the proposed algorithm can provide faster convergence and better accuracy when considering a high measurement noise level. In addition, the three filters are evaluated using four performance indicators, namely, maximum absolute error (MaxAE), mean absolute error (MAE), root mean square error (RMSE), and convergence time. It is concluded that the presented method offers faster convergence and lower error. Results have demonstrated that the proposed algorithm provides an RMSE of 0.3%, an MAE of 0.01%, and a MaxAE of 1.7% for SoC estimation.

Phase mutual information as a similarity measure has been demonstrated to perform comparably to an intensity method even when there is no strong intensity relationship between images. The estimation of local phase is significantly affected by the choice of bandpass filter and its parameter selection. The effect of the parameter selection of Log-Gabor filter on local phase estimation and performance of registration has been studied. The Log-Gabor filter is mainly constructed using two parameters, the center frequency w(0) and bandwidth B. Forty-two different transformations for magnetic resonance imaging (MRI) and simulated positron emission tomography (PET) data were used in this study, with mean and standard deviation of the distance between the gold standard position and the computed position taken as an error measure. The results showed that there was a tendency for wider B to be required to generate clear phase images with increasing of w(0). However, wider B could not improve the performance of registration for a certain w0. Parameters (w(0), B) with the values of (0.1, 3) are recommended to obtain optimum performance. There were no large differences in the registration errors among noise levels of 5%, 10%, 15% and 20%, suggesting that phase-based registration is robust against noise. When using the Log-Gabor filter with parameters (w(0), B) of (0.1, 3), the registration errors were always smaller than those in intensity-based registration for both cases with intensity non-uniformity in MRI of 20% and 40%. These results suggest that phase-based registration can be used as an alternative to intensity-based registration even in intensity non-uniform MRI.

In Vilnius and in other bigger towns the noise generated by mobile sources accounts for up to 90 % of the total noise level in a town. A high noise level is detected at motor vehicle parking lots. To measure this noise level, testing was carried out at guarded parking lots which were divided into certain types. One lot of each type was chosen for testing. The number of measuring spots was conditioned by the size of a lot. The data obtained during testing reveal that the highest noise level is generated not at a parking lot but on a nearby street. Such conclusions are proved by the results of testing carried out at a parking lot on E. Sugihara street. Although this lot parks over 100 vehicles, the equivalent noise level is 47 dBA. Basing on the testing data, the numeral simulation of the noise dispersion in areas in the vicinity of parking lots has been run with the help of the numeral simulation software IMMI.

Magnetic resonance imaging (MRI) coils are typically associated with high acoustic noise levels, which can pose problems for the patient and attending medical staff. Lorentz forces are generated by gradient coils, which are switched rapidly. The Lorentz forces displace the coil former and promote a pressure wave that is responsible for acoustic noise up to 130 dB. The high noise levels are an unavoidable consequence of requiring the gradient coils to generate highly homogeneous linear magnetic fields. However, in this article, we present a mathematical method for designing coils that achieve a drastic reduction in noise level by deliberately sacrificing field linearity. We show that useful images can nevertheless be obtained from the nonlinear fields associated with these quiet coils. Examples are given that demonstrate the robustness of the method. © 2011 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 39B: 191–205, 2011

The deleterious effects of noise pollution on public health have been well documented, with traffic noise being identified as a significant contributor to stress and adverse impacts on the human body and mind. In this study, sound levels at 12 different points in Al-Oqailat Park in Buraydah, Saudi Arabia, were measured using a sound level meter (SLM), with the study’s primary objective being to conduct this measurement. The experimental results were then compared with perception measurements collected from users who frequently visited Al-Oqailat park. Sound measurements were taken in four different zones (A, B, C, and D) during rush hours between 1:30 p.m. and 5:20 p.m. It was found that noise levels at point A1 peaked at 79 dBA at 4:40 p.m., while the lowest level recorded was 41.1 dBA at point D2 at 2:35 p.m. The range of noise levels varied between 79 and 41 dBA, with a rate of decline of 48.10%. Zones A and B seemed to have the highest noise levels during rush hours, since they were located closest to King Fahd Road and Al-Adl Street, while zone D exhibited the lowest noise levels due to its location as a parking lot for Buraydah Court. An intermediate noise level was found in zone C, in the middle of Al-Oqailat park. The people perception results, completed by 84 park visitors, showed that zone A was identified as having exceptionally high noise levels compared to the other zones, with zone D having the lowest levels. These results were consistent with the experimental findings and reflected that the points along King Fahd Road and Al-Adl Street had the highest noise levels. Overall, the research highlighted the dominance of car traffic and horns as the primary sources of noise pollution in and around Al-Oqailat Park, emphasizing the significance of meticulous site selection for parks in urban areas.

This study describes the effects of broadband background noise on the average discharge rate to best-frequency (BF) tones of auditory nerve fibers in the cat. The effects of exposure to long-term continuous noise are compared to the effects of noise gated on and off simultaneously with test tones. Addition of background noise causes a shift of the dynamic portion of tone-evoked rate versus level functions to higher tone intensities. The shift occurs at a mean rate of 0.61 dB of shift for each 1-dB increment in noise level. The rate of shift is independent of best frequency and spontaneous discharge rate. The noise level at which the shift begins is frequency dependent and is consistent with the frequency-dependent bandwidths of auditory nerve fiber tuning curves. The adjustment of the dynamic range shows many similarities to two-tone suppression. Therefore, it is most likely that it is caused by suppression of the response to the BF test tone by energy present in the noise at surrounding frequencies. At high noise levels, the ability of auditory nerve fibers to respond to test tones is limited by the rate response to the noise. As noise level increases, the discharge rate it evokes approaches a fiber's saturation rate and ultimately eliminates the fiber's ability to respond to test tones. Low spontaneous rate fibers, which have been shown to have higher thresholds and wider dynamic range (17,29), are significantly more resistant to saturation by high noise levels. Exposure to broadband noise prior to onset of test tones produces an overall decrement in response rate. This phenomenon is similar to the effects of short-term adaptation (32) and seems to develop independently of the shift of dynamic range. At high noise levels, previous exposure to the noise produces a small dynamic range shift. This effect is similar to that produced by suppression but is smaller. The effect is occluded in continuous noise backgrounds by the adjustment of sensitivity produced by suppression.

Canalization is a form of network robustness found in genetic regulatory networks that results in a reduction of the variation of phenotypic expression relative to the complexity of the genome. Recently, it was discovered that canalization can evolve in a complex network through a self-organization of node (gene) behavior resulting from a competition of a network's nodes that selects for a diversity of behavior [K.E. Bassler, C. Lee, and Y. Lee, Phys. Rev. Lett. 93, 038101 (2004)]. Previously, this mechanism for the evolution of canalization has been studied only in deterministic model systems. This paper considers the effects of stochastic noise in the signals exchanged between nodes on the self-organized evolution of canalization. We find that small levels of stochastic noise increase the amount of canalization produced. At higher levels of noise, the amount of canalization produced levels off and reaches a maximum value, before it reduces at large levels of noise.

Background . Noise pollution is a burden exerting a harmful and irritating effect on human health. Children are particularly sensitive to noise burden. In this connection, it is especially important to control the noise pollution level in public education organizations where children spend significant time. Objective . The study is aimed at determining objective and subjective parameters of noise pollution in public education organizations based on the analysis of data obtained by measuring noise levels in school campuses in Saransk and directly in classrooms, as well as by questioning the teachers of these schools. Methods . The measurement of noise burden was carried out in 10 schools using the noise and vibration level meter “Assistant” with class I accuracy. Noise measurements in school campuses and classrooms were performed in accordance with the GOST 23337-2014 requirements. Assessment of results was conducted in accordance with sanitary standards 2.2.4/2.1.8.562-96 “Noise in the workplace, residential and public buildings and housing developments”. Results . Based on noise measurement results, the highest noise levels were found in school № 2 (65.5 dBА on the campus, 51.2 dBA in the classroom) which is located in the center of a traffic interchange. The lowest noise parameters were found in school № 35 (45.2 dBА on the campus, 37.7 dBА in the classroom) which is located in the residential quarter quite far away (242-321 m) from the main source of noise, the motorway. Conclusion . Study results attest that maximum noise levels at school campuses do not exceed the permissible exposure limit of 70 dBA. In all schools noise values conform to the noise standards (maximum sound pressure level in classrooms did not exceed 55 dBA).

In dental practical classes, the acoustic environment is characterized by high noise levels in relation to other teaching areas, due to the exaggerated noise produced by some of these devices and use of dental equipment by many users at the same time. To measure, analyze and compare noise levels of equipments among dental learning areas under different working conditions and also to measure and compare noise levels between used and brand new handpieces under different working conditions. Noise levels were measured and analyzed in different dental learning areas that included clinical, pre-clinical areas and laboratories selected as representatives of a variety of learning-teaching activities. The noise levels were determined using a precision noise level meter (CENTER® 325 IEC 651 TYPE II) with a microphone. The mean of the maxima was determined. The data were collected, tabulated, and statistically analyzed using t tests. The noise levels measured varied between 64 and 97 dB(A).The differences in sound levels when the equipment was merely turned on and during cutting operations and also between used and brand new equipments were recorded. The laboratory engines had the highest noise levels, whereas the noise levels in high-speed turbine handpieces and the low-speed contra angle handpieces were decreased. The noise levels detected in this study are considered to be close to the limit of risk of hearing loss.

The purpose of this study was to compare threshold-matched ears with and without suspected cochlear dead regions in terms of the speech perception benefit from high-frequency amplification. The Threshold Equalizing Noise Test (TEN) was used to assess the presence of dead regions. Speech perception was measured while participants were wearing a hearing aid fit to approximate DSL[i/o] targets. Consonant identification of nonsense vowel-consonant-vowel combinations was measured in quiet using a forced-choice procedure. Phoneme recognition was measured at signal-to-noise ratios ranging from 0 to +15 dB using the Computer-Assisted Speech Perception Assessment test (CASPA). Recognition scores were obtained for unfiltered stimuli and stimuli that were low-pass filtered at the estimated boundary of the suspected dead regions, 1/2 octave above and 1 octave above the boundary. Filter settings for the ears without suspected dead regions were the same as settings of the threshold-matched counterpart. In quiet and in low levels of noise, speech perception scores were significantly higher for the wide-band (unfiltered) condition than for the filtered conditions, and performance was similar for the ears with and without suspected dead regions. In high levels of noise, mean scores were highest in the wide-band condition for the ears without suspected dead regions, but performance reached an asymptote for the ears with suspected dead regions. These results suggest that patients with cochlear dead regions may experience speech perception benefit from wide-band high-frequency gain in quiet and low levels of noise, but not in high levels of noise.

Objectives: The purpose of this study was to observe and record the levels and sources of noise in an adult ICU. These results and observations are to form the basis of protocols to control noise levels in an ICU. These will also be treated as baseline values for comparison with results obtained in future studies to determine the effectiveness of noise reduction protocols. Methods: Average noise levels were recorded in the adult ICU of S.L. Raheja Hospital (A Fortis Associate) over a period of 10 days and 10 nights. A digital sound meter was used to record the sound levels and an average of 5 readings at the start of every hour was recorded. Along with measurements, physical observation and a literature review of recent noise studies in ICUs was also undertaken. Result: Noise levels in the ICU were found to be higher than the guideline values in accordance with most recent studies. It was observed that the major source of high noise levels was caregivers such as ward boys who tended to speak loudly while doing their duties. During the day, noise levels were higher than at night and noise levels increased sharply during shift changes. Conclusion: Almost 61% of the noise in the ICU was found to be modifiable. In future, on the basis of the results of this study, protocols will be formed and steps will be taken to reduce the modifiable noise to bring down noise levels further to ensure faster recovery and greater patient comfort.