Affect Image Quality Research Articles

CSDM: A Cross-Scale Decomposition Method for Low-Light Image Enhancement

Inadequate lighting condition is one of the main factors affecting image quality. For high-quality image display and vision applications, low-light image enhancement is an extremely challenging task. However, most existing methods are difficult to remove heavy noise in the low-light enhancement process effectively. To solve this problem, this paper presents a novel cross-scale decomposition method (CSDM) for low-light image enhancement. The main idea is to capture the small-scale texture and heavy noise, and preserve the large-scale structure by designing a Gaussian regularization based on a cross-scale relative relationship. An optimization objective function is established to transform image decomposition, low-light enhancement and noise suppression into a unified optimization framework. The framework uses sequential decomposition to estimate texture and structure layers. Firstly, the structure layer of the image is estimated, and an illumination prior is introduced to improve the contrast. Then the texture layer is estimated, and a low-rank prior is applied to eliminate noise. Finally, the structure and texture layers are combined to obtain a final enhanced image. Experiment results on public datasets and an industrial site demonstrate that the advantages of our method from both qualitative and quantitative perspectives.

Characterization of diffractive relief structures over large areas by stitching interference microscopic topography

The development of diffractive optical elements (DOEs)enables fascinatingly compact design and chromatic aberration correction. Fabrication errors of DOEs include periodic pattern error, relief profile error and roughness which affect imaging quality and diffraction efficiency. Characterization of the DOE requires thus multi-scale measurement of the surface topography over the full aperture of 10 mm scale. This paper presents a method based on the white light interferometry in combination of subaperture stitching. Firstly, the principle of measurement and subaperture layout design is introduced. The measuring system is easily set up by integrating a scanning platform with the interference microscope. Subaperture stitching algorithm is developed based on the surface height change related to the scanning motion error. The slope of the relief profile is used to model the deviations of overlapping point pairs induced by lateral shift and rotation. Finally, the topography and fabrication error of a Fresnel lens surface are experimentally obtained and characterized over the full aperture through stitching of totally 67 subapertures.

A comparison of doses from contemporary extraoral bitewing radiography: Child and adult examinations

<h3>Objective</h3> To compare the effective doses (E) from two panoramic (PAN)/extraoral bitewing (EOBW) systems with an industry-standard intraoral bitewing (IOBW) system for adult and child phantoms. The feasibility and impact of thyroid shielding during EOBW was also evaluated. <h3>Study Design</h3> This preclinical experimental study utilizing anthropomorphic phantoms (average adult and 10-year-old child) modified to accept optically stimulated luminescence dosimeters evaluated E from two extraoral units: RayScan ALPHA (Buena Park, CA) and Sirona ORTHOPHOS SL (Charlotte, NC), and one conventional IO unit using circular (CC) and rectangular (RC) collimation (FOCUS Instrumentarium, Brea, CA). Phantom sequences were triplicated for all modality combinations and average E was calculated. Exposure parameters were: Orthophos- 85kV, 7-13mA, 5.1s; RayScan- 80kV, 12-14mA, 7.2s; Focus- 70kV, 7mA, 0.5-1.28s. <h3>Results</h3> E from child and adult PAN and EOBW examinations was significantly lower for Orthophos compared to RayScan (p<.0001). Standard adult EOBW E (µSv) was 4.3 and 28.1 (child) and 8.6 and 30.2 (adult) for Orthophos and RayScan, respectively. For both extraoral units, EOBW E was reduced compared to PAN E. IOBW E (µSv) ranged from 7.0-11.8 (child) and 4.6-14.2 (adult) for CC and RC, respectively. IOBW examinations with CC yielded higher E than Orthophos EOBW and lower E than RayScan EOBW for the adult phantom. Significant reductions in thyroid dose (53%) from EOBW examinations were achieved using shielding with RayScan adult scans (p<.0001). Shielding did not yield notable thyroid dose reductions for child EOBW scans and produced minor artifacts intermittently. <h3>Conclusion</h3> IOBW examinations employing RC continue to yield lower E than alternative EOBW systems for adults. Dramatic dose differences may be associated with extraoral equipment selection. Detector type (2D-array vs. flat-panel) may be an indicator of potential dose differences among machines. Shielding during EOBW imaging can reduce adult thyroid dose without negatively affecting image quality. <b>Statement of Ethical Review</b> Ethical review was sought and study was exempted from ethical review

The prevalence of image degradation due to motion in rest-stress rubidium-82 imaging on a SiPM PET-CT system

BackgroundMotion of the heart is known to affect image quality in cardiac PET. The prevalence of motion blurring in routine cardiac PET is not fully appreciated due to challenges identifying subtle motion artefacts. This study utilizes a recent prototype Data-Driven Motion Correction (DDMC) algorithm to generate corrected images that are compared with non-corrected images to identify visual differences in relative rubidium-82 perfusion images due to motion. Methods300 stress and 300 rest static images were reconstructed with DDMC and without correction (NMC). The 600 DDMC/NMC image pairs were assigned Visual Difference Score (VDS). The number of non-diagnostic images were noted. A “Dwell Fraction” (DF) was derived from the data to quantify motion and predict image degradation. ResultsMotion degradation (VDS = 1 or 2) was evident in 58% of stress images and 33% of rest images. Seven NMC images were non-diagnostic—these originated from six studies giving a 2% rate of non-diagnostic studies due to motion. The DF metric was able to effectively predict image degradation. The DDMC heart identification and tracking was successful in all images. ConclusionMotion degradation is present in almost half of all relative perfusion images. The DDMC algorithm is a robust tool for predicting, assessing and correcting image degradation.

Patient-centred care with self-compression mammography in clinical practice: a randomized trial compared to standard compression.

To test the efficacy of self- compared to radiographer-led compression to reduce the average glandular dose without affecting image quality and compliance to follow-up mammography. Women presenting for mammography for breast cancer follow-up, symptoms, opportunistic screening, or familial risk were asked to participate and, if willing, were randomized to self-compression or radiographer-led compression. Image quality was assessed blindly by two independent radiologists and two radiographers. Pain and discomfort were measured immediately after mammography and their recall was asked when the women participated in the follow-up mammogram, 1 or 2 years later. In total, 495 women (mean age 57 years +/-14) were enrolled, 245 in the self-compression and 250 radiographer-compression arms. Image quality was similar in the two arms (radiologists' judgement p = 0.90; radiographers' judgement p = 0.32). A stronger compression force was reached in the self- than in the radiographer-arm (114.5 vs. 10.25 daN, p < .001), with a 1.7-mm reduction in thickness (p = .14), and almost no impact on dose per exam (1.90 vs. 1.93 mGy, p = .47). Moderate/severe discomfort was reported by 7.8% vs 9.6% (p = .77) and median pain score was 4.0 in both arms (p = .55). Median execution time was 1 min longer with self-compression (10.0 vs. 9.1 min, p < 0.001). No effect on subsequent mammography was detectable (p = 0.47). Self-compression achieved stronger compression of the breast, with comparable image quality, but did not substantially reduce glandular dose. The proportion of women who attended follow-up mammography was also similar in the two groups. clinicaltrials.gov NCT04009278 KEY POINTS: • In mammography, appropriate compression is essential to obtain high image quality and reduce dose. Compression causes pain and discomfort. • Self-compression has been proposed to reach better compression and possibly increase participation in mammography. • In a randomized trial, self-compression reached stronger compression of the breast, with comparable image quality but with no glandular dose reduction or impact on participation in follow-up mammography.

Design of a versatile microfluidic device for imaging precision-cut-tissue slices

Precision-cut-tissues (PCTs), which preserve many aspects of a tissue’s microenvironment, are typically imaged using conventional sample dishes and chambers. These can require large amounts of reagent and, when used for flow-through experiments, the shear forces applied on the tissues are often ill-defined. Their physical design also makes it difficult to image large volumes and repetitively image smaller regions of interest in the living slice. We report here on the design of a versatile microfluidic device capable of holding mouse or human pancreas PCTs for 3D fluorescence imaging using confocal and selective plane illumination microscopy (SPIM). Our design positions PCTs within a 5 × 5 mm × 140 µm deep chamber fitted with 150 µm tall channels to facilitate media exchange. Shear stress in the device is localized to small regions on the surface of the tissue and can be easily controlled. This design allows for media exchange at flowrates ∼10-fold lower than those required for conventional chambers. Finally, this design allows for imaging the same immunofluorescently labeled PCT with high resolution on a confocal and with large field of view on a SPIM, without adversely affecting image quality.

Aerial photography trajectory-tracking controller design for quadrotor UAV

Quad-rotor unmanned aerial vehicles (UAV) are prone to external interference during aerial photography of farmland environments. For example, they are affected by external airflow and load, resulting in route deviation and irregular image overlap, which seriously affects image quality. An aerial trajectory tracking controller is designed for this aerial photography process. To ensure that a drone can fly according to the established route during the aerial photography process and meet the requirements of large-scale topographic map stereo mapping for the flight control accuracy of the drone platform, the system was divided into a full-drive subsystem and an underactuated subsystem. The full-drive subsystem uses a fast terminal sliding mode controller to ensure that the variable ([Formula: see text]) reaches the desired value. The under-actuated subsystem adopts the second-order sliding mode control was used to achieve effective position and attitude tracking of variables ([Formula: see text]). The flight controllers are derived by using Lyapunov theory. Finally, with the aerial trajectory of a farmland taken as an example, the flight path control of the UAV is simulated. Simulation results show that the designed control system can be applied to the aerial photography process of the UAV and has strong anti-system parameter perturbation, robustness and good trajectory tracking.

Study on a new “One-stop-shop” scan protocol combining brain CT perfusion and head-and-neck CT angiography by using 256-detector CT for stroke patients

PurposeWe sought to evaluate the performance of a new “one-stop-shop” scan protocol combining brain computed tomography perfusion (CTP) and head-and-neck CT angiography (CTA) imaging for acute stroke patients using a 256-detector CT scanner. MethodFrom March to August 2020, 60 patients (30 men and 30 women) aged 22–88 years with suspected acute stroke were enrolled and randomly divided into 2 groups to undergo brain CTP and head-and-neck CTA with a 256-detector CT system. Group A used traditional scan protocol with a separate brain CTP and head-and-neck CT examination that included non–contrast-enhanced and contrast-enhanced acquisitions; group B used the new “one-stop-shop” scan protocol with head-and-neck CTA data inserted into brain CTP scans at the peak time (PT) of the arterial phase. The insertion point of the head-and-neck CTA data was determined by a test bolus. The examination time, contrast dose, radiation dose, and image quality were compared between the groups. ResultsThe total contrast dose was reduced by 40% in group B compared to group A (60 mL vs. 100 mL). The imaging time was 52.5 ± 2.6 s in group B and 74.9 ± 3.3 s in group A, showing a reduction of approximately 43% in group B. There was no significant difference in image quality both quantitatively and qualitatively between the groups (all P > 0.05). Group B had a slight reduction in dose length product (1139.0 ± 45.3 vs. 1211.6 ± 31.9 mGy·cm, P < 0.001). ConclusionsThe proposed “one-stop-shop” scan protocol combining brain CTP and head-and-neck CTA on a 256-detector CT system can reduce imaging time and contrast dose, without affecting image quality or perfusion results, compared to the traditional protocol of separating the examinations.

Optimization of scan parameters to reduce acquisition time for RESOLVE-based diffusion kurtosis imaging (DKI) in nasopharyngeal carcinoma (NPC).

To shorten acquisition time of readout segmentation of long variable echo trains (RESOLVE)-based diffusion kurtosis imaging (DKI) via Readout Partial Fourier (RPF) and b-value combinations. The RESOLVE-based DKI images of 38 patients with nasopharyngeal carcinoma (NPC) were prospectively enrolled. For RESOLVE-based DKI images with 5/8 RPF and without RPF, objective and subjective evaluations of image quality were performed. A total of nine groups with different b-value combinations were simulated, and the influence of different b-value combinations for RESOLVE-RPF-based DKI sequences was assessed using the intraclass correlation coefficient (ICC). The mean values of signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in DKI images without RPF were higher than those with 5/8 RPF (252.9 ± 77.7 vs 247.3 ± 85.5 and 5.8 ± 2.8 vs 5.4 ± 2.3, respectively), but not significantly (p = 0.460 and p = 0.180, respectively). In comparing the ICCs between nine groups of different b-value combinations in RESOLVE-RPF-based DKI, group (200, 800, 2000 s/mm2), group (200, 400, 800, 2000 s/mm2) and group (200, 800, 1500, 2000 s/mm2) were not significantly different (p > 0.001) and showed excellent agreement (0.81-1.00) with that of group (200, 400, 800, 1500, 2000 s/mm2). Using b-value optimization and RPF technology, the group with RPF (200, 400, 800, 2000 s/mm2) showed a 56% reduced scanning compared with the group without RPF (200, 400, 800, 1500, 2000 s/mm2; 3 min 46 s vs 8 min 31 s, respectively). DKI with RPF did not significantly affect image quality, but both RPF and different b-value combinations can affect the scanning time. The combination of RPF and b-value optimization can ensure the stability of DKI parameters and reduce the scanning time by 56%. This work is to optimize scan parameters, e.g. RPF and b-value combinations, to reduce acquisition time for RESOLVE-based DKI in NPC. To our knowledge, the effect of RESOLVE-RPF and b-value combinations on DKI has not been reported.

CT coronary angiogram in children with Kawasaki patients: experience in 52 patients.

CT is an accepted non-invasive imaging tool to assess the coronary arteries in adults; however, its utilisation in children is limited by high heart rate and lack of standardised protocol. We sought to assess diagnostic quality and factors that affect image quality of CT in assessing coronary artery lesions in Kawasaki patients less than 18 years of age. CT coronary angiography was performed on patients with Kawasaki disease diagnosed with coronary aneurysm or suspected to have coronary stenosis. Studies were performed using electrocardiogram-gated protocols. General anaesthesia was used in patients who were not cooperative for breathing control. Heart rate, image quality, and effective radiation dose were documented. Fifty-two Kawasaki patients underwent CT coronary angiography to assess coronary artery lesions. Median heart rate was 88 beats per minute (range 50-165 beats/minute). Image quality was graded as excellent in 34 (65%) patients, good in 17 (32%), satisfactory in 1, and poor in 1 patient. Coronary artery aneurysm was found in 25 (bilateral = 6, unilateral = 19, multiple = 11). Thrombus was found in 11 patients resulting in partial and total occlusion in 8 and 3 patients, respectively. Coronary stenosis was noted in 2 patients. The effective radiation dose was 1.296 millisievert (median 0.81 millisievert). Better diagnostic imaging quality was significantly related to lower heart rate (p = 0.007). Electrocardiogram-triggered CT coronary angiography provides a good diagnostic assessment of coronary artery lesions in children with Kawasaki disease.

Hardware Optimizations of the X-ray Pre-Processing for Interventional Computed Tomography Using the FPGA

In computed tomography imaging, the computationally intensive tasks are the pre-processing of 2D detector data to generate total attenuation or line integral projections and the reconstruction of the 3D volume from the projections. This paper proposes the optimization of the X-ray pre-processing to compute total attenuation projections by avoiding the intermediate step to convert detector data to intensity images. In addition, to fulfill the real-time requirements, we design a configurable hardware architecture for data acquisition systems on FPGAs, with the goal to have a “on-the-fly” pre-processing of 2D projections. Finally, this architecture was configured for exploring and analyzing different arithmetic representations, such as floating-point and fixed-point data formats. This design space exploration has allowed us to find the best representation and data format that minimize execution time and hardware costs, while not affecting image quality. Furthermore, the proposed architecture was integrated in an open-interface computed tomography device, used for evaluating the image quality of the pre-processed 2D projections and the reconstructed 3D volume. By comparing the proposed solution with the state-of-the-art pre-processing algorithm that make use of intensity images, the latency was decreased 4.125×, and the resources utilization of ∼6.5×, with a mean square error in the order of 10−15 for all the selected phantom experiments. Finally, by using the fixed-point representation in the different data precisions, the latency and the resource utilization were further decreased, and a mean square error in the order of 10−1 was reached.

Application and interpretation of vessel wall magnetic resonance imaging for intracranial atherosclerosis: a narrative review

Background and ObjectiveAtherosclerosis is a systemic disease that occurs in the arteries, and it is the most important causative factor of ischemic stroke. Vessel wall magnetic resonance imaging (VWMRI) is one of the best non-invasive methods for displaying the vascular features of intracranial atherosclerosis. The main clinical applications of this technique include the exploration of the pathogenesis of intracranial atherosclerotic lesions, follow-up monitoring, and treatment prognosis judgment. As the demand for intracranial VWMRI increases in clinical practice, radiologists should be aware of the selection of imaging parameters and how they affect image quality, clinical indications, evaluation methods, and limitations in interpreting these images. Therefore, this review focused on describing how to perform and interpret VWMRI of intracranial atherosclerotic lesions.MethodsWe searched the studies on the application of VWMRI in the PubMed database from January 1, 2000 to March 31, 2022, and focused on the analysis of related studies on VWMRI in atherosclerotic lesions, including technical application, expert consensus, imaging characteristics, and the clinical significance of intracranial atherosclerotic lesions.Key Content and FindingsWe reviewed and summarized recent advances in the clinical application of VWMRI in atherosclerotic diseases. Currently accepted principles and expert consensus recommendations for intracranial VWMRI include high spatial resolution, multiplanar two and three-dimensional imaging, multiple tissue-weighted sequences, and blood and cerebrospinal fluid suppression. Understanding the characteristics of VWMRI of normal intracranial arteries is the basis for interpreting VWMRI of atherosclerotic lesions. Evaluating VWMRI imaging features of intracranial atherosclerotic lesions includes plaque morphological and enhancement characteristics. The evaluation of atherosclerotic plaque stability is the highlight of VWMRI.ConclusionsVWMRI has a wide range of clinical applications and can address important clinical questions and provide critical information for treatment decisions. VWMRI plays a key role in the comprehensive evaluation and prevention of intracranial atherosclerosis. However, intracranial VWMRI is still unable to obtain in vivo plaque pathological specimens for imaging—pathological comparison is the most significant limitation of this technique. Further technical improvements are expected to reduce acquisition time and may ultimately contribute to a better understanding of the underlying pathology of lesions on VWMRI.

Evaluating the use of anti-scatter grids in adult knee radiography

IntroductionAnti-scatter grids efficiently reduce scatter radiation from reaching the imaging receptor, enhancing image quality; however, the patient radiation dose increases in the process. There is disagreement regarding the thickness thresholds for which anti-scatter grids are beneficial. This study aims to establish a thickness threshold for the use of anti-scatter grids to optimise adult knee radiography. MethodsThe study consisted of two phases. In Phase 1 phantom knee radiographs were acquired at varying thicknesses (10–16 cm) and tube voltages (60–80 kV). For each thickness and tube voltage, images with and without an anti-scatter grid were obtained. In Phase 2, two radiologists and three radiographers, evaluated the image quality of these images. Visual Grading Analysis (VGA) scores were analysed using Visual Grading Characteristics (VGC) based on the visualisation of five anatomic criteria. ResultsThe average DAP decreased by 72.1% and mAs by 73.1% when removing the anti-scatter grid. The VGC revealed that overall images taken with an anti-scatter grid have better image quality (AUC ≥0.5 for all comparisons). However, the anti-scatter grids could be removed for thicknesses 10, 12 and 14 cm in conjunction with using 80 kVp,. ConclusionAnti-scatter grids can be removed when imaging adult knees between 10 and 12 cm using any kVp setting since the radiation dose is reduced without significantly affecting image quality. For thicknesses >12 cm, the use of anti-scatter grids significantly improves image quality; however, the radiation dose to the patient is increased. The exception is at 14 cm used with 80 kVp, where changes in image quality were insignificant. Implications for practiceOptimisation by removing anti-scatter grids in adult knee radiography seems beneficial below 12 cm thickness with any kVp value. Since the average knee thickness ranges between 10 and 13 cm, anti-scatter grid can be removed for most patients. Nevertheless, further studies are recommended to test if this phantom-based threshold applies to human subjects.

Impact of patient body habitus on image quality and quantitative value in bone SPECT/CT.

The first edition of guidelines for standardization of bone single photon emission computed tomography (SPECT) imaging was published in 2017, and the optimization and standardization are widely promoted. To the purpose, clarification of the factors related to image quality and quantitative values and their influence are required. The present study aimed to clarify and optimize the influence of patient body habitus on image quality and quantitative values in bone SPECT/CT. National Electrical Manufacturers Association body phantom (S-size) and custom-made large body phantoms (M-size and L-size) that simulate the abdomens of Japanese patients weighing 60, 80, and 100kg, were used. Each phantom was filled with 99mTc-solutions of 108 and 18kBq/mL for the hot spheres and background, respectively. Dynamic SPECT acquisition was performed for 6000s (150s /rotation × 40 rotation). The data were divided into six projection data and reconstructed each acquisition time (150, 300, 450, 600, 750, 900s, and single projection 6000s). Image quality was evaluated for contrast (QH, 17mm), background noise (NB, 17mm), contrast-to-noise ratio (CNR), maximum standardized uptake value (SUVmax, 17mm), and visual assessment for a 17mm hot sphere. Image quality in the 300s acquisition showed that values of QH, 17mm, CNR, and SUVmax, 17mm decreased (-16.7%, -11.8%, and -11.3%) for M-size and (-28.2%, -30.1%, and -21.7%) for L-size compared with S-size, respectively. No significant difference was observed in NB, 17mm values. M-size and L-size required 1.2 and 2.3 times longer acquisition, to achieve same CNR as S-size. In visual assessment, 17mm hot sphere could not be detected only in the L-size. When the Japanese bone SPECT guidelines criteria were applied in 600s, the sphere could be detected between all phantoms. Patient body habitus significantly affects image quality and decreases the quantitative value in bone SPECT/CT. For the optimization, extend acquisition time according to the patient body habitus is effective for image quality. And for the standardization, it is important to achieve imaging conditions that meet the Japanese bone SPECT guidelines criteria to ensure adequate detectability.

A blind medical image denoising method with noise generation network

In the process of medical images acquisition, the unknown mixed noise will affect image quality. However, the existing denoising methods usually focus on the known noise distribution. In order to remove the unknown real noise in low-dose CT images (LDCT), a two-step deep learning framework is proposed in this study, which is called Noisy Generation-Removal Network (NGRNet). Firstly, the output results of L0 Gradient Minimization are used as the labels of a dental CT image dataset to form a pseudo-image pair with the real dental CT images, which are used to train the noise generation network to estimate real noise distribution. Then, for the lung CT images of the LIDC/IDRI database, we migrate the real noise to the noise-free lung CT images, to construct a new almost-real noisy images dataset. Since dental images and lung images are all CT images, this migration can be achieved. The denoising network is trained to realize the denoising of real LDCT for dental images by using this dataset but can extend for any low-dose CT images. To prove the effectiveness of our NGRNet, we conduct experiments on lung CT images with synthetic noise and tooth CT images with real noise. For synthetic noise image datasets, experimental results show that NGRNet is superior to existing denoising methods in terms of visual effect and exceeds 0.13dB in the peak signal-to-noise ratio (PSNR). For real noisy image datasets, the proposed method can achieve the best visual denoising effect. The proposed method can retain more details and achieve impressive denoising performance.

Validation of a dedicated positron emission tomography scanner for imaging of the distal limb of standing horses.

A positron emission tomography (PET) scanner, with an openable ring of detectors, was specifically designed to image the distal limb of standing horses. The goals of this prospective, preclinical, experimental, methods comparison study were to validate the safety of the scanner, assess image quality, and optimize scanning protocols. Six research horses were imaged three times (twice standing, once anesthetized) and six horses in active race training were imaged once under standing sedation. Multiple scans of both front fetlocks were obtained with different scan durations and axial fields of view. A total of 94 fetlock scans were attempted and 90 provided images of diagnostic value. Radiotracer uptake was the main factor affecting image quality, while motion did not represent a major issue. Scan duration and field of view also affected image quality. Eight specific lesions were identified on PET images from anesthetized horses and were all also independently recognized on the PET images obtained on standing horses. Maximal standardized uptake values (SUVmax) had good repeatability for the assessment of specific lesions among different scans. Three feet and six carpi were also successfully imaged. This study validated the safety and practicality of a PET scanner specifically designed to image the distal limb in standing horses. Proper preparation of horses, similar to bone scintigraphy, is important for image quality. A 4-min scan with 12cm field of view was considered optimal for clinical fetlock imaging. Evaluation of a larger clinical population is the next step for further assessment of the clinical utility of PET imaging in horses.

TAO-Net: Task-Adaptive Operation Network for Image Restoration and Enhancement

Recently, deep learning based models have been extensively applied to image restoration and enhancement tasks. However, existing approaches neglect the potential correlation among these tasks, and do not fully consider the different intensity factors of degradation which affect image quality. To this end, we propose Task-Adaptive Operation Network (TAO-Net) that stacks a series of operation blocks, guided by the supervised attention mechanism to adaptively enable the model to assign corresponding intensity weights for different degradation factors depending on the input signals. To better recover and preserve the accurate details during the repeated operations, we make full use of the image prior to intruduce structure refinement block as auxiliary information for reconstructing high-quality results. Furthermore, feature aggregation block is also adopted to avoid feature interference caused by the direct concatenation between the backbone operation block and the auxiliary refinement block together. Extensive experiments on multiple benchmark datasets demonstrate that our proposed method outperforms previous baselines in image deraining and low-light image enhancement.

Service quality and public satisfaction with Indonesia's tax amnesty program

Functional aspects have dominated the measurement of service quality. This paper investigates the perception of taxpayers on the quality of tax amnesty services and the factors influencing the quality of tax amnesty services using multi-dimensional aspects or multi-attribute constructs. Gronroos service quality model is used as the bedrock for the study, and structural equation modelling (SEM) informed the analysis of the data. A research questionnaire was used to collect data from 100 tax amnesty participants, and each latent variable was verified. The results show that both functional quality and technical quality positively and substantially affect image quality. Image and technical quality have a positive and significant influence on service quality perceptions, while functional quality has a positive but insignificant impact upon service quality perceptions. Further, the results reveal that service quality perceptions positively and significantly affect taxpayers' satisfaction. The results provided an advice policy design that delivers excellent services to taxpayers.

Aberration analysis of a wedge as a compensator element in augmented and virtual reality systems

The paper considers the optical systems of virtual reality, which use an optical wedge to eliminate or reduce the conflict of convergence and accommodation (vergence-accommodation conflict, VAC). The inclined surfaces of the optical wedge introduce specific aberrations into the optical system that can critically affect image quality. The authors analyzed wedge aberrations using relationships derived from the third-order aberration theory. In contrast to existing approaches, the relationships were obtained without the assumption of a small refractive angle or wedge thickness. The results demonstrate that in the scheme with an optical wedge, with characteristics typical for virtual reality systems, the dependence of astigmatism on the angular field is linear and significantly exceeds the other types of aberrations. It is shown that to obtain a high-quality image, the most successful compensation for such aberration can be achieved by using diffractive optical elements (kinoforms) or a Fresnel lens. The paper gives examples of optical systems with a wedge, developed taking into account the requirements for the overall dimensions of virtual reality systems and image quality. The obtained ratios for the aberrations of the optical wedge and the inclined surface make it possible to evaluate the correction capabilities of schemes where such elements are used with arbitrary characteristics. The proposed solutions can be used in virtual reality systems with a reduced value of vergence-accommodation conflict.

Image Speckle Denoising for Securing Internet of Smart Sensors

How to improve utility performance when securing sensitive data is an important research problem in Internet of smart sensors. In this paper, we study secured image speckle denoising for networked synthetic aperture radar (SAR). Speckle noise of SAR affects image quality and has a great influence on target detection and recognition. MSTAR dataset is often used in image target recognition. In this paper, a subregion-based method is proposed in order to improve the accuracy of target recognition and better retain target information while filtering and denoising the image. The new method applies advanced encryption techniques to protect sensitive data against malicious attack. Firstly, the image is divided into marked areas and unmarked areas through edge extraction and hole filling. Secondly, we use different size windows and filtering methods to filter the image in different areas. The experimental results show that the proposed algorithm has obvious advantages over MR-NLM, SSIM-NLM, Frost, and BM3D filtering in terms of equivalent view number and preserving edge and structure.