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The voltage waveform applied in the reset period has been modified to lower the background light, which is one of the causes of the image quality degradation in the AC plasma display panel. In gene...

The aim was to improve single-photon emission computed tomography (SPECT) quality for sparsely acquired 111In projections by adding deep learning generated synthetic intermediate projections (SIPs). Method: The recently constructed deep convolutional network for generating synthetic intermediate projections (CUSIP) was used for improving 20 sparsely acquired 111In-octreotide SPECTs. Reconstruction was performed with 120 (120P) or 30 (30P) projections, or 120 projections with 90 SIPs generated from 30 projections (30–120SIP). The SPECT reconstructions were performed with attenuation, scatter and collimator response corrections. Postfiltered 30P reconstructed SPECT was also analyzed. Image quality were quantitatively evaluated with root-mean-square error, peak signal-to-noise ratio and structural similarity index metrics. Result: The 30–120SIP reconstructed SPECT had statistically significant improved image quality parameters compared to 30P reconstructed SPECT with and without post filtering. The images visual appearance was similar to slightly filtered 120P SPECTs. Thereby, substantial acquisition time reduction with SIPs seems possible without image quality degradation.

Photoacoustic computed tomography (PACT) is an emerging hybrid imaging modality which can noninvasively reconstruct high-resolution and high-contrast images in deep tissues. However, due to the presence of acoustic heterogeneities within biological tissues, most existing image reconstruction algorithms based on the assumption of constant speed of sound (SOS) will cause image artifacts and distortions. In this paper, to account for the effects of acoustic heterogeneity in PACT image reconstruction, we introduce ultrasound computed tomography (USCT) to provide detailed SOS distribution of the biological tissues and coupling media. Numerical simulation shows that if the variation of SOS is small enough, image reconstruction algorithm with a constant SOS assumption could produce visually acceptable results; otherwise, significant image artifacts and distortions would appear. While with the aid of USCT, image artifacts induced by acoustic heterogeneity in PACT would be effectively suppressed. Since image artifacts and distortions are common image quality degradation factors in PACT, the proposed technique is expected to expedite the development of high-performance imaging, which is essential for widespread applications of PACT.

In wide-field telescopes, relatively small misalignments in the optical system can cause large aberrations. The nominal system is normally designed to show a good optical performance over the whole field of view but, in presence of misalignments, the symmetry is broken and the aberrations increase towards the edge of the field. No new aberrations arise, but the known aberrations behave differently and originate multiple nodes, according to the Nodal Aberration Theory. The effects, in terms of image quality degradation, can be especially deleterious for wide-field imagers. This issue can be studied in detail by the ray-tracing programs that are normally adopted for the optical design. Nevertheless, these codes are not optimal for applications where a high execution speed is needed. Here, an application of PSF reconstruction for a wide-field telescope by using an integrated modeling approach is presented. Ray-tracing data are adopted as input to build a fully analytical model. The example of the VST telescope (1x1 deg field of view) is discussed as a case study.

Robust watermarking is a widely used technology to protect image copyright. Robustness, the ability to resist various distortions, is the most important property of robust watermarking algorithm. So to improve the robustness of the watermarking schemes, watermark attacking algorithms also attract much attention. Far from now, the existing watermarking attack methods cannot well balance the removal ability and visual quality. To address this issue, this paper proposed a removal attack by a convolutional neural network (CNN). Considering the speed requirements of real-time attack applications, for short computing time, we use a simple but powerful CNN. According to the amount of knowledge of watermarking, a corresponding dataset of watermark images is constructed. After that, the CNN model is trained to remove watermark with these datasets. The experiments show that the trained model can not only effectively remove the watermark, but also recover the original image without much image quality degradation.

Advances in image quality research have shown the benefits of modeling functional components of the human visual system in image quality metrics. Recently, visual saliency, an important aspect of the human visual system, is increasingly investigated in relation to visual quality perception. Existing studies have showed that incorporating visual saliency leads to improved performance of image quality metrics. However, current applications of visual saliency in image quality metrics mainly focus on the extension of a specific metric with a specific visual saliency model. Issues regarding the optimal use of visual saliency in image quality metrics remain. Psychophysical experiments conducted in the literature have revealed that visual artifacts occurring in an image can change fixation deployment relative to that of the image without distortion. As such, instead of using saliency models as add-ons to image quality metrics, we explored the approach of directly assessing image quality by measuring the visual saliency deviation triggered by visual artifacts. We first analyzed the relationship between visual saliency deviation and image quality degradation on the basis of a large-scale eye-tracking dataset. A saliency deviation-based image quality index was then devised. Experimental results showed that the proposed metric features high prediction accuracy and relatively low computational cost.

Soil is a highly scattering media that inhibits imaging of plant-microbial-mineral interactions that are essential to plant health and soil carbon sequestration. In this work, we seek to overcome the fundamental challenges of imaging through soil minerals by developing a custom wavefront sensor-less adaptive optics (AO) system for a multiphoton microscope. We are using a combined experimental and modeling approach, characterizing mineral optical characteristics with scatterometry, modeling the wavefront distortion and the image quality degradation after imaging through the soil medium, simulating the image quality improvement with AO correction, and experimentally testing our models with a stand-alone AO testbed.

Depth distortion in an image yields some geometric errors which leads certain image quality degradation. Therefore, it is important to enhance the depth information in the left as well as right stereo images and achieve them in a substantial way. The Disparity Map Acquisition (DMA) algorithm gives rise to the depth distortion with improved disparity matrix. In this paper, we emphasis on depth score enhancement in 3D stereo images retargeting to accomplish the acceptable 3D images with improved depth distortion score. The experimental results show the stereo seam carving which deconsideres the unwanted image patches in order to generate an acceptable 3D stereo images. The obtained 3D stereo images are widely used in the applications of 3D animated movies by abolishing the blurriness in the stereo images and generate the images where the users can relish with the better visual effects. This may lead to the non-usability of 3D sterilize googles and eventually helps and reduces the burden on Indian economy.

Holographic display is widely known for aberration correction capability. In this paper, we analyze the image quality degradation when aberration is present in the holographic display system. Though built with lenses with minimal aberrations, it is inevitable from undesirable error when perceived with an usual eye. Thus, we mainly analyze holographic image quality in two cases: when eye gets defocused and rotated. In simulation, accommodation-dependent schematic eye model is utilized for precise acquisition of aberration-corrected hologram. The hologram acquired with ray tracing is assessed with the bench-top prototype of holographic near-eye display.

Underwater images provide the most information for man-machine collaboration of underwater operations, however severe image quality degradation due to light absorption and scattering in water medium with suspended matter greatly affects efficiency to preceive the surrounding environment. In this paper, we develop a system for fast underwater enhancement to assist efficient underwater operations by giving more detailed and clear vision information. It uses auto multi-thread method to squeeze computing ability of hardware by creating a optimal number of processing threads considering both consistency and real time. And it is flexible to apply other algorithms or methods with a few changes as it is a method irrelavant framework and it can improve their efficiency.

The recent commercialization of virtual reality (VR) has led to various studies in multiple fields that can apply VR technologies, including gaming, design, and virtual experiences. However, when a VR system transmits images through a display located close to the eyes of the user, image output problems, such as image quality degradation and processing speed limitation, could result in a gap between reality and virtual reality, as well as reduce user immersion. Thus, in this study, we have developed an improved image processing algorithm that enhances image sharpness and processing speed to alleviate the user immersion problem in VR environments.

Effective compression technology is required to reduce the huge amount of information for integral three-dimensional (3D) television. For compressing an integral 3D image, we propose a compression method of converting elemental images to multiview images and of applying multiview video coding to part of the multiview images and their depth maps. In this method, the relationship between the number of the part of the multiview images and the image quality degradation of a reconstructed 3D image was studied by subjective evaluation experiment, and we confirmed the amount of information required for displaying an acceptable reconstructed 3D image. As a result, the reconstructed 3D images with acceptable image quality were obtained with about 2/9 times the amount of information for coding all the multiview images converted from the elemental images.

X-ray scatter is a major cause of image quality degradation in dimensional CT. Especially, in case of highly attenuating components scatter-to-primary ratios may easily be higher than 1. The corresponding artifacts which appear as cupping or dark streaks in the CT reconstruction may impair a metrological assessment. Therefore, an appropriate scatter correction is crucial. Thereby, the gold standard is to predict the scatter distribution using a Monte Carlo (MC) code and subtract the corresponding scatter estimate from the measured raw data. MC, however, is too slow to be used routinely. To correct for scatter in real-time, we developed the deep scatter estimation (DSE). It uses a deep convolutional neural network which is trained to reproduce the output of MC simulations using only the acquired projection data as input. Once trained, DSE can be applied in real-time. The present study demonstrates the potential of the proposed approach using simulations and measurements. In both cases the DSE yields highly accurate scatter estimates that differ by

Image deblurring under impulse noise is a typical ill-posed problem which requires regularization methods to guarantee high-quality imaging. L1-norm data-fidelity term and total variation (TV) regularizer have been combined to contribute the popular regularization method. However, the TV-regularized variational image deblurring model often suffers from the staircase-like artifacts leading to image quality degradation. To enhance image quality, the detailpreserving total generalized variation (TGV) was introduced to replace TV to eliminate the undesirable artifacts. The resulting nonconvex optimization problem was effectively solved using the alternating direction method of multipliers (ADMM). In addition, an automatic method for selecting spatially adapted regularization parameters was proposed to further improve deblurring performance. Our proposed image deblurring framework is able to remove blurring and impulse noise effects while maintaining the image edge details. Comprehensive experiments have been conducted to demonstrate the superior performance of our proposed method over several state-of-the-art image deblurring methods.

The loss in contrast-discrimination ability of the human visual system under high ambient illumination level can cause image quality degradation in mobile phones. In this paper, we propose a perceived contrast compensation method by processing the original displayed image. With consideration that the perceived contrast significantly varies across the image, this method extracts the local band contrast from the original image; it then compensates these contrast components to counteract the perceived contrast degradation. Experimental results demonstrate that this method can maintain most contrast details even in high ambient illumination levels.

We have developed a new 7-inch WQXGA RGBW mobile LCD with local dimming backlight technology. This panel achieves a 20% power reduction compared to that of the prior RGBW displays, with no image quality degradation. It also realizes contrast improvement and a total module thickness of 1.16mm.

Residual stresses inside molded glass lenses contribute to image quality degradation. In this research, a circular polariscope was employed to investigate the residual stresses inside molded glass lenses. Residual stresses were calculated from optical measurements obtained by using of the circular polariscope. From the measurements both the magnitude and distribution of residual stresses in a molded glass lens were obtained.

This paper described various blur detection methods along with proposed method. Digital photos are massively produced while digital cameras are becoming popular; however, not every photo has good quality. Blur is one of the conventional image quality degradation which is caused by various factors like limited contrast; inappropriate exposure time and improper device handling indeed, blurry images make up a significant percentage of anyone's picture collections. Consequently, an efficient tool to detect blurry images and label or separate them for automatic deletion in order to preserve storage capacity and the quality of image collections is needed. There are various methods to detect the blur from the blurry images some of which requires transforms like DCT or Wavelet and some doesn‟t require transform.

In this paper, the impact of the gradient delay and its anisotropy on FSE-MRI was studied. It is shown by experiments that FSE imaging sequence is sensitive to uncorrected gradient delay. A simple correction method of this problem is proposed, in which the delay of the gradient waveform is compensated by shifting the gradient waveform directly. We have demonstrated that the proposed method is effective to overcome the image quality degradation cause by the gradient delay. The correction does not depend on specific samples or subjects and total delay can be used without recalibrating in each scan.

Three-dimensional (3D) whole heart techniques form a cornerstone in cardiovascular magnetic resonance imaging of congenital heart disease (CHD). It offers significant advantages over other CHD imaging modalities and techniques: no ionizing radiation; ability to be run free-breathing; ECG-gated dual-phase imaging for accurate measurements and tissue properties estimation; and higher signal-to-noise ratio and isotropic voxel resolution for multiplanar reformatting assessment. However, there are limitations, such as potentially long acquisition times with image quality degradation. Recent advances in and current applications of 3D whole heart imaging in CHD are detailed, as well as future directions.

Sacrificing exact calculations to improve digital circuit performance is at the foundation of approximate computing. In this paper, an approximate multiply-and-accumulate (MAC) unit is introduced. The MAC partial product terms are compressed by using simple OR gates as approximate counters; moreover, to further save energy, selected columns of the partial product terms are not formed. A compensation term is introduced in the proposed MAC, to reduce the overall approximation error. A MAC unit, specialized to perform 2D convolution, is designed following the proposed approach and implemented in TSMC 40nm technology in four different configurations. The proposed circuits achieve power savings more than 60%, compared to standard, exact MAC, with tolerable image quality degradation.

Compression molding of glass optics is gradually becoming a viable fabrication technique for high precision optical lenses. However, refractive index variation was observed in compression molded glass lenses, which would contribute to image quality degradation. In this research, annealing experiments were applied to control the refractive index variation in molded glass lenses. The refractive index variations pre and post annealing experiment in molded lenses were measured by an experiment setup based on Mach-Zehnder interferometer. The experimental results showed that the refractive index variation can be controlled providing that a proper cooling process is applied during cooling.

Cardiac and respiratory motion cause image quality degradation in PET imaging, affecting diagnostic accuracy of the images. Whole-body simultaneous PET-MR scanners allow for using motion information estimated from MR images to correct PET data and produce motion-compensated PET images. This article reviews methods that have been proposed to estimate motion from MR images and different techniques to include this information in PET reconstruction, in order to overcome the problem of cardiac and respiratory motion in PET-MR imaging. MR-based motion correction techniques significantly increase lesion detectability and contrast, and also improve accuracy of uptake values in PET images.

This paper clarifies the relationship between image quality and accommodation in human vision through two types of experiments. One examines how image-quality degradation influences the accommodation mechanism, and the other examines which type of information of quality-degraded images activates the accommodation mechanism. Actually, accommodative responses are measured using an infrared optometer while subjects are subjectively evaluating sharpness, noise, and pseudo-contours and while they are observing sine, square, and missing fundamental (MF) square waves. The following results were derived: (1) the accommodation lag increases as the degree of sharpness is degraded regardless of the tone-reproducing methods; (2) the accommodation lag decreases considerably in the existence of noise or pseudo-contours, whereas it increases for uniform or gently curved planes; (3) the spatial features of presented images activate the accommodation mechanism. These results suggest that accommodative responses influence human subjective judgments as well as being a human factor related closely to image quality and that the spatial features of quality-degraded images underlie human subjective judgments. In other words, they imply that objective image-quality evaluation metrics should satisfy the following two conditions: the incorporation of the accommodation characteristics into such metrics and the formulation of such metrics in the spatial region.

In order to realize the measurement for Modulation Transfer Function(MTF) of an on-orbit hyperspectral remote sensing system,factors of image quality degradation of the system were analyzed and the detection method for MTF was discussed by taking the dispersive hyperspectral remote sensing system for an example.Firstly,the three-dimensional separability of the MTF of the dispersive hyperspectral remote sensing system was illustrated.Then,an anti-noise MTF detecting technique was proposed concerning the charateristic of the low signal-to-noise ratio of the hyperspectral remote sensing system.A criterion of selecting MTF detection region was also proposed based on the large quantity of the bands in hyperspectral systems.Finally,the proposed methods were demonstrated by using the PHI remote sensing images and the PHI degraded images were restored with the detected MTF.Experimental results indicate that the average gradient has been improved by 67.1% and the detail-signal energy improved by 65.2%,which proves the effectiveness of the proposed method.

We are completing the construction of GIANO, a high resolution near-infrared cryogenic spectrograph for the Telescopio Nazionale Galileo (TNG). Most of the optics are made of aluminium and operate at cryogenic temperature. We evaluated the optical degradation due to mis-matches between the thermal expansion coefficients of the different aluminium parts of the instrument. We performed accurate measurements of the relative thermal expansion coefficients (CTE) of Al-6061 and Al-6082 over the 300–77 K temperatures range. We find that the two alloys have identical thermal expansion coefficient within a maximum (3σ) uncertainty of Δα/α

The European Solar Telescope, EST , ([1], [2]) is a 4-meter solar telescope to be built in the Canary Islands in the near future. In order to select the best configuration for the EST telescope facilities, thermal and CFD analyses have been carried out to evaluate the seeing degradation produced by the telescope environment. The aim of this study is to calculate the values of optical parameters in different configurations and to find out which one causes the lowest image quality degradation. Starting from the determination of seeing degradation along the optical path by CFD techniques, several configurations have been compared making it possible to decide the future development line for the EST .

In this paper, we present one simplify underwater image restoration model combined with Total variation (TV) regularized Richardson-Lucy (RL) algorithm. Poor visibility in the sea and the variations in the illumination, viewpoints, etc., have been comprehensively taken into consideration for image restoration. An adaptive image restoration strategy by Improvement signal-to-noise ratio (ISNR) is then made full use of to undertake the underwater image restoration. A non-reference restored image quality evaluation criterion called relative gray mean grads (RGMG) is defined on the basis of other evaluation criterion called gray mean grads (GMG). It is shown in the simulation experiment that the proposed approach could achieve great performances in both robustness and effectiveness, with good behaviors in the vision effects and matching precision for the underwater images.

To investigate whether gadoxetate disodium affects peripheral capillary oxygen saturation (SpO2) and/or heart rate (HR) during dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging in patients with liver diseases.This retrospective study was approved by the institutional review board, who waived the requirement for informed consent. Four hundred fifty-eight patients (171 women [mean age, 66.5 years; range, 23-87 years] and 287 men [mean age, 61.1 years; range, 25-89 years]) who underwent liver DCE MR imaging with gadoxetate disodium (0.025 mmol per kilogram of body weight) from October 28, 2013, to June 24, 2014, were included in this study. They were monitored for SpO2 and HR during DCE MR imaging. Motion artifact severity was graded by using a five-point scale, and transient severe motion (TSM) was defined by a score of at least 4. The association between TSM and baseline predictors was assessed, and HR and SpO2 at each postcontrast phase were compared with those at the precontrast phase in the TSM and non-TSM groups.Four hundred thirty-six patients were included in the non-TSM group, and 22 were included in the TSM group. Although the motion score was the worst at the arterial phase, the observed mean differences in SpO2 and HR between the precontrast phase and the arterial phase were less than 1% and 5 beats per minute, respectively (mean SpO2 ± standard deviation for the non-TSM group, 96.7% ± 1.8 vs 96.9% ± 1.8 [P = .11]; SpO2 for the TSM group, 96.4% ± 1.6 vs 96.1% ± 1.6 [P.99]) (HR for the non-TSM group, 68.9 beats per minute ± 12.4 vs 70.9 beats per minute ± 12.1 [P.0001]; HR for the TSM group, 75.0 beats per minute ± 11.8 vs 79.9 beats per minute ± 10.2 [P.0001]).Intravenous gadoxetate disodium (a weight-based dose) does not cause changes in SpO2 and HR that lead to image quality degradation.

An enormous number of images are currently shared through social networking services such as Facebook. These images usually contain appearance of people and may violate the people's privacy if they are published without permission from each person. To remedy this privacy concern, visual privacy protection, such as blurring, is applied to facial regions of people without permission. However, in addition to image quality degradation, this may spoil the context of the image: If some people are filtered while the others are not, missing facial expression makes comprehension of the image difficult. This paper proposes an image melding-based method that modifies facial regions in a visually unintrusive way with preserving facial expression. Our experimental results demonstrated that the proposed method can retain facial expression while protecting privacy., ICME 2015 : IEEE International Conference on Multimedia and Expo , Jun 29-Jul 3, 2015 , Torino, Italy

The investigated hypothesis is that quantization of the transmit delay profiles degrades the image quality in plane wave ultrasound imaging. Simulated point spread functions show that transmit delay profile quantization gives rise to artefacts behind the point target. The axial and lateral 6 dB resolution is unaffected, but contrast is reduced. This is quantified by a 20 dB cystic resolution of 1.23 mm compared to 0.53 mm for the ideal (non-quantized) case at 10 mm depth. It is also shown that providing individually phase-shifted excitation waveforms to each element restores the image quality, as seen by the 20 dB cystic resolution being restored to 0.53 mm. The impact on high-quality imaging is discussed.

Cross-sectional imaging utilizing computed tomography (CT) and magnetic resonance (MR) imaging have become routine components in the imaging assessment of patients with musculoskeletal disease. Unfortunately, in the setting of a postoperative orthopedic patient with associated orthopedic metallic instrumentation, these imaging techniques are prone to artifacts resulting in image quality degradation. An understanding of the physical basis of such metal-related artifacts, and their appearance on CT and MR imaging, has led investigators to the implementation of a series of techniques and modifications to imaging protocols to decrease CT and MR imaging artifacts in the vicinity of metallic instrumentation. Utilizing such modified imaging techniques, consistent, improved CT and MR image quality may be achieved in imaging of the postoperative orthopedic patient.

Purpose To evaluate the effect of pupil size, degree of intraocular lens (IOL) decentration, and rotation of 4 aspheric toric IOLs on the image quality. Setting Department of Ophthalmology, Seoul St. Mary's Hospital, Seoul, South Korea. Design Experimental study. Methods Four aspheric toric intraocular lenses (IOLs)—the Precizon (transitional conic toric IOL), AT Torbi 709M (bitoric IOL), SN6AT4 (posterior toric surface IOL), and ZCT225 (anterior toric surface IOL)—were evaluated using the optical bench metrology system. Measurements included changes in spherical aberrations, relative spherical equivalent (SE), and image quality at different pupil diameters and image quality degradation due to decentration and rotation of the IOLs. Results Change in relative SE with pupil size in aberration-free toric IOLs (transitional conic toric and bitoric IOLs) was greater than in negatively aspheric toric IOLs (posterior toric surface and anterior toric surface IOLs). In contrast, the aberration-free IOLs showed higher contrast than the negatively aspheric IOLs. When IOLs were decentered by 1.0 mm, the contrast reduction rates at 17.6 cycles per degree for the transitional conic toric IOL, bitoric IOL, posterior toric surface IOL, and anterior toric surface IOL were 5.1%, 3.1%, 12.2%, and 15.8%, respectively. Rotation-induced deterioration of contrast to 0.5 required a much higher rotation for the transitional conic toric IOL than for the other 3 IOLs. Conclusions The transitional conic toric IOL and bitoric IOL provided superior image quality despite pupil size changes and the presence of decentration. The transitional conic toric IOL demonstrated maximum rotation tolerance compared with the other IOLs. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

As the numerical aperture (NA) increasing and process factor k 1 decreasing in 193nm immersion lithography, polarization aberration (PA) of projection optics leads to image quality degradation seriously. Therefore, this work proposes a new scheme for compensating polarization aberration. By simulating we found that adjusting the illumination source partial coherent factors σ out is an effective method for decreasing the PA induced pattern critical dimension (CD) error while keeping placement error (PE) within an acceptable range. Our simulation results reveal that the proposed method can effectively compensate large PA in actual optics.

The polar format algorithm (PFA) is widely used in spotlight synthetic aperture radar image formation. In PFA, the range curvature effect is the main factor that causes geometric distortion of the image and limits the size of the scene that can be well focused. This paper presents a new algorithm for the geometric distortion correction. Analysis and simulation results show that the new algorithm is computationally efficient without image quality degradation.