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- 摘要
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- 实验方案
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In situ Photoluminescence Study of Plasma Effects on Passivation of Crystalline Silicon Coated with Aluminum Oxide
摘要： A degradation of crystalline silicon surface passivation provided by aluminum oxide (Al2O3) is generally observed after plasma processes, e.g., deposition of amorphous silicon nitride. To minimize such detrimental effect, a better understanding of the interaction between plasma species and the Al2O3 layer is required. Using in situ photoluminescence, the passivation quality of as-deposited and annealed crystalline silicon wafers coated with Al2O3 grown by atomic layer deposition is characterized in real time during argon-hydrogen plasma exposure. The photoluminescence intensity of as-deposited samples instantly steps up after the plasma ignition, and then it gradually decreases as a function of plasma exposure time. However, only degradation of photoluminescence signal can be found if the samples are annealed prior to the plasma treatment. The interaction between vacuum UV light from plasma and different types of chemical bonds in the Al2O3 layer is proposed to explain the obtained results. Understanding the mechanisms and root cause leading to different behavior between as-deposited and annealed samples under plasma exposure is a first step toward redesigning the process flow for better surface passivation.
关键词： in situ photoluminescence,plasma exposure,aluminum oxide,surface passivation
更新于2025-09-23 15:23:52
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Comparison of block-based stereo and semi-global algorithm and effects of pre-processing and imaging parameters on tree disparity map
摘要： One method of creating a 3D model of a tree is stereo vision technique. Tree geometric characteristics have been used to predict yield, fertilizer application in citrus crops, water consumption or biomass. So, a disparity map and 3D model of the tree can be useful. There are different algorithms to match the stereo pair for calculating disparity maps. Many parameters affect the disparity map, such as the lighting that affects camera and imaging parameters, the calibration that needed to rectify the image, etc. In this study, the block-based stereo and semi-global algorithms with 5 implementations were compared to calculate tree disparity maps. Also, the effects of ISO speed, exposure time, metering mode (imaging parameters) and image un-distortion and rectification (pre-processing) were investigated. The results showed that the semi-global algorithm was better than the block-based stereo algorithm. Windows size affected on disparity maps and best results obtained when this parameter was set to default. Maximum disparity value limits search space. Best results obtained in real value. For smaller value than real value, disparity map was not calculated outside that maximum disparity. Therefore, disparities or pixels missed. It observed that image rectifying, ISO speed, exposure time and metering mode were affected on disparity map. When pictures did not rectify, disparity map calculated but with some errors. Camera parameters were affected on light intensity of pictures. Best disparity map obtained in conditions that ISO speed and exposure time had fewer value and metering mode was set to pattern mode and these parameters were similar for both left and right images.
关键词： ISO speed,Exposure time,Rectify,Disparity map,Semi-global matching,Tree
更新于2025-09-23 15:23:52
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Current Status of Patient Radiation Exposure of Cardiac Positron Emission Tomography and Single-Photon Emission Computed Tomographic Myocardial Perfusion Imaging
摘要： BACKGROUND: Radiation exposure during nuclear cardiology procedures has received much attention and has prompted citations for radiation reduction. In 2010, the American Society of Nuclear Cardiology recommended reducing the average patient study radiation exposure to <9 mSv in 50% of studies by 2014. Cardiac positron emission tomography (PET) for myocardial perfusion imaging (MPI) has emerged within recent years, but current radiation exposure in cardiac nuclear PET laboratories is unknown. This study evaluated current reported patient radiation exposure from nuclear laboratories in the United States applying for Intersocietal Accreditation Commission accreditation for MPI using single photon emission computed tomography (SPECT) or PET. METHODS AND RESULTS: This was an analysis of nuclear cardiology studies submitted to the Intersocietal Accreditation Commission for either or both cardiac PET and SPECT accreditation. Cardiac SPECT data represented year 2015 while PET data combined years 2013 to 2015. Data was analyzed with χ2 and Mann-Whitney U tests (reported as median, 25th percentile, and 75th percentile). Reported PET MPI radiation exposure for 111 laboratories (532 patient cases) was 3.7 (3.2–4.1) mSv per study with no geographic variation. Reported SPECT MPI radiation exposure for 665 laboratories (3067 patient studies) was 12.8 (12.2–14.3) mSv. Highest radiation exposure was found in the South region. Technetium-only studies resulted in a median of 12.2 mSv per study. CONCLUSIONS: Radiation exposure from cardiac PET MPI in US laboratories applying for Intersocietal Accreditation Commission accreditation is low (111 laboratories, 3.7 mSv) and substantially lower than cardiac SPECT (665 laboratories, 12.8 mSv).
关键词： technetium,accreditation,myocardial perfusion imaging,positron emission tomography,radiation exposure
更新于2025-09-23 15:23:52
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Controllable Motion-Blur Effects in Still Images
摘要： Motion blur in a photo is the consequence of object motion during the image acquisition. It results in a visible trail along the motion of a recorded object and can be used by photographers to convey a sense of motion. Nevertheless, it is very challenging to acquire this effect as intended and requires much experience from the photographer. To achieve actual control over the motion blur, one could be added in a post process but current solutions require complex manual intervention and can lead to artifacts that mix moving and static objects incorrectly. In this paper, we propose a novel method to add motion blur to a single image that generates the illusion of a photographed motion. Relying on a minimal user input, a filtering process is employed to produce a virtual motion effect. It carefully handles object boundaries to avoid artifacts produced by standard filtering methods. We illustrate the effectiveness of our solution with various complex examples, including multi-directional blur, reflections, multiple objects, and illustrate how several motion-related artistic effects can be achieved. Our post-processing solution is an alternative to capturing the intended real-world motion blur directly and enables fine-grained control of the motion-blur effect.
关键词： post-production,long exposure,motion blur,image processing
更新于2025-09-23 15:22:29
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Reducing radiation exposure in an electrophysiology lab with introduction of newer fluoroscopic technology
摘要： The use of fluoroscopic devices exposes patients and operators to harmful effects of ionizing radiation in an electrophysiology (EP) lab. We sought to know if the newer fluoroscopic technology (Allura Clarity) installed in a hybrid EP helps to reduce prescribed radiation dose. We performed radiation dose analysis of 90 patients who underwent various procedures in the EP lab at a community teaching hospital after the introduction of newer fluoroscopic technology in June of 2016. Watchman device insertion, radiofrequency ablation procedures, pacemaker permanent (PPM)/implantable cardioverter defibrillator (ICD) placement and battery changes were included in the study to compare radiation exposure during different procedures performed commonly in an EP lab. In all cases of watchman device placement, radiofrequency ablation procedures, PPM/ICD placement and battery changes, there was a statistically significant difference (<0.05) in radiation dose exposure. Significant reduction in radiation exposure during various procedures performed in an EP lab was achieved with aid of newer fluoroscopic technology and better image detection technology.
关键词： watchman device,permanent pacemaker,Radiation exposure,insertable cardioverter defibrillator,electrophysiology lab,newer fluoroscopic system,radiofrequency ablation
更新于2025-09-23 15:22:29
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Robust artifact-free high dynamic range imaging of dynamic scenes
摘要： The irradiance range of the real-world scene is often beyond the capability of digital cameras. Therefore, High Dynamic Range (HDR) images can be generated by fusing images with different exposure of the same scene. However, moving objects pose the most severe problem in the HDR imaging, leading to the annoying ghost artifacts in the fused image. In this paper, we present a novel HDR technique to address the moving objects problem. Since the input low dynamic range (LDR) images captured by a camera act as static linear related backgrounds with moving objects during each individual exposures, we formulate the detection of foreground moving objects as a rank minimization problem. Meanwhile, in order to eliminate the image blurring caused by background slightly change of LDR images, we further rectify the background by employing the irradiances alignment. Experiments on image sequences show that the proposed algorithm performs significant gains in synthesized HDR image quality compare to state-of-the-art methods.
关键词： Multi-exposure fusion,High dynamic range imaging,Rank minimization,Motion blur,Optical flow,Ghost removal
更新于2025-09-23 15:22:29
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An innovative technique for real-time adjusting exposure time of silicon-based camera to get stable gray level images with temperature evolution
摘要： Silicon-based sensor cameras are known to be sensitive in the near infrared spectral range, in which a small temperature variation leads to a large modi?cation in the image gray level. It induces acquired images with local saturation or poor dynamic range of gray levels. In order to address this problem, the present study proposes an innovative technique to precisely and automatically adjust the exposure time to obtain stable gray level images when the temperature evolution occurs on the surface of the observed object. Two algorithms, including linear algorithm and Planck’s algorithm, are proposed to predict the exposure time to obtain stable gray level images. Blackbody heating experiment is conducted to validate the accuracy of these two algorithms, and the result indicates that stable gray level images can be obtained using Planck’s algorithm. Moreover, this technique is applied to the specimen heating experiment, and the stable gray level images can also be obtained using Planck’s algorithm. These two experimental results prove that the technique is effective and reliable. Finally, the thermal ?elds are reconstructed on images of blackbody.
关键词： Silicon-based camera,Exposure time adjustment,Thermal ?eld,Planck’s algorithm
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 3rd Advanced Information Technology, Electronic and Automation Control Conference (IAEAC) - Chongqing, China (2018.10.12-2018.10.14)] 2018 IEEE 3rd Advanced Information Technology, Electronic and Automation Control Conference (IAEAC) - A Fast Fusion Method for Multi-exposure Image in YUV Color Space
摘要： Using multiple exposures fusion to obtain high dynamic images of very large dynamic scenes, the traditional multi-resolution fusion method based on RGB color space has some shortcomings, such as low efficiency and color shift. In this paper, a method of multi-exposure fusion in YUV color space is proposed. The multi-resolution fusion based on Laplacian pyramid is carried out on Y channel, and the contrast factor and color degree factor are introduced to construct the weight map of the fusion. The maximum value of UV channel is taken to avoid color weakening caused by weighted fusion of color components. Finally, an objective evaluation of the fusion algorithm is carried out through experiments. Compared with the multi-resolution fusion based on Laplacian pyramid in traditional RGB color space, the color obtained by this method is more abundant, and the fusion time is about one-third of the traditional method.
关键词： Fast fusion,Multi-exposure fusion,YUV color space,HDR,Lapulacian pyramid
更新于2025-09-23 15:22:29
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[IEEE 2018 25th IEEE International Conference on Image Processing (ICIP) - Athens, Greece (2018.10.7-2018.10.10)] 2018 25th IEEE International Conference on Image Processing (ICIP) - Reduction of Poisson Noise in Coded Exposure Photography
摘要： Coded exposure photography (CEP), originally proposed by Raskar et al., has been known as one of the promising techniques for motion deblurring. In this area, much efforts have been made for designing a fluttered shutter sequence to shape the spectrum of a uniformly motion-blurred image into an invertible one. Since the duty cycle of the fluttered shutters proposed thus far is generally low, the number of photons entering into an image sensor is reduced, which leads to a large Poisson noise in a low lighting condition. In the existing design techniques for the fluttered shutter, an increase of the duty cycle leads to a failure in the motion deblurring due to the singularities in the Fourier domain. To overcome the difficulty, this paper proposes a new motion deblurring framework using a higher duty-cycle fluttered shutter and a compressed sensing technique. The experimental results given in this paper demonstrate that the proposed technique is advantageous over a conventional one, in particular in a low lighting condition.
关键词： coded exposure photography,fluttered shutter,compressed sensing,image recovery,motion deblurring
更新于2025-09-23 15:22:29
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[ACM Press the 2nd International Conference - Chengdu, China (2018.06.16-2018.06.18)] Proceedings of the 2nd International Conference on Advances in Image Processing - ICAIP '18 - A Novel Experimental Technique for Recovering Camera Response Function for High Dynamic Range Imaging
摘要： Recovering the camera’s response function has wide application in computational photography and computer vision. Traditional computational approach using multiple differently exposed photographs is based on solving a constrained linear least square problem and can only recover the function up to a scaling factor. In this paper, we present a novel experiment based technique to recover the true response curves of specific sensors. Our method first measures the average pixel intensities of a neutrally-grey cardboard for the full range of the shutter speed and gain control values of the sensor. After a simple data smoothing procedure, the camera’s response function is recovered through simple table look-up. We have implemented our technique on different kinds of sensors and show that it works well. The new technique recover the actual range of the sensor and is more accurate than the computational technique. The procedure is easy to set up and simple to implement which will be useful for developing applications such as High Dynamic Ranging (HDR) imaging.
关键词： Exposure,Camera Response Curve,HDR
更新于2025-09-23 15:22:29