132 research outputs found
Weakly supervised deep semantic segmentation using CNN and ELM with semantic candidate regions.
The task of semantic segmentation is to obtain strong pixel-level annotations for each pixel in the image. For fully supervised semantic segmentation, the task is achieved by a segmentation model trained using pixel-level annotations. However, the pixel-level annotation process is very expensive and time-consuming. To reduce the cost, the paper proposes a semantic candidate regions trained extreme learning machine (ELM) method with image-level labels to achieve pixel-level labels mapping. In this work, the paper casts the pixel mapping problem into a candidate region semantic inference problem. Specifically, after segmenting each image into a set of superpixels, superpixels are automatically combined to achieve segmentation of candidate region according to the number of image-level labels. Semantic inference of candidate regions is realized based on the relationship and neighborhood rough set associated with semantic labels. Finally, the paper trains the ELM using the candidate regions of the inferred labels to classify the test candidate regions. The experiment is verified on the MSRC dataset and PASCAL VOC 2012, which are popularly used in semantic segmentation. The experimental results show that the proposed method outperforms several state-of-the-art approaches for deep semantic segmentation
Real-time spatial frequency domain imaging by single snapshot multiple frequency demodulation technique
We have presented a novel Single Snapshot Multiple Frequency Demodulation (SSMD) method enabling single snapshot wide field imaging of optical properties of turbid media in the Spatial Frequency Domain. SSMD makes use of the orthogonality of harmonic functions and extracts the modulation transfer function (MTF) at multiple modulation frequencies and of arbitrary orientations and amplitudes simultaneously from a single structured-illuminated image at once. SSMD not only increases significantly the data acquisition speed and reduces motion artifacts but also exhibits excellent noise suppression in imaging as well. The performance of SSMD-SFDI is demonstrated with experiments on both tissue mimicking phantoms and in vivo for recovering optical properties. SSMD is ideal in the implementation of a real-time spatial frequency domain imaging platform, which will open up SFDI for vast applications in, for example, mapping the optical properties of a dynamic turbid medium or monitoring fast temporal evolutions. © (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only
Single snapshot multiple frequency modulated imaging of subsurface optical properties of turbid media with structured light
We report a novel demodulation method that enables single snapshot wide field imaging of optical properties of turbid media in the Spatial Frequency Domain (SFD). This Single Snapshot Multiple frequency Demodulation (SSMD) method makes use of the orthogonality of harmonic functions to extract the modulation transfer function (MTF) at multiple modulation frequencies simultaneously from a single structured-illuminated image at once. The orientation, frequency, and amplitude of each modulation can be set arbitrarily subject to the limitation of the implementation device. We first validate and compare SSMD to the existing demodulation methods by numerical simulations. The performance of SSMD is then demonstrated with experiments on both tissue mimicking phantoms and in vivo for recovering optical properties by comparing to the standard three-phase demodulation approach. The results show that SSMD increases significantly the data acquisition speed and reduces motion artefacts. SSMD exhibits excellent noise suppression in imaging as well at the rate proportional to the square root of the number of pixels contained in its kernel. SSMD is ideal in the implementation of a real-time spatial frequency domain imaging platform and will open up SFDI for vast applications in imaging and monitoring dynamic turbid medium and processes
In vivo real-time imaging of cutaneous hemoglobin concentration, oxygen saturation, scattering properties, melanin content, and epidermal thickness with visible spatially modulated light
We present the real-time single snapshot multiple frequency demodulation - spatial frequency domain imaging (SSMD-SFDI) platform implemented with a visible digital mirror device that is capable of imaging and monitoring dynamic turbid medium and processes over a large field of view. One challenge in quantitative imaging of biological tissue such as the skin is the complex structure rendering techniques based on homogeneous medium models to fail. To address this difficulty we have also developed a novel method that maps the layered structure to a homogeneous medium for spatial frequency domain imaging. The varying penetration depth of spatially modulated light on its wavelength and modulation frequency is used to resolve the layered structure. The efficacy of the real-time SSMD-SFDI platform and this two-layer model is demonstrated by imaging forearms of 6 healthy subjects under the reactive hyperemia protocol. The results show that our approach not only successfully decouples light absorption by melanin from that by hemoglobin and yields accurate determination of cutaneous hemoglobin concentration and oxygen saturation, but also provides reliable estimation of the scattering properties, the melanin content and the epidermal thickness in real time. Potential applications of our system in imaging skin physiological and functional states, cancer screening, and microcirculation monitoring are discussed at the end. © 2017 Optical Society of Americ
Compensatory Movement of Contralateral Vocal Folds in Patients With Unilateral Vocal Fold Paralysis.
OBJECTIVES(#br)Previous studies of subjects with unilateral vocal fold paralysis (UVFP) as observed in a positron emission tomography-computed tomography (PET-CT) examination have demonstrated false positive results in the contralateral cricoarytenoid, in which the metabolism may be higher. This area may also be the site of contralateral compensatory movement in these patients. In this study, we compared the adduction speed of the contralateral vocal folds in patients with UVFP and in healthy subjects as measured by the stroboscopic laryngoscope frame rate. This study aimed to explore the contralateral compensatory movement of the vocal folds in subjects with UVFP.(#br)METHODS(#br)(1) We collected visual data from 14 patients with UVFP and 14 healthy subjects through a stroboscopic laryngoscope. These subjects were divided into a vocal fold paralysis group and a control group, and we analyzed the excessive adduction of the contralateral vocal folds in the vocal fold paralysis group by examining vocal fold movement speed (pixels/s) as featured in a stroboscopic laryngoscope video. (2) We analyzed the uptake of 18-FDG in the posterior vocal fold from positron emission tomography-computed tomography imaging from four subjects with UVFP and 12 healthy subjects. An independent sample t test and a χ2 test were used to compare data.(#br)RESULTS(#br)Four subjects with UVFP had a higher metabolic rate in the contralateral cricoarytenoid joints, with a significant difference between the two groups, P 0.05.(#br)CONCLUSION(#br)Subjects with UVFP exhibited faster adduction compensation in the contralateral vocal folds, and the contralateral cricoarytenoid joint’s metabolism in subjects with UVFP was higher. These data may help clarify the diagnostic criteria for laryngeal nerve damage
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