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- 2017
- spectral reconstruction
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- Optoelectronic Information Science and Engineering
- BITTT
- Zhejiang University
- Guilin University of Aerospace Technology
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Tattoo Inks EM Characterization for MRI Interaction Evaluation
摘要： The lack of knowledge about the safety implications of tattooed individuals subjected to Magnetic Resonance Imaging (MRI) may, sometimes, lead to an exaggerate reaction from physicians such as the avoidance of the exam for tattooed patients. To explore the actual risks, in this work, the magnetic and electrical properties of five different tattoo inks have been measured to investigate their interaction with the MRI electromagnetic (EM) fields. Results highlight that the magnetic and electrical behaviour strongly depend on the type of analyzed ink. Magnetic measurements also reveal a different response between the ink solutions and the relative pigments.
关键词： Magnetic Resonance Imaging,electrochemical impedance,magnetization measurements,tattoo ink,Electrical conductivity,tattoo pigment
更新于2025-09-23 15:23:52
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[IEEE 2018 Colour and Visual Computing Symposium (CVCS) - Gj?vik (2018.9.19-2018.9.20)] 2018 Colour and Visual Computing Symposium (CVCS) - Evaluation of Color Correction Methods for Printed Surfaces
摘要： Achieving truthful reproduction of color is a well-known problem for printing applications. In this paper, we evaluate different methods for camera color calibration, within the scope of a moving image acquisition system. The acquisition device consists of a RGB camera and two fixed tungsten lamps. Our goal is to determine the most robust end-to-end framework given the acquisition conditions. We tested some color mapping methods commonly mentioned in the literature and made modifications to our specific needs. Our modified 3D lookup table (LUT) based method performs the best in the given conditions with future possibilities of hybrid LUTs combining the best performing aspects of different types of LUTs.
关键词： color correction,camera calibration,color calibration,color imaging
更新于2025-09-23 15:23:52
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Identification and imaging of miR-155 in the early screening of lung cancer by targeted delivery of octreotide-conjugated chitosan-molecular beacon nanoparticles
摘要： Lung cancer is still the most common cancer globally. Early screening remains the key to improve the prognosis of patients. There is currently a lack of specific and sensitive methods for early screening of lung cancer. In recent years, studies have found that microRNA plays an important role in the occurrence and development of lung cancer and become a biological target in the early diagnosis of lung cancer. In this study, lung cancer cells, subcutaneous xenografts of lung cancer in nude mice, and Lox-Stop-lox K-ras G12D transgenic mice were used as models. The transgenic mice displayed the dynamic processes from normal lung tissue to atypical hyperplasia, adenomas, carcinoma in situ and lung adenocarcinoma. It was found that miR-155 and somatostatin receptor 2 (SSTR2) were expressed in all the disease stages of transgenic mice. Through molecular beacon (MB) technology and nanotechnology, chitosan-molecular beacon (CS-MB) nanoparticles and targeted octreotide (OCT) were conjugated and synthesized. The octreotide-conjugated chitosan-molecular beacon nanoparticles (CS-MB-OCT) can specifically bind to SSTR2 expressed by the lung cancer cells to achieve the goal of identification of lung cancer cells and imaging miR-155 in vivo and in vitro. Fluorescence imaging at different disease stages of lung cancer in Lox-Stop-lox K-ras G12D transgenic mice was performed, and could dynamically monitor the occurrence and development of lung cancer by different fluorescence intensity ranges. The current research, in turn, provides new idea, new method, and new technology for the early screening of lung cancer.
关键词： chitosan nanoparticles,molecular imaging,molecular beacon,Lung cancer,microRNA-155
更新于2025-09-23 15:23:52
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Mouse optical imaging for understanding resting-state functional connectivity in human fMRI
摘要： Resting-state functional connectivity (FC), which measures the temporal correlation of spontaneous hemodynamic activity between distant brain areas, is a widely accepted method in functional magnetic resonance imaging (fMRI) to assess the connectome of healthy and diseased human brains. A common assumption underlying FC is that it reflects the temporal structure of large-scale neuronal activity that is converted into large-scale hemodynamic activity. However, direct observation of such relationship has been difficult. In this commentary, we describe our recent progress regarding this topic. Recently, transgenic mice that express a genetically encoded calcium indicator (GCaMP) in neocortical neurons are enabling the optical recording of neuronal activity in large-scale with high spatiotemporal resolution. Using these mice, we devised a method to simultaneously monitor neuronal and hemodynamic activity and addressed some key issues related to the neuronal basis of FC. We propose that many important questions about human resting-state fMRI can be answered using GCaMP expressing transgenic mice as a model system.
关键词： mouse,calcium imaging,functional connectivity,fMRI,resting-state
更新于2025-09-23 15:23:52
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Optical Sensing of Broadband RF Magnetic Field Using a Micrometer-Sized Diamond
摘要： High-resolution ?eld imaging with minimized invasiveness is of growing interest with the development of radio frequency (RF) integrated circuits and planar antenna characterization. In this paper, we propose an optical broadband sensor with static offset magnetic ?eld using a diamond crystal that contains an ensemble of nitrogen-vacancy (NV) centers. The spatial resolution of micrometer scale is demonstrated by using a diamond crystal of this size. This technique is based on the modulation of ?uorescence emitting by NV center under green laser excitation, by an off-axis magnetic ?eld at radio frequencies. We demonstrate experimentally the detection of an RF magnetic ?eld, with minimum measurable amplitude on the order of 0.1 Gauss, which is limited by the noise ?oor of the avalanche photodetector. The sensitivity can be further improved by noise suppression in optics. The bandwidth of the sensor is measured to be 15 MHz.
关键词： near-?eld imaging,magnetic ?eld,magnetic resonance,Instrumentation and measurement,real time,laser
更新于2025-09-23 15:23:52
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Incoherent Range Walk Compensation for Spaceborne GNSS-R Imaging
摘要： Global navigation satellite system reflectometry (GNSS-R) receivers produce delay-Doppler maps (DDMs) by incoherently integrating coherent integration results. Due to system dynamics, during incoherent integration, the receiver aligns each coherent result by tracking the delay and Doppler of the specular point. This is known to cause a blurring of the spatial footprint of the Woodward ambiguity function (WAF) on the reflecting surface. In this paper, we demonstrate that the blurring of the WAF varies over the glistening zone (GZ), and even if a fixed point on the ground is tracked, blurring still occurs. We derive the expressions for the delay and Doppler change rates over the GZ and then predict the error introduced by range walk for typical GNSS-R scatterometry configurations. We find that ≈6 dB of loss is expected for a point scatterer near the edge of the GZ when a fixed point on the surface is tracked. The incoherent range walk compensation (IRWC) method is then presented for GNSS-R receivers to mitigate this loss. The IRWC method focuses the power in the DDM to the isodelay and iso-Doppler configuration occurring at the midpoint of the integration time. DDMs produced by tracking a fixed point with and without IRWC are simulated, and errors are found to be in agreement with those predicted. Spatial domain GNSS-R products will be improved with IRWC. Target detection will benefit from a larger usable swath, allowing longer tracking and detection times as a result of the increased target to clutter and noise ratio. At the same time, imaging applications will no longer suffer from a spatially variant blurring of the WAF, which limits the resolution of the estimated products. IRWC is shown to mitigate the range migration losses and improve the SNR of an imaging GNSS-R receiver by ≈6 dB near the edge of the GZ.
关键词： integration,global navigation satellite system reflectometry (GNSS-R),reflectometry,imaging,target detection,receiver,incoherent range walk compensation (IRWC),Dynamic corrections
更新于2025-09-23 15:23:52
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Imaging and Biomechanics
摘要： Over the past 3 decades, our ability to noninvasively image structures of the musculoskeletal system has facilitated clinical diagnoses and provided insight into the success of various therapeutic interventions. As imaging modalities are refined and novel approaches are introduced, imaging technologies can provide objective measures to better understand the natural history and mechanisms of diseases and optimize and evaluate their treatment. While traditional radiography and computed tomography are commonly used to evaluate the integrity of bony structures, recent advances include biplanar videoradiography, which can now be used to directly track 3-dimensional joint motion in vivo with a high degree of accuracy.11 As such, biplanar videoradiography has been applied to study the progression of arthrosis after anterior cruciate ligament (ACL) injury.4 Based on recent technological advances, ultrasound is now being used to measure cartilage thickness to study the progression of arthrosis in vivo after ACL injury.8 Likewise, there has been a real boon in the use of magnetic resonance imaging (MRI) to evaluate anatomic, biomechanical, and compositional interactions among the structures of an injured joint. For example, MRI has been used to evaluate compositional changes of the articular cartilage in the injured joint in relation to changes in loading during gait.13 These kinds of studies provide opportunities to better understand mechanisms of posttraumatic osteoarthritis following joint injury. Furthermore, MRI has been recently applied to gain insight into the mechanisms of ACL injury.9 By using the projections of the bone bruises that occurred during ligament rupture onto the articular surfaces within the 2 compartments of the knee via models derived from 3-dimensional MRI scans, the position of the tibia relative to the femur at the time of injury can be determined.9 MRI has also been used to evaluate the structural and mechanical integrity of the menisci3 and ACL grafts after surgery.1
关键词： biomechanics,knee,MRI,imaging
更新于2025-09-23 15:23:52
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Void fraction measurement using imaging and phase isolation method in horizontal annular flow
摘要： A new imaging method was proposed to measure the void fraction of annular flow based on phase isolation technology in horizontal circular tube. As gas liquid mixture passes through the phase isolation device, which is arranged upstream, a strong swirl flow is created, due to centrifugal effect. Liquid phase is pushed to the tube wall and forms a uniform liquid film, while the gas phase is concentrated to the tube center and forms a gas core. This rectified core-annular flow has more smooth and clear phase interface than that of natural annular flow, which makes the accurate measurement of some inherent flow parameters of gas-liquid two phase flow become available and much easier. The backlight collimated illumination and high resolution CCD camera were employed to capture the gas core and liquid film. A calibration experiment was conducted to acquire accurate edge detection criterion for recognition of phase interface. The image morphological characteristics of core-annular flow and the beam path diagram of imaging procedure were analyzed in detail and the corresponding image processing algorithm was developed. The working fluid were air and water and the range of void fraction covered in experiment were 0.736-0.978(Usg=4.35m/s-39.12m/s, Usl=0.016m/s-0.504m/s). For each experiment condition, about 800 raw images were processed to obtain average result. Comparisons to a representative mode of void fraction of natural annular flow showed that the void fraction of the core-annular flow rectified by the phase isolation device keeps consistent well with that of natural annular flow in the range of low gas volume fraction, but becomes a little lower than the later as gas volume fraction become very high.
关键词： void fraction,annular flow,imaging,core-annular flow,phase isolation
更新于2025-09-23 15:23:52
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MicroCT imaging dose to mouse organs using a validated Monte Carlo model of the small animal radiation research platform (SARRP)
摘要： The goal of this work was to establish imaging dose to mouse organs with a validated Monte Carlo (MC) model of the image-guided Small Animal Radiation Research Platform (SARRP) and to investigate the effect of scatter from the internal walls on animal therapy dose determination. A MC model of the SARRP was built in the BEAMnrc code and validated with a series of homogeneous and heterogeneous phantom measurements. A segmented microCT scan of a mouse was used in DOSXYZnrc to determine mouse organ microCT imaging doses to 15–35 g mice for the SARRP pancake (mouse lying on couch) and standard (mouse standing on couch) imaging geometries for 40–80 kVp tube voltages. Imaging dose for off-center positioning shifts and maintaining image noise across tube voltages were also calculated. Half-value layer (HVL) measurements for the 220 kVp therapy beam in the presence of the SARRP shielding cabinet were modeled in BEAMnrc and compared to the 100 cm source-to-detector distance (SDD) in the scatter free, narrow-beam geometry recommended by the American Association of Physicists in Medicine Task Group 61 (AAPM TG-61). For a 60 kVp, 0.8 mA, and 60 s scan protocol, maximum mean organ imaging doses to boney and non-boney structures were 10.5 cGy and 3.5 cGy, respectively, for an average size 20 g mouse. Current-exposure combinations above 323, 203, 147, 116, and 95 mAs for 40–80 kVp tube voltages, respectively, will increase body doses above 10 cGy. MicroCT mean body dose was 18% lower in pancake compared to standard imaging geometry. An 11% difference in measured HVL at a 50 cm SDD was found compared to MC simulated HVL for the AAPM TG-61 recommended scatter free geometry at a 100 cm SDD. This change in HVL resulted in a 0.5% change in absorbed dose to water calculations for the treatment beam.
关键词： SARRP,HVL,microCT,Monte Carlo,imaging dose,small animal irradiator
更新于2025-09-23 15:23:52
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A thermo-sensitive fluorescent agent based method for excitation light leakage rejection for fluorescence molecular tomography
摘要： Fluorescence molecular tomography (FMT) is widely used in preclinical oncology research. FMT is the only imaging technique able to provide three-dimensional distribution of fluorescent probes within thick highly scattering media. However, its integration into clinical medicine has been hampered by its low spatial resolution caused by the undetermined and ill-posed nature of its reconstruction algorithm. Another major factor degrading the quality of FMT images is the large backscattered excitation light component leaking through the rejection filters and coinciding with the weak fluorescent signal arising from a low tissue fluorescence concentration. In this paper, we present a new method based on the use of a novel thermo-sensitive fluorescence probe. In fact, the excitation light leakage is accurately estimated from a set of measurements performed at different temperatures and then is corrected for in the tomographic data. The obtained results show a considerable improvement in both spatial resolution and quantitative accuracy of FMT images due to the proper correction of fluorescent signals.
关键词： Excitation Light Leakage,Biomedical Imaging,Fluorescence Molecular Tomography
更新于2025-09-23 15:23:52