靶影象(target imaging)

CT在中枢神经系统应用中,一般层厚为5～10毫米,大的象素使空间分辨力不比目前应用的X线图象好。同时CT 分度范围为-1000～+1000,高密度物质分辨力差,在骨骼系统诊断中有困难。为此减小象素以提高空间分辨力,考虑延长CT 值分度范围,以提高密度分辨力。在新的改良软件中加入高分解能力的演算方法,由于变调传导相关系数的改良使空间分辨力大幅度提高。

SAR Moving Target Detection and Imaging Based on WVH Transform

Aim To propose a generalized and closed representation of the Wigner Ville Hough transform(WVHT), for the moving target detection and imaging in the design of synthetic aperture radar(SAR). Methods Based on the line integral, the WVH transform was derived by combining the Wigner Ville distribution (WVD) and the Hough transform (HT) together. The new transform was then verified with computer by the simulated SAR echoes. Results and Conclusion The correctness and the validity of the WVH transform were proved by the computer simulation. Compared with the conventional WVD HT method, the new approach based on the WVHT can simplify the processing procedure, it can translate the chirp echoes of multi targets of SAR from the time domain into the parameter space directly, while suppressing the cross terms of WVD and estimating the motion coefficients for the final imaging. It is obvious that the WVH transform can be also used in other cases for the chirp signal detection.

STUDY ON THE SIGNATURE OF GROUND MOVING TARGET FOR AIRBORNE SQUINT SAR IMAGING

Compared with the side-looking Synthetic Aperture Radar (SAR), the flexible beampointing of squint SAR makes great application value. This paper derives the image signature of the ground moving target after the processing of Range-Doppler (RD) algorithm, the SAR signatures of ground moving targets are analyzed, including the geometry correction, the offsets and defocusing in both range and azimuth direction. Finally, computer simulation results validate its effectiveness. The research results are especially significant for moving targets detection and parameters estimation in squint mode SAR.

Human induced pluripotent stem cells labeled with fluorescent magnetic nanoparticles for targeted imaging and hyperthermia therapy for gastric cancer

Objective: Human induced pluripotent stem(i PS) cells exhibit great potential for generating functional human cells for medical therapies. In this paper, we report for use of human i PS cells labeled with fluorescent magnetic nanoparticles(FMNPs) for targeted imaging and synergistic therapy of gastric cancer cells in vivo. Methods: Human i PS cells were prepared and cultured for 72 h. The culture medium was collected, and then was coincubated with MGC803 cells. Cell viability was analyzed by the MTT method. FMNP-labeled human i PS cells were prepared and injected into gastric cancer-bearing nude mice. The mouse model was observed using a small-animal imaging system. The nude mice were irradiated under an external alternating magnetic field and evaluated using an infrared thermal mapping instrument. Tumor sizes were measured weekly. Results: iP S cells and the collected culture medium inhibited the growth of MGC803 cells. FMNP-labeled human iP S cells targeted and imaged gastric cancer cells in vivo, as well as inhibited cancer growth in vivo through the external magnetic field. Conclusion: FMNP-labeled human i PS cells exhibit considerable potential in applications such as targeted dual-mode imaging and synergistic therapy for early gastric cancer.

Construction of Ship Target Image Library Based on 3DS MAX and AP Algorithm

To achieve accurate classification and recognition of ship target types,it is necessary to establish a sample library of ship targets to be identified.On the basis of exploring the principles of building a ship target image library,the paper determines the sample set.Using 3DS MAX software as the platform,combined with the accurate 3D model of the ship in an offline state,the software fully utilizes its own rendering and animation functions to achieve the automatic generation of multi-view and multi-scale views of ship targets.To reduce the storage capacity of the image database,a construction method of the ship target image database based on the AP algorithm is presented.The algorithm can obtain the optimal cluster number,reduce the data storage capacity of the image database,and save the calculation amount for the subsequent matching calculation.

IMAGING AND MTI PROCESSING BASED ON DUAL-FREQUENCIES DUAL-APERTURES SPACEBORNE SAR

Based on dual-frequencies dual-apertures spaceborne SAR （Synthetic Aperture Radar）, a new SAR system with four receiving channels and two operation modes is presented in this paper, SAR imaging and Moving Target Indication （MTI） are studied in this system. High resolution imaging with wide swath is implemented by the Mode Ⅰ, and MTI is completed by the Mode Ⅱ. High azimuth resolution is achieved by the Displaced Phase Center （DPC） multibeam technique. And the Coherent Accumulation （CA） method, which combines dual channels data of different carrier frequency, is used to enhance the range resolution. For the data of different carrier frequency, the two aperture interferometric processing is executed to implement clutter cancellation, respectively. And the couple of clutter suppressed data are employed to implement Dual Carrier Frequency Conjugate Processing （DCFCP）, then both slow and fast moving targets detection can be completed, followed by moving target imaging. The simulation results show the validity of the signal processing method of this new SAR system.

Inverse synthetic aperture radar imaging based on sparse signal processing

Based on the measurement model of inverse synthetic aperture radar (ISAR) within a small aspect sector,an imaging method was presented with the application of sparse signal processing.This method can form higher resolution inverse synthetic aperture radar images from compensating incomplete measured data,and improves the clarity of the images and makes the feature structure much more clear,which is helpful for target recognition.The simulation results indicate that this method can provide clear ISAR images with high contrast under complex motion case.

Optimal ship imaging for shore-based ISAR using DCF estimation

The optimal imaging time selection of ship targets for shore-based inverse synthetic aperture radar （ISAR） in high sea conditions is investigated. The optimal imaging time includes opti- mal imaging instants and optimal imaging duration. A novel method for optimal imaging instants selection based on the estimation of the Doppler centroid frequencies （DCFs） of a series of images obtained over continuous short durations is proposed. Combined with the optimal imaging duration selection scheme using the image contrast maximization criteria, this method can provide the ship images with the highest focus. Simulated and real data pro- cessing results verify the effectiveness of the proposed imaging method.

Carbon dots based on targeting unit inheritance strategy for Golgi apparatus-targeting imaging

The Golgi apparatus is one of the important organelles,where the final processing and packaging of cellular secretions(such as proteins)are completed.The disorder of Golgi apparatus structure and function will induce many diseases.Therefore,monitoring the morphological structure of Golgi apparatus is crucial for the diagnosis and treatment of relevant diseases.In order to achieve Golgi apparatus-targeting imaging,the strategy of targeting unit inheritance was adopted and carbon dots(CDs)with Golgi apparatus-targeting ability were synthesized by one-step hydrothermal method with L-ascorbic acid with high reactivity and reducibility as the carbon source and L-cysteine as the targeting unit.CDs have a certain amount of cysteine residues on their surface,and have excitation dependence,satisfactory fluorescence and cysteine residues stability and low toxicity.As an imaging agent,CDs can be used for targeting imaging of Golgi apparatus.

Cucurbit[8]uril-based non-covalent heterodimer realized NIR cell imaging through topological transformation from nanowire to nanorod

In recent years,multicolor cascade supramolecular assemblies with controllable topological morphology have become a research hotspot due to their wide application in light-emitting materials,cell imaging and other fields.Herein,several kinds of macrocycles including cucurbiturils,calixarene and cyclodextrins are used as building blocks to construct fluorescent assemblies with anthryl-conjugated phenylpyridine(G),wherein cucurbit[8]uril(CB[8])and G can form nanowires at a stoichiometric ratio of n:n through host-guest encapsulation to form a non-covalent heterodimer.Significantly,the macrocycle confinement effect drastically enhances the fluorescence emission of G and emission peak generated bathochromic shift from 500 nm to 600 nm.When the supramolecular polymer is further assembled with amphiphilic calix[4]arene(SC_(4)A8),the fluorescence emission of G?CB[8]further increases to 1.4 times,accompanied by the morphological transformation from linear structure to nanorod structure.Subsequently,a very small amount of dye Cy5 is added to the assembly solution as an energy receptor,and the negatively charged G?CB[8]@SC_(4)A8 system is regarded as an energy donor.The efficient energy transfer process enables near-infrared(NIR)emission at 675 nm with 71%energy transfer efficiency(ΦET)at a donor/receptor ratio of 100:1.Finally,the cascade supramolecular assembly has been successfully applied to targeted imaging in the nucleus of HeLa and A549 cancer cells.

Specific Recognition of Breast Cancer Cells In Vitro Using Near Infrared-Emitting Long-Persistence Luminescent Zn_3Ga_2Ge_2O_(10):Cr^(3+)Nanoprobes

In this paper, near-infrared emitting long-persistence luminescent Zn3Ga2Ge2O10:Cr3?(ZGG) nanoparticles with diameters of 30–100 nm and bright luminescence were prepared by a sol–gel synthesis method. After the surface amination, the nanoparticles were further bioconjugated with breast cancer-specific monoclonal antibody(anti-Ep CAM) to form ZGG-Ep CAM nanoprobes which can specifically target breast cancer cell lines(MCF7) in vitro. The results of in vitro images show that the luminescence signals from the cells treated with ZGG-Ep CAM nanoprobes are stronger than those from cells treated with ZGG-unconjugated antibody, indicating that the prepared ZGG-Ep CAM nanoprobes possessed excellent specific recognition capability. Furthermore, due to their long afterglow properties, the imaging could persist more than 1 h. Therefore, these nanoprobes could not only provide a high specificity detection method for cancer cells but also realize the long-time monitoring. Developed near-infrared emitting long-persistence luminescent nanoprobes will be expected to find new perspectives for cell therapy research and diagnosis applications.

FMCW-InISAR imaging for high-speed target based on bistatic configuration

Interferometric inverse synthetic aperture radar(InISAR)imaging has been proved to be a powerful means for obtaining threedimensional(3-D)space shape of noncooperative targets.Frequency modulated continuous wave(FMCW)InISAR(FMCWInISAR)has unique advantages of low power,low cost,and small volume compared with traditional coherent pulsed InISAR.However,FMCW-InISAR imaging has two additional issues to consider,the one is the invalidation of the assumption of stop&go,which is caused by the relatively long sweep interval of FMCW;the other is the isolation of the transmitting and receiving antennas,which is the inherent issue of the transmitter-receiver community radar systems.To solve these two problems,a bistatic FMCW-InISAR imaging algorithm for high-speed targets is proposed in this paper.For improving the isolation of the transmitting and receiving antennas,a bistatic configuration based FMCW-InISAR system is designed.According to the characteristics of bistatic,a bistatic equivalent motion model and corresponding signal model are established.Since the assumption of stop&go is invalid in the case of FMCW,indicating that the target cannot be viewed as motionless during a sweep repetition interval(SRI),a parametric estimation based quadratic phase factor(QPF)compensation method is investigated to eliminate the range walk caused by the radial motion of the target during the SRI.In addition,considering the farfield trait of the target and combining the traditional InISAR imaging process,a combined QPF compensation technique is proposed to reduce the computational burden of the algorithm.Finally,the effectiveness and the robustness of the proposed algorithm are evaluated by some simulations.

Functionalization of small black phosphorus nanoparticles for targeted imaging and photothermal therapy of cancer

Black phosphorus(BP) nanomaterials have attracted extensive attention due to their unique physical,chemical, and biological properties. In this study, small BP nanoparticles were synthesized and modified with dextran and poly(ethyleneimine) for functionalization with folic acid and cyanine 7. The functionalized BP nanoparticles exhibit excellent biocompatibility, stability, and near infrared optical properties for targeted imaging of tumors through photoacoustic imaging and near-infrared fluorescence imaging.They also display high photothermal conversion efficiency for photothermal therapy of cancer. This work demonstrates the potential of functionalized small BP nanoparticles as an emerging nanotheranostic agent for the diagnosis and treatment of cancer.

磁共振钆靶向对比剂的研究现状及展望

特异性MR靶向对比剂通过与体内特定的靶点结合显示活体分子靶点状态,为临床提供分子水平的信息。选择针对特定靶点的特异性运载体和良好的MR显像剂,是构建良好分子探针的一个关键因素。钆剂作为临床常用的MR对比剂,在构建分子探针上具有诸多优势,目前在MR分子成像领域进行了大量实验研究。就目前研究常用的分子靶点和分子探针,对MR钆靶向对比剂的研究现状及展望进行综述。

Double Encryption Using Trigonometric Chaotic Map and XOR of an Image

In the most recent decades,a major number of image encryption plans have been proposed.The vast majority of these plans reached a highsecurity level;however,their moderate speeds because of their complicated processes made them of no use in real-time applications.Inspired by this,we propose another efficient and rapid image encryption plan dependent on the Trigonometric chaotic guide.In contrast to the most of current plans,we utilize this basic map to create just a couple of arbitrary rows and columns.Moreover,to additionally speed up,we raise the processing unit from the pixel level to the row/column level.The security of the new plot is accomplished through a substitution permutation network,where we apply a circular shift of rows and columns to break the solid connection of neighboring pixels.At that point,we join the XOR operation with modulo function to cover the pixels values and forestall any leaking of data.High-security tests and simulation analyses are carried out to exhibit that the scheme is very secure and exceptionally quick for real-time image processing at 80 fps(frames per second).

Epidermal growth factor receptor-targeted ultra-small superparamagnetic iron oxide particles for magnetic resonance molecular imaging of lung cancer cells in vitro

Background Magnetic resonance （MR） molecular imaging can detect abnormalities associated with disease at the level of cell and molecule. The epidermal growth factor receptor （EGFR） plays an important role in the development of lung cancer. This study aimed to explore new MR molecular imaging targeting of the EGFR on lung cancer cells. Methods We attached ultra-small superparamagnetic iron oxide （USPIO） particles to cetuximab （C225） anti-human IgG using the carbodiimide method. We made the molecular MR contrast agents C225-USPIO and IgG-USPIO, the latter as a control reagent, and determined concentrations according to the Fe content. Lung cancer A549 cells were cultured and immunocytochemistry （SP） was used to detect the expression of EGFR on cells. We detected the binding rate of C225-USPIO to A549 cells with immunofluorescence staining and flow cytometry. We cultured A549 cells with C225-USPIO at a Fe concentration of 50 pg/ml and assayed the binding of C225-USPIO after 1 hour with Prussian blue staining and transmission electron microscopy （TEM）. We determined the effects on imaging of the contrast agent targeted to cells using a 4.7T MRI. We did scanning on the cells labeled with C225-USPIO, IgG-USPIO, and distilled water, respectively. The scanning sequences included axial T1WI, T2WI. Results Immunocytochemical detection of lung cancer A549 cells found them positive for EGFR expression. Immunofluorescence staining and flow cytometry after cultivation with different concentrations of C225-USPIO showed the binding rate higher than the control. Prussian blue staining and transmission electron microscopy revealed that in the C225-USPIO contrast agent group of cells the particle content of Fe in cytoplasmic vesicles or on surface was more than that in the control group. The 4.7T MR imaging （MRI） scan revealed the T2WI signal in the C225-USPIO group of cells decreased significantly more than in unlabeled cells, but there was no significant difference between the time gradients. Conclusions We successfully constructed the molecular imaging agent C225-USPIO targeting the EGFR of A549 lung cancer cells. The imaging agent showed good targeting effect and specificity, and reduced MRI T2 value significantly, thus such molecular contrast agents could provide a new way to measure EGFR levels.

Ghost imaging for an axially moving target with an unknown constant speed

The influence of the axial relative motion between the target and the source on ghost imaging(GI) is investigated.Both the analytical and experimental results show that the transverse resolution of GI is reduced as the deviation of the target’s center position from the optical axis or the axial motion range increases. To overcome the motion blur,we propose a deblurring method based on speckle-resizing and speed retrieval, and we experimentally validate its effectiveness for an axially moving target with an unknown constant speed. The results demonstrated here will be very useful to forward-looking GI remote sensing.

Design of a wide-field target detection and tracking system using the segmented planar imaging detector for electro-optical reconnaissance

Detecting and tracking multiple targets simultaneously for space-based surveillance requires multiple cameras,which leads to a large system volume and weight. To address this problem, we propose a wide-field detection and tracking system using the segmented planar imaging detector for electro-optical reconnaissance. This study realizes two operating modes by changing the working paired lenslets and corresponding waveguide arrays： a detection mode and a tracking mode. A model system was simulated and evaluated using the peak signal-to-noise ratio method. The simulation results indicate that the detection and tracking system can realize wide-field detection and narrow-field, multi-target, high-resolution tracking without moving parts.

Automatic target recognition method for inverse synthetic aperture sonar imaging

To address the randomness of target aspect angle and the incompleteness of observed target in inverse synthetic aperture sonar（ISAS） imaging,a method for target recognition is proposed based on topology vector feature（TVF） of multiple highlights. Analysis of the projection relationship from 3 D space to 2 D imaging plane in ISAS indicates that the distance between two highlights in the cross-range scale calibrated image is determined by the distance between the corresponding physical scattering centers. Then, TVFs of different targets, which remain stable in various possibilities of target aspect angle, can be built. K-means clustering technique is used to effectively alleviate effect of the point missing due to incompleteness of the observed target. A nearest neighbor classifier is used to realize the target recognition. The ISAS experimental results using underwater scaled models are provided to demonstrate the effectiveness of the proposed method. A classification rate of 84.0% is reached.

Statistical Tests of Hypothesis Based Color Image Retrieval

This paper proposes a novel method based on statistical tests of hypotheses, such as F-ratio and Welch’s t-tests. The input query image is examined whether it is a textured or structured. If it is structured, the shapes are segregated into various regions according to its nature;otherwise, it is treated as textured image and considered the entire image as it is for the experiment. The aforesaid tests are applied regions-wise. First, the F-ratio test is applied, if the images pass the test, then it is proceeded to test the spectrum of energy, i.e. means of the two images. If the images pass both tests, then it is concluded that the two images are the same or similar. Otherwise, they differ. Since the proposed system is distribution-based, it is invariant for rotation and scaling. Also, the system facilitates the user to fix the number of images to be retrieved, because the user can fix the level of significance according to their requirements. These are the main advantages of the proposed system.