Spatial-temporal Image Research Articles

Image Denoising Using Multi-Frame Image Content in Curvelet Transform Domain

We present a multi-frame information involved image denoising approach through spatiotemporal GSM (Gaussian Mixture Scales Modeling) of image Curvelet statistics both considering of the innerframe and inter-frame statistics. By using the Bayes inference based least square estimation, we construct a Bayesian Least Squared GSM (BLS-GSM) based image denoising model for single image noise cancellation and estimate the optimal coefficient of the uncontaminated image through this model in the Curvelet domain in advance. Then, we carry out a novel spatial-temporal jointed image noise removing method by combining the single image denoising model with a weighted impact factor conducted on multi-frame images based on the relativity of the image coefficients among the image sequences. The image denoising performance is evaluated in terms of the visual effect of the denoised images and compared against the other methods by the objective criterion, Peak Signal-to-Noise Ratio. The comparative results demonstrated that this method outperforms the Curvelet based counterpart and achieves close or better processing results in terms of PSNR, namely that the proposed method is capable of achieving higher reconstruction quality while protecting more image details.

Motility and Segregation of Hsp104-Associated Protein Aggregates in Budding Yeast

During yeast cell division, aggregates of damaged proteins are segregated asymmetrically between the bud and the mother. It is thought that protein aggregates are cleared from the bud via actin cable-based retrograde transport toward the mother and that Bni1p formin regulates this transport. Here, we examined the dynamics of Hsp104-associated protein aggregates by video microscopy, particle tracking, and image correlation analysis. We show that protein aggregates undergo random walk without directional bias. Clearance of heat-induced aggregates from the bud does not depend on formin proteins but occurs mostly through dissolution via Hsp104p chaperon. Aggregates formed naturally in aged cells also exhibit random walk but do not dissolve during observation. Although our data do not disagree with a role for actin or cell polarity in aggregate segregation, modeling suggests that their asymmetric inheritance can be a predictable outcome of aggregates' slow diffusion and the geometry of yeast cells.

OP19.02: Stromal ovarian vascularization assessed by spatial temporal image correlation (STIC)‐high definition flow (HDF) in women with PCOS

OP19.02: Stromal ovarian vascularization assessed by spatial temporal image correlation (STIC)‐high definition flow (HDF) in women with PCOS

Dynamic CT technique for assessment of wrist joint instabilities

To develop a 4D [three-dimensional (3D) + time] CT technique to capture high spatial and temporal resolution images of wrist joint motion so that dynamic joint instabilities can be detected before the development of static joint instability and onset of osteoarthritis (OA). A cadaveric wrist was mounted onto a custom motion simulator and scanned with a dual source CT scanner during radial-ulnar deviation. A dynamic 4D CT technique was utilized to reconstruct images at 20 equidistant time points from one motion cycle. 3D images of carpal bones were generated using volume rendering techniques (VRT) at each of the 20 time points and then 4D movies were generated to depict the dynamic joint motion. The same cadaveric wrist was also scanned after cutting all portions of the scapholunate interosseus ligament to simulate scapholunate joint instability. Image quality were assessed on an ordinal scale (1-4, 4 being excellent) by three experienced orthopedic surgeons (specialized in hand surgery) by scoring 2D axial images. Dynamic instability was evaluated by the same surgeons by comparing the two 4D movies of joint motion. Finally, dose reduction was investigated using the cadaveric wrist by scanning at different dose levels to determine the lowest radiation dose that did not substantially alter diagnostic image quality. The mean image quality scores for dynamic and static CT images were 3.7 and 4.0, respectively. The carpal bones, distal radius and ulna, and joint spaces were clearly delineated in the 3D VRT images, without motion blurring or banding artifacts, at all time points during the motion cycle. Appropriate viewing angles could be interactively selected to view any articulating structure using different 3D processing techniques. The motion of each carpal bone and the relative motion among the carpal bones were easily observed in the 4D movies. Joint instability was correctly and easily detected in the scan performed after the ligament was cut by observing the relative motion between the scaphoid and lunate bones. Diagnostic capability was not sacrificed with a volume CT dose index (CTDI(vol)) as low as 18 mGy for the whole scan, with estimated skin dose of approximately 33 mGy, which is much lower than the threshold for transient skin erythema (2000 mGy). The proposed dynamic 4D CT imaging technique generated high spatial and high temporal resolution images without requiring periodic joint motion. Preliminary results from this cadaveric study demonstrate the feasibility of detecting joint instability using this technique.

Structure and Dynamics of Epithelial Cell Cortical Actomyosin Networks

Cortical actomyosin networks consist of filamentous actin (F-actin) bundles crosslinked into highly dynamic networks that are linked physically to the extracellular matrix via integrins. These networks play an active role in tissue morphogenesis during development as well as metastasis in cancer, by enabling rapid remodelling of cell shape via F-actin polymerization and interaction with myosin-II motor proteins. Here we investigate a newly discovered isotropic actomyosin network on the dorsal surface of epithelial MDCK cells and characterize its structure and dynamics using computational analysis of timelapse fluorescence microscopy data provided by Lifeact, a highly specific marker for F-actin in living cells. At low cell density, F-actin bundles depolymerise and polymerize continuously, splitting and merging into large bundle clusters. Spatial Temporal Image Correlation Spectroscopy and Optical Flow are used to characterize the oscillatory dynamics of the bundled networks, and reveal characteristic length- and time-scales associated with their motions.

Scanning laser image correlation for measurement of flow

Scanning laser image correlation (SLIC) is an optical correlation technique for measuring the fluid velocity of particles suspended in a liquid. This technique combines laser scanning of an arbitrary pattern with pair cross-correlation between any two points in the pattern. SLIC overcomes many of the limitations of other optical correlation techniques for flow measurement, such as laser speckle, spatial temporal image correlation spectroscopy, and two-foci methods. One of the main advantages of SLIC is that the concept can be applied to measurements on a range of scales through simple zooming or modifications in the instrumentation. Additionally, SLIC is relatively insensitive to instrument noise through the use of correlation analysis and is insensitive to background. SLIC can provide detailed information about the direction and pattern of flow. SLIC has potential applications ranging from microfluidics to blood flow measurements.

Atividades rítmicas e Educação Física escolar: possíveis contribuições ao desenvolvimento motor de escolares de 08 anos de idade

In child development, motor activities are of real importance to interpersonal relations, proprioceptive and environmental. Whereas the teaching of rhythmic activities in the school environment can contribute to more effective communication and apprehension of the world by students, helping to develop better perception and spatial-temporal parallel body image, this study was to evaluate the contributions of a program of rhythmic activities for motor development in relation to the variables balance, body scheme, General Motor Age, Motor Quotient General and Chronological Age. All variables showed significant improvements, but most significant was made to balance. So the program of rhythmic activities apply to the school environment and can give contributions to the development of students.

3D/4D Echocardiography—STIC

Abstract Fetal cardiac screening is an obligation for everybody performing prenatal ultrasound. The heart, as a small and always moving object, is still the most difficult part of the fetal anatomy evaluation. Knowing this, different methods of improving antenatal screening for congenital heart defects (CHD) were introduced. Spatial temporal image correlation (STIC) is the newest one. Its target was to automatic acquisition of the fetal scan from the abdomen, through 4 chamber view toward the three vessel view and off-line analysis of the anatomy of the fetal cardiovascular system. Is that really possible? Does STIC improve screening of CHD? Would it be helpful in the more precise diagnosis of complicated heart defects? These are still the open questions, which will be discussed in the article.

Motion detection using Fourier image reconstruction

In video surveillance, detection of moving objects from an image sequence is very important for object tracking, activity recognition and behavior understanding. The conventional background subtraction suffers from slow updating of environmental changes, and temporal difference cannot accurately extract the moving object boundaries. In this paper, a Fourier reconstruction scheme for motion detection is proposed. A series of consecutive 2D spatial images along the time axis are first reorganized as a series of 2D spatial–temporal images along a spatial axis. In each of the 2D spatial–temporal images, a static background region forms a vertical line pattern, and a moving object creates an irregular, non-vertical structure in the image. Fourier transforms are applied to remove the vertical line pattern (i.e. the background) and retain only the foreground in the reconstructed image. The proposed method is a global approach that identifies the moving objects based on structural variations in the whole patterned image. It is therefore very robust to accommodate noise and local gray-level variations. It can well extract the shapes of foreground objects at various moving speeds, and is very responsive to dynamic environments. High computational cost is the major drawback of the proposed method. However, it can still achieve 11 frames per second for small images of size 150 × 200.

OP02.06: Satisfactory visualization rates of standard cardiac views at 18–22 weeks gestation: A comparison of static 2‐D and spatial temporal image correlation (STIC 4‐D)

OP02.06: Satisfactory visualization rates of standard cardiac views at 18–22 weeks gestation: A comparison of static 2‐D and spatial temporal image correlation (STIC 4‐D)

EVALUATION OF THE POTENTIALITY OF WFI/CBERS-3 SENSOR DATA FOR LAND USE AND LAND COVER CLASSIFICATION

The high cost involved in the development and launching of optical orbital sensors makes the planning and study of the potential uses of their products necessary before their launch. CBERS-3 satellite is planned to be launched in 2008 and will carry on board, among other sensors, the Wide Field Imager Camera (WFI). Its technical characteristics will benefit users who need moderate spatial and high temporal resolution images. Then, the objective of this work is to simulate and evaluate the potentiality of a WFI/CBERS-3 image for land use and land cover classification in two landscapes with different characteristics. The first site is characterized by intensive agricultural area in São Paulo State located in the Southeast region of Brazil, and the second area is characterized by deforested areas in Mato Grosso State, located in the Amazon region. The simulation of the WFI/CBERS-3 images was made using two ETM+/Landsat-7 scenes. The obtained classification results achieved for both studied sites show that WFI /CBERS-3 images will be a useful source of information for land use and land cover classification.
 Key-words: Digital image processing, CBERS-3 satellite, WFI sensor, Image simulation.

A Spatial-Temporal Multiresolution CMOS Image Sensor With Adaptive Frame Rates for Tracking the Moving Objects in Region-of-Interest and Suppressing Motion Blur

In this paper, we report a CMOS image sensor for spatial-temporal multiresolution images. This image sensor simultaneously generates two outputs: one for normal images (<30 fps) of stationery background and the other for adaptable frame-rate images (over 960 fps) of moving objects. The moving objects are tracked with a reduced spatial resolution in the region-of-interest (ROI). The entire image is reconstructed from the two images with the details in stationery objects and the suppressed motion blur in moving objects. High frame rate only applies to the ROI; therefore, the proposed scheme can significantly reduce power consumption by adjusting the optimal use of bandwidth. In order to provide real-time decision of ROI, the sensor employs on-chip motion-detection circuits based on the inter-pixel switch operation by storing the previous frame signal in a floating diffusion node. This allows a small pixel implementation without adding any extra in-pixel memory components. A prototype chip has been implemented using a 0.35 mum 1P4M standard CMOS process and multiresolution images have been successfully captured. The fabricated chip operates at 3.3 V and consumes 75 mW in the multiresolution readout of a 256times256 normal image at 30 fps and a 64times64 ROI image at 240 fps.

Distinct Pathways for the Early Recruitment of Myosin II and Actin to the Cytokinetic Furrow

Equatorial organization of myosin II and actin has been recognized as a universal event in cytokinesis of animal cells. Current models for the formation of equatorial cortex favor either directional cortical transport toward the equator or localized de novo assembly. However, this process has never been analyzed directly in dividing mammalian cells at a high resolution. Here we applied total internal reflection fluorescence microscope (TIRF-M), coupled with spatial temporal image correlation spectroscopy (STICS) and a new analytical approach termed temporal differential microscopy (TDM), to image the dynamics of myosin II and actin during the assembly of equatorial cortex. Our results indicated distinct and at least partially independent mechanisms for the early equatorial recruitment of myosin and actin filaments. Cortical myosin showed no detectable directional flow during early cytokinesis. In addition to equatorial assembly, we showed that localized inhibition of disassembly contributed to the formation of the equatorial myosin band. In contrast to myosin, actin filaments underwent a striking flux toward the equator. Myosin motor activity was required for the actin flux, but not for actin concentration in the furrow, suggesting that there was a flux-independent, de novo mechanism for actin recruitment along the equator. Our results indicate that cytokinesis involves signals that regulate both assembly and disassembly activities and argue against mechanisms that are coupled to global cortical movements.

Space-Time Light Field Rendering

In this paper, we propose a novel framework called space-time light field rendering, which allows continuous exploration of a dynamic scene in both space and time. Compared to existing light field capture/rendering systems, it offers the capability of using unsynchronized video inputs and the added freedom of controlling the visualization in the temporal domain, such as smooth slow motion and temporal integration. In order to synthesize novel views from any viewpoint at any time instant, we develop a two-stage rendering algorithm. We first interpolate in the temporal domain to generate globally synchronized images using a robust spatial-temporal image registration algorithm followed by edge-preserving image morphing. We then interpolate these software-synchronized images in the spatial domain to synthesize the final view. In addition, we introduce a very accurate and robust algorithm to estimate subframe temporal offsets among input video sequences. Experimental results from unsynchronized videos with or without time stamps show that our approach is capable of maintaining photorealistic quality from a variety of real scenes.

Computer-Assisted Analysis of 4D Cardiac MR Image Sequences after Myocardial Infarction

Spatial-temporal MR image sequences of the heart contain information about shape and motion changes and pathological structures after myocardial infarction. In this paper a Heart Analysis Tool (HeAT) for the quantitative analysis of 4D MR image sequences of infarct patients is presented. HeAT supports interactive segmentation of anatomical and pathological structures. Registration of Cine- and DE-MR image data is applied to enable their combined evaluation during the analysis process. Partitioning of the myocardium in segments enables the analysis with high local resolution. Corresponding segments are generated and used for inter/intrapatient comparison. Quantitative parameters were extracted and visualized. Parameters like endocard movement in the infarcted area of six infarct patients were computed in HeAT. Parameters in the infarct area show the expected dysfunctional characteristics. Based on theses parameters passive endocardial movement and myocardial areas with decreased contraction could be identified. In contrast to other software tools HeAT supports the combination of contour information of Cine-MR and DE-MR, local analysis with high resolution and inter/intra patient comparison. HeAT enables an observer-independent evaluation of the complex cardiac image data. Using HeAT in further studies can increase the understanding of left ventricle (LV) remodeling.

Observation of nonlinear shear wave propagation using magnetic resonance elastography.

MR elastography (MRE) is an MRI modality that is increasingly being used to image tissue elasticity throughout the body. One MRE technique that has received a great deal of attention is based on visualizing shear waves, which reveal stiffness by virtue of their local wavelength. However, the shape of propagating shear waves can also provide valuable information about the nonlinear stress-strain behavior of tissue. Here an experiment is proposed that allows the observation of nonlinear wave propagation based on spatial-temporal phase contrast images. A theoretical description of the wave propagation was developed that reflects typical MRE excitation, which involves excitation modes both parallel and perpendicular to B0. Based on this model, it is shown that both odd and even higher harmonics are produced with their amplitudes dependent on the details of the actuator, imaging geometry, and the nonlinear tissue properties. With appropriate motion encoding, harmonic vibrations arising from nonlinear tissue response can be detected. The effect is demonstrated on an agarose gel phantom using a sinusoidal shear vibration of 150 Hz, and clearly shows the presence of harmonics at 600 and 750 Hz. Using an estimate of the strain energy of the phantom, we were able to determine the nonlinear tissue properties.

時系列低空間分解能画像からの情報を活用した複数シーンの高空間分解能画像分類

Elaborate processes are required for land cover classification using multiscene high spatial resolution satellite images, like selecting training area on each scene with sufficient a priori knowledge. The classification method proposed in this paper is assumed to use both high spatial resolution images and temporal low spatial resolution images. It can automatically produce training data set on each scene, optimized considering land cover characteristics to the scene. Moreover, it prevents from deteriorating into low classification accuracy, by referring to and checking consistency to the class candidate information derived from temporal low spatial resolution images. Experiments were conducted that used twenty-eight scenes of Landsat TM and NOAA AVHRR images as high and low spatial resolution images, respectively. Validation results by using three visually interpreted images demonstrate the optimization of training data set improved the classification accuracy from 59.0% to 66.2%, and the class candidate information improved from 61.9% to 66.2%.

Fossils from Lake Sediments in Northern Québec and Labrador: A Window into Past Climate Changes

... The overall objectives of my study are 1) to establish a high-resolution temporal reconstruction of environmental and climatic impacts on aquatic conditions at three sites, each at a different latitude and in a different ecoclimatic zone; 2) to develop a spatial-temporal image of postglacial environmental changes in the Quebec-Labrador region through the use of radiocarbon dating; and 3) to compare the synchronicity of several indicators (diatoms, chironomids, and pollen) in order to assess differences between the responses of aquatic and terrestrial organisms to climate change. ... The first lake, K2 (informal name), is located at 58° 44' N, 65° 56' W, 6 km northeast of the town of Kangiqsualujjuaq and about 11 km southwest of Ungava Bay. The second lake, Oksana (informal name), is located at 54° 49 N, 66° 50' W, near Schefferville. The third lake, Lac au Sable at 51° 24' N, 66° 13' W, was sampled by researchers George A. King and Herb E. Wright (Limnological Research Center, University of Minnesota) and is located about 130 km north of Sept-Iles. The sediment cores from each lake were subsampled at 1 cm intervals, each representing a period of approximately 10 - 50 years. ... So far, diatoms and chironomids have been underexploited as biological indicators of change in northern Quebec-Labrador, and they will be increasingly used in future research. ...