Frame Transfer Research Articles

Analysis of Molecular Concentration and Brightness from Fluorescence Fluctuation Data with an Electron Multiplied CCD Camera

We demonstrate the calculation of particle brightness and concentration from fluorescence-fluctuation photon-counting statistics using an electron-multiplied charge-coupled device (EMCCD) camera. This technique provides a concentration-independent measure of particle brightness in dynamic systems. The high sensitivity and highly parallel detection of EMCCD cameras allow for imaging of dynamic particle brightness, providing the capability to follow aggregation reactions in real time. A critical factor of the EMCCD camera is the presence of nonlinearity at high intensities. These nonlinearities arise due to limited capacity of the CCD well and to the analog-to-digital converter maximum range. However, we show that the specific camera we used (with a 16-bit analog-to-digital converter) has sufficient dynamic range for most microscopy applications. In addition, we explore the importance of camera timing behavior as it is affected by the vertical frame transfer speed of the camera. Although the camera has microsecond exposure time for illumination of a few pixels, the exposure time increased to milliseconds for full-field illumination. Finally, we demonstrate the ability of the technique to follow concentration changes and measure single-molecule brightness in real time in living cells.

CCD Charge Injection Structure at Very Small Signal Levels

A frame transfer charge-coupled device (CCD) designed for X-ray detection on board the SUZAKU spacecraft includes an input serial register and a charge injection structure which allows a very uniform injection of extremely small charge packets into the imaging section of the device. A variation of the fill-and-spill method was implemented to inject charge into the CCD. Very small charge packets (down to just a few electrons) can be reproducibly injected with noise as low as five-electron rms. The operation of the structure is described, and the results of the measurements are compared with the simulations. We have measured electron ldquoevaporationrdquo over potential barrier as a function of time, results being in excellent agreement with our model. By fitting a model to the data, it is possible to determine the internal capacitance of the input node. Charge injection noise as a function of signal charge was measured, and the results are also in agreement with theory. The designed structure can be used as a tool for studying and mitigating radiation damage effects in CCDs.

Identification of Farnesyl Pyrophosphate and N-Arachidonylglycine as Endogenous Ligands for GPR92

A series of small compounds acting at the orphan G protein-coupled receptor GPR92 were screened using a signaling pathway-specific reporter assay system. Lipid-derived molecules including farnesyl pyrophosphate (FPP), N-arachidonylglycine (NAG), and lysophosphatidic acid were found to activate GPR92. FPP and lysophosphatidic acid were able to activate both G(q/11)- and G(s)-mediated signaling pathways, whereas NAG activated only the G(q/11)-mediated signaling pathway. Computer-simulated modeling combined with site-directed mutagenesis of GPR92 indicated that Thr(97), Gly(98), Phe(101), and Arg(267) of GPR92 are responsible for the interaction of GPR92 with FPP and NAG. Reverse transcription-PCR analysis revealed that GPR92 mRNA is highly expressed in the dorsal root ganglia (DRG) but faint in other brain regions. Peripheral tissues including, spleen, stomach, small intestine, and kidney also expressed GPR92 mRNA. Immunohistochemical analysis revealed that GPR92 is largely co-localized with TRPV1, a nonspecific cation channel that responds to noxious heat, in mouse and human DRG. FPP and NAG increased intracellular Ca(2+) levels in cultured DRG neurons. These results suggest that FPP and NAG play a role in the sensory nervous system through activation of GPR92.

FPGA-based System for Real-Time Video Texture Analysis

This paper describes a novel system for real-time video texture analysis. The system utilizes hardware to extract second-order statistical features from video frames. These features are based on the Gray Level Co-occurrence Matrix (GLCM) and describe the textural content of the video frames. They can be used in a variety of video analysis and pattern recognition applications, such as remote sensing, industrial and medical. The hardware is implemented on a Virtex-XCV2000E-6 FPGA programmed in VHDL. It is based on an architecture that exploits the symmetry and the sparseness of the GLCM and calculates the features using integer and fixed point arithmetic. Moreover, it integrates an efficient algorithm for fast and accurate logarithm approximation, required in feature calculations. The software handles the video frame transfers from/to the hardware and executes only complementary floating point operations. The performance of the proposed system was experimentally evaluated using standard test video clips. The system was implemented and tested and its performance reached 133 and 532 fps for the analysis of CIF and QCIF video frames respectively. Compared to the state of the art GLCM feature extraction systems, the proposed system provides more efficient use of the memory bandwidth and the FPGA resources, in addition to higher processing throughput, that results in real time operation. Furthermore, its fundamental units can be used in any hardware application that requires sparse matrix representation or accurate and efficient logarithm estimation.

SU‐DD‐A4‐04: Micro Angiographic and Fluoroscopic Real‐Time Image Data Handling Using Parallel Coding Techniques in LabVIEW

Purpose: Multicore programming coding techniques have been designed to meet the high‐speed requirements of a High‐Sensitivity, Micro Angiographic‐Fluoroscope (HSMAF) detector for 30 fps acquisition, image‐processing, display, and rapid frame transfer of high‐resolution, region‐of‐interest (ROI) images. Method and Materials: The HSMAF detector was built by our group using a CsI(Tl) phosphor, a light image intensifier, and a fiber‐optic taper coupled to a charge‐coupled device (CCD) camera which provides real‐time 12 bit, 1k × 1k images capable of greater than 10 lp/mm resolution. A graphical user interface (GUI) was developed to control the system and enable real‐time acquisition, image‐processing, display, and rapid storage of high‐resolution images. To accommodate all these processes working in real‐time, parallel coding methods, such as instruction pipelining and task parallelism, were designed and used to take advantage of the available multicore processors (dual and quad cores). Results: The parallel coding techniques of the GUI can handle radiographic procedures that require on‐the‐fly image processing at 30fps such as Roadmapping, Digital‐Subtraction‐Acquisition (DSA), and rotational DSA. On a 2.4 GHz dual processor a high resolution image is acquired, processed and stored in less than 30ms. Recursive temporal filtering, as well as gain correction can be added to the above procedures and still maintain the required high frame rates when a quad‐core processor is used. Moreover, the overall system design offers virtually unlimited memory for acquisition and huge, expandable storage capacity. Conclusion: The ability of high frame‐rate acquisition, image processing and display for this unique high‐resolution detector along with the user friendly implementation of the interface should provide angiographers and interventionalists with a new capability for visualizing details of small vessels and endovascular devices such as stents. Such capability should enable more accurate diagnoses and image guided interventions. (Support from NIH Grants R01NS43924, R01EB002873 and Toshiba Medical Systems Corporation).

A Single Luminally Continuous Sarcoplasmic Reticulum with Apparently Separate Ca2+ Stores in Smooth Muscle

Whether or not the sarcoplasmic reticulum (SR) is a continuous, interconnected network surrounding a single lumen or comprises multiple, separate Ca2+ pools was investigated in voltage-clamped single smooth muscle cells using local photolysis of caged compounds and Ca2+ imaging. The entire SR could be depleted or refilled from one small site via either inositol 1,4,5-trisphosphate receptors (IP3R) or ryanodine receptors (RyR) suggesting the SR is luminally continuous and that Ca2+ may diffuse freely throughout. Notwithstanding, regulation of the opening of RyR and IP3R, by the [Ca2+] within the SR, may create several apparent SR elements with various receptor arrangements. IP3R and RyR may appear to exist entirely on a single store, and there may seem to be additional SR elements that express either only RyR or only IP3R. The various SR receptor arrangements and apparently separate Ca2+ storage elements exist in a single luminally continuous SR entity.

On the Implementation of one Process Control Application Type through a Network. Considering Three LANS: CAN, WiFi, ZigBee

This paper wants to present the first reasoning in order to implement on a network a process control application type which is, in a first time, specified with a continuous model (transfer function in the Laplace domain). The network is a local area network and we only consider the MAC layer (frame scheduling) and the physical layer (serial frame transmission). By first reasoning, we mean that, we study the case of a network which is dedicated to the process control application type, and we want to link the stability and the reactivity that the application can get from the service provided by the network (link between the parameters of the open loop transfer function and the network characteristics (frame transfer, frame format, bit rate)). Three networks are considered: CAN, WiFi, ZigBee. This work is a basic work which wants to emphasize the necessary interplay between Automatic Control theory and Networks mechanisms.

Long-Range Reconnaissance Imager on New Horizons

The LOng-Range Reconnaissance Imager (LORRI) is the high resolution imaging instrument for the New Horizons mission to Pluto, its giant satellite Charon, its small moons Nix and Hydra, and the Kuiper Belt, which is the vast region of icy bodies extending roughly from Neptune's orbit out to 50 astronomical units (AU). New Horizons launched on January 19, 2006 as the inaugural mission in NASA's New Frontiers program. LORRI is a narrow angle (field of view=0.29 deg), high resolution (4.95 microrad pixels), Ritchey-Chretien telescope with a 20.8 cm diameter primary mirror, a focal length of 263 cm, and a three lens field-flattening assembly. A 1024 x 1024 pixel (optically active region), thinned, backside-illuminated charge-coupled device (CCD) detector is used in the focal plane unit and is operated in frame transfer mode. LORRI provides panchromatic imaging over a bandpass that extends approximately from 350 nm to 850 nm. LORRI operates in an extreme thermal environment, situated inside the warm spacecraft with a large, open aperture viewing cold space. LORRI has a silicon carbide optical system, designed to maintain focus over the operating temperature range without a focus adjustment mechanism. Moreover, the spacecraft is thruster-stabilized without reaction wheels, placing stringent limits on the available exposure time and the optical throughput needed to satisfy the measurement requirements.

Evaluation and Measurement of 3D Form Errors of Ground Curve Surface

Evaluation and measurement of form errors distributed on 3D ground curved surface are proposed due to the difficulty of processing measured points of 3D ground curve surface in comparison with axisymmetric curved surface. First form curved surface grinding is conducted by arc-shaped diamond grinding wheel, second ground curved surface is measured by contact measurement to obtain 3D measuring data, next transfer mode from CNC grinding to measuring reference frames is established, then effective and applicable 3D compensation arithmetic for probe sphere error is introduced, finally 3D form errors are investigated in connection with reference frame transfer and probe sphere compensation. It is confirmed that form error PV of is improved form 203 m / 8 cm2 is obtained by using reference frame transfer and probe sphere compensation, enhancing measuring accuracy by about 29 %.

Transfer of Frames during Simultaneous Interpreting

L’nterprétation simultanée est considérée comme un processus difficile où l’interprète doit jongler plusieurs tâches en même temps. Pour cette raison, toute augmentation de la capacité de traitement de l’interprète peut déclencher des déficits dans la communication. Le désaccord de cadre entre la langue source et la langue cible pose des difficultés pour l’interprète puisque l’interprète doit mettre plus d’efforts de traitement supplémentaires pour combler le fossé. Pour réaliser la communication, l’interprète doit stratégiquement convertir des cadres de la langue source à ceux de la langue cible pour des tâches différentes. Dans ces recherches, il est montré que l’interprète non seulement reconnaît le désaccord de cadre et ajuste ses productions pour l’audience de la langue cible mais aussi la conversion est faite dans une façon d’économiser le temps et des efforts stratégiquement.

STIM1 Knockdown Reveals That Store-operated Ca2+ Channels Located Close to Sarco/Endoplasmic Ca2+ ATPases (SERCA) Pumps Silently Refill the Endoplasmic Reticulum

Stromal interaction molecule (STIM) proteins are putative ER Ca2+ sensors that recruit and activate store-operated Ca2+ (SOC) channels at the plasma membrane, a process triggered by the Ca2+ depletion of the endoplasmic reticulum (ER). To test whether STIM1 is required for ER refilling, we used RNA interference and measured Ca2+ signals in the cytosol, the ER, and the mitochondria of HeLa cells. Knockdown of STIM1 (mRNA levels, 73%) reduced SOC entry by 73% when sarco/endoplasmic Ca2+ ATPases (SERCA) were inhibited by thapsigargin but did not prevent Ca2+ stores refilling when cells were stimulated by physiological agonists. Stores could be fully refilled by increasing the external Ca2+ concentration above physiological values, but no cytosolic Ca2+ signals were detected during store refilling even at very high Ca2+ concentrations. [Ca2+](ER) measurements revealed that the basal activity of SERCA was not affected in STIM1 knockdown cells and that [Ca2+](ER) levels were restored within 2 min in physiological saline following store depletion. Mitochondrial inhibitors reduced ER refilling in wild-type but not in STIM1 knockdown cells, indicating that ER refilling does not require functional mitochondria at low STIM1 levels. Our data show that ER refilling is largely preserved at reduced STIM1 levels, despite a drastic reduction of store-operated Ca2+ entry, because Ca2+ ions are directly transferred from SOC channels to SERCA. These findings are consistent with the formation of microdomains containing not only SOC channels on the plasma membrane and STIM proteins on the ER but also SERCA pumps and mitochondria to refill the ER without perturbing the cytosol.

A 3 × 6 arrayed CCD X-ray detector for continuous rotation method in macromolecular crystallography

A 3 x 6 arrayed charge-coupled device (CCD) X-ray detector has been developed for the continuous-rotation method in macromolecular crystallography at the Photon Factory. The detector has an area of 235.9 mm x 235.9 mm and a readout time of 1.9 s. The detector is made of a 3 x 6 array of identical modules, each module consisting of a fiber-optic taper (FOT), a CCD sensor and a readout circuit. The outputs from 18 CCDs are read out in parallel and are then digitized by 16-bit analog-to-digital converters. The advantage of this detector over conventional FOT-coupled CCD detectors is the unique CCD readout scheme (frame transfer) which enables successive X-ray exposures to be recorded without interruption of the sample crystal rotation. A full data set of a lysozyme crystal was continuously collected within 360 s (180 degrees rotation, 3 s/1.5 degrees frame). The duty-cycle ratio of the X-ray exposure to the data collection time was almost 100%. The combination of this detector and synchrotron radiation is well suited to rapid and continuous data collection in macromolecular crystallography.

SU‐FF‐I‐45: Labview Graphical User Interface for Micro Angio‐Fluoroscopic High Resolution Detector

Purpose: A graphical user interface based on LabView software was developed to control a Micro Angio‐Fluoroscopic detector (MAF) for real‐time acquisition, display and rapid frame transfer of high resolution images of a region‐of‐interest. Method and Materials: A MAF detector was built by our group using a CsI(Tl) phosphor, fiber‐optic taper and Light Amplifier optically coupled to a progressive scan charged coupled device (CCD) camera which provides real‐time 12 bit, 1k × 1k images. During image acquisition, the MAF detector is inserted in the x‐ray beam of an angiographic unit, between the x‐ray image intensifier and the patient. Images can be captured in continuous or triggered mode and the camera can be programmed by a computer using the serial communication. A graphical user interface was developed to control the camera modes such as gain and pixel binning as well as to acquire, store, display, and process the images. Results: The program, written in LabView, has the following capabilities: camera initialization, synchronized image acquisition with the x‐ray pulses, flat field correction, window and level adjustment, brightness and contrast control, and looped play‐back of the acquired images. Acquisition starts when the first triggering pulse is read by the interface. The acquired sequence of images is automatically displayed in a loop after completion of acquisition and the images can be stored or deleted at the user's discretion. Frame rates can be up to 30fps in 2×2 binning mode and 25fps unbinned. Conclusion: The user friendly implementation of the interface along with the high frame rate acquisition and display for this unique high resolution detector may provide angiographers a new capability for visualizing details of small endovascular devices such as stents and hence enable more accurate image guided localization. (Support: NIH Grants R01NS43924, R01EB002873).

MPScope: A versatile software suite for multiphoton microscopy

MPScope is a software suite to control and analyze data from custom-built multiphoton laser scanning fluorescence microscopes. The acquisition program MPScan acquires, displays and stores movies, linescans, image stacks or arbitrary regions from up to four imaging channels and up to two analog inputs, while plotting the intensity of regions of interest in real-time. Bidirectional linescans allow 256 × 256 pixel frames to be acquired at up to 10 fps with typical galvanometric scanners. A fast stack mode combines movie acquisition with continuous z-focus motion and adjustment of laser intensity for constant image brightness. Fast stacks can be automated by custom programs running in an integrated scripting environment, allowing a 1 mm 3 cortical volume to be sampled in 1 billion voxels in approximately 1 h. The analysis program MPView allows viewing of stored frames, projections, automatic detection of cells and plotting of their average intensity across frames, direct frame transfer to Matlab, AVI movie creation and file export to ImageJ. The combination of optimized code, multithreading and COM (Common Object Model) technologies enables MPScope to fully take advantage of custom-built two-photon microscopes and to simplify their realization.

Real-time gain correction method using a reference light for an area-parallel-type frame-transfer charge-coupled device with multi-output taps

The authors propose a technique for performing real-time correction of the gain nonuniformity at output taps in an area-parallel-type frame transfer CCD (FT-CCD) by incorporating a reference optical signal. This technique activates a reference light source every vertical blanking (V-blanking) period, during which time the image sensor is shielded from incident light, and uses that output signal level to automatically adjust the gain of each block. For this method, a color-separation prism with reference light sources has been developed. In addition, to obtain a reference signal from the reference light source emitting for about 11% of the V-blanking period, a new method of accumulating the electron signal generated by the reference light source is described for the CCD. The results of a camera experiment using an 8-million-pixel CCD are described, and the compensation accuracy of this method is discussed.

Argos: An optimized time-series photometer

We designed a prime focus CCD photometer, Argos, optimized for high speed time-series measurements of blue variables (Nather & Mukadam 2004) for the 2.1 m telescope at McDonald Observatory. Lack of any intervening optics between the primary mirror and the CCD makes the instrument highly efficient. We measure an improvement in sensitivity by a factor of nine over the 3-channel PMT photometers used on the same telescope and for the same exposure time. The CCD frame transfer operation triggered by GPS synchronized pulses serves as an electronic shutter for the photometer. This minimizes the dead time between exposures, but more importantly, allows a precise control of the start and duration of the exposure. We expect the uncertainty in our timing to be less than 100μs.

From the echocardiography machine to the lecture room: a simple method for transferring echocardiographic frames and loops to a personal computer.

The use of computers in scientific and educational presentations is rapidly increasing. As a digital presentation is ideal for showing moving images, the use of multimedia files, e.g., echocardiographic loops within these presentations, is common. Even though recent echocardiography machines store acquired data in a digital format, these data are often not readily accessible to be transferred to a personal computer. We present an easy and cost-efficient method for transferring frames and loops from any echocardiography machine into a personal computer using a digital video camera equipped with a standard analog input and flash memory. Still images and movies are stored in the camera to be subsequently transferred to a personal computer. In the computer, still images and movies are post-processed with graphical and video editing software. Finally, the still images and movies can be projected from the video camera or presented with specialized software such as PowerPoint. The images can also be used for Web-based publications and production of educational material or books on electronic media such as CD-ROM. The described method can also be used to transfer images from other proprietary devices and programs, as long as the devices are equipped with an analog video outlet. The transfer of frames and loops from echocardiographic machines to personal computers is often useful for publication, teaching, and educational purposes. We present an easy and cost-effective method for transferring frames and loops from any echocardiography machine into a personal computer using a digital video camera.

High-Speed Imaging and Spectro-Polarimetry with Subaru Telescope

AbstractWe are developing a high-speed option for the Faint Object Camera and Spectrograph (FOCAS) at the Cassegrain focus of the Subaru 8.2 meter telescope at Mauna Kea, Hawaii. FOCAS has been used for direct imaging, low-dispersion multi-object spectroscopy, imaging polarimetry and spectro-polarimetry of faint objects. The high-speed option utilizes an EEV CCD47-20 with the frame transfer operation to achieve up to ~ 0.1 sec time resolution. This paper presents a summary of the expected capability and the implementation schedule.

클라이언트의 동적 버퍼 제어 신호에 의한 서버의 프레임 생략 전송 정책

VOD 서비스의 대부분 정책들은 주로 서버 시스템에 대해 연구되고 있고, 단절감 없는 재생과 재생질 보증의 근간이 되는 클라이언트의 버퍼 안정화 문제에 대해서는 언급되지 않고 있다. 본 논문에서는 클라이언트의 버퍼 상태가 스타베이션 또는 오버런인 경우 서버에 동적인 제어신호를 발하고, 서버에서는 수신된 제어 요구 신호에 따라 프레임을 생략하여 전송하는 정책을 제안한다. 그리고 시뮬레이션을 통하여 제안 정책이 클라이언트의 버퍼 상태 악화로 인한 프레임의 미수신 및 손실을 방지하여 클라이언트의 버퍼를 안정화시켜 재생질 보증에 더 효율적임을 보인다. Most policies of VOD services are mainly studied about server system, and make no touch on clients buffer stabilization which is the basis of guaranteeing playback quality and playing without cut off. In this paper, we proposed a skipping frame transfer policy that can sending dynamic buffer control signal to server in accordance with clients buffer state of starvation or overrun, and server transfers a skipped frame to client after receive the control signal. And through a simulation, we show the suggested policy is more efficiency on playback quality by buffer stabilization which is by preventing loss and miss for receiving frame due to grow worse client buffer state.

Mars Exploration Rover Athena Panoramic Camera (Pancam) investigation

The Panoramic Camera (Pancam) investigation is part of the Athena science payload launched to Mars in 2003 on NASA's twin Mars Exploration Rover (MER) missions. The scientific goals of the Pancam investigation are to assess the high‐resolution morphology, topography, and geologic context of each MER landing site, to obtain color images to constrain the mineralogic, photometric, and physical properties of surface materials, and to determine dust and aerosol opacity and physical properties from direct imaging of the Sun and sky. Pancam also provides mission support measurements for the rovers, including Sun‐finding for rover navigation, hazard identification and digital terrain modeling to help guide long‐term rover traverse decisions, high‐resolution imaging to help guide the selection of in situ sampling targets, and acquisition of education and public outreach products. The Pancam optical, mechanical, and electronics design were optimized to achieve these science and mission support goals. Pancam is a multispectral, stereoscopic, panoramic imaging system consisting of two digital cameras mounted on a mast 1.5 m above the Martian surface. The mast allows Pancam to image the full 360° in azimuth and ±90° in elevation. Each Pancam camera utilizes a 1024 × 1024 active imaging area frame transfer CCD detector array. The Pancam optics have an effective focal length of 43 mm and a focal ratio of f/20, yielding an instantaneous field of view of 0.27 mrad/pixel and a field of view of 16° × 16°. Each rover's two Pancam “eyes” are separated by 30 cm and have a 1° toe‐in to provide adequate stereo parallax. Each eye also includes a small eight position filter wheel to allow surface mineralogic studies, multispectral sky imaging, and direct Sun imaging in the 400–1100 nm wavelength region. Pancam was designed and calibrated to operate within specifications on Mars at temperatures from −55° to +5°C. An onboard calibration target and fiducial marks provide the capability to validate the radiometric and geometric calibration on Mars.