scholarly journals Fast Calculation of Computer Generated Holograms for 3D Photostimulation through Compressive-Sensing Gerchberg–Saxton Algorithm

2018 ◽  
Vol 2 (1) ◽  
pp. 2 ◽  
Author(s):  
Paolo Pozzi ◽  
Laura Maddalena ◽  
Nicolò Ceffa ◽  
Oleg Soloviev ◽  
Gleb Vdovin ◽  
...  
Keyword(s):  
Compressive Sensing ◽  
High Speed ◽  
High Performance ◽  
High Efficiency ◽  
Three Dimensions ◽  
Spatial Light Modulators ◽  
Multiple Diffraction ◽  
Excitation Light ◽  
Computer Generated Holograms

The use of spatial light modulators to project computer generated holograms is a common strategy for optogenetic stimulation of multiple structures of interest within a three-dimensional volume. A common requirement when addressing multiple targets sparsely distributed in three dimensions is the generation of a points cloud, focusing excitation light in multiple diffraction-limited locations throughout the sample. Calculation of this type of holograms is most commonly performed with either the high-speed, low-performance random superposition algorithm, or the low-speed, high performance Gerchberg–Saxton algorithm. This paper presents a variation of the Gerchberg–Saxton algorithm that, by only performing iterations on a subset of the data, according to compressive sensing principles, is rendered significantly faster while maintaining high quality outputs. The algorithm is presented in high-efficiency and high-uniformity variants. All source code for the method implementation is available as Supplementary Materials and as open-source software. The method was tested computationally against existing algorithms, and the results were confirmed experimentally on a custom setup for in-vivo multiphoton optogenetics. The results clearly show that the proposed method can achieve computational speed performances close to the random superposition algorithm, while retaining the high performance of the Gerchberg–Saxton algorithm, with a minimal hologram quality loss.

Five-Dimensional Microscopy using Widefield-Deconvolution: Practical Considerations and Biological Applications

1996 ◽  
Vol 54 ◽  
pp. 268-269
Author(s):  
W.F. Marshall ◽  
K. Oegema ◽  
J. Nunnari ◽  
A.F. Straight ◽  
D.A. Agard ◽  
...  
Keyword(s):  
Confocal Microscopy ◽  
High Speed ◽  
Laser Scanning ◽  
Ccd Camera ◽  
Image Plane ◽  
Time Lapse ◽  
Laser Scanning Confocal Microscopy ◽  
Three Dimensions ◽  
Excitation Light ◽  
Cooled Ccd

The ability to image cells in three dimensions has brought about a revolution in biological microscopy, enabling many questions to be asked which would be inaccessible without this capability. There are currently two major methods of three dimensional microscopy: laser-scanning confocal microscopy and widefield-deconvolution microscopy. The method of widefield-deconvolution uses a cooled CCD to acquire images from a standard widefield microscope, and then computationally removes out of focus blur. Using such a scheme, it is easy to acquire time-lapse 3D images of living cells without killing them, and to do so for multiple wavelengths (using computer-controlled filter wheels). Thus, it is now not only feasible, but routine, to perform five dimensional microscopy (three spatial dimensions, plus time, plus wavelength).Widefield-deconvolution has several advantages over confocal microscopy. The two main advantages are high speed of acquisition (because there is no scanning, a single optical section is acquired at a time by using a cooled CCD camera) and the use of low excitation light levels Excitation intensity can be much lower than in a confocal microscope for three reasons: 1) longer exposures can be taken since the entire 512x512 image plane is acquired in parallel, so that dwell time is not an issue, 2) the higher quantum efficiently of a CCD detect over those typically used in confocal microscopy (although this is expected to change due to advances in confocal detector technology), and 3) because no pinhole is used to reject light, a much larger fraction of the emitted light is collected. Thus we can typically acquire images with thousands of photons per pixel using a mercury lamp, instead of a laser, for illumination. The use of low excitation light is critical for living samples, and also reduces bleaching. The high speed of widefield microscopy is also essential for time-lapse 3D microscopy, since one must acquire images quickly enough to resolve interesting events.

scholarly journals Research on Distance Transform and Neural Network Lidar Information Sampling Classification-Based Semantic Segmentation of 2D Indoor Room Maps

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1365
Author(s):  
Tao Zheng ◽  
Zhizhao Duan ◽  
Jin Wang ◽  
Guodong Lu ◽  
Shengjie Li ◽  
...  
Keyword(s):  
Neural Network ◽  
High Speed ◽  
High Performance ◽  
High Efficiency ◽  
Semantic Segmentation ◽  
Raspberry Pi ◽  
Distance Transform ◽  
Testing Stage ◽  
Sampling Points ◽  
Information Sampling

Semantic segmentation of room maps is an essential issue in mobile robots’ execution of tasks. In this work, a new approach to obtain the semantic labels of 2D lidar room maps by combining distance transform watershed-based pre-segmentation and a skillfully designed neural network lidar information sampling classification is proposed. In order to label the room maps with high efficiency, high precision and high speed, we have designed a low-power and high-performance method, which can be deployed on low computing power Raspberry Pi devices. In the training stage, a lidar is simulated to collect the lidar detection line maps of each point in the manually labelled map, and then we use these line maps and the corresponding labels to train the designed neural network. In the testing stage, the new map is first pre-segmented into simple cells with the distance transformation watershed method, then we classify the lidar detection line maps with the trained neural network. The optimized areas of sparse sampling points are proposed by using the result of distance transform generated in the pre-segmentation process to prevent the sampling points selected in the boundary regions from influencing the results of semantic labeling. A prototype mobile robot was developed to verify the proposed method, the feasibility, validity, robustness and high efficiency were verified by a series of tests. The proposed method achieved higher scores in its recall, precision. Specifically, the mean recall is 0.965, and mean precision is 0.943.

scholarly journals High-speed high-resolution laser diode-based photoacoustic microscopy for in vivo microvasculature imaging

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Xiufeng Li ◽  
Victor T C Tsang ◽  
Lei Kang ◽  
Yan Zhang ◽  
Terence T W Wong
Keyword(s):  
High Resolution ◽  
High Speed ◽  
High Performance ◽  
Continuous Wave ◽  
Signal To Noise Ratio ◽  
Cost Effective ◽  
High Signal ◽  
Photoacoustic Microscopy ◽  
Mouse Ear

AbstractLaser diodes (LDs) have been considered as cost-effective and compact excitation sources to overcome the requirement of costly and bulky pulsed laser sources that are commonly used in photoacoustic microscopy (PAM). However, the spatial resolution and/or imaging speed of previously reported LD-based PAM systems have not been optimized simultaneously. In this paper, we developed a high-speed and high-resolution LD-based PAM system using a continuous wave LD, operating at a pulsed mode, with a repetition rate of 30 kHz, as an excitation source. A hybrid scanning mechanism that synchronizes a one-dimensional galvanometer mirror and a two-dimensional motorized stage is applied to achieve a fast imaging capability without signal averaging due to the high signal-to-noise ratio. By optimizing the optical system, a high lateral resolution of 4.8 μm has been achieved. In vivo microvasculature imaging of a mouse ear has been demonstrated to show the high performance of our LD-based PAM system.

scholarly journals Identification of cellular-activity dynamics across large tissue volumes in the mammalian brain

2017 ◽  
Author(s):  
Logan Grosenick ◽  
Michael Broxton ◽  
Christina K. Kim ◽  
Conor Liston ◽  
Ben Poole ◽  
...  
Keyword(s):  
High Speed ◽  
Dorsal Hippocampus ◽  
Computational Imaging ◽  
Three Dimensions ◽  
Large Field ◽  
Mammalian Brain ◽  
Subcortical Structures ◽  
Intact Tissue ◽  
Context Learning

Tracking the coordinated activity of cellular events through volumes of intact tissue is a major challenge in biology that has inspired significant technological innovation. Yet scanless measurement of the high-speed activity of individual neurons across three dimensions in scattering mammalian tissue remains an open problem. Here we develop and validate a computational imaging approach (SWIFT) that integrates high-dimensional, structured statistics with light field microscopy to allow the synchronous acquisition of single-neuron resolution activity throughout intact tissue volumes as fast as a camera can capture images (currently up to 100 Hz at full camera resolution), attaining rates needed to keep pace with emerging fast calcium and voltage sensors. We demonstrate that this large field-of-view, single-snapshot volume acquisition method—which requires only a simple and inexpensive modification to a standard fluorescence microscope—enables scanless capture of coordinated activity patterns throughout mammalian neural volumes. Further, the volumetric nature of SWIFT also allows fast in vivo imaging, motion correction, and cell identification throughout curved subcortical structures like the dorsal hippocampus, where cellular-resolution dynamics spanning hippocampal subfields can be simultaneously observed during a virtual context learning task in a behaving animal. SWIFT’s ability to rapidly and easily record from volumes of many cells across layers opens the door to widespread identification of dynamical motifs and timing dependencies among coordinated cell assemblies during adaptive, modulated, or maladaptive physiological processes in neural systems.

scholarly journals Experimental research in automobile non-pneumatic tire force heterogeneity

2018 ◽  
Vol 224 ◽  
pp. 02019 ◽  
Author(s):  
Vladimir Mazur
Keyword(s):  
High Speed ◽  
High Performance ◽  
High Efficiency ◽  
Motor Vehicle ◽  
Heavy Traffic ◽  
Polymeric Materials ◽  
Air Pressure ◽  
Motor Vehicles ◽  
Tire Force ◽  
Excess Air

Simplicity and high efficiency of a wheeled mover as a mechanism for converting rotational motion into a translatory one have conditioned its wide application in overland machines including motor vehicles. However a wheel with a non-pneumatic tyre (NPT) has a sufficient drawback lying in termination of a wheeled machine movement at the excess air pressure loss. Moreover, the loss of excess air pressure in a pneumatic tyre of traditional design at high speed of movement of a motor vehicle can lead to a traffic accident with heavy consequences. The stop of a motor vehicle to change a wheel on a heavy traffic roadway or roadside also poses a threat. These reasons determine the necessity of both well-known design improvements and search for the new wheeled mover design solutions to enhance a motor vehicle safety, the use of wheels with non-pneumatic tyres of elastic polymeric materials being one of them. Safety enhancement by means of non-pneumatic tyre use along with keeping the high performance of wheeled machine operational properties, is an important scientific and technical task that determines the research urgency.

scholarly journals High-Speed, High-Performance Real-Time Imaging of Physiological Sarcomere Dynamics in the Beating Mouse Heart in Vivo

2016 ◽  
Vol 110 (3) ◽  
pp. 463a
Author(s):  
Fuyu Kobirumaki-Shimozawa ◽  
Kotaro Oyama ◽  
Togo Shimozawa ◽  
Takashi Ohki ◽  
Takako Terui ◽  
...  
Keyword(s):  
Real Time ◽  
High Speed ◽  
High Performance ◽  
Mouse Heart ◽  
Real Time Imaging ◽  
Sarcomere Dynamics

Advantages and Drawbacks of Popular Supercritical Fluid Chromatography / Mass Spectrometry Interfacing Approaches—A User's Perspective

2005 ◽  
Vol 11 (2) ◽  
pp. 189-197 ◽  
Author(s):  
J. David Pinkston
Keyword(s):  
Mass Spectrometry ◽  
Supercritical Fluid ◽  
Supercritical Fluid Chromatography ◽  
High Speed ◽  
High Performance ◽  
High Efficiency ◽  
User Friendliness ◽  
Chromatographic Separations ◽  
Bioanalytical Applications ◽  
Column Pressure

Mobile phases in supercritical fluid chromatography (SFC) have low viscosities and high diffusion coefficients with respect to those of traditional high-performance liquid chromatography (HPLC). These properties allow higher mobile phase flow rates and/or longer columns in SFC, resulting in rapid analyses and high efficiency separations. In addition, chiral SFC is becoming especially popular. Mass spectrometry (MS) is arguably the most popular “informative” detector for chromatographic separations. Most SFC/MS is performed with atmospheric pressure ionization (API) sources. Unlike LC/MS, the interface between the SFC column and the API source must allow control of the downstream (post-column) pressure while also providing good chromatographic fidelity. Here, we compare and contrast the popular interfacing approaches. Some are simple, such as direct effluent introduction with no active back pressure regulator (BPR) in high-speed bioanalytical applications. The pressure-regulating fluid interface is more versatile and provides excellent chromatographic fidelity, but is less user friendly. The pre-BPR-split interface and an interface which provides total flow introduction with a mechanical BPR are good compromises between user friendliness and performance and have become the most popular among practitioners. Applications of SFC/MS using these various interfaces are also discussed.

Sintering of Vitrified Bond CBN Grinding Tool

2007 ◽  
Vol 280-283 ◽  
pp. 1391-1394 ◽  
Author(s):  
Zhi Hong Li ◽  
Yong Hong Zhang ◽  
Y.M. Zhu ◽  
Zheng Fang Yang
Keyword(s):  
High Speed ◽  
High Performance ◽  
High Efficiency ◽  
Sintering Temperature ◽  
Cubic Boron Nitride ◽  
Heating Process ◽  
Initial Oxidation ◽  
Grinding Tool ◽  
Vitrified Bond ◽  
Lower Temperature

Cubic boron nitride(CBN) is a superhard materials with many advantages and many uses. Vitrified bond CBN grinding tool is a promising abrasive tool of high performance used for high speed, high efficiency, high precision grinding with lower grinding cost and less environment pollution. Sintering of vitrified bond CBN grinding tool was investigated in this paper. The results showed that practical sintering temperature of this tool was much lower than the initial oxidation temperature of CBN particle measured by comprehensive thermal analysis. The upper limit of sintering temperature should be determined by taking account of the thermal analyzing results, heating process of CBN and its change in strength and structure. Within the sintering temperature range of the vitrified bond, relatively higher sintering temperature was beneficial to the strength of bond bridge and the holding strength between bond and CBN abrasive particles. CBN tool sintered at relatively lower temperature tended to fracture through the bond bridge, while the one sintered at higher temperature tended to fracture along the boundary between CBN abrasive grain and vitrified bond.

scholarly journals Adverse Effects of Hydroalcoholic Extracts and the Major Components in the Stems of Impatiens balsamina L. on Caenorhabditis elegans

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Hong-Fang Jiang ◽  
Zi-Heng Zhuang ◽  
Bei-Wei Hou ◽  
Bao-Jun Shi ◽  
Cheng-Jie Shu ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Adverse Effects ◽  
High Speed ◽  
High Performance ◽  
Negative Impact ◽  
C Elegans ◽  
Impatiens Balsamina ◽  
Annual Herb ◽  
Survival Frequency

Impatiens balsamina L. (Balsaminaceae), an annual herb found throughout China, has been extensively used in traditional Chinese medicine (TCM). However, our knowledge regarding the adverse effects of I. balsamina in vivo is very limited. In this present study, the nematode Caenorhabditis elegans model was employed to fully assess the adverse effects of hydroalcoholic (EtOH 55%) extracts of I. balsamina stems (HAEIBS) in vivo. After exposure to 10 mg/mL HAEIBS, the major organism-level endpoints of C. elegans of percent survival, frequency of head thrash and body bends, and reproduction had decreased by 24%, 30%, and 25%, respectively. The lifespan of C. elegans was also greatly reduced after HAEIBS exposure compared to the controls. The active compounds in HAEIBS were separated using high speed countercurrent chromatograph (HSCCC) and characterized by high performance liquid chromatography (HPLC) and nuclear magnetic resonance (NMR). Two compounds, lawsone and 2-methoxy-1,4-naphthoquinone (MNQ), and their adverse effects were then more thoroughly detailed in this study. It was found that lawsone is the major toxin in HAEIBS with a higher toxicity than MNQ in terms of negative impact on C. elegans mortality, locomotion, reproduction, and lifespan. Our data also suggests that the C. elegans model may be useful for assessing the possible toxicity of other Chinese medicines, plant extracts, and/or compounds.

scholarly journals High Speed Parallel SAD Architecture Implementation on FPGA for HEVC encoder

2019 ◽  
Vol 8 (6) ◽  
pp. 1235-1238
Keyword(s):  
Motion Estimation ◽  
Video Compression ◽  
High Speed ◽  
High Performance ◽  
High Efficiency ◽  
Block Size ◽  
Video Encoding ◽  
Computational Time ◽  
Absolute Difference ◽  
Asymmetric Mode

Video compression is a very complex and time consuming task which generally pursuit high performance. Motion Estimation (ME) process in any video encoder is responsible to primarily achieve the colossal performance which contributes to significant compression gain. Summation of Absolute Difference (SAD) is widely applied as distortion metric for ME process. With the increase in block size to 64×64 for real time applications along with the introduction of asymmetric mode motion partitioning(AMP) in High Efficiency Video Encoding (HEVC)causes variable block size motion estimation very convoluted. This results in increase in computational time and demands for significant requirement of hardware resources. In this paper parallel SAD hardware circuit for ME process in HEVC is propound where parallelism is used at various levels. The propound circuit has been implemented using Xilinx Virtex-5 FPGA for XC5VLX20T family. Synthesis results shows that the propound circuit provides significant reduction in delay and increase in frequency in comparison with results of other parallel architectures.

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