scholarly journals On the determination of 3D position and orientation of spheroidal particles using defocusing and deep learning

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Massimiliano Rossi
Keyword(s):  
Spherical Particles ◽  
Single Camera ◽  
Reference Library ◽  
Complex Objects ◽  
Tracer Particles ◽  
Reference Images ◽  
Unicellular Organisms ◽  
Position And Orientation ◽  
Particle Images

Tracking the 3D position of tracer particles or small objects like cells or unicellular organisms in miniaturized lab-on-a-chip or biomedical devices is complicated since it is often not possible in these setups to use multi-camera approaches. Most successful single-camera approaches for these applications are based on holography or defocusing. Holographic methods have been used to track complex objects such has bacteria (Bianchi et al. (2019)) and even to estimate their orientation (Wang et al. (2016)). However, these methods require a complex and expensive experimental setup which is not always available in research laboratories. On the other hand, defocusing methods work with conventional microscopic optics, are easy to implement, and have shown excellent results in 3D PTV experiments (Qiu et al. (2019)). One main drawback is that they normally work only with spherical and mono-dispersed tracer particles. A defocusing method that has potential to measure non-spherical particles is the General Defocusing Particle Tracking (Barnkob and Rossi (2020)) which is based on pattern recognition and can be conceptually extended to more complex tasks by extending the reference library of particle images, including not only spherical particles at different depth positions, but also non-spherical particles at different orientations. However, whether this approach could work in practice is still unknown. First, is the information contained in simple defocused images sufficient to reconstruct depth and orientation of non-spherical particles, and eventually under which circumstances? Second, how to practically collect the labelled reference images?

scholarly journals On the uncertainty of defocus methods for 3D particle tracking velocimetry

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Christian Cierpka ◽  
Sebastian Sachs ◽  
Patrick Mäder ◽  
Minqian Chen ◽  
Rune Barnkob ◽  
...  
Keyword(s):  
Velocity Vector ◽  
Particle Tracking Velocimetry ◽  
Low Cost ◽  
Optical Systems ◽  
Single Camera ◽  
Additional Equipment ◽  
Image Processing Algorithms ◽  
Processing Algorithms ◽  
Particle Images

Defocus methods have become more and more popular for the estimation of the 3D position of particles in flows (Cierpka and Kahler, 2011; Rossi and K ¨ ahler, 2014). Typically the depth positions of particles are ¨ determined by the defocused particle images using image processing algorithms. As these methods allow the determination of all components of the velocity vector in a volume using only a single optical access and a single camera, they are often used in, but not limited to microfluidics. Since almost no additional equipment is necessary they are low-cost methods that are meanwhile widely applied in different fields. To overcome the ambiguity of perfect optical systems, often a cylindrical lens is introduced in the optical system which enhances the differences of the obtained particle images for different depth positions. However, various methods are emerging and it is difficult for non-experienced users to judge what method might be best suited for a given experimental setup. Therefore, the aim of the presentation is a thorough evaluation of the performance of general advanced methods, including also recently presented neural networks (Franchini and Krevor, 2020; Konig et al., 2020) based on typical images.

Closed-Form Determination of the Location of a Rigid Body by Seven In-Parallel Linear Transducers

1996 ◽  
Author(s):  
Carlo Innocenti
Keyword(s):  
Rigid Body ◽  
Linear Equations ◽  
Parallel Manipulators ◽  
Rigid Bodies ◽  
Body Location ◽  
Position And Orientation ◽  
General Geometry ◽  
Two Bodies

Abstract The paper presents an original analytic procedure for unambiguously determining the relative position and orientation (location) of two rigid bodies based on the readings from seven linear transducers. Each transducer connects two points arbitrarily chosen on the two bodies. The sought-for rigid-body location simply results by solving linear equations. The proposed procedure is suitable for implementation in control of fully-parallel manipulators with general geometry. A numerical example shows application of the reported results to a case study.

scholarly journals The Structure and Function of the DNA from Bacteriophage Lambda

1966 ◽  
Vol 49 (6) ◽  
pp. 29-57 ◽  
Author(s):  
David S. Hogness
Keyword(s):  
Early Gene ◽  
Second Step ◽  
Wild Type ◽  
Gene Orientation ◽  
Variant Gene ◽  
Position And Orientation ◽  
The Right ◽  
And Function ◽  
Lambda Dna

The position and orientation of genes in lambda and lambda dg DNA are described. The position of six genes located in the right half of isolated lambda DNA was found to be -(N, iλ)--O-P---Q-R-(right end of DNA), which is their order on the genetic map of the vegetative phage. The order of the three genes of the galactose operon (k, t, and e) located in the left half of lambda dg DNA was found to be (left end of DNA)----k-t-e-, consistent with Campbell's model (5) for the formation of this variant. Gene orientation, defined as the direction of transcription along the DNA, is inferred to be from right to left for the galactose operon in lambda dg DNA. The strand of lambda DNA which functions as template in transcription of N, an "early" gene required for normal replication of lambda DNA, was determined as a first step in ascertaining the orientation of this gene. The method includes isolation of each strand, formation of each of two heteroduplex molecules consisting of one strand from wild-type and one from an N mutant) and comparison of their N activities. The second step, which consists of ascertaining the 5'-to-3' direction of each strand, is discussed, as is a determination of the orientation of gene R.

Closing in on Cracks

1998 ◽  
Vol 120 (07) ◽  
pp. 68-69
Author(s):  
Henry Baumgartner
Keyword(s):  
High Resolution ◽  
Digital Camera ◽  
Field Size ◽  
Reference Library ◽  
Advanced Imaging ◽  
Technology Center ◽  
Basic Issue ◽  
Reference Images ◽  
Flexible Imaging ◽  
Associated Data

This article focuses on a high-resolution digital camera that provides fast, flexible imaging for photomicrography and microscopy. Digital images are not only equal in quality to traditional images, but they are also three times faster to acquire, less expensive, easier to distribute, and more useful as reference images for future analysis. In terms of quality, the basic issue is matching images on 4-by-5-inch instant film, and recording the same field size with the same resolution. Reports with embedded digital image links are issued over the LAN so users do not have to seek out images separately on the Technology Center server. The department is also creating a reference library of microstructure images that have been captured digitally. Image Central software from Advanced Imaging Concepts in Princeton, N.J., is to be used to create the database with reference images and associated data.

Determination of Particle Size of a Dispersed Phase by Small-Angle X-ray Scattering

1989 ◽  
Vol 171 ◽  
Author(s):  
Frank C. Wilson
Keyword(s):  
Particle Size ◽  
High Resolution ◽  
Spherical Particles ◽  
Dispersed Phase ◽  
X Ray ◽  
X Ray Scattering ◽  
Resultant Data ◽  
Log Normal ◽  
Log Normal Distribution

ABSTRACTA method for determining particle diameters up to ca 500 rnm is described. X-ray data are obtained with an ultra-high resolution Bonse-Hart diffractometer and subsequently desmeared. The resultant data, viewed as the invariant argument h l(h), are interpreted as arising from a log-normal distribution of independent spherical particles. The distribution is characterized by its median value and breadth.

Real-time cooperative interaction between structured-light and reflectance ranging for robot guidance

Robotica ◽  
1985 ◽  
Vol 3 (1) ◽  
pp. 7-11 ◽  
Author(s):  
Ernest W. Kent ◽  
Thomas Wheatley ◽  
Marilyn Nashman
Keyword(s):  
Real Time ◽  
Moving Objects ◽  
Structured Light ◽  
Video Camera ◽  
The Other ◽  
Cooperative Interaction ◽  
Complex Objects ◽  
Improved Performance ◽  
Log Linear

SUMMARYWhen applied to rapidly moving objects with complex trajectories, the information-rate limitation imposed by video-camera frame rates impairs the effectiveness of structured-light techniques in real-time robot servoing. To improve the performance of such systems, the use of fast infra-red proximity detectors to augment visual guidance in the final phase of target acquisition was explored. It was found that this approach was limited by the necessity of employing a different range/intensity calibration curve for the proximity detectors for every object and for every angle of approach to complex objects. Consideration of the physics of the detector process suggested that a single log-linear parametric family could describe all such calibration curves, and this was confirmed by experiment. From this result, a technique was devised for cooperative interaction between modalities, in which the vision sense provided on-the-fly determination of calibration parameters for the proximity detectors, for every approach to a target, before passing control of the system to the other modality. This technique provided a three hundred percent increase in useful manipulator velocity, and improved performance during the transition of control from one modality to the other.

VISCOSITY METHOD FOR THE DETERMINATION OF THE THICKNESS OF SOLVATION LAYERS NEAR PARTICLES DISPERSED IN A LIQUID

2005 ◽  
Vol 12 (03) ◽  
pp. 457-462 ◽  
Author(s):  
SHAOXIAN SONG ◽  
YIMIN ZHANG ◽  
TOMLINSON FORT
Keyword(s):  
Size Distribution ◽  
Spherical Particle ◽  
Volume Fraction ◽  
Spherical Particles ◽  
Viscosity Method ◽  
Theoretical Derivation ◽  
Solid Spheres

In this paper, we present a method for determining the thickness of solvation layers near spherical particles dispersed in a liquid through measurements of the viscosity of the dispersion as a function of the volume fraction of the dry particles in the dispersion and the size distribution of the particles. It is termed viscosity method. The theoretical derivation for the method is based on Einstein's theory of viscosity of dispersions, while two assumptions are made: 1. Solvation layers contribute to increasing the viscosity of the dispersion in c times as the same volume of rigid solid spheres. 2. The thickness of solvation layers is the same near every chemically similar spherical particle in a given dispersion.

scholarly journals Automatic Mobility Analysis of Parallel Mechanisms: An Algorithm Approach Based on Position and Orientation Characteristic Equations

2019 ◽  
Author(s):  
Xiaorong Zhu ◽  
Huiping Shen ◽  
Chengqi Wu ◽  
Damien Chablat ◽  
Tingli Yang
Keyword(s):  
Systematic Approach ◽  
Fundamental Problem ◽  
Parallel Mechanisms ◽  
Mobility Analysis ◽  
Topological Structures ◽  
Design And Optimization ◽  
Logical Operations ◽  
Intelligent Analysis ◽  
Position And Orientation

Abstract The determination of the mobility of parallel mechanisms (PM) is a fundamental problem. An automatic and intelligent analysis software will be a significant tool for the design and optimization of mechanical systems. Based on the theory of position and orientation characteristics (POC) equations, a systematic approach to computer-aided mobility analysis of PMs is presented in this paper. First, a digital model for topological structures which has a mapping relationship with position and orientation characteristics of mechanism is proposed. It describes not only the dimension of the motion output, but also gives the mapping relationship between the output characteristic and the axis of the kinematic joints. Secondly, algorithmic rules are established that convert the union and intersection operations of POC into the binary logical operations and the automatic analysis of POC are realized. Then, the algorithm of the automatic mobility analysis of PMs and its implementation with VC++ are written. The mobility and its properties (POC) will also be analyzed and displayed automatically after introducing by users of the data of topological structures representation. Finally, typical examples are provided to show the effectiveness of the software platform.

Sign in / Sign up

Export Citation Format

Share Document