scholarly journals PROBES, POPULATIONS, SAMPLES, MEASUREMENTS AND RELATIONS IN STEREOLOGY

2011 ◽  
Vol 19 (1) ◽  
pp. 1 ◽  
Author(s):  
Robert T Dehoff

This summary paper provides an overview of the content of stereology. The typical problem at hand centers around some three dimensional object that has an internal structure that determines its function, performance, or response. To understand and quantify the geometry of that structure it is necessary to probe it with geometric entities: points, lines, planes volumes, etc. Meaningful results are obtained only if the set of probes chosen for use in the assessment is drawn uniformly from the population of such probes for the structure as a whole. This requires an understanding of the population of each kind of probe. Interaction of the probes with the structure produce geometric events which are the focus of stereological measurements. In almost all applications the measurement that is made is a simple count of the number of these events. Rigorous application of these requirements for sample design produce unbiased estimates of geometric properties of features in the structure no matter how complex are the features or what their arrangement in space. It is this assumption-free characteristic of the methodology that makes it a powerful tool for characterizing the internal structure of three dimensional objects.

2003 ◽  
Vol 11 (1) ◽  
pp. 12-17 ◽  
Author(s):  
John M. Basgen

Many us who use microscopes are interested in the internal structure or components of three-dimensional objects. Often we must section these objects to observe these internal components. For many years, microtomes have been used to make physical sections, but in recent years confocal microscopes, MR imaging, CT scanners, and even standard optical microscopes have been used to obtain “optical” sections. Two-dimensional images of these different types of sections can be used to extract three-dimensional quantitative information about the objects and their internal components, The sectioning process reduces the observed dimensions of the object and components. With apologies to Rene Magritte, the structure portrayed in Figure 1 is not a three-dimensional glomerulus but a two-dimensional profile of a glomerulus. In most cases, interest is on the structure of the three-dimensional object and not the structure in the two-dimensional image. Thus, care must be taken when obtaining and interpreting data from two-dimensional images.


2021 ◽  
Vol 58 (3) ◽  
pp. 137-142
Author(s):  
A.O. Dauitbayeva ◽  
◽  
A.A. Myrzamuratova ◽  
A.B. Bexeitova ◽  
◽  
...  

This article is devoted to the issues of visualization and information processing, in particular, improving the visualization of three-dimensional objects using augmented reality and virtual reality technologies. The globalization of virtual reality has led to the introduction of a new term "augmented reality"into scientific circulation. If the current technologies of user interfaces are focused mainly on the interaction of a person and a computer, then augmented reality with the help of computer technologies offers improving the interface of a person and the real world around them. Computer graphics are perceived by the system in the synthesized image in connection with the reproduction of monocular observation conditions, increasing the image volume, spatial arrangement of objects in a linear perspective, obstructing one object to another, changing the nature of shadows and tones in the image field. The experience of observation is of great importance for the perception of volume and space, so that the user "completes" the volume structure of the observed representation. Thus, the visualization offered by augmented reality in a real environment familiar to the user contributes to a better perception of three-dimensional object.


2012 ◽  
Vol 220-223 ◽  
pp. 2803-2808
Author(s):  
Xiao Ping Wang ◽  
Xiu Cheng Dong

Collision detection in Vega Prime is based on the simple line segment, and collision detection based on bounding box is not realized. By studying the composition of three-dimensional object based on Oriented Bounding Box (OBB), we define a collision detection class, which inherits from vpIsector. After finding out all vertices of geometry in object, we connect these vertices one by one and constitute a tend line. The trend line constitutes our bounding box based on OBB. Now, our collision detection is based on three-dimensional objects, but not the simple line segment. At the same time, we can control the efficiency of collision detection by increasing or decreasing the number of collision lines on the actual demand. Additionally, on this basis, we have made the further application. By adjusting parameter, we can get a bounding box with early warning mechanism or collision tolerance.


Author(s):  
Andrew J. Birnbaum ◽  
Athanasios P. Iliopoulos ◽  
John C. Steuben ◽  
John G. Michopoulos

Despite increasing levels of acceptance, traditional additive manufacturing techniques continue to suffer from a number of fundamental drawbacks that act to limit broad adoption. These drawbacks include limits on processable materials, part properties/performance, geometric deviation and repeatability. The vast majority of existing processes also rely on a point-by-point approach to generate parts, resulting in exceedingly long build times and extremely poor scaling behavior. Furthermore, in general, current systems require significant levels of complexity for operation, resulting in the need for considerable upfront capital investment as well as continuing maintenance costs. A new manufacturing approach is presented here, based upon the generation of objects from the direct creation of constituent volumetric sub-regions. This process addresses many of the limitations described above, and has the potential to significantly alter the manner with which three-dimensional objects are realized.


2010 ◽  
Vol 8 (54) ◽  
pp. 144-151 ◽  
Author(s):  
Johan Hattne ◽  
Victor S. Lamzin

Chirality is an important feature of three-dimensional objects and a key concept in chemistry, biology and many other disciplines. However, it has been difficult to quantify, largely owing to computational complications. Here we present a general chirality measure, called the chiral invariant (CI), which is applicable to any three-dimensional object containing a large amount of data. The CI distinguishes the hand of the object and quantifies the degree of its handedness. It is invariant to the translation, rotation and scale of the object, and tolerant to a modest amount of noise in the experimental data. The invariant is expressed in terms of moments and can be computed in almost no time. Because of its universality and computational efficiency, the CI is suitable for a wide range of pattern-recognition problems. We demonstrate its applicability to molecular atomic models and their electron density maps. We show that the occurrence of the conformations of the macromolecular polypeptide backbone is related to the value of the CI of the constituting peptide fragments. We also illustrate how the CI can be used to assess the quality of a crystallographic electron density map.


Author(s):  
Eleni Ira Panourgia ◽  
Finbar Wheelaghan ◽  
Xue Yang

This article discusses a prototype that explores the simultaneous manipulation of three-dimensional digital forms and sound. Our multi-media study examines the aesthetic affordances of tight parameter couplings between digital three-dimensional objects and sound objects based on notions of process and user-machine interaction. It investigates how effective cohesion between visual, spatial and sonic might be established through changes perceived in parallel; what Michel Chion refers to as 'synchresis'. Drawing from Mike Blow's work On the Simultaneous Perception of Sound and Three-Dimensional Objects and processual art, this prototype uses computer technology for forming and mediating a creative practice involving 3D animation, sound synthesis, digital signal processing and programming. Our practice-based approach entails the rendering of a three-dimensional digital object in Processing whose form changes over time according to specific actions. Spatial data is sent via Open Sound Control (OSC) to Max MSP in real time, where sound is synthesized and then manipulated. Sonic parameters such as amplitude, spectral density/width and timbre are controlled by select spatial parameters from the three-dimensional object. Sound processing is realized based on the changing of the three-dimensional object in time through basic actions such as splitting, distorting, cutting, shattering and rotating. We use digital technology to look beyond basic synchronisation of sound and vision to a more complex cohesion of percepts, based on changes to myriad sonic and visual parameters experienced concurrently.


1988 ◽  
Vol 32 (18) ◽  
pp. 1299-1303 ◽  
Author(s):  
James A. Kleiss ◽  
David G. Curry ◽  
David C. Hubbard

Three-dimensional objects placed on simulated terrain surfaces are particularly effective as cues for altitude in simulated low-level flight. To conserve the limited edge processing capacity of computer image generators (CIGs), objects have typically been simple in shape and therefore fairly abstract in appearance. The present investigation sought to determine whether the apparent size of more detailed and familiar appearing objects (e.g., trees and bushes) serves as an additional cue for altitude in simulated low-level flight. Results showed no differences in performance between abstract objects and familiar objects. However, performance did improve with increases in object density, at least for some performance measures. These results suggest that CIG processing capacity may be most effectively utilized by increasing object density rather than individual object detail.


Perception ◽  
1994 ◽  
Vol 23 (8) ◽  
pp. 905-912 ◽  
Author(s):  
Ilpo Kojo ◽  
Marja Liinasuo ◽  
Jyrki Rovamo

Rotation of a Kanizsa triangle in depth around its vertical axis causes a perception of a three-dimensional object with a flat, rigid illusory triangle between the inducing discs. When the inducing discs of a Kanizsa triangle were made thicker, the illusory triangle between the discs also became thicker. In the experiments both computer animation and real inducers made of plastic were used. The method promoted border perception in a three-dimensional illusory figure. We suggest that the perception of three-dimensional illusory objects is due to a process which is also used in the perception of real three-dimensional objects.


2019 ◽  
Vol 2 (3) ◽  
pp. 116-121
Author(s):  
Akbar Begmatov

We consider the problem of determining the internal structure of the three-dimensional object from integral data obtained by tomografic scanning using a cone scheme over a family of right circular cones. Stability estimates are proven and inversion formula is obtained.


2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Gede Setiadarma ◽  
Agus Adiarta ◽  
Nyoman Santiyadnya

Research development aims to: 1) create a media instructional videos electrically conductive include three-dimensional objects, 2) determine the feasibility of video media learning electrical conductors include three-dimensional object, 3) determine the response of students to use video media learning electrical conductors include three-dimensional object. This research is a study of R & D to adapt the pace of development of Sugiyono development model. Media that was developed in the validation by experts and expert media content. Calculation of instruments to the experts and field trials using a scale Linkert. The results of this study in the form of video media products and media learning objects in three dimensions. The results of the percentage gain media expert feasibility level by 98, 67% with a very decent qualifications and earn a percentage of content expert feasibility level of 100% with a very decent qualifications. Results of a small study group trial amounted to 91.27% (excellent qualifications) and a large group trial that shows a student's response amounted to 93.72% (excellent qualifications). So media instructional video and three-dimensional objects that are developed feasible in the subject of wiring and installation techniques for the third semester students of Electrical Engineering Education Program Undiksha.


Sign in / Sign up

Export Citation Format

Share Document