Mapping of ultrasonic thickness measurements using laser grid projection and image processing

2019 ◽  
Vol 61 (11) ◽  
pp. 643-649 ◽  
Author(s):  
T Tesfaye ◽  
M S Mohammed ◽  
K Ki-Seong

A three-dimensional surface mapping method for ultrasonic thickness measurements is proposed to enable the dimensions and positions of measured values obtained by the conventional ultrasonic thickness gauges and flaw detectors on curved surfaces to be determined. The proposed system consists of a laser pattern generator and image processing methods. The laser grid produced by the pattern generator is projected onto the surface of the item to be inspected, mathematical relationships are developed to localise the grid nodes on the inspection surface and images are then captured using a complementary metal-oxide semiconductor (CMOS) camera. An image processing algorithm is developed to plot the scanned surface. The measurements performed using a thickness gauge are correlated with the plotted surface, which will enable thickness mapping. The experiments were carried out on a pipe with an artificial metal loss defect and the results showed that the developed method can accurately locate measured thickness values on a three-dimensional plotted surface.

2010 ◽  
Vol 10 (04) ◽  
pp. 531-544 ◽  
Author(s):  
FLORIAN DRAMAS ◽  
SIMON J. THORPE ◽  
CHRISTOPHE JOUFFRAIS

Although artificial vision systems could potentially provide very useful input to assistive devices for blind people, such devices are rarely used outside of laboratory experiments. Many current systems attempt to reproduce the visual image via an alternative sensory modality (often auditory or somatosensory), but this dominant "scoreboard" approach, is often difficult to interpret for the user. Here, we propose to offload the recognition problem onto a separate image processing system that then provides the user with just the essential information about the location of objects in the surrounding environment. Specifically, we show that a bio-inspired image processing algorithm (SpikeNet) can not only robustly, precisely, and rapidly recognize and locate key objects in the image, but also in space if the objects are in a stereoscopic field of view. In addition, the bio-inspired algorithm allows real-time calculation of optic flow. We hence propose that this system, coupled with a restitution interface allowing localization in space (i.e. three-dimensional virtual sounds synthesis) can be used to restore essential visuomotor behaviors such as grasping desired objects and navigating (finding directions, avoiding obstacles) in unknown environments.


Robotica ◽  
1993 ◽  
Vol 11 (4) ◽  
pp. 329-337 ◽  
Author(s):  
M. Mehdian ◽  
P.M. Johns-Rahnejat ◽  
H. Rahnejat

SUMMARYThis paper presents a sensory gripper, consisting of two tactile sensing matrices which acquire three dimensional images of objects of interest. The image processing algorithm uses elastostatic contact information to discriminate among a host of parts made of different materials. The algorithm also enables the assessment of orientation of parts without the pre-requisite of having to recognise them. The positions of stable holdsites and a safe gripping force are also evaluated.


2013 ◽  
Vol 846-847 ◽  
pp. 1068-1071
Author(s):  
Yu Fu

Under the background of information age, the computer plays a dominant role, and especially the emergence of the network makes the parallel computing possible. It makes the computer do a lot of image information processing in a short period of time, so as to obtain the best effect of art image design. Based on this principle, we design the model and algorithm of art image design through computer. We use normal bump of texture image processing technology, transforming two-dimensional image to 3D display, so as to achieve a good effect of art show. Finally, based on the construction of city public environmental art and city image, using the public environmental logo design as an example, we study the three-dimensional effect in identification system, so as to get a good image of the city, and provide a theoretical reference for the study of city public art and the image of the city.


Author(s):  
Weiping Liu ◽  
John W. Sedat ◽  
David A. Agard

Any real world object is three-dimensional. The principle of tomography, which reconstructs the 3-D structure of an object from its 2-D projections of different view angles has found application in many disciplines. Electron Microscopic (EM) tomography on non-ordered structures (e.g., subcellular structures in biology and non-crystalline structures in material science) has been exercised sporadically in the last twenty years or so. As vital as is the 3-D structural information and with no existing alternative 3-D imaging technique to compete in its high resolution range, the technique to date remains the kingdom of a brave few. Its tedious tasks have been preventing it from being a routine tool. One keyword in promoting its popularity is automation: The data collection has been automated in our lab, which can routinely yield a data set of over 100 projections in the matter of a few hours. Now the image processing part is also automated. Such automations finish the job easier, faster and better.


Author(s):  
Jose-Maria Carazo ◽  
I. Benavides ◽  
S. Marco ◽  
J.L. Carrascosa ◽  
E.L. Zapata

Obtaining the three-dimensional (3D) structure of negatively stained biological specimens at a resolution of, typically, 2 - 4 nm is becoming a relatively common practice in an increasing number of laboratories. A combination of new conceptual approaches, new software tools, and faster computers have made this situation possible. However, all these 3D reconstruction processes are quite computer intensive, and the middle term future is full of suggestions entailing an even greater need of computing power. Up to now all published 3D reconstructions in this field have been performed on conventional (sequential) computers, but it is a fact that new parallel computer architectures represent the potential of order-of-magnitude increases in computing power and should, therefore, be considered for their possible application in the most computing intensive tasks.We have studied both shared-memory-based computer architectures, like the BBN Butterfly, and local-memory-based architectures, mainly hypercubes implemented on transputers, where we have used the algorithmic mapping method proposed by Zapata el at. In this work we have developed the basic software tools needed to obtain a 3D reconstruction from non-crystalline specimens (“single particles”) using the so-called Random Conical Tilt Series Method. We start from a pair of images presenting the same field, first tilted (by ≃55°) and then untilted. It is then assumed that we can supply the system with the image of the particle we are looking for (ideally, a 2D average from a previous study) and with a matrix describing the geometrical relationships between the tilted and untilted fields (this step is now accomplished by interactively marking a few pairs of corresponding features in the two fields). From here on the 3D reconstruction process may be run automatically.


Author(s):  
B.V.V. Prasad ◽  
E. Marietta ◽  
J.W. Burns ◽  
M.K. Estes ◽  
W. Chiu

Rotaviruses are spherical, double-shelled particles. They have been identified as a major cause of infantile gastroenteritis worldwide. In our earlier studies we determined the three-dimensional structures of double-and single-shelled simian rotavirus embedded in vitreous ice using electron cryomicroscopy and image processing techniques to a resolution of 40Å. A distinctive feature of the rotavirus structure is the presence of 132 large channels spanning across both the shells at all 5- and 6-coordinated positions of a T=13ℓ icosahedral lattice. The outer shell has 60 spikes emanating from its relatively smooth surface. The inner shell, in contrast, exhibits a bristly surface made of 260 morphological units at all local and strict 3-fold axes (Fig.l).The outer shell of rotavirus is made up of two proteins, VP4 and VP7. VP7, a glycoprotein and a neutralization antigen, is the major component. VP4 has been implicated in several important functions such as cell penetration, hemagglutination, neutralization and virulence. From our earlier studies we had proposed that the spikes correspond to VP4 and the rest of the surface is composed of VP7. Our recent structural studies, using the same techniques, with monoclonal antibodies specific to VP4 have established that surface spikes are made up of VP4.


2020 ◽  
pp. 1192-1198
Author(s):  
M.S. Mohammad ◽  
Tibebe Tesfaye ◽  
Kim Ki-Seong

Ultrasonic thickness gauges are easy to operate and reliable, and can be used to measure a wide range of thicknesses and inspect all engineering materials. Supplementing the simple ultrasonic thickness gauges that present results in either a digital readout or as an A-scan with systems that enable correlating the measured values to their positions on the inspected surface to produce a two-dimensional (2D) thickness representation can extend their benefits and provide a cost-effective alternative to expensive advanced C-scan machines. In previous work, the authors introduced a system for the positioning and mapping of the values measured by the ultrasonic thickness gauges and flaw detectors (Tesfaye et al. 2019). The system is an alternative to the systems that use mechanical scanners, encoders, and sophisticated UT machines. It used a camera to record the probe’s movement and a projected laser grid obtained by a laser pattern generator to locate the probe on the inspected surface. In this paper, a novel system is proposed to be applied to flat surfaces, in addition to overcoming the other limitations posed due to the use of the laser projection. The proposed system uses two video cameras, one to monitor the probe’s movement on the inspected surface and the other to capture the corresponding digital readout of the thickness gauge. The acquired images of the probe’s position and thickness gauge readout are processed to plot the measured data in a 2D color-coded map. The system is meant to be simpler and more effective than the previous development.


Author(s):  
Supriyadi Supriyadi

Pipa  penyalur  minyak  umumnya  menggunakan  material  baja  karbon.  Salah  satu  masalah  besar  dalam penggunaan material tersebut yang berkaitan dengan korosi yaitu terjadinya kebocoran akibat adanya pengaruh konsentrasi ion klorida yang terlarut dalam media air sehingga lingkungan bersifat korosif (asam). Oleh karena itu sebagai upaya untuk mengatasi masalah tersebut perlu diketahui besaran laju korosi material baja karbon tersebut. Dalam penelitian ini dilakukan perbandingan antara laju korosi yang diperoleh dari metode pengujian linear polarisasi resistance dan pengukuran metal loss dengan peralatan ultrasonic thickness meter. Output dari kedua metode tersebut selanjutnya diperoleh hubungan laju korosi melalui analysis of variance dengan menggunakan software. Studi pengaruh kadar klorida dilakukan untuk mengetahui korosi internal pipa baja karbon API 5L Grade B yang digunakan sebagai pipa penyalur minyak di lapangan. Metode pengujian polarisasi resistance dilakukan dalam media larutan air formasi NaCl 1%, 2% dan 3.5%. Laju korosi internal pipa baja karbon API 5L Grade B cenderung meningkat seiring dengan meningkatnya konsentrasi klorida dalam media larutan. Penelitian ini juga menunjukkan bahwa pipa baja karbon API 5L Grade B memiliki ketahanan korosi yang cukup pada fluida dengan konsentrasi klorida 1%, 2% dan 3.5%.


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