where expertise comes together - since 1996 -

The Largest Open Access Portal of Nondestructive Testing (NDT)

Conference Proceedings, Articles, News, Exhibition, Forum, Network and more

where expertise comes together
- since 1996 -

607 views
Technical Discussions
Philippe Rubbers
Engineering
SCM, South Africa, Joined Nov 1998, 21

Philippe Rubbers

Engineering
SCM,
South Africa,
Joined Nov 1998
21
06:51 Mar-14-2002
SAFT

Dear Sir

I would like to know if SAFT (Synthetic Aperture Focusing Technique) used in ultrasonics is the same as SAR (Synthetic Aperture Radar) and if SAFT requires coherent pulses to work.

If it does not use coherent pulses, where can I get more information on the equations used (since it cannot use diffraction equations).

If it does use coherent pulses, are there any manufacturers of industrical UT equipment which make coherent pulsers.

Best regards
Philippe Rubbers ( Philippe.Rubbers@eskom.co.za )


    
 
 
M. Schickert
R & D,
Institute for Materials Research and Testing, Germany, Joined Jan 2000, 18

M. Schickert

R & D,
Institute for Materials Research and Testing,
Germany,
Joined Jan 2000
18
00:05 Mar-18-2002
Re: SAFT
SAFT/SAR: SAFT has been developed in analogy to SAR (also adopting principles from optical holography and geophysics), so the algorithms are similiar except that in SAR usually far field approximations are made to accelerate computation. For synthetic focusing, all ultrasonic imaging techniques (SAFT, SAR, holography, tomography) require coherent superposition of received signals, although special incoherent methods exist.

Coherent Pulses: The term "coherent" applies to continuous waves in the first place. When using short pulses as a container for a broad frequency spectrum, the temporal relation of pulses determines the phase relation of the waves and therefore their coherence. So all one has to do in an imaging experiment is to assure fixed temoral relationship between the transmitted and each received signal. This can be done by triggering A/D-conversion by the transmitted pulse. For increased accuracy, the instruments clocks involved should be coupled. It should be noted that coherent imaging also requires coherent propagation of pulses in the medium imaged. Problems might occur in, e.g., fluctuating and strongly scattering media.


    
 
 

Product Spotlight

IRIS 9000Plus - Introducing the next generation of heat exchanger inspection.

Representing the seventh generation of the IRIS system, the IRIS 9000 Plus has nearly 200 years of c
...
ombined field inspection experience incorporated in its design. This experience combined with a strong commitment to quality and a history of innovation has made Iris Inspection Services® the undisputed leader in IRIS technology.
>

HD-CR 35 NDT Computed Radiography System

Portable high-resolution CR scanner for all radiography applications - weld testing, profile images
...
and aerospace. No matter what type of radiographic testing you are performing, the unique TreFoc Technology of the HD-CR 35 NDT imaging plate scanner always guarantees the highest image quality.
>

GEKKO - Portable Phased Array Testing with TFM in Real-Time

The portable phased array testing system GEKKO provides 64 parallel test channels. On creating testi
...
ng parameters the operator is assisted by the CIVA software. Due to its modular set-up the GEKKO instrument is suitable for operators of all skill levels.
>

Magnetic X-Ray Pipeline Crawler

Zhong Yi brand pipeline crawler is magnetic/micro-video controlled crawler with DC X ray unit inst
...
alled for checking welding of pipeline. Move steadily inside the pipeline 6''-60''diameter with speed of up to 18m/min, Max. moving diatance 5 kilometers and provide the efficient inspection of the pipeline.
>

Share...
We use technical and analytics cookies to ensure that we will give you the best experience of our website - More Info
Accept
top
this is debug window