African Fusion June 2015

AFRICAN FUSION

June 2015

NDT: DICONDE

ow available in South Africa

through GammaTec, VIDAR

Systems Corporation, a 3D

digital radiography systems company,

is introducing a cost-effective industrial

scanner to digitise radiographic film,

which are then accessed and stored

using ASNT’s DICONDE (digital image

and communication for non destruc-

tive evaluation) imaging standard for

portability and compatibility with all

digital NDT analysis software.

“20 years ago, we saw the transition

in photography from35mm film to digi-

tal cameras. We have since

seen a similar

transition in

DICONDE:

Bridging NDT’s

digital divide

The VIDAR NDTPRO industrial film digitiser uses

the DICONDE standard for converting radiographic

film into a transportable and accessible format for

industrial users.

At an evening meeting at the SAIW earlier this year, Michael

Beaugrand (right) from Larivière of the US presented on the

latest technology for transitioning from film-based to digital

radiography.

African Fusion

reports

the medical market,” says Beaugrand,

adding that the medical radiography

transition is already 100% complete in

Scandinavian countries and over 80%

in most of the developed world. The

NDT fraternity is now going though that

same transition, albeit 15 years later, so

Beaugrand expects the full transition to

digital NDT to be nearing completion 10

to 15 years from now.

Highlighting the advantages of

digital radiography, he says that, in

principle, the sources, shielding and

collection techniques are the same as

those use for film-based methods.

But a detector is used to

capture the image instead

of film – and there are two

detector technologies cur-

rently in use, computed

radiography (CR) anddirect

radiography (DR) detec-

tors.

“The post exposure im-

age formation, however, is

different from film. Instead

of a light box, a computer

and monitor are re-

quired to view digital

radiographs, and

instead of the grey

exposure shades

fixed on photo-

graphic film, ex-

posure values are

digitally stored as

an array of pixels.

Each pixel has a

value proportional

to its radiation expo-

sure, which are con-

verted into analogue

grey values of varying

brightness on thedisplaymoni-

tor,” he explains.

Key advantages of digital systems

are: the brightness and contrast can

be very easily adjusted to suit differ-

ent areas of the image; magnification

is easy; the image can be enhanced

and processed; measurements can be

applied and used in calculations and

statistics; and annotations and stamps

(metadata) can easily be incorporated

directly into the image file. “I have seen

an experienced Level 3 NDT Inspector

being amazed by how much more in-

formation can be revealed on a digital

image simply by zooming into an area

of interest and adjusting the contrast,”

Beaugrand reveals.

“The biggest problem with using

digital systems, whether they are CR- or

DR-based, is that companies all over the

world havemillions of film-based radio-

graphs, in vaults and filing cabinets, and

these also need to be easy to access and

use inone common system,”heexplains.

Tomonitor changes over time, it is often

necessary to compare a radiograph from

the past with a current image, and it

is very difficult to compare a film on a

light box with an image on a computer

screen, because the visual quality of the

two technologies is far too inconsistent,

he points out.

“What was needed, therefore, was

a platform that would enable archived

radiographs to be digitised so that they

couldbe accessed andusedon the same

platform and to the same standards as

newly collecteddigital images,” he adds.

In transforming the medical radi-

ography market, after an initial period

with multiple file formats, the industry

decided on a standard file format to

streamline procedures and workflow,

where all manufacturers adopted the

same format. The idea was to enable

any image to be transferred between

doctors using equipment fromdifferent

manufacturers without any compatibil-

ity problems. This led to the develop-

ment of the DICOM (digital imaging and

communications in medicine) compat-