Newsletter | EN | 2016-10

10/16
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Company News
VISION 2016: The world's
leading machine vision
trade fair
Worldwide, you won't find more machine vision in one location at the same time: From the
8th to the 10th of November 2016, the industry meets for the world's leading machine vision
trade fair at VISION in Stuttgart.
In 2014, VISION show changed from being
an annual event to a two year cycle. The
considerable rise of 23 percent in the
number of visitors in 2014 proved the
success of changing to the new rotation.
The technology has reached a high level
of maturity during the last few years with
a larger focus on easy of use and interoperability
across all elements of a vision
system from the sensor to the software.
We are still seeing rapid improvements in
sensor resolution, speed and image quality
combined with feature combinations that
really easy integration.
In 2016, a lot of exciting
topics will be waiting
for visitors again: The
buzzword Industrie 4.0,
or Smart Factory, is still
one of the industry's
major phrases.
At VISION, many
manufacturers will be
displaying their ideas
and approaches as
to how the advanced
integration of machine
vision into production
processes and systems
might be achieved in the future to realize
the smart factory concept.
On a technology level, topics like Embedded
Vision and the advanced possibilities of
3D machine vision will surely be major
subjects at this year's show. In addition,
a lot of innovation will be on display in
the field of hyperspectral imaging where
historical research technologies have
matured and are now translating to easy to
use industrial solutions.
Continued on page 2
Welcome to our VISION
2016 show newsletter!
STEMMER IMAGING has
been exhibiting at the
world’s leading machine
vision show since its
inception. Alongside our
partners on the joint
exhibition stand „STEMMER City“, we are
presenting the latest advances in vision
technologies for your consideration on
future projects.
At our booth E52 in Hall 1 we focus on
communicating with our guests. We want
to convince you that with our unique
combination of extensive experience,
comprehensive consulting and support
and an independent selection of the
optimal components, we deliver real
advantage to our customers. A substantial
machine vision training program, in-depth
feasibility studies and many other services
can add significant value to our customers
by getting to the best solution quickly and
efficiently.
In this newsletter, we show the benefits of
working together with STEMMER IMAGING
showcasing three successful applications
from customer where our technology made
a difference. The section on technology
trends introduces the innovative focus
tunable liquid lenses from our partner
Optotune, an exciting new technology. You
can also watch videos on each of the topics
on our homepage!
Enjoy the read!
• CONTENTS
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Company News
VISION show 2016
Title
VISION show news P. 2
New hyperspectral supplier Specim P. 3
News from our European offices P. 12
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Case Studies
No two loaves of bread are alike:
Machine vision for bakery inspection P. 4
Film inspection with speeds
up to 1,200 m/min P. 6
Vision systems provide safety
by inspecting tyres P. 8
Technology Trends
Optotune variable focus lenses:
Rapid focusing P. 10
Peter Keppler
Director of Corporate Sales
NEWSLETTER October 2016 STEMMER IMAGING 01

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Company News
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Continued from page 1
VISION 2016: Hyperspectral,
3D and other highlights
This technology truly allows the
visualisation of the invisible for example
ripening of fruit or the chemical
composition of white pills. Hyperspectral
systems analyse a spectral range of 100's of
wavelengths, thus opening up completely
new application options beyond the
current range of multi-spectral imaging
applications.
Hyperspectral imaging visualises the
molecular structure of materials, getting
to a unique „chemical fingerprint“, and
enables easy and reliable identification
of identical or different looking objects. In
many cases, this is impossible with existing
machine vision systems.
Together with our partners Allied Vision,
Perception Park and Specim we are
presenting many interesting ideas in this
exciting area of technology during this
year's VISION show!
In this newsletter it is impossible to publish
all the current developments we and our
partners will have on display during VISION
2016. For that reason we invite you to
attend the show, visit the news section on
our web site or sign up for our e-news.
+ + + VISION SHOW NEWS + + + + + + VISION SHOW NEWS + + +
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Teledyne DALSA (booth
E62) has released the
new Piranha XL 8k and
16k Colour TDI cameras.
The first color TDI camera
in machine vision,
Piranha XL Color is based
on Teledyne DALSA's
latest CMOS technology. It delivers the best
performance for color imaging with high speed,
high resolution, high responsivity and low noise.
Powered by Teledyne DALSA's advanced multiline
CMOS color TDI technology, the Piranha XL 8k and
16k Color TDI delivers a line rate of up to 70 kHz in
full color mode via Camera Link HS. The Piranha
XL Color family uses Teledyne DALSA’s new multiline
CMOS color sensors with 4 rows for each
red, green and blue color channel for 12 rows in
total. TDI summing technology has demonstrated
outstanding sensitivity and signal to noise ratio
in high-speed color imaging in light starved
conditions.
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With uniform
sensitivity in the
SWIR spectrum from
900 - 1700 nm, high
frame rates and small
pixel size, the Goldeye
G-033 cameras from
Allied Vision (booth F62) are ideally suited
to hyperspectral imaging applications. They
feature a VGA (640 x 512 pixel) high sensitivity
InGaAs sensor. The sensor benefits from active
thermoelectric cooling to reduce noise and
enable a constant image quality. Goldeye cameras
can be operated at high frame rates of up to 301
fps at full resolution in 12-bit mode and capture
outstanding low-noise images. Available in GigE
or CameraLink versions, Goldeye cameras have
the same compact and ruggedized housing
(55 mm x 55 mm x 78 mm) and feature set.
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Featuring a
custom highspeed
CMOS
imager, JAI's
new Sweep
series monochrome line scan cameras push
throughput to new levels of productivity. The
SW-4000M-PMCL offers 4K resolution (4096
pixels) and runs at up to 200,000 lines per
second (200 kHz). The 7.5-micron pixels have
two user-selectable well sizes - a large well for
better dynamic range when ample illumination
is available, and a small well for improved
responsivity under more limited lighting
conditions. The SW-8000M-PMCL doubles the
resolution to 8192 pixels per line (8K), and is able
to run at up to 100,000 lines per second (100 kHz).
Pixels are 3.75 µm x 5.78 µm in size. Both cameras
feature Mini CameraLink interfaces supporting
power over the interface or via a 12-pin connector,
and can be ordered with either an F-mount or
M42x1 lens mount. In addition, the JAI Go series
keeps on growing. At Vision 2016, JAI displays
the latest additions to this family of small
CMOS industrial cameras, the Go-2400-USB and
Go-5100-USB with USB 3.0 interfaces as well as
Go-5101-PMCL and Go-2401-PGE models.
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Automation Technology (booth F54) launches
its newest model of the successful C5 series. This
3D sensor applies the laser-triangulation principle
for the scanning of objects and features a
resolution of 1280 x 1024 pixel with measurement
speeds of up to 200 kHz. It
gives subpixel precision of 1/64
pixel and scores a dynamic of
512 height values even at its
maximal profile rate of 200,000
profiles per second. A distinctive
feature is the independence of
the measuring speed from the
used evaluation algorithm.
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The new Mitsubishi Electric
CX series of high-speed
Contact Image Sensors
(CIS) offer a compact,
distortion-free alternative
to line scan
cameras. The sensors
allow the scanning of object surfaces
distortion-free right up to the edges. With the
maximum resolution of 600 dpi, they can scan
surfaces at a speed of 138 metres per minute. The
commonly used resolution of 300 dpi enables
reliable inspection of up to 450 metres per minute,
whereas the resolution of 150 dpi even allows
inspection speeds of 1100 metres per minute. The
new CIS CX models are able to transfer the huge
data amounts resulting from these high speeds
via one or two CoaxPress interfaces depending on
the sensor length.
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The fourth generation of the successful CVS
Trevista Surface, Cylinder and Multiline surface
inspection systems is now available from
STEMMER IMAGING. The new Trevista X4 models,
also based on a patented 2.5D process called
“Shape from Shading”, enable image acquisition
being up to 20 % faster and with a measuring
field by up to 50 % larger than before. The CVS
Trevista X4 is available in all three of the previous
versions as CVS Trevista Surface for the inspection
of flat, stationary component
surfaces, CVS Trevista Cylinder
for the inspection of cylindrical
shell surfaces and CVS Trevista
Multiline for the examination
of components in rotational or
translational motion. Compared
with the previous models,
the X-4 generation offers
illumination that is brighter
by a factor of 2.5. As with the
previous models in the CVS
Trevista series, the new X4
systems are also available from STEMMER
IMAGING as complete systems.
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The new Zeiss Interlock Compact lens family
consists of four lenses: Zeiss Interlock Compact
2.8/21, 2/35, 2/50 and 2.4/85. The family features a
short M42x1 mount (18 mm FFD) and screws that
allow exact locking of aperture and focus. The
M42x1 mount offers outstanding stability. The
camera lenses feature an image circle measuring
43 mm and are therefore suitable for line sensors
of up to 43 mm (2k - 8k) or for area scan sensors
of up to 24 x 36 mm (16 - 71 Mpixels). All lenses
impress with their high and unwavering image
quality and precise manual focus. If needed the
aperture can be continuously adjusted by taking
advantage of the de-click function, allowing
precise exposure setting. Their low weight and
robust metal design make the lenses suitable for
rough industrial use. The Zeiss Interlock Compact
2.8/21 and Zeiss Interlock Compact 2.4/85 display
02 STEMMER IMAGING NEWSLETTER October 2016

+ + + VISION SHOW NEWS + + +
excellent contrast across the entire image field
whereas the Zeiss Interlock Compact 2/35 and
Zeiss Interlock Compact 2/50 show extremely low
distortion.
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LMI Technologies (booth H51) announces
the release of the first two models of the new
Gocator 2400 series of smart 3D line profilers:
Gocator 2410 and 2420. These blue-laser profiling
sensors are ideal for electronics and small parts
inspection. They provide a high X resolution of
6 µm, along with repeatable
results down to 0.2 µm in
height. Leveraging industryleading
2-megapixel cameras
and a powerful, next-generation
embedded processor, Gocator
2410 and 2420 offers higher
data density while achieving
50% larger fields of view over
competitors. Twice as fast as
the Gocator 2300 series (400 - 5000 Hz with
windowing), the sensors double the possible
resolution of scan data in the direction of travel. In
addition, because the sensors use a blue laser to
create profiles, data around the edge of specular
targets is cleaner, which is crucial for electronics
and small part feature recognition.The Gocator
2410 and 2420 comes in a revised IP67 industrial
housing offering web-based user setup, built-in
3D visualization, and drag and drop measurement
tools unmatched in the 3D sensor market.
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The new LFX3 series from CCS (booth E53) has
an extended lineup of sizes and colors in order to
fit the growing diversity of applications and needs
of the market. The newly designed housing of the
LFX3 series has new mounting holes and nut slots,
and with a thickness of just 13.1 mm, it is spacesaving,
easy to set up and very user-friendly. In
addition to the normal dot pattern, the LFX3
series adds models with a line pattern, which are
ideal for the inspection of irregularities on glossy
or mirror-like surfaces.
CCS also announces the all-new LNSP2 series
of light units for line scan applications with
increased light intensity of up to 900,000 lx.
In addition to the standard version, the LNSP2
illumination can be ordered as NDF type without
a diffusion sheet. This leads to higher intensities
and can be used for dark field inspection.
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Company News
STEMMER IMAGING and Specim:
Hyperspectral partnership
After signing a partnership agreement with the Finnish hyperspectral technology manufacturer
Specim, FX series hyperspectral cameras are now available from all European subsidiaries of
STEMMER IMAGING.
The new FX series of hyperspectral cameras
for the first time combine a very compact
spectrometer, high speed sensor and
integrated calibration in to a single off the
shelf unit. The FX10 is designed for the visible
wavelength range of 400 to 1000 nm and
the FX16 for the SWIR wavelength range of
900 to 1700 nm. By combining the required
spectrograph inside the camera body using a
patented process with integrated calibration
and flexible sensor control the FX series
delivers the most capable hyperspectral head
with an extremely small footprint of only
150 x 85 x 71 mm.
Users of the Specim FX cameras have the
option to select and evaluate from 220
(FX10) or 230 (FX17) wavelengths that are
optimally suited for an application due to
the material properties of the test object.
The number of selected wavelengths directly
affects the speed of the solution: The fewer
wavelengths that are selected for testing,
the faster the evaluation. If a user needs e.g.
all 220 wavelengths of the Specim FX10, the
maximum recording speed is 330 fps. If the
inclusion of only 20 wavelengths is enough
to solve the application, a speed of
2830 frames per second is possible,
and 6510 frames per second can be
achieved by selecting 5 wavelengths
in 3 different areas. The Specim FX17
is the first InGaAs based camera
that has true multi region of interest
capability.
Other features of the Specim FX cameras
are specially adapted C-mount lenses and
an excellent signal to noise ratio of 600:1.
Calibration directly supplied by the Finish
manufacturer guarantees identical results
even if a camera module needs to be replaced
due to failure or maintenance in the field.
At STEMMER IMAGING, users can obtain the
Specim FX hyperspectral cameras including
image acquisition software and SDK and
appropriate image acquisition cards and
cables from a single source, which greatly
simplifies the entry into hyperspectral
imaging.
The FX series of cameras can be used stand
alone or as part of our hyperspectral systems
which can learn the chemical signatures and
classify each material as a unique colour
then can be connected to any GigE Vision
compatible machine vision software solution.
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Silicon Software (booth C72) present the new
VisualApplets 3.0 version of their development
environment. New features are, amongst others,
operators which represent loops in the data flow
model. By this, it is possible to calculate image
sequences and matchings along with image
batch processing resource-saving on the FPGA
for applications such as rolling average. The FFT
operator has been enhanced to implement more
complex filters with a high computing time
such as band-pass filters resource-efficient. It is
possible to use Xilinx Vivado software for the final
creation of the FPGA hardware code as applets,
which increases the speed of the realization in
many cases.
www.stemmer-imaging.com STEMMER IMAGING 03

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Case Study
No two loaves of bread are alike
The Dutch company Niverplast is one of the world's largest manufacturers of machines for
inspecting bakery products. These machines are supplied all over the world and use image
processing technology from STEMMER IMAGING for the reliable detection of faulty loaves of
bread and bread rolls.
addition, the machine recognises at this point
whether there are any breakage errors or, for
example, whether features like browning,
topping or roundness of the bakery product
is correct.
After this first station, faulty products are
separated out fully automatically via dynamic
conveyor belts before the positively evaluated
bakery products are counted at the second
station. "We offer this first test cell for quality
inspection as an option, but most customers
order their system with both cells", says
Danneberg.
Subsequently, the bakery products are packed
in the desired quantity according to the
customer's specifications, e.g. in cartons or
bags. In the system described, the customer
wanted to pack the inspected bakery products
in certain quantities in bags placed in cartons.
Two separately controllable belts are used
here for the transport of the empty and full
cartons.
System overview: The bakery products arrive at the left end of the machine and pass two test stations
before they get packed into cardboard boxes at the right end.
It all began with plastic bags: Niverplast was
founded in 1986 and initially sold plastic
bags, such as those offered in supermarkets
for carrying home one's purchases. That soon
became too little for the Dutch, however, and
machines followed that could automatically
open such bags, machines that could place
the bags in cartons or erect cartons, and
devices for welding and folding plastics.
Today, Niverplast's core competence is the
manufacture of complete systems with
which objects can be inspected, counted and
packed. Apart from plants for meat, fish, oils
and greases as well as other products for the
non-food segment, the company specialises
in the field of bakery products.
Niverplast only entered the field of bakery
products in 2009, but has grown in the short
time since then into one of the world's largest
manufacturers of such systems. "About
80 percent of our plants are conceived for
industrial-size bakeries and are used all over
the world", says Albert Danneberg from the
Niverplast R&D team.
Quality inspection and counting
Danneberg describes the basic process of
such a system for inspecting and counting
bakery products as follows: "The pre-baked
loaves or rolls can be fed to the machine in
two different ways, depending on the user's
wishes: we either develop an automated
supply direct from the deep freezer, or the
frozen dough products are manually placed
on the conveyor belt. Before the products
enter the machine, a metal detector first of
all checks whether undesired metal parts
have got into the bakery products in the
preceding processes."
Image processing as the core element
The essential core element of the two test
cells is the image processing, for which
Niverplast relies fully on its long-standing
partner STEMMER IMAGING. Dietmar
Serbée, managing director of the Benelux
branch office of STEMMER IMAGING, well
remembers the start of the cooperation with
Niverplast: "Initially the requirement was only
to count the bakery products; the detection of
errors was added later. Niverplast had already
approached several other image processing
companies in search of solutions, but in
the end they decided to choose STEMMER
IMAGING as their machine vision partner.
A metal detector checks the baked goods against
possible metal parts at the beginning of the
process.
Image processing systems play the decisive
part in the steps that follow: At the first
station a quality inspection takes place in
which the geometrical dimensions such as
the length, width and height of the bakery
products are measured and analysed. In
The frozen bakery products are supplied to the
plant via a conveyor belt.
04 STEMMER IMAGING NEWSLETTER October 2016

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Case Study
line scan cameras and the matching line scan
illumination and lenses. With those we can
optimally cover the conveyor belts, which are
up to 1300 mm wide."
Service from one single source
Apart from the delivery of a few further
components such as the PC systems and
various cables, STEMMER IMAGING also
took care of the connection of the imaging
software to the graphical user interface of
the system, via which amongst other things
the programs for the next batch of bakery
products are adjusted. "The GUI itself was
developed by Niverplast. We cooperated
closely on the connection in order to fully
satisfy our customer's wishes", Serbée
remembers.
The loaves are conveyed through under a line
scan illumination and a line scan camera where
the images are taken.
According to Serbée, the particular difficulty
with the task was that no two loaves of bread
are alike: "The shapes of the pre-baked loaves
of bread and bread rolls are never identical.
They are always slightly different. It is very
difficult for an automated system to decide,
for example, whether a depression in the
surface of a baguette is a deliberate cut or the
start of an undesired breakage."
Following an intensive development phase,
Serbée was able with a proprietary software
solution based on the image processing library
Common Vision Blox to reliably distinguish
between such features. Serbée also selected
the necessary hardware components for the
image processing system.
"In the preliminary investigations we carried
out tests to determine which camera, lens
and illumination could achieve optimum
results. In the end we chose a combination of
Danneberg is more than satisfied with
his partner's service: "Niverplast has its
own in-house image processing specialist,
but nevertheless we are happy to rely on
additional support from STEMMER IMAGING
when needed." This support doesn't end after
the delivery of a system either: “Whenever we
need further information about new machine
vision developments or technologies, we
know whom to contact!”
Good development
The largest system that Niverplast has
developed and delivered so far encompasses
two parallel lines, each with test cells based
Depending on the width of the conveyor belt, one
or two lines scan cameras are used.
on image processing for the quality inspection
and counting of bakery products.
Despite the very good order book situation,
the developers at Niverplast have further
ideas that will be incorporated into the
design of future systems. Danneberg reveals
one of these ideas: "The height of bakery
products can be measured using a multiple
3D triangulation system. Loaves of bread and
bread rolls can thus be measured even more
accurately and defects in the bakery products
can be recognised more reliably, therefore we
will be offering this possibility as a further
option for our systems."
• WATCH VIDEO
This video tells more
details about the
Niverplast machine:
The setup for the next bakery products is made
via a touch panel at the machine.
At the end of the line the inspected bakery
products are placed in cartons.
• BACKGROUND INFORMATION
Niverplast (www.niverplast.com) develops innovative
packaging solutions to protect and transport
a wide range of products. Bread, meat, fish, liquids
and non-food products that have to be packed in
a bag and box are the core business of the Dutch
company, whose systems are in use on every
continent in the world.
www.stemmer-imaging.com STEMMER IMAGING 05

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Case Study
Real time film inspection with
speeds up to 1,200 m/min
Witten-based OCS GmbH is one of the world’s leading manufacturers of productionintegrated
film inspection systems. Up to ten cameras operate side by side in scalable systems
enabling production speeds of up to 1,200 metres per minute. Machine vision components
from STEMMER IMAGING make up the optical solution.
includes up to ten cameras operating side
by side. In practice, most applications use
systems with two cameras for the inspection
of film widths ranging from 1500 mm to 2000
mm.
In addition to the line scan camera’s sensor
size of up to 8192 pixels (8k) the camera
distance defines the attainable resolution.
For example, films for the packaging industry
generally do not require resolutions over 150
μm to 200 μm, which corresponds with the
use of one camera per metre of film width.
Technical films are inspected from double to
triple the resolution and therefore require a
greater number of cameras.
The mere number of pixels is not the
measure of all things. The sensor elements
in 8k cameras are smaller and consequently
less light-sensitive. In the case of less lightpermeable
material you would be more likely
to opt for a 4k camera with a larger sensor
diameter. This simple consideration shows
that plant engineers must bring along a great
deal of experience in order to optimally meet
the technical requirements and minimise the
costs.
OCS inspection system in the Witten-based demo centre.
Plastic films can be found in a wide variety
of different thicknesses and colours –
transparent or opaque, structured or coated
– in almost all industries and areas of life.
Applications range from flat screens, cell
phone displays, pharmaceutical tablet
blisters, food packaging to baby diapers.
Films are produced in huge plants 24/7,
around the globe. Their quality depends on
many parameters. Quality monitoring and
quality assurance during production have
a significant impact on the end product’s
quality. There are a variety of standards: the
specific requirements are agreed individually
between manufacturers and users. Type and
number of permissible errors are reflected in
the production costs and, consequently, in the
prices for the end users.
„In simple terms: nobody likes to spot sealed
insects in packaged cheese; there shouldn’t
be any turbidities on TFT screens, and you
definitely do not want to find any holes in the
insulation of high-voltage cables,” exemplifies
Mendo Gusevski. He is a product manager at
OCS, short form for Optocal Control Systems,
a company which specialises in the optical
quality assurance of polymers and the films
produced from them.
The measurement range of defects in
extruded films mostly depends on their
intended use. For example, packaging film
(PET) requires reliable detection of defect sizes
between 150 μm and 500 μm. In technical film
the defect sizes range from 50 to 200 μm. In
surface protection film they range from 60
μm to 160 μm, and in film with specific optical
characteristics it may be necessary to reliably
detect defects ranging from 25 μm to 100 μm.
Defects occur during the extrusion process
due to incorrectly melted material (so-called
specks or burn marks), fisheye, thin places,
holes, streaks, flow lines or simply dirt.
Whether quality monitoring should classify
inhomogeneities as defects depends on
the subsequent use of the film. It would be
impossible to detect all these defects at the
required speed without the use of machine
vision.
Over the years of working together with
STEMMER IMAGING, OCS have developed a
scalable, modular inspection system, which
Each camera with its own frame grabber
In order to manage the amounts of image
data resulting from real time production
speeds of up to 1,200 metres per minute,
each camera is equipped with its own frame
grabber. Camera and frame grabber are both
included in a common housing attached to
the machine. These work stations offer the
necessary modularity and short signalling
pathways between camera and frame
grabber. Integrated cooling fans generate a
slight overpressure to prevent the deposition
of production-related dust on the lens. In
Special Truecolor illumination with controllable
LED elements allows the setting of different
colours and the use of near-infrared light if
required.
06 STEMMER IMAGING NEWSLETTER October 2016

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Case Study
class," explains Georg Schelle. "Basically, we
deliver a modular platform for OCS solutions
across all machine vision elements, which can
be adapted to specific applications."
OCS in-house test and training centre
A front bar illumination (in this example,
with blue light colour) ensures optimal light
conditions.
harsh and extremely dirty environments,
hermetically sealed housings are used,
which are then cooled by a separate dust and
moisture purge air circuit.
OCS and STEMMER IMAGING have agreed on
a number of internal standards for cameras,
cabling and illumination. The collaboration
led to special firmware versions regarding
JAI and Teledyne Dalsa cameras as well as
Teledyne Dalsa frame grabbers successfully
delivering around 90 % of the applications.
Pre-assembled modules
STEMMER IMAGING has long left their role
as pure component distributor: „In order
to better support our key customers we
have built up profound expertise in the preassembly
of modules “, explains Georg Schelle,
Senior Key Account Manager at STEMMER
IMAGING, who has been supporting OCS
for many years. „These modules save our
customers a lot of integration time compared
to individual components. Especially for OCS
we are working with highly complex optical
modules with Qioptiq lenses and filters from
Schneider Kreuznach or Midwest Optical
Systems. Our clients benefit from shorter
delivery times, higher operational safety and
reduced cost.“
The LED lines lights for OCS with lengths
ranging from 100 to 3,600 mm are now
manufactured by STEMMER IMAGING
supplier CCS in Japan. Today's design is based
on a proven standard product line, that has
continuously been improved over the years.
"This is reflected in a number of characteristics:
for example, the homogeneity of the LED
light output, the diffuser properties in all
three axes, the concept of connectors and
maintenance as well as the IP54 protection
A rewinder located in OCS’s in-house test and
training centre is available for pre-testing the
equipment of a planned system. Sample film
material can be verified under real conditions
at speeds of up to 400 m/min and system
designs can be optimised according to the
customer’s needs.
OCS are constantly testing new technologies
with this system, such as a specific Truecolour
illumination with controllable LED elements
which allow the setting of different colours
and, if necessary, even the use of near infrared
light. The Mitsubishi Electric Contact Imaging
Sensors, innovative polarisation cameras as
well as the uncooled Teledyne Dalsa Calibir
LWIR thermography cameras have all been
tested with this system.
„We normally use traditional monochrome
line scan cameras in our systems”, explains
OCS expert Gusevski. „For special applications
we use JAI cameras with three sensor lines
and an RGB prism.“
However, the possibilities of a machine
builder like OCS are constantly growing with
new, innovative technologies. This is why
OCS always thinks outside the box in order to
find new technologies for future systems at
an early stage. Here again, working together
with STEMMER IMAGING pays off for us“,
Gusevski emphasises.
Inspection for process control
In the current OCS systems all errors are
recorded as individual images, which can
be evaluated retrospectively. The analysis
software developed by OCS allows operating
personnel the use of different kinds of error
trends, which help derive alarms and specific
modifications of process parameters in the
production process.
Trend data show tendencies as a result
of modifications. This way, problems can
easily be detected whether it is with certain
additives fed, with extraordinary dirt ingress
or when changing the pellet tanks, and can
then be allocated to certain sections. The
defective film sections can then be cut out in
subsequent commissioning processes.
Oliver Hissmann, Sales Manager at OCS, explains
the function of a film inspection system.
A few years ago the QS management was
satisfied with an inspection rate of 10%
the web width. Today, as computing power
constantly increases, there is a growing
demand for 100% inspection which can be
reliably provided by OCS.
„Currently the widest web section we are able
to inspect with our FSP 600 system at the
speed of 1,200 m/min, is 870 cm wide. This
enormous amount of data, which sums up to
400 MByte per camera, can only be handled
on a hardware level. For that reason and if
necessary, we talk directly with Teledyne
Dalsa developers about details that do not
affect other users with less time-critical
processes”, explains Oliver Hissmann, Sales
Manager at OCS. „The highest resolution
required by a customer is currently 25 µm at
a web width of 1,500 mm. This is solved with
ten synchronised cameras.“
• WATCH VIDEO
Watch our short video
about the OCS film
inspection system:
• BACKGROUND INFORMATION
OCS Optical Control Systems GmbH (www.ocsgmbh.
com) based in Witten, Germany, offers individual
complete solutions in the areas of raw material and
web inspection as well as turn-key laboratories to
many international customers.
www.stemmer-imaging.com STEMMER IMAGING 07

ңң
Case Study
For safely rolling tyres
Every day the lives of millions of people depend on intact tyres on cars and airplanes. The
Zeiss Optotechnik tyre inspection systems equipped with STEMMER IMAGING’s state-of-theart
machine vision components provide the maximum possible safety in this domain.
direct phase measurement with only one
shearing image. In addition to tyre testing,
shearography is used for non-destructive
testing of composites.
Over 1,000 measuring heads worldwide
Intact systems are used worldwide by all
well-known tyre manufacturers as well
as by a large number of medium-sized
retreading companies. A total of more than
1,000 measuring heads have already been
installed, including licensed systems with
Zeiss measuring heads.
For inspecting the treads the measuring heads are automatically lowered into the tyre.
Carl Zeiss Optotechnik GmbH generates
about one third of their annual sales with
systems for the non-destructive inspection
of tyres. The company, which has been known
as Steinbichler Optotechnik GmbH until 2015,
is one of the world’s leading suppliers in
this segment and has already implemented
inspection systems for tyres with diameters
of up to 4300 mm. Such enormous tyres are
used in huge mining vehicles, but also new
and retreaded pneumatic tyres of passenger
cars, trucks, aircraft, motorcycles. Even the
racing tyres of all current Formula 1 teams are
tested for defects by these systems.
The company’s „Intact“ tyre inspection
systems are based on shearography, an
optical measurement technology which
has established itself as the standard in
the automotive sector, in aviation it is even
required by law.
Intact measuring device with four measuring
heads each at an angle of 90 degrees.
Shearography is an interferometric testing
method that is able to detect even the smallest
defects with a size of only a few microns
on stressed components. The test object is
illuminated with a laser light and inspected
by a CCD camera with a so called shearing
lens. These lenses project the object image
onto the camera chip twice; each object point
is thus represented twice which results in an
interferogram. When the test object deforms
under load, the laser light, reflected by the
component, changes. Due to superposition of
an image in its unloaded state, the recording
under load means the changes of each point
in the image can be detected.
When testing tyres the required load is
generated by varying the ambient pressure.
Between the first and second recording the
pressure is lowered by about 50 mbar. Any
air bubbles enclosed in the tyre expand as a
result of the negative pressure and slightly
deform the surface of the tyre at the weak
points. Conclusions on defect type and size
can be drawn by comparing and evaluating
the resultant images.
„We have been working with shearography
technologies since around 1990“, explains
Rainer Huber, NDT product manager at Carl
Zeiss Optotechnik who is responsible for
the tyre testing system developments. His
company holds several relevant patents,
such as one for the spatial phase shift, the
„Our goal is one hundred percent safety – the
failure of a tyre in operation or when being
inflated can have fatal consequences“, says
Huber. In the testing process the tyre tread
and the side walls are examined for internal
detachments and air inclusions, which would
not be visible by a human. „When testing
retreaded truck tyres experience shows that
about 20 percent of the visually impeccable
used tyres are classified unsafe when applying
shearography“, Huber points out. The use of
shearography is also cost-effective, especially
in the area of retreading. The customers
benefit from cost savings in production and
purchasing.
Positioning of the measuring heads for side wall
inspection
The Intact systems are characterised by their
non-contact and non-destructive application.
Since there is no need for preparation of
the tyre surface the application is simple,
fast and cost-effective: After loading the
pressure-tight test chamber the measuring
heads are precisely placed inside the tyre to
record the tread from the inside thanks to the
automated detection of the tyre size. Each
of the four measuring heads inspects two
sectors of 45 degrees.
In the second step the measuring heads are
automatically positioned on the outside to
inspect the side wall on top. Finally, the tyres
08 STEMMER IMAGING NEWSLETTER October 2016

ңң
Case Study
been working with STEMMER IMAGING on all
aspects of machine vision for many years."
Rainer Huber, NTD Product Manager at Carl Zeiss
Optotechnik, in front of an Intact system with
tyre flipper.
are flipped for the final examination of the
second side wall. „Thanks to the automated
process we are able to achieve cycle times
below one minute for a complete tyre test”,
says Huber.
Machine vision is the base
Machine vision is the technical base of the
tyre testing systems: Each measuring device
consists of four measuring heads, each
containing a camera with a corresponding
lens. Since the 90s, the company – at that time
still operating under the name Steinbichler
Optotechnik GmbH – has been dealing with
machine vision and has developed extensive
know-how in this field.
For almost that long, they have been
successfully working with STEMMER
IMAGING, who supplies cameras and other
optical and electromechanical components.
„Our clients expect reliable machines in
order to be successful in their markets.
This is exactly what Carl Zeiss Optotechnik
is able to guarantee on the basis of many
years of experience“, explains Huber. „It is
very important for us that every component
is supplied by a reliable partner with the
appropriate know-how and the right range of
product and services. For this reason, we have
Shearography detect errors in the micron range
So it is no surprise that he and his team
again relied on their proven machine vision
technology partner when developing a new
system generation. The starting point for the
innovation was the desire for standardisation,
according to Huber: „A multitude of different
measuring heads have been developed over
time. In the future, we wanted to use only one
single type for different applications.“
A great challenge was reducing the size of
the measuring devices to allow the testing of
even smaller tyre diameters. So far, the limit
has been 16-inch-tyres due to the footprint of
the measuring heads. Now the goal was, to be
able to inspect even 12-inch-tyres. However,
the concept of having up to four measuring
heads per device should remain the same;
the simple formula was: the more measuring
heads, the shorter the measuring time,
the higher the throughput. However, the
necessary downscaling of the measurement
device could not be achieved geometrically
with the Allied Vision standard cameras that
had been used so far.
Camera modification as key to success
A substantial redesign was necessary, at the
same time continuity was required: Carl Zeiss
Optotechnik had been using the monochrome
Allied Vision Prosilica GC1380 cameras for
years. These cameras are equipped with
a Sony ICX285 CCD sensor providing a
resolution of 1388 x 1038 pixels. This sensor is
especially designed for infrared applications
and is ideally suited for this application when
being combined with the optics Zeiss had
developed for shearography measurement.
For the redesign Carl Zeiss Optotechnik opted
for a high-speed version of the previously
used Prosilica camera with the same CCD
sensor: The Allied Vision Manta G145B-30fps
with a frame rate of up to 30 fps is now
being used. Due to the discontinuation of the
built-in Sony CCD sensor by the year 2020,
Huber does not expect any major problems:
"Since Allied Vision also offers a mechanically
identical CMOS camera, easy exchangeability
of the cameras is guaranteed."
More headaches were caused by a mechanical
problem: the standard version of the selected
Manta cameras including cabling was too long
to inspect 12-inch tyres with four measuring
heads contained in one measurement device.
The Allied Vision Manta camera – left: integrated
in the standard housing, right: modified version
for Carl Zeiss Optotechnik
„This problem could be successfully solved
through a special modification by STEMMER
IMAGING’s hardware development“, praises
Huber: „In close cooperation with our
mechanical design department, these experts
developed a housing variant in which the
cable connections are arranged at an angle of
90 degrees to the image layer and not linear
as in the case of the standard housing." That
way, the length of each Manta camera could
be reduced from 80 to 64 mm – and thus met
the geometrical needs for the inspection of
12-inch tyres.
Further customer-specific services at
STEMMER IMAGING, like aperture presetting
and the sealing of all screws on every
individual lens, or the selection and longterm
tests of cables helped Carl Zeiss
Optotechnik keeping their new Intact tyre
inspection system generation at a constant
high level, proving their daily use worldwide
in development and production.
• WATCH VIDEO
This video explains the
modifications and the
tyre inspection system:
• BACKGROUND INFORMATION
More than 25 years of experience and competence
in optical measurement and sensor technology have
written the success story of Carl Zeiss Optotechnik
GmbH (http://optotechnik.zeiss.com/). Since 1987,
the company has been developing high-precision
optical measurement systems and corresponding
software solutions, which are used in a wide range
of application areas.
www.stemmer-imaging.com STEMMER IMAGING 09

ңң
Technology Trends
Brought into focus at
lightning speed
Variable focal length lenses enable rapid focusing in image-processing applications where
the working distance between the object and the camera system is frequently changing.
A current-controlled actuator presses fluid through a ring from the outside into the interior of the lens,
thus altering the curvature of the lens and hence its focal length.
Particularly during the mass manufacture
of products, the working distance between
an object and a camera system generally
changes little or not at all. In these cases the
optical design of a vision system is easy: the
prevailing working distance and the desired
resolution are used to calculate the optical
characteristics of the system which, after
the selection of suitable components and
integration into the installation, performs
its function without any further adaptation.
While conversion of the installation to
products with a different geometry only
requires a one-time adaptation of the vision
system until the next change.
In contrast to this, in many applications vision
systems must deal with frequent changes
in the working distance. In an extreme case,
the distance between the inspection plane
and the camera system can change from one
object to the next, which can best be seen in
the example of a system for reading addresses
on packages: the heights of such packages
can vary continually. In order to be certain of
capturing the desired information in focus,
in this example the working distance to the
vision system or the focus of the optics would
have to be adjusted for each package, which
often is not achievable with the necessary
speed using mechanical means.
mechanical guides, which limit not only the
overall size and the response time, but also
the robustness and life of any solution.
Variable lens curvature
Variable focal length lenses provide an
interesting alternative for such applications.
The technical basis of this is the variable
curvature of a lens which consists of a
membrane filled with fluid. If the pressure
within the lens is altered, the curvature can
be adjusted (see Figure 1). A change to the
lens radius of a few micrometres can achieve
the same optical effect as the mechanical
displacement of a lens by several centimetres.
Optical systems can thus be designed to be
more compact, often with fewer lenses and
without any translational movement.
Swiss company Optotune specialises in the
development of such variable focal length
lenses. The company controls the electro-
optical components by means of a control
current from an electromagnetic actuator.
The change in refractive power (measured in
dioptres) is a linear function of the impressed
current, is reproducible and free of hysteresis.
The relationship between refractive power
and current will vary from lens to lens due to
production tolerances, and even temperature
fluctuations affect the control. To enable
accurate control of the refractive power,
Optotune lenses use a temperature sensor
with calibration data for the particular lens
stored. In combination with a current driver, an
absolute accuracy of typically 0.1 dioptres can
be achieved. Communication with the driver
takes place via a USB connection and a serial
protocol which can be implemented in various
programming languages. The source code for
the controller is available in C# and Labview.
An alternative current driver with GigE, RS232
and analogue interfaces is available from
Gardasoft. To simplify system integration
for the user, Optotune is collaborating with
various camera and software manufacturers
with a view to implementing integrated
autofocus functions.
Fast and robust
Liquid lenses offer a range of other advantages.
They dispense completely with expensive
mechanical drives and furthermore enable
a more robust design that can work with
higher precision than mechanically based
optics solutions. While mechanical autofocus
systems often reach their limits with respect
to speed and reliability, variable focal length
lenses enable focusing over large changes in
working distance within milliseconds (see
Figure 3) and guarantee billions of cycles.
Furthermore they can be completely sealed
so that no dust can enter, thus reducing the
susceptibility to errors during image capture
and subsequent evaluation.
While traditional optical systems enable
focusing within certain limits according to
the required distance, one or more lenses
have to be moved along the optical axis
to achieve this. This requires motors and
Control of the variable focal length lens: a USB-based current driver enables accurate control of
refractive power by reading calibration data and temperature from the lens.
10 STEMMER IMAGING NEWSLETTER October 2016

ңң
Technology Trends
is also increasing against the background of
Industry 4.0: Anyone wanting to manufacture
small batches down to a quantity of 1 must
equip his production with solutions that
can react quickly and flexibly to changing
geometries of the inspected parts.
Difference between optics with fixed focal length
(left) and variable focus optics.
Another interesting feature of variable focal
length lenses is that various optical materials
can be used. A liquid with low dispersion
with a refractive index of 1.300 and an
Abbe number of 100 is particularly suitable
for polychromatic imaging optics. There is
practically no chromatic aberration.
For this reason, variable focal length lenses
can also be combined with standard objective
lenses to produce high quality autofocus
systems without having to take additional
measures for colour correction.
Application examples
A rapid change of working distance and
resultant frequent focusing are becoming
necessary more often in many applications.
The importance of variable focal length lenses
• CHROMATIC ABERRATION
Chromatic aberrations (colour deviations) are image
defects that arise due to the different focal points for
different colours. White light is composed of various
colours or wavelengths. When white light impinges
on a lens, each colour takes a slightly different path.
This is called dispersion. If a lens is not designed
to correct this dispersion, colour fringes appear on
every exposure. Exact measurements are therefore
not possible, as the edges of the inspected object
appear out of focus. The degree of this blurring
increases towards the edge of the picture. As can be
seen on the following figure, the effects of chromatic
aberration become visible as colour fringes at the
edges of the objects.
There are already many examples where
Optotune electro-optical components are in
use. One of the most obvious applications of
variable focal length lenses is the reading of
2-D codes on, among other things, objects of
differing sizes in the logistics, pharmaceutical
or automotive sectors. While 1-D codes can
be scanned with a laser, reading 2-D codes
requires a camera.
This opens up additional inspection and
measurement functions. Here, variable focal
length lenses enable a significant expansion
of the working range, e.g., from infinity down
to a few mm. In a typical optical set-up, the
variable focal length lens is mounted directly
in front of an objective lens with a fixed focal
length.
Lens control principles
There are various control principles: If the
distance to the object is known by the system,
the working distance can be controlled
directly in an open control loop where the
lens is set to the corresponding focal length.
The distance information can be provided by
a suitable sensor or via programming. In this
mode, focus setting times of 5 to 15 ms are
possible.
If the distance is not known, the lens can
also be operated in an oscillatory mode. At
low frequencies of e.g. 5 Hz, several images,
each with different working distances, can
be captured until a code has been read
successfully. While this approach is not
particularly fast, it is simple to implement
and can be used without calibration.
At high frequencies (up to some 100s of Hz) it
is possible to tune through the entire working
range during the shutter time. The result
is an image with extended depth of field,
albeit with reduced contrast as the individual
“images” with different focus superimpose
during the shutter time. Nevertheless, codes
with good contrast can readily be recognised.
The applications where Optotune lenses have
proved to be a very suitable resource also
include the inspection of optical components
with several surfaces such as camera lenses
The Optotune Model EL-16-40 installed between
camera and objective lens
for mobile phones, or counting particles in a
3-dimensional fluid volume.
In applications that require a high
magnification, the variable focal length lens
is generally placed between the objective
lens and the tube lens. The achievable z-range
thus depends on the magnification factor. A
typical system achieves a z-range of 16 mm
with a magnification of 5x. If the variable
focal length lens is operated by a 12-bit
current source which permits 4096 steps, an
axial resolution of 4 µm can be achieved.
Part of a complete system
STEMMER IMAGING has been selling
Optotune variable focal length lenses already
for some time now. In combination with all
the other components required, including
suitable lighting, optics and cameras, the
Gardasoft current driver as well as auxiliary
services such as feasibility studies or support
in designing systems, we thus provide
everything from a single source to simplify
the use of this technology.
Thanks to the increasing availability of
electronics and software, the integration of
variable focal length lenses is easier today
than ever before.
• WATCH VIDEO
We have prepared a
video to explain the
Optotune technology:
www.stemmer-imaging.com STEMMER IMAGING 11

www.stemmer-imaging.com
ңң
Company News
News from STEMMER IMAGING
across Europe
STEMMER IMAGING now has 13 offices in eleven European countries. Here we inform you about
current local activities and news in these offices.
• EVENTS
■■
8 th - 10 th November 2016
VISION, Stuttgart, Germany
International Trade Fair for
Machine Vision and Identification
Technologies
Hall 1, Booth E52
UNITED KINGDOM ▹ The colleagues
from our UK office have won the prestigious
award for the ‘Most Innovative Vision Project’
at the PPMA (Processing and Packaging
Machinery Association) Group Awards
announced at the end of September. The
winning project was for the supply and
integration of 25 cameras on the Bloodhound
Supersonic Car. This project is a British
endeavour to build a jet and rocket powered
vehicle capable of reaching 1000 mph, for
a new world land speed record attempt. 25
cameras are located at strategic points on
the car, e.g. to deliver live streamed video for
broadcast purposes or to look at the output
from the rocket and jet engine exhausts.
Other cameras monitor critical engineering
parameters such as the wheel-ground
interface. In-cockpit cameras monitor controls
and driver actions. In making the award, the
judges commented: “The STEMMER IMAGING
project demonstrates ground-breaking
innovation. It is a complex undertaking,
involving several aspects of machine vision
technology from optics through to data
handling.”
GERMANY ▹ We have already been asked
about the dates of our next technology forum
series. The next tour will start in Germany on
the 17th and 18th of October 2017. Dates and
venues for the the other offices and countries
are not yet fixed, but we will of course keep
you informed in time.
FINLAND ▹ In order to give our customers
better service, the STEMMER IMAGING office
in Finland is moving to new modern premises.
The new office is situated in a striking modern
building in Espoo's Keilaniemi dynamic
business district in Greater Helsinki. The area
is characterized by technology and innovation
• TRAININGS
STEMMER IMAGING runs free regular training
sessions on different machine vision topics in our
European Imaging Academy training suites. These
trainings cover topics like:
■■
Introduction to machine vision
■■
Lighting & lenses technology
■■
Common Vision Blox
■■
Sherlock machine vision application suite
■■
Machine vision solutions from Teledyne DALSA
■■
Hyperspectral imaging
■■
3D image processing with the LMI Gocator
STEMMER IMAGING offers these training courses in
several of our offices in different countries.
For information on events, training and courses,
please visit our homepage!
with many corporate headquarters, hi-tech
industries and startups. One of Keilaniemi's
major draws is its close proximity to the
university region of Otaniemi and the easy
access to public transport and road routes.
SWITZERLAND ▹ A well-attended technology
day focusing on the subject of 3D
image processing was carried out by our
office in Switzerland in September. After an
introduction into the basics on this topic, LMI
as a company and their the sensor platform
have been introduced. Successful application
examples with different models of the LMI
Gocator series as well as a presentation of
current trevista systems for surface testing
completed the day.
DENMARK ▹ The Danish office move
within the city of Copenhagen has been
completed.
• CONTACT
HEAD OFFICE
GERMANY . AUSTRIA
Phone: +49 89 80902-0
info@stemmer-imaging.de
FRANCE
Phone: +33 1 45069560
info@stemmer-imaging.fr
DENMARK
Phone: +45 33 73 00 00
info@stemmer-imaging.dk
POLAND
Phone: +48 664 921 922
info@stemmer-imaging.pl
FINLAND . BALTICS
Phone: +358 9 43 555 00
info@stemmer-imaging.fi
SWEDEN . NORWAY . ICELAND
Phone: +46 8 555 110 00
info@stemmer-imaging.se
IMAGING
IS OUR
PASSION.
SWITZERLAND
LIECHTENSTEIN
Phone: +41 55 415 90 90
info@stemmer-imaging.ch
THE NETHERLANDS
BELGIUM . LUXEMBOURG
Phone: +31 575 798888
info@stemmer-imaging.nl
UNITED KINGDOM
IRELAND
Phone: +44 1252 780000
info@stemmer-imaging.co.uk
Find us on:
12 STEMMER IMAGING www.stemmer-imaging.com