Phantom
TMX: A new era of FAST backside illumination
With increased speeds comes the need for more light. The backside
illuminated sensor found in the Phantom TMX cameras address this
issue by shifting the metal parts of a traditional sensor that
interfere with incident light to the back of the sensor. Backside
illumination also provides increased processing efficiency, which
allows cameras to maintain their high throughput levels even as
frame rates increase.
The
TMX cameras offer an Export Controlled FAST mode option for even
higher frame rates. By expanding on its internationally recognised
range of
Phantom cameras with the TMX series, Vision Research deliver groundbreaking
ultra-highspeed imaging. The backside illuminated custom CMOS
sensors produce clear, high quality images at speeds not previously
possible.
Backside Illuminated
Sensors (BSI) sensors have been available for over 10-years in
mobile phones and specialist digital cameras. However, because
of the larger pixel-size required, it has been difficult to design
with the high frame rates that many machine vision applications
require. With modern technology advancements, in recent years,
we've started to see machine vision manufacturers incorporate
BSI Sensors into high-speed machine vision camera designs. With
Vision Research's capability to design and fabricate their own
sensors they have broken new ground with the sensors in the TMX
series.
High speed sensors need to work with very short exposure times
and so light sensitivity is a critical factor in their design.
High speed sensors are designed with large pixels to improve sensitivity
however this in-turn makes the sensors larger and so difficult
to manufacture as BSI. BSI requires additional manufacturing steps.
Among them is a wafer backthinning step to remove the bulk silicon
on the back of the sensor which becomes the light gathering side.
This brings the photodiodes closer to the light source. There
are also additional processing steps on the backside of the wafer
to anneal the surface and to provide electrical contacts to the
front side of the sensor. When thinning the backside of a large
sensor there is a much greater probability of defects which creates
a low-yield and so many sensors are discarded. Vision Research
have been able to achieve a commercially viable yield with their
new techniques and this has resulted in these mind-blowingly fast
TMX cameras.
The
BSI sensor on the Phantom TMX cameras delivers great advantages:
Speed
The
Phantom TMX 7510 is the world's first high-speed camera that utilizes
a back-side illuminated sensor. This camera delivers over 75,000
fps at full 1 Mpx resolution and with the FAST option can run at
up to 1,750,000 fps. The Phantom TMX 6410 is able to deliver Phantom
quality images at nearly 66,000 fps at full 1 Mpx resolution and
considerably faster with the FAST option. Historically, the resolutions
associated with high speed cameras when running at hundreds of thousands
of FPS were too low for nearly all scientific uses. The TMX series
changes this and offers resolutions suitable for scientific applications
at speeds previously unheard of.
Exposure
Times
The
new sensor supports minimum exposure times as short as 95 ns with
FAST option, making it the fastest in its class. The short exposure
times make it possible to capture faster events without motion blur,
which can be a limiting factor in obtaining high-quality images
in applications as wide ranging as cytometry and combustion analysis.
Pixel
size
To
work in light-starved conditions, high-speed cameras have historically
used very large pixel sizes as a means to catch as many photons
as possible. Our existing Front Side Illuminated (FSI) ultra high
speed sensors, for example, have a pixel size of 28 x 28 µm
with an area of 784 µm2. The new BSI high-speed image sensor
has an 18.5 x 18.5 µm pixel, but its proficiency at capturing
light makes it as sensitive as earlier FSI sensors at three times
the speed. Smaller pixels also improve sampling frequency (Nyquist),
allowing the sensor to resolve higher lp/mm spatial frequencies
before aliasing. This capability enhances the imaging systems
performance in flow cytometry, particle image velocimetry (PIV),
digital image correlation (DIC) and other high speed applications
limited by the resolving power of the sensor.
Solving analog-to-digital conversion challenges.
Embedding analog-to-digital converters (ADC) on CMOS image
sensors is standard practice, but the BSI sensors speed
requires a massive increase in the amount of analog to digital
conversion.
While
modern CMOS image sensors typically have between 1,000 and
10,000 embedded ADC's, the new BSI high-speed sensor has 40,000
ADC's, each converting every 523 ns and generating a large
amount of data to off-load from the sensor. To accomplish
this task, it incorporates 160 high-speed serial outputs operating
at greater than 5 Gbps. This technology is common on CPUs
and FPGAs but new on a high-speed imaging sensor.
The density of ADC's on the new sensor created power management
and electrical crosstalk challenges, which were solved with
clever, innovative design. Design engineers discovered that
the crosstalk exhibited predictable patterns and developed
modeling techniques that helped eliminate the crosstalk altogether,
which in turn mitigated imaging artefacts.
The sensor supports 2 x 2 binning to maximize throughput at
faster speeds. Though not common in high-speed sensors, Vision
Research has implemented binning in two previous cameras.
It helps mitigate limitations of the sensors column
ADC architecture, enabling faster speeds than simply decreasing
the y-dimension. This approach is subtly different than binning
as applied in CCD cameras, where its used to primarily
boost sensitivity. In this case, were using it to boost
speed.
BSI
Difference
BSI is not a new technology, and it has been used with great
success in standard and cellphone cameras. By adapting it
to high-speed imaging, Vision Research have been able to create
a sensor that pushes the boundaries on speed in light-starved
conditions.
Key
Features
Designed
for high speed applications:
-
TMS series offer 3 models that provide extreme high frame
rates at larger resolutions, up to 1.75 million fps
-
Real data for real results: unlike other manufacturers VRI
frame rates are actual with no interpolation. 2 x 2 Binning
Mode provides double the vertical resolution at high frame
rates for added flexibility
-
Very high native light sensitivity, made possible by backside
illuminated CMOS sensor
Focus
on data management:
-
Record multiple experiments in a single block of 512 GB by
partitioning up to 511 times
-
10 Gb Ethernet is standard for the fastest data download directly
from the camera's RAM buffer
-
Use the Phantom CineMag V for up to 8TB of non-volatile memory
and fast image transfer
Applications
Ballistics
Due
to the TMX's light sensitivity and incredibly high frame rates,
it makes it perfectly suited to ballistics e.g gunshot analysis
or explosives etc.
Digital
Image Correlation (DIC)
Digital
Image Correlation is a non-contact method of observing how an object
is affected by impact and vibration. It can also be used to create
3D imaging of the object to help researchers take exact measurements.
Combustion
Combustion
applications often have unique difficulties that need to be overcome.
Aside from being exceptionally fast events they often have lighting
issues as they quickly fluctuate between being very dark and very
bright. Phantom cameras have features that aid researchers in dealing
with these issues.
Particle
Image Velocimetry (PIV)
Particle
Image Velocimetry (PIV), is a research method that allows scientists
to observe and measure flow. Phantom cameras are equipped with high-resolution
sensors to make particle tracking simple.
Quick
Specifications
TMX
5010
TMX
6410
TMX
7510
FPS
at max res
50,725
65,940
fps
76,000
fps
Maximum
FPS
583,330,
1,166,660 with FAST option
758,330
(standard), 1,516,660 with FAST option
722,050
(standard), 1,750,000 with FAST option
Pixel
Size/Binned Pixel Size
18.5
µm / 37 µm
Maximum
Resolution
1280
x 800
Sensor
Type
CMOS,
Backside Illuminated (BSI)
Sensor
Size
23.7
mm x 14.8 mm
Need
a price or more application information? Please
email Adept Turnkey or call our offices Adept Turnkey Pty Ltd are "The Machine
Vision and Imaging Specialists" and distributor of Vision Research
products in Australia and New Zealand. To find out more about any
Vision Research product, please call Adept Turnkey at Perth (08)
9242 5411 / Sydney (02) 9905 5551 / Melbourne (03) 9384 1775 or
contact us online.
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