Q:
Why does IMI-NA use more than one brand of sensors?
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A:
IMI-NA cameras are
built with sensors from Kodak, Micron and Sony. This
is because each of
the sensor vendors have different strengths and weaknesses so
IMI-NA cameras employ
the best sensor for a particular set of requirements. When
selecting a CCD or
CMOS sensor, one must consider type of device, resolution, pixel
size, sensor size,
color or monochrome, frame rate, well depth, dynamic range,
spectral sensitivity
and a host of other technical attributes.
Q:
What differentiates IMI-NA from other camera
manufacturers ?
Top
A:
IMI-NA cameras
are uniquely designed around the selected sensor to
provide excellent out
of the box reliability and outstanding image quality. The
mechanical packaging
is minimal and robust. Beyond the product, IMI-NA provides
superior per and post
sale support by individuals that have decades of experience
in digital camera
system integration. IMI-NA is big enough to provide support and
small enough to
provide flexible solutions.
Q:
How
do I know which IMI-NA camera I need?
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A:
The IMI-NA digital camera line provides a vast choice that includes
CCD
and CMOS cameras at
resolutions from 640x480 to 4Kx4K. There are cameras
with a variety of pixel
sizes and frame rates, monochrome and color, and different
form factors. Contact
IMI-NA and their experienced systems designers can discuss
your application
requirements and recommend the specific camera to satisfy your
needs.
Q: What effect
does pixel size have
on camera sensitivity?
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A:
Among other things,
the size of the pixel directly effects the sensitivity of the camera, as
well as the % of the surface area of the pixel that is capable of
integrating photons of light "fill factor". A HAN
IMx-1050FT camera
with a 9.9 micron square pixel will tend to be more sensitive than a HAN
IMx-1040 camera with a 7.4 micron pixel.
Q: What is
Signal-to-Noise Ratio
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A:
Like most things in
science, nothing is ever perfect. A CCD sensor is incapable of
converting incident light exactly into an output signal. The
variation
from the expected
output signal is referred to as noise. Noise is dependent upon
such things as sensor
and component quality, camera electronics design, temperature
and external
interference.
Signal-to-Noise Ratio is usually stated in
decibels (dB). The formula for calculating
Signal-to-Noise in dB is SNR = 20X log(Signal/Noise) Increasing
gain does not increase
SNR, because it increases both the signal and the noise.
Q: Define Bit
Depth!
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A:
Bit Depth is the
number of usable bits of signal that a camera provides.
In an eight bit
camera, each pixel will integrate light over a range of 256 levels of
gray from black to
white. In a 10 bit camera, there will be 1000 gray levels, and
there will be 4000
gray levels in a 12 bit camera. Just because a camera is designed
with a 12 bit
analog/digital converter does not mean that the camera is capable
of delivering a true
4000 gray levels. A lot depends on the quality and design of
the sensor, the
quality of the electronic components, the quality and design of the
camera, signal transfer speeds, temperature and external interference.
Q: Define Binning!
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A:
Binning is a
technique that combines groups of pixels and treats their collective
output as one pixel. An example is to bin 2 x 2 or 3 x 3 pixels.
The advantage is to increase sensitivity and dynamic range by
multiplying the well depth of the pixel. The
disadvantage is that you give up resolution.
Q: What is
Partial Scanning?
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A:
A digital camera is
designed to run at a certain number of full frames per
second. Often,
the user is willing to trade off resolution for frame rate. In
partial
scanning mode, a
camera is designed to integrate less than the entire active area
of the sensor and at
a faster frame rate. The simplest strategy is to divide the active area by
row. By cutting the frame in half vertically, the camera can
usually run at
almost twice the full
frame rate. Reduced size field of interest is another effective
strategy to increase frame rate.
Q: Is the camera
output FireWire, Camera Link,
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USB 2.0 or GigE?
A:
The digital data and clock output from the camera depends on the camera.
The HAN, RHEIN and
PEARL Series of cameras produce a FireWire output. The YUKON
Series of cameras
produces Camera Link output. The HUDSON Series of cameras
produce a USB 2.0
output and the COLORADO Series of cameras produce GigE output.
Q: How do these cameras connect to
a computer?
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A:
Historically, industrial digital cameras have been integrated to a
computer through a frame grabber board. The board must have a
driver and a configuration file
for the specific camera. The
previous standard for this connection was LVDS. Recently,
a new standard, Camera Link, has evolved.
A more recent development is the integration of high resolution digital
cameras with desk top or laptop computer using either the FireWire or
USB 2.0 connection. Now GigE
has been added as
another protocol that does not require a frame grabber.
Q: What shutter speed
do I need?
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A:
The shutter speed is used to eliminate blur in recorded images. Blur is
a function of movement of an object through the field of view during
exposure, and movement of the camera---usually by vibration. One of the
advantages of digital imaging for repetitive events is that trial and
error may be used to quickly select an appropriate shutter speed.
Camera shutters are either mechanical or electrical. Just about
all
digital cameras now
employ electronic shuttering.
Q: How many frames per second do I need?
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A:
Various formulas are used for specific types of motion depending on
whether the motion is linear or cyclic or a combination. However, a rule
of thumb is that the recording rate should be 3 to 10 times the cycle
count or there should be 3 to 10 images of the event of interest.
Q: What is the difference
between sample rate and shutter speed?
Top
A:
Sample rate is the number or frequency of images taken, usually measured
in images per second. Standard NTSC video is 30 frames (60 fields) per
second. Shutter speed is the duration of exposure for the image, usually
measured in hundredths or thousandths of a second.
A high shutter
speed does not equal a high sample rate! Most consumer camcorders offer
high- speed shutter capability for their 30 frame per second record
rates. It is possible to have 30 samples each taken at 1/2,000 of a
second exposure rate. For example, if on a high-speed packaging line one
package fills the field of view and if 60 packages move through the
field of view in one second, the standard camera will only record,
"see," every second package.
Q:
What
determines image quality in a digital camera?
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A: Image quality starts with the sensor. IMI-NA
cameras use excellent
sensors from Kodak,
Micron and Sony. But the sensor is just the beginning. The
actual camera design
is a high wire balancing act trading off physical size, heat,
internal and external
noise, channel transfer rate, algorithms and a host of other
subtle nuances that
can negatively effect ultimate image quality. We believe that
when you evaluate an
IMI-NA camera, you will be impressed with the image
quality that these
cameras deliver!
Q:
What
software is usually provided
with a digital camera?
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A:
IMI-NA cameras come with an image acquisition software. This
software
contains a Driver,
Demo Software and an ImCam API Library which
facilitates executing the many various camera commands. Frame
grabber vendors usually supply basic image acquisition and processing
software which might include color algorithms, flat field correction and
histograms. In depth image processing is available from a variety
of vendors who usually specialize in a specific field .
