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gravste
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 Posted: Sat Dec 06, 2003 11:14 pm Post subject: Triggered Double Exposure Mode of the Kodak ES1.0, PIV |
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I am trying to use Kodak>s ES1.0 digital camera in triggered double
exposure mode to capture images at 10Hz. I am using Coreco Imaging>s
(formely Imaging Technology) IC-PCI image capture board with the
AM-DIG acquisition module in conjunction with their ITEX-IC software.
The application is for Particle Image Velocimetry.
My problem is as follows: after acquiring a series of image pairs a
small percentage of the pairs will not be correlated. In other words,
in triggered double exposure mode, every time the camera is triggered
two exposures are obtained where each exposure is illuminated by a
laser pulse. Each laser pulse is timed to occur within the window of
the first and second exposure. The separation time between each pulse
is ~100 microseconds. With such a small separation time between
pulses, it is reasonable to expect the second image to resemble the
first. This occurs most of the time but a small percentage of pairs of
images do not resemble each other, i.e. they do not correlate.
I feel this is a problem with the code I wrote for acquisition. It is
based on the Application Note #: AP-001-99 provided by Coreco execpt
that it is modified to capture a series of images instead of just one.
Has anyone encountered this problem? Should I be using a certain
function call within the ITEC-IC software? Any suggestions? |
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Jarek Dekowski
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| Posted: Fri Dec 12, 2003 5:02 pm Post subject: Re: Triggered Double Exposure Mode of the Kodak ES1.0, PIV |
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I am working with the same camera but with the softwer from Dantec.
The problem with this camera is that the second exposition time is
very long, if you have exposition time of the first image about 2
microseconds, second one is about 60 miliseconds. I do not know is
this a software problem or camera. But mayby this will help you.
Other thing is whot is the flow you measure, mayby you have large
instabilities, or the flow is passing through the plane not along it,
and you loose pairs of particles. Mayby if you discribe your
experiment I could help you.
gravste@iit.edu (gravste) wrote in message news:<1ef609a0.0312060914.634cf320@posting.google.com>...
[quote]I am trying to use Kodak>s ES1.0 digital camera in triggered double
exposure mode to capture images at 10Hz. I am using Coreco Imaging>s
(formely Imaging Technology) IC-PCI image capture board with the
AM-DIG acquisition module in conjunction with their ITEX-IC software.
The application is for Particle Image Velocimetry.
My problem is as follows: after acquiring a series of image pairs a
small percentage of the pairs will not be correlated. In other words,
in triggered double exposure mode, every time the camera is triggered
two exposures are obtained where each exposure is illuminated by a
laser pulse. Each laser pulse is timed to occur within the window of
the first and second exposure. The separation time between each pulse
is ~100 microseconds. With such a small separation time between
pulses, it is reasonable to expect the second image to resemble the
first. This occurs most of the time but a small percentage of pairs of
images do not resemble each other, i.e. they do not correlate.
I feel this is a problem with the code I wrote for acquisition. It is
based on the Application Note #: AP-001-99 provided by Coreco execpt
that it is modified to capture a series of images instead of just one.
Has anyone encountered this problem? Should I be using a certain
function call within the ITEC-IC software? Any suggestions?[/quote] |
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Mike Halloran
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| Posted: Sat Dec 13, 2003 11:03 am Post subject: Re: Triggered Double Exposure Mode of the Kodak ES1.0, PIV |
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You guys must be measuring cannonballs oozing through gelatin.
In a typical Coulter Counter(r), red blood cells of approximately 8um diameter
pass entirely through the sensing zone in eight microseconds, carried by a
stream of saline at a bulk velocity of 10 meters/ second. At that speed and
scale, two images 100usec apart could not possibly include the same particle.
Your mileage may vary, but you need to do the math relating particle size,
speed, and exposure separation.
-Mike- |
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