|
> What
are High-Speed Digital Video Cameras?
> Why Use High-Speed
Digital Video Cameras?
> What are the Advantages
of High-Speed Digital Video Cameras?
> Who Uses High-Speed
Digital Video Cameras?
> What Is It Used For?
> What Are The Technical
Considerations?
What
are High-Speed Digital Video Cameras?
High-speed digital video cameras can be used as a diagnostic
tool that helps engineers and researchers analyze high-speed
processes. It captures a sequential series of images that
are recorded at very high frame rates and played back in slow-motion
to allow the viewer to see, measure and understand events
that happen too fast to see with the unaided eye. High-speed
video is simply the technique of recording an event at a high
frame rate and playing the images back at a much slower rate,
thus slowing down the event so you can actually see what’s
happening.
High-speed video can help you understand your unique motion
analysis applications. Whether your work involves product
design, research, machinery maintenance, or biomechanics,
ultrahigh-speed video can become one of the most important
tools at your disposal. The world moves much too quickly to
catch it all with our own eyes.
If you use ultra-high speed video cameras instead of standard
camcorders to capture motion sequences at hundreds or thousands
of frames per second, you can see the detail that occurs within
that high-speed event. At 500 frames per second, you get nearly
17 images for every one that would be captured by standard
(30 fps) video. And at 3,000 frames per second, you have 100
images for each standard video frame. With high-speed video,
you can view important high-speed applications in a manner
that allows for a meaningful analysis of that event. And if
you capture a motion sequence at 500 fps and view it at 30
fps, you see a smooth, continuous motion. High-speed video
gives you a better understanding of the actual motion you
are studying. With high-speed video, problems can now be seen
and solved.
Return to top>
Why Use High-Speed Video Cameras?
Understanding high-speed motion is absolutely critical in
today's fast-paced manufacturing and research environments.
Using high-speed video is one of the easiest and most cost
effective ways to achieve this important information.
Standard camcorders can only record at 30 frames per second,
and as a result, usually miss most of the action in fast-moving
events. However, if we use high-speed cameras to record these
events at hundreds or even thousands of frames per second,
it is a different story. When we play the images back in slow
motion, or even stop and examine a single frame, we can see
details that go unnoticed at normal speed.
We can learn a great deal about motion sequences if we record
them with high-speed video cameras and then study the recordings
in slow motion – or even as individual frames. We’ve
all seen the slow motion images of automobile crash testing
on TV commercials that illustrate seat belt safety or airbag
inflation. Trying to capture and view these images at 30 fps
would have far less impact and would be difficult, if not
impossible, to analyze in any meaningful way.
As noted above, frame rate is the number or frequency of images
taken, measured in images per second. Standard NTSC video
(camcorders) is 30 frames 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 necessarily equal a high sample
or frame 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.
Return to top>
What are the Advantages of High-Speed
Video Cameras?
While it’s possible to use standard video equipment
to record and analyze motion, there are limitations to this
technology:
The sampling rate of 30 frames per second (standard NTSC video)
is too slow for most motion problems. Many high-speed activities
occur within 100 milliseconds, 1/10 of a second. With standard
30 fps video we are only able to capture one image every 33
milliseconds. In an event that occurs within 100 milliseconds,
standard video would provide a user with approximately three
frames of information. With a high-speed video camera recording
at 1,000 fps, the user would be able to view 100 frames of
that same event.
A motion sequence recorded at 30 frames per second and slowed
down by a factor of ten allows us to view it at 3 frames per
second. The resulting image is very “jerky” and
therefore extremely difficult to analyze with any accuracy
or in meaningful detail. This is extremely important when
a critical understanding of motion is crucial to your success.
Who Uses High-Speed Video Cameras?
Industries where high-speed video is solving a wide range
of problems include:
| Aerospace program |
Paper products |
| Appliances |
Personal care products |
| Automotive |
Petroleum products |
| Beverages |
Pharmaceuticals |
| Can manufacturing |
Plastics |
| Chemicals |
Printing and publishing |
| Computer & office products |
Research facilities |
| Electronic components |
Rubber products |
| Food processing |
Switches and controls |
| Household products |
Sporting goods |
| Machine tools |
Test instruments |
| Medical devices |
Textiles |
| Metal stamping |
Universities |
| Motors and engines |
|
| Munitions |
|
| |
|
| Return to top> |
|
|
