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drobbins99
11-17-2008, 03:45 AM
Hi all,


As promised here are the responses to my query about video cameras - to
recap I have included the original posting below. A big thanks to everyone
that replied I found all help/advice very usefull!!!!


Hopefully this will also be usefull to others too, if anyone has any
questions feel free to contact me and I will do my best to answer or direct
you to someone who can help you better.


Thanks again

Daniel Robbins


Original post:

I am looking to obtain a video camera that I can use for human motion
analysis. I am currently preparing to start bases supervised experience
scheme and will hopefully be looking at gait analyses and work with martial
artists. Obviously I will be looking to undertake some experience within a
3D motion analysis lab, but would also like to purchase a standard video
camera in order to obtain some footage from actual training sessions.

I am on somewhat of a budget and so am fairly limited as to what I can buy.
I would prefer to get something faster than 30fps. However, to date the only
option I can see is the samsung VP-HMX10 HD (50fps) that is within my price
range. I dont mind if the camera produces interlaced files requiring offline
processing, but I would prefer a camera with internal storage as at this
point in time I am working with a desktop computer (I appreciate it may
well be an idea to also purchase a laptop - but as I say I am on a budget so
these things take time).

I am interested to hear if anyone has reccomendations as to what is
available and/or what are the most important things to consider when
purchasing a camera for human motion analysis??

I would appreciate any help or advice that can be offered and will of course
post a summary of any replies.
--
Many Thanks
Daniel Robbins
d.w.e.robbins@googlemail.com
Royal National Orthopaedic Hospital



Daniel,
I recommend the Canon EXF1 camera. It is essentially an SLR with video. It
uses SD memory cards (we use 4GB cards to get 30mins of video at 300fps) and
it will take 60, 300, 600, and 1200fps video. It divides the CCD to increase
speed, so 300fps gives you 512x384 pixels. It has burst mode in still camera
mode so you don't have to worry about missing the critical frame when
photographing fast action. It is rather more expensive than a standard video
camera, but is well worth the extra because of the tremendously increased
functionality. See a review at:
http://gizmodo.com/383843/casio-exilim-ex+f1-slow+mo-super-cam-full-review-v
erdict-totally-unique-shockingly-powerful
Hope this is helpful.

Dr Alan Walmsley



Hi Daniel,

>From my (limited) experience with martial arts motion capture we found 50 Hz
to be far too slow to capture the movements required. Bear in mind also that
a single camera will only give you 2D capture and this is not ideally suited
to this application. Finally if working with actual training session then
check potential camera purchases for resolution and ability to deal with
light conditions as well as frame rate.

If your budget stretches to high speed cameras I would recommend Basler or
AOS of which I believe that Basler are cheaper.

Good luck,
Sian

Dr. Sian E. M. Lawson



Pax!

I was recently surveying camrecorders for gait analysis. Appeared that the
cheapest one was among the most suitable; that is, it included firewire and
mircophone input (used for for synch signal). The model was Canon MD215
(special price 119 ) dvd. Otherwise ordinary and basic. Note that there are
also webcameras that do 100 fps and cost around $ 100 or less. We have used
webcamera for gait analysis and is ok for visual analysis. And because they
are cheap one can afford several :).

Regards Frank Borg



What I did for Badminton was use a standard video camera that was 25 frames
(PAL) but, as it was interlaced, in software I separated the fields for
50fps. OK, this halves the spatial resolution but temporal resolution was
more important to me.

I'm guessing you're using NTSC which would give you 60Hz using this method.

Regards, Joe



Hi Daniel,

I was in Fry's Electronics in Tempe, Arizona, a few days ago and saw
some really nice JVC "full HD" camcorders that were less than $1000 US
each. Each had a fairly large hard drive built in (60 or 120 GB). What
made them stand out was their claim to capture progressive scan (not
interlaced) at 60 full frames per second with a resolution of 1920 x
1080 pixels. These cameras also could record at other "HD compatible"
resolutions like 1440 x 1080 (progressive and interlaced, "1080i").

>From what I understand, the original USA HDTV specifications defined the
highest HD resolution to be 1440 x 1080 (a 4:3 ratio with rectangular
[4:3] pixels). When displayed, the full width would be equivalent to
1920 square pixels. In other words, the TV would "stretch" the 1440
pixel horizontal resolution using a 4:3 ratio to make it equivalent to
1920 square pixels. In fact, this is how they got to a 16:9 ratio for
wide screen TV from the conventional 4:3 ratio of regular TV (4:3 x
4:3).

Anyway, now that most "full HD" LCD displays have square pixels most
advertize 1920 x 1080 resolution and it is nice to find a camcorder that
actually records at this exact resolution (rather than 1440 x 1080 with
rectangular pixels). The bonus is that you get 60 full frames per second
as well rather than 30.

Perhaps they are also availble in 50 Hz versions if you want deltaT to
be exactly 0.02 seconds rather than 0.016666... Seconds. You can check
out Fry's Electronics at www.frys.com. Perhaps they have the cameras on
line. Good luck. Let me know what you end up buying. We are also looking
here.

Regards,

--Rick



Dear Daniel Robins
I would recommend standard firewire camcorders. They can be found in various
price levels, all depending on what you prefer and the images can be
de-interlaced to 50/60 fps.
A good lens is of importance, you don't want to much distortion.
Zoom influences the demands for the measuring room (if measuring inside) and
distortion.
Some of the cheapest camcorders have limited access to shutter speed. This
parameter is important since even regular gait has quite fast periods
(at least if you want to auto-track as in our KineView software)
Hope this helps
Best regards
Baldur



Hi Daniel,

If you don't care if the video is interlaced, actually all those regular
video cameras of 30fps (frame per second) are actually 60 interlaced fields
per second. You can get 60Hz interlaced video from these cameras.

And if the video footage you are to processing is not very long, all Sony HD
video cameras using CMOS have the capacity of taking 240 fps short video for
3 to 6 seconds (then you need to wait for around 30 seconds for processing
before you can capture another piece of video.

Yungchien Chu







Hi Daniel,

I can suggest several awesome cameras which we integrate into our motion
analysis systems. Unfortunately, budget drives what you can buy. So, I
have listed 4 of my favorites. In my expert opinion, take a look at the
InLine camera which has on board memory. It can also go wireless and
battery pack for mobility. Coool huh. I give this camera 4 stars and 2
thumbs up.

Starting with my favorite....

#1 - InLine by Fastec 250Hz USB +/-$5,000 (new list price for 2009)
note: 500Hz and 1000Hz also avail. Laptop freiendly.
http://www.fastecimaging.com/pdf/PDF/Fastec_InLine_Datasheet.pdf
#2 - SportsCam by Fastec 250Hz USB and compact flash card +/-$6,500 (new
list price for 2009)note: 500Hz and 1000Hz also avail. Laptop friendly.
http://www.fastecimaging.com/pdf/PDF/Fastec_SportsCam_Datasheet.pdf
#3 - Sentech USB 60Hz +/-$800 (STC-TB33USB-A)
http://www.sentechamerica.com/pages/groups/digital_usb.htm Laptop
Friendly.
#4 - Basler 105Hz Firewire +/-$1,900
http://www.baslerweb.com/downloads/11684/A601602622_2_web.pdf Will need
a robust computer if your using more then one camera.

For additional information on these cameras, and others
http://www.innovision-systems.com/Products-Hardware.aspx.



Regards,
Victoria L. Berger



HI Daniel
I am not sure exactly of how much you are willing to spend -
But might I suggest Basler 602f (black & white) or 602fc (color) cameras -
with the right software driving the cameras they can film at a frame rate of
100 fps, and with streampix you can support multiple cameras at the same
time - perfect for 3D. Although these cameras do not store images in the
camera head (which is an advantage becuase it makes the camera unit very
small). These cameras are used frequently for human motion studies - You can
find more information on the streampix site
http://www.norpix.com/
I hope this helps,
Regards,
Chris Sanford


--
Many Thanks
Daniel Robbins
d.w.e.robbins@googlemail.com
07930 919600



--
Many Thanks
Daniel Robbins
d.w.e.robbins@googlemail.com
07930 919600