Thanks to all who responded to my original posting regarding reflective
paint.
ORIGINAL POSTING:
I need to paint a golf ball with a reflective paint to track its movement
with an optical/video-based motion analysis system. I have tried the
following with no success.
1. Covering the ball with a Scotchlite reflective "tape". This
product is used to create most of the commercially available reflective
markers in use today. However, this product alters the surface and physical
characteristics of the ball.
2. We have tried other metallic or chrome paints, but they do not
reflect enough light and the ball is not visible in the video images.
3. We have investigated the use of highway/traffic sign paint that
contains reflective beads. However, the manufacturer's specifications for
this paint indicate that it is very "thick". As such, it also will alter
the surface and physical characteristics of the ball.
4. We have investigated adding Scotchlite reflective glass
beads(manufactured by 3M) to paint and creating a reflective paint.
However, this requires the use of special spray equipment to maintain the
glass beads in suspension and we do not have access to this equipment.
I am aware of a previous BIOMCH-L posting on this
topic(http://isb.ri.ccf.org/biomch-l/archives/biomch-l-1992-11/00063.html).
This posting recommended the following: Scotchlite 7216 White Reflective
Liquid, 3M Company I.D. No. 75-0299-0461-4. However, this product was not
located in a search of the 3M website and does not appear to currently be
manufactured.
Has anyone in the community identified a commercially available paint that
provides sufficient reflectivity to create markers for use with
video/optical imaging systems?
SUMMARY:
It appears that the 3M Scotchlite product referenced in the 1992 message has
been discontinued (see message below from Patrick Sparto) by 3M. A
follow-up communication with JDL Industries (JDL Industries, 9500 NW 12th
St., Miami, FL 33172, Telephone: 305-599-2022, Fax: 305-599-2078, E-mail
address: creisler@jdlindustries.com) indicated they still carry this paint
and several other reflective paint products. Prices for the Scotchlite 7216
(bright white) equivalent paint are: $222.50/gallon (3.79 liters);
$74.50/quart (0.95 liter); $45.00/pint (0.47 liter). The paint is also
available in silver-white, black and yellow. Technical specifications
indicate that the silver-white paint provides the greatest reflective
intensity. However, as noted in the postings listed below (see the message
from Andrew Findlow), the technical specifications indicate that the
reflective intensity of the paint product is approximately 70-90% less than
the sheet form of the material.
Other suggested solutions included:
1. The use of a "glowing" golf ball. This is a ball that is exposed to a
light source and then emits light for a brief period of time " - e.g.,
http://www.driwash.com/ngprod.html
2. Use of a retroreflective ink instead of paint.
3. Using a paint designed to reflect a specific wavelength of light (e.g,
UV) together with an associated light source and possibly a lens filter to
reduce all light outside the defined band of the spectrum.
4. Change the nature of the data collection process. Suggested were 1)
collect at night when more light may be reflected from the "normal" ball; 2)
change the background to provide more contrast.
We are purchasing some of the silver-white retroreflective paint and will
test with this product.
INDIVIDUAL REPLIES:
________________________________________
>From Ned Frederick [nederick@mediaone.net]
Indoors you may be able to use a luminous (non-reflective) paint.
There is a compound called Luminova used to paint the hands of
watches so that they glow in the dark. I'm not sure that it will be
bright enough, but when it is "charged" with strong sunlight (or
direct incandescent light) it glows brightly enough to read by! The
strength of this luminosity declines quickly after exposure to light,
but it may hold on long enough for your measurements, and it could be
"recharged" between trials.
There are other tritium based compounds that do not require light to
glow (the tritium's emissions excite a phosphor) and they are very
expensive. Generally the luminous paints are brighter for a short
time. The advantage of the
See the attached link for a review of these technologies and the
secondary links for luminova and a watch hand recipe that could be
adapted for your use.
http://www.europastar.com/ESWatch/index.html?watchtech/questions/QIT200.html
http://www.nemoto.co.jp/products/luminova/index_e.html
http://network54.com/Hide/Forum/message?forumid=50573&messageid=970457009
I hope this works.
As a postscript on reflective technologies. ILLUMINITE is generally
considered the brightest of the reflective and flexible systems. You
may want to pursue that avenue. The material is made by Reflective
Technologies, Inc. (they were in Cambridge, MA but I belive have
moved to Virginia)
There is also a hybrid reflective and photoluminescent system from
OmniGlow called, Glowflex. Very cool stuff. I wonder if they sell
suspensions of the material.
http://www.glo-flex.com/
________________________________________
>From Patrick Sparto [psparto+@pitt.edu]
I am also looking for the same product. I wrote to 3M and this is their
response:
SCOTCHLITE REFLECTIVE LIQUID - 7200 SERIES has been DISCONTINUED from
the 3M Traffic Control Division as of 1998. "JDL Industries may have a
suitable product to meet your specifications.
JDL Industries
9500 NW 12th St.
Miami, FL 33172
305-599-2022
Fax: 305-599-2078
Hrs. 7:30-6:30 (ET)
E-mail address: creisler@jdlindustries.com
________________________________________
>From Chuck Pell [cap@nektonresearch.com]
Try this: Day-Glo UV fluorescent paint, ME (thincoat), spray,
commercially available. I'd choose the blue-white. Then use
a 1/2-silvered mirror at 45 degrees to the camera axis through
which camera shoots, bounce the light from a TI-150W UV
bulb with reflector at 90 degrees to the camera axis.
Light goes from bulb, to mirror, to ball, back to camera.
Works best when camera has been white balanced focused on
a flat panel of the same paint under the TI-150W bulb.
______________________________________
>From Andrew Findlow [findlowa@netcomuk.co.uk]
I've looked into this, and found a company called Everglo in the UK, URL is
www.quickfitsbs.co.uk/everglo/1b.htm now I can't remember if when I rang
these people they did or 3m Scotland 01475793600 or Reflec Systems 01606
593911 Chris Guinness (sorry only phone numbers for the last two in the UK)
which do retro-reflective ink. One thing Chris the polymer engineer /
designer did say was that the inks and paint are only 30% reflective as
opposed to the paper which is about 70-80% because they are able to line
almost all the beads when manufacturing the paper and the beads are random
in the paint!
________________________________________
>From Davies, Steve [Steve.Davies@dciem.dnd.ca]
Place reflective tape/whatever on the background a minimal distance from the
trajectory; the ball's silhouette may be visible. To track ball spin,
remove microthin surface portions and inlay these 'holes' with reflective
tape. Light the background and ball with different colours. Golf nightly
with candle power.
________________________________________
>From Peter Sinclair [p.sinclair@cchs.usyd.edu.au]
What type of analysis system are you using? We have previously tracked a
tennis ball using a Motion Analysis Corporation EV3D system using no
reflective material at all on the ball. We just had a very non-reflective
background and conducted the experiments at night. I imagine an APAS system
would track non-reflective materials even more easily. Have you tried
modifying the background and leaving the ball unchanged? I think this is
the only way to be really sure that the properties of the ball were not
affected.
________________________________________
>From Garry T Allison [gta@cms.uwa.edu.au]
Check with the reflective properties of these "bead" solutions since
they are often highly dependent upon the angle of the light source
relative to the camera. Have you considered other methods of creating a
contrast with the background.. e.g a coloured ball & matching filter, glow
paint and a
night shot? Just guessing.
________________________________________
>From Trena Herring [4fish4christ@cleanweb.net]
There is a 'nite-glow' golf ball in which is used to play golf at night.
Here is a link http://www.driwash.com/ngprod.html
________________________________________
>From Daina Sturnieks [dainals@cyllene.uwa.edu.au]
As I have had problems accessing reflective materials to cover spheres for
motion analysis, I have also been experimenting with different products and
techniques. I found a reflective heat-shrinkable material, produced by 3M,
which is used by a local company to make safety vests. The material is
relatively thin and when heat-applied, snugs the shape of the sphere very
well. The design of your pattern used to best fit the golf ball will
determine the degree of alteration to its surface and physical
characteristics. I can chase up the product number if you think you might
be interested.
________________________________________
>From Simon Monnington [simon.monnington@hsl.gov.uk]
In the past we have used a similar paint that you refer to in the
message. However, this is silver and has a model number 7210
(75-0299-0458-0). I
purchased some about 2 yrs ago from a company here in the UK. It may be
worth
trying searching using this mod number. If you don't have any joy I would be
happy to find the company details etc from which I purchased the silver
paint.
________________________________________
>From Coen Elemans [Coen.Elemans@Morf.EDC.WAU.NL]
Have you tried or thought of fluorescent markers? You can cover the ball
with
say FITC (exitation max. 490nm; emissionmax 519nm), which is common stuff
in
biology. Use band pass light filters for your camera's so only 520 nm
passes.
This considerably increases your contrast with the environment. When the
environment is autofluorescent it might be a problem. Find out first what is
the sensitivity of your camera! I tried FITC and found out that my (high
speed) camera is most sensitive to red and not green, so I could see
anything.
The manufacturors of the camera I used did not want to provide me with the
specification, so I had to make a senetivity curve using a
spectrophotometer.
This is ideal if you choose your fluorecent paint.
I use this idea for reconstructing membrane movements with small (50um)
beads.
________________________________________
>From Simon, Jan [Jan.Simon@ok.uni-heidelberg.de]
Video cameras are sensitive for infrared light. This is used by most
motion analysis systems, which registrate the IR light reflekted by the
markers. A hot ball emits IR light too. So heat it up and measure at night,
perhaps use a IR filter. A first estimation is a temperature of 200C, which
means a danger for the test person - but this is another problem.
________________________________________
>From Bill Anderst [anderst@bjc.hfh.edu]
Try www.golfballs.com. They offer balls that are made for night time
golf. They might show up better.
________________________________________
>From Secco Emanuele Lindo [Emanuele@bioing.unipv.it]
If you are doing some measurements with an infra-red illumination (but I'm
not
sure is your system) you could use reflective material typical for
motor-bike.
If you want I can send to you a piece of it: I'm sure it is ok for red
illumination (I'm using it).
________________________________________
>From Beth Boyd [mboyd@hsc.usf.edu]
No matter what you do, the physical and surface characteristics of the ball
will
be altered. The challenge is to come up with the strategy that will least
alter
them. Could you try #3 painting small dots or #1 taping small dots on the
ball
so that 3 or more are visible in each frame and calculate the velocity as
the
average of the 3 markers or get your program to triangulate the 3 markers as
"the ball" and determine the centroid and take calculations from there. If
you
have some "missing" points in the trajectory, they could be mathematically
interpolated.
________________________________________
>From Patterson, Rita [rpatters@utmb.edu]
3M manufactures a scotchlite "reflective liquid", #7216 white. It is not
too thick and works well for tracking markers.
________________________________________
>From Joann Johnson [jjohnso6@d.umn.edu]
Can you alter your background to as black as possible? If so, you may not
need it reflective at all. Just contrasted to the black background.
----------------------------------------
Michael E. Feltner, Ph.D.
Dept. of Sports Medicine | Phone: (310) 456-4312
Pepperdine University | Fax: (310) 317-7270
Malibu, CA 90263 | michael.feltner@pepperdine.edu
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