[visionlist] Trying to demonstrate stereoscopic vision remotely

Terrance Boult tboult at vast.uccs.edu
Sun Mar 22 10:50:40 -04 2020

You can also just make your own filters with clear  plastic (e.g. from
food cartons) and permanent markers, making paper/cardboard lens
holders  Can also often find different color plastic in the recycle
bin..   E.g. might find green plastic from saint patty's day (or soda
bottles) and red plastic from a valentines box wrapping.   Plenty of DIY
instructions on the net

On 3/22/2020 5:30 AM, Andrew Parker wrote:
> Dear Lester
> Concerning option 3, I agree with you about red/green or red/blue
> glasses. Difficult to order single versions. But all they need for a
> home demo are the filters . The filters are readily available from
> photo suppliers, theatre lighting supplies, disco suppliers…and if all
> else fails Amazon.
> Andrew
> Andrew Parker, DPAG
> Oxford University and St John’s College
> andrew.parker at dpag.ox.ac.uk <mailto:andrew.parker at dpag.ox.ac.uk>
>> On 21 Mar 2020, at 02:45, Lester Loschky <loschky at ksu.edu
>> <mailto:loschky at ksu.edu>> wrote:
>> Hi Everybody,
>> If you teach Sensation and Perception, and are currently preparing to
>> teach it remotely, you may have the same question I have: how can you
>> demonstrate stereovision remotely?
>> As preface, the following are methods I have used in in-person
>> classes to demonstrate stereo vision:
>>  1. an actual stereoscope and example stereoimages to share with
>>     students (including the classic Julesz square tile
>>     random-dot-stereogram image)
>>  2. example stereoscopic lenticular lens images to share with students
>>  3. red/green anaglyph images with sets of cardboard & plastic
>>     red/green anaglyph glasses
>>  4. Google Cardboard plus cell phone to share with students
>>  5. random dot autosterographic images
>>  6. touching two pen tips together using two eyes versus one eye
>>  7. learning about crossed vs. uncrossed disparity using two fingers
>>     at different distances
>> Unfortunately, my students don't uniformly have access to the
>> apparatuses required for 1-4 above.  
>> Re. # 3 (red/green anaglyph images), I've thought of having students
>> order a single pair of red/green anaglyph glasses online.  However,
>> it appears that the cardboard and plastic ones can only be purchased
>> in bulk. (I guess they're too cheap to sell individually.)  They also
>> might not arrive in time, but students could still enjoy them once
>> they get them.
>> Re. #4 (Google Cardboard), I recall getting a free Google Cardboard
>> from the NYTimes several years ago.  However, they are now no cheaper
>> than $5 (Irisu, of India), and likely wouldn't arrive in time.
>> Regarding option #5 (random-dot autostereograms), I have found that
>> since seeing random dot autostereographic images in depth requires
>> perceptual learning, a large proportion of students don't manage to
>> learn (within the short time period given in a single class period).
>>  (Of course, many students may have a lot of time on their hands now,
>> so they might keep at it long enough to learn to perceive them.  But
>> there will definitely be a good proportion of students who don't try
>> long enough to learn, and so don't get it.)
>> #6 (touching two pen tips together) is definitely something that can
>> be done remotely.  However, it doesn't have the "Wow!" factor of
>> other demonstrations.  It is more of an "oh, really..." experience to
>> realize how much worse you are with one eye than two.  
>> #7 (using two fingers at different distances to teach crossed vs.
>> uncrossed disparity) can definitely be done remotely.  It is very
>> educational, but again does not have the "Wow" factor. 
>> There is also the finger "hot dog" illusion, which can be done
>> remotely.  It is interesting, but quite different from all of the
>> others in that stereoscopic depth perception is not involved.
>> For the related phenomenon of motion parallax, "wiggle vision" is a
>> very nice demonstration:
>> http://www.well.com/user/jimg/stereo/stereo_gate.html
>> https://www.3dwiggle.com/2016/06/28/5-wigglegrams-you-need-to-see-before-you-die/
>> Of course, depth perception from motion parallax is importantly
>> theoretically related to stereoscopic vision (both involve two
>> different images from two different views, one seen over time (and
>> only needing one eye)--motion parallax--and the other seen
>> simultaneously (and requiring two eyes)--stereovision).  But it is
>> not the same as stereoscopic vision, so is a separate but related issue.
>> For the related phenomenon of binocular disparity, there is the
>> famous "hole in your hand" illusion using a cardboard paper towel
>> roll.  If students have a spare cardboard paper towel roll, they can
>> do this remotely.  But, again, it is a theoretically related but
>> separate issue. 
>> Any other suggestions would be appreciated. 
>> Best wishes,
>> Les
>> -- 
>> Lester Loschky
>> Professor
>> Associate Director, Cognitive and Neurobiological Approaches to
>> Plasticity Center
>> Department of Psychological Sciences
>> 471 Bluemont Hall
>> 1114 Mid-Campus Dr North
>> Kansas State University
>> Manhattan, KS  66506-5302 
>> email: loschky at ksu.edu <mailto:loschky at ksu.edu>
>> research page: https://www.k-state.edu/psych/research/loschkylester.html
>> lab page: http://www.k-state.edu/psych/vcl/index.html
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Terrance E. Boult,    Cell: (719)963-0573
El Pomar Prof. of Innovation and Security & Co-director Bachelor of Innovation 
U. Colorado at Colorado Springs
IEEE Fellow

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