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Vision.  Psychology 131A = BioSci 182.  Email questions answered.  FALL, 2009
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Subject: Re: Stereogram homework 
From: George Sperling  
Date: Wed, 18 Nov 2009 16:18:15 -0800 
To: Chris Fagan  
CC: George Sperling  

Hi Chris - 
     Have to start with three numbers to get the fourth.  In Slide 27, the 
three given numbers are: 

   IPD=6.0cm 
   R<->P=15-x 
   C<-> unlabeled adjacent point=0.16cm  (distance between C and adj point)

The fourth number to be determined is the stereoscopic depth, x. 

The 0.16cm comes from the shift of the penny (second coin from top) in the R 
configuration relative to the L configuration. 

By similar triangles, one can calculate the depth "x". 

(To be absolutely correct, depth is determined by a perpendicular to the 
surface, and the line C<->R is not quite perpendicular.  However, to 
avoid trigonometry, we assume that these are such small angles that the 
difference will turn out to negligible.) 

The diagrams are almost but not quite to proportion because, if the distance 
between the two intersections on the horopter were only 0.16 cm, the lines in 
the triangles would be too close to see clearly and to mark. 

Note that even the real 0.16cm shift of the penny (as shown) corresponds
to 0.6 deg (36 min of visual angle) at this small viewing distance.
This disparity is 5x Panum's fusional area in the fovea, i.e., this 1.6mm
is a very large disparity for the visual system.   Very sensitive!

-George 

----- On Nov 18, 2009 2:44 PM Chris Fagan wrote: 

> George, 
> 
> I am unsure of how to determine the binocular disparity. Specifically, 
> on slide #27 in lecture 13, how would one get that value of 0.16 cm? A 
> couple students asked about this, and I have not been able to explain it... 
> 
> - Chris 
> 
> 


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Subject: Re: midterm 2 
From: George Sperling  
Date: Sat, 14 Nov 2009 23:10:24 -0800 
To: pakjj@uci.edu 
CC: George Sperling  
Hi James Pak - 
    The slide is from a previous quarter. Sorry.  Midterm 2 is on
Tuesday Nov 17 as per the up-to-date syllabus. 
------------------------------------------------------------------------- 
George Sperling, UCI Distinguished Professor  (949) 824-6879 (Office) 
 Departments: Cognitive Sciences              (949) 824-3772 (Adm Asst) 
              Neurobiology and Behavior       (949) 824-2517 (Fax) 
University of California                      Email:  sperling@uci.edu 
Irvine CA 92697-5100                  http://www.socsci.uci.edu/HIPLab 
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pakjj@uci.edu wrote: 
Dear Professor Sperling, 
On the first slide of lecture 15, it says that the midterm has been moved 
to Thursday however you did not mention this in lecture. So i just wanted 
to clarify that midterm 2 is on Thursday. 
Thank you, 
James Pak 


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Re: PSY131A Problem Set 1 Question  
Subject: Re: PSY131A Problem Set 1 Question 
From: George Sperling  
Date: Tue, 29 Sep 2009 00:49:58 -0700 
To: sturmmann@earthlink.net 
CC: George Sperling , Chris Fagan  
On 9/28/09 6:01 PM sturmmann@earthlink.net wrote: 
> Hello Professor Sperling, 
> 
>     Is problem set 1 due tomorrow or on thursday? Thank you. 
> 
> -Adam 
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Dear Adam - 
      Problem set 1 has not yet been assigned. 
      Problem set 1 (as with every problem set) will be due on the first Tuesday after it has been 
assigned. 
      Problem sets will be made available when they are assigned. 
------------------------------------------------------------------------- 
George Sperling, UCI Distinguished Professor  (949) 824-6879 (Office) 
 Departments: Cognitive Sciences              (949) 824-3772 (Adm Asst) 
              Neurobiology and Behavior       (949) 824-2517 (Fax) 
University of California                      Email:  sperling@uci.edu 
Irvine CA 92697-5100                  http://www.socsci.uci.edu/HIPLab 
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