This is an old revision of the document!
To Do List
AC:
- Fix application of Binary2Depth function to GERT-generated 3-letter images.
- Make sure can display convex version of 3D letters too.
- Generate more letters for use with GERT (not just G,E,R,T)
MH:
- Tweak HolesCrowd_TEST.m to find best-looking depth multiplier for images
“Depth multiplier:”
im = double(imread('BigFatT.png','png')); im = mean(im,3); im = Binary2Depth_thin(~logical(im)); %im = im/255; %im = ~im; %%%%%% im = round(im*2.5); %% MH tweak this number %%%%%%
Design notes
Great article for methods:
http://www.journalofvision.org/content/13/1/24
Visual angle of letters:
Boots CRT monitor is 36.5 cm wide. Comfortable sitting distance for AC is 50cm exactly, so use this as viewing distance. Currently, PTB whole-screen window is 1024 pixels wide, so 20.48 px/cm.
NOTE: this size is for use with the boots PC and monitor only! This pixel size is tiny on diego's monitor.
Strasburger & Malania used 4 deg. eccentricity targets
4 deg. at 50cm on the boots CRT monitor: 3.49cm = 71.47px ~ 71 px.
.5 deg at 50cm on boots CRT: .44cm = 9.01 ~ 9 px.
Can use stimulus width as the distance between flankers.
Plan: scale these numbers up, but keep the ratios.
First try: if boots CRT is 1024 px wide, can go up to almost 512 px eccentricity, 512/71 ~ 7. So let's scale up by 5 to be safe:
Place target at 71*5 ~ 350 px away from fixation cross (which should be at the center of the monitor) Make targets 9*5 = 45 px tall and 45 pixels apart.