WorldViz User Forum  

Go Back   WorldViz User Forum > Vizard

Reply
 
Thread Tools Rate Thread Display Modes
  #1  
Old 12-08-2011, 06:04 AM
dpamplona dpamplona is offline
Member
 
Join Date: Dec 2011
Posts: 7
focal length

Hi!
I would like to control the focal length of the viewpoint.
I have found the field of view command, but I cannot find something equivalent to the focal length.
Do you know how can I do that?
Best,
Daniela
Reply With Quote
  #2  
Old 12-08-2011, 04:59 PM
Jeff Jeff is offline
WorldViz Team Member
 
Join Date: Aug 2008
Posts: 2,466
Can you describe the effect you are trying to achieve?
Reply With Quote
  #3  
Old 12-12-2011, 07:01 AM
dpamplona dpamplona is offline
Member
 
Join Date: Dec 2011
Posts: 7
effect

Sure! I will try to be as clear as possible.

In normal cameras, eyes, etc, the size of the sensor is fixed and we can control manually (or automatically) the focal length. From that, the field of view of the image, is relatively easy to estimate. (If we assume the perspective tranform, then it is just the fov = 2*arctan(sensor_array_length/(2focal_length)))

In vizard, we can control easily the fov of the viewport, I would like to adjust the viewport size (in pixels) depending on the focal length. Can you help me?
Cheers,
Daniela
Reply With Quote
  #4  
Old 12-12-2011, 06:53 PM
Jeff Jeff is offline
WorldViz Team Member
 
Join Date: Aug 2008
Posts: 2,466
Do you want the viewport to remain rectangular?
When the viewport gets smaller are you wanting to see a black border around it?
Reply With Quote
  #5  
Old 12-19-2011, 02:53 AM
dpamplona dpamplona is offline
Member
 
Join Date: Dec 2011
Posts: 7
problem explanation

Hi!
Thank you for your reply.
I can have the viewpoint window rectangular or squared, (that we can control with the fovH, or fovV, or h2vRatio).

I think I was not very clear with my problem.
If the "frame size"/"sensor size" is fixed in Vizard, than the focal length is easy to estimate/set with the fov.

http://en.wikipedia.org/wiki/Angle_o..._angle_of_view

For instance, it seems that openGL uses the tipical frame size:24mm x 36mm,
http://www.opengl.org/discussion_boa...&Number=193124
is Vizard also using this values?

Thank you in advance,
Reply With Quote
  #6  
Old 12-20-2011, 11:02 AM
farshizzo farshizzo is offline
WorldViz Team Member
 
Join Date: Mar 2003
Posts: 2,849
You can adjust the size of the window by using the viz.window.setSize([width,height]) command.
Reply With Quote
  #7  
Old 12-23-2011, 04:18 AM
dpamplona dpamplona is offline
Member
 
Join Date: Dec 2011
Posts: 7
Set size option

Hi!
I thought about that as well, but the setsize function comes in pixels, and the focal length in mm. If I could set the size of the window in mm, that would be enough!
Thank you!
Reply With Quote
  #8  
Old 12-25-2011, 04:26 AM
dpamplona dpamplona is offline
Member
 
Join Date: Dec 2011
Posts: 7
... which leads to...

How can we set the window size in mm?
Reply With Quote
Reply

Tags
field of view, focal length

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
VRPN info sdiverdi Precision Position Tracker (PPT) 5 01-16-2011 12:00 PM
vcc avatars: defining bone length bjgold Vizard 1 08-08-2007 11:24 AM


All times are GMT -7. The time now is 01:40 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Copyright 2002-2018 WorldViz LLC