[robocup-msrs] About the RoboCam

[Kyle Johns]

Aspect is short for Aspect Ratio and it is simply the number of horizontal pixels divided by the number of vertical pixels.  If you are displaying square pixels (and the robudog cams are) then you can calculate the vertical field of view (the half-angle covered by the view vertically) by dividing the Field of View (FOV) by the aspect ratio.

The number of centimeters per pixel depends on how far away you are looking.  If you are looking at something 0.1 meters away from the eye, the distance corresponding to a single pixel horizontally can be calculated by:

tan of viewing angle = horizontal distance / distance from the eye = hDist/0.1

viewing angle = horizontal field of view * 2 / horizontal pixels = 90 degrees / 320 = 0.28125 degrees per pixel
hDist = 0.1 * tan(0.28125 degrees) = 4.9e-4 which is around half a millimeter per pixel.

If you are looking at something 1000 meters away, the horizontal distance covered by a single pixel is:
hDist = 1000 * tan(0.28125 degrees) = about 4.9 meters per pixel.

-Kyle
________________________________
From: robocup-msrs-bounces at cc.gatech.edu [robocup-msrs-bounces at cc.gatech.edu] On Behalf Of Ivan Fuentes [jivfur at gmail.com]
Sent: Thursday, June 14, 2007 11:03 AM
To: robocup-msrs at cc.gatech.edu; leonardo.garrido at itesm.mx
Subject: [robocup-msrs] About the RoboCam

Hello,

What's is the meaning of the Aspect Propierty of the RobuDogCam? I press F5 and there is a propierty called "Aspect", what does it mean?

is it possible to know the scale of the camera? i mean, is it posible to know how many pixeles are a centimeter?

Thanks.

--
"... and to make the darkness bright
paint the sky with stars"
[Ivan Fuentes]